integrated pest management guide for texas forage...

B-1401Texas Agricultural Extension ServiceThe Texas A&M University System

IntegratedPest ManagementGuide forTexas Forage Crops

Texas Agricultural Extension Service Zerle L. Carpenter, Director

The Texas A&M University SystemCollege Station, Texas

INSECTICIDE APPLICATION ..................................................................................................................................................................1POLICY STATEMENT ..................................................................................................................................................................................1INSECTICIDE RESISTANCE MANAGEMENT ..............................................................................................................................1BIOLOGICAL CONTROL............................................................................................................................................................................2ENDANGERED SPECIES REGULATIONS ........................................................................................................................................2WORKER PROTECTION STANDARD ..............................................................................................................................................2PROTECTION OF BEES AND OTHER POLLINATORS FROM INSECTICIDES ........................................................2PHYTOTOXICITY PRECAUTIONS......................................................................................................................................................3

ALFALFA AND CLOVER PESTS ........................................................................................................................................................3RESISTANT CULTIVARS ..............................................................................................................................................................3FIELD SCOUTING ............................................................................................................................................................................8

Stem Sampling ..........................................................................................................................................................................8Sweep Net Sampling ..............................................................................................................................................................8

SUCKING PESTS ................................................................................................................................................................................8Pea Aphid ....................................................................................................................................................................................8Spotted Alfalfa Aphid ..........................................................................................................................................................8Blue Alfalfa Aphid ..................................................................................................................................................................8Three Cornered Alfalfa Hopper ......................................................................................................................................9Thrips ........................................................................................................................................................................................10

CHEWING PESTS............................................................................................................................................................................10Alfalfa Weevil..........................................................................................................................................................................10Clover Head Weevil ............................................................................................................................................................12Grasshopper ............................................................................................................................................................................12Blister Beetle ............................................................................................................................................................................13

COMMON CATERPILLAR PESTS ..........................................................................................................................................14Alfalfa Caterpillar..................................................................................................................................................................14Armyworm ..............................................................................................................................................................................15Corn Earworm........................................................................................................................................................................15

OCCASIONAL CATERPILLAR PESTS ................................................................................................................................16Army Cutworm......................................................................................................................................................................16Webworm..................................................................................................................................................................................16

VETCH PESTS ..............................................................................................................................................................................................17SUCKING PESTS..............................................................................................................................................................................17CHEWING PESTS............................................................................................................................................................................17

Vetch Bruchid ........................................................................................................................................................................17Armyworm and Cutworm ................................................................................................................................................18

FORAGE SORGHUM PESTS ..............................................................................................................................................................18SOIL PEST TREATMENT METHODS..................................................................................................................................18

Pre-plant Seed Treatment–Commercial Seed Treaters..........................................................................................18Pre-plant Seed Treatment–On Farm ............................................................................................................................18Planter Box Seed Treatment ............................................................................................................................................18At Planting Soil Insecticides ............................................................................................................................................18Postemergence ........................................................................................................................................................................18

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SOIL PESTS ..................................................................................................................................................................................................................................18Wireworm ..........................................................................................................................................................................................................................19White Grub ......................................................................................................................................................................................................................19Corn Rootworm..............................................................................................................................................................................................................19Cutworm ............................................................................................................................................................................................................................19Lesser Cornstalk Borer ................................................................................................................................................................................................20Fire Ant ..............................................................................................................................................................................................................................20

ABOVE-GROUND PESTS......................................................................................................................................................................................................21Greenbug ............................................................................................................................................................................................................................21Armyworm ........................................................................................................................................................................................................................21Grasshopper ....................................................................................................................................................................................................................21Chinch Bug........................................................................................................................................................................................................................23

PESTS OF PERMANENT AND IMPROVED PASTURES..........................................................................................................................................23Grasshopper ......................................................................................................................................................................................................................23Armyworm ........................................................................................................................................................................................................................23Desert Termite ................................................................................................................................................................................................................24Red Imported Fire Ant ................................................................................................................................................................................................24

In planning an integrated pest man-agement (IPM) program, the producershould consider the effective use of cul-tural control practices, natural enemies,resistant crop seed and accurate fieldscouting and, when warranted, chemi-cal control. IPM programs utilize allavailable means to keep pest numbersbelow levels that cause economic cropdamage.

Although non-chemical managementtools provide the first line of defense,chemicals are an important part of thepest management system. Major fac-tors to be considered when using insec-ticides include: 1) protection of naturalenemies of crop pests; 2) resurgence ofsecondary pests following application;3) insect resistance to insecticides; 4)effects on livestock, man and othernon-target organisms, 5) the effective-ness of the product against the targetpest; and 6) cost of the product. Bestmanagement practices call for use ofinsecticides at the proper rates andonly when field counts indicate eco-nomic losses will occur if insecticidesare not used.

Insecticide ApplicationGround equipment or aircraft may

be used to apply most insecticides. Forbest results with aerial applications,flag the swaths to overlap. Spray appli-cations are most effective and drift haz-ards minimized when wind velocitydoes not exceed 10 miles per hour.

Nozzle size number and condition,ground speed and application pressureinfluence the rate of insecticide appliedper acre. The sprayer should be careful-ly calibrated to insure proper applica-tion of approved label rates. Plant cov-erage is essential for optimum insect ormite control. Use of excess insecticidemay result in residue accumulation,possible injury to the plants or live-

stock and an increase in the cost ofproduction. Low rates may result inpoor control.

Insecticide ResistanceManagement

Experience has shown that repeat-ed use of a single group of insecticidesthat act in the same way may causepests to develop resistance to theentire group of insecticides. A goodstrategy to help avoid pest resistance isto use non-pesticidal control tech-niques. And, when chemicals must beused, rotate insecticide groups, takingadvantage of different modes of action.These management strategies shoulddelay the development of resistanceand also provide better overall insectcontrol.

Insecticides with similar chemicalstructures affect insects in similarways. For example, pyrethroids(including esfenvalerate and perme-thrin) act on an insect’s nervous sys-tem in the same way. Other types ofinsecticides such as organophosphates(methyl parathion, chlorpyrifos,dimethoate, malathion and acephate)or carbamates (methomyl and car-baryl) also affect the insect’s nervous

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Charles T. Allen1

Suggestions in this publication arebased on the results of an annualreview of pest management researchby a committee of state and federalresearch personnel and Extensionspecialists. Insect management prac-tices are directed toward the mosteffective, safest and most profitablemeans of minimizing crop loss frominsect pests.

1Extension Entomologist, The Texas A&MUniversity System

The information and suggestions included in this publica-tion reflect the opinions of Extension entomologists based onfield tests and use experience. Our management suggestionsare a product of research and are believed to be reliable.However, it is impossible to eliminate all risk. Conditions orcircumstances which are unforeseen or unexpected may resultin less than satisfactory results even when these suggestionsare used. The Texas Agricultural Extension Service will notassume responsibility for risks. Such risks shall be assumedby the user of this publication.

Suggested pesticides must be registered and labeled for useby the Environmental Protection Agency and the Texas

Department of Agriculture. The status of pesticide labels issubject to change and may have changed since this publicationwas printed. County Extension agents and appropriate special-ists are a good source of information on the label status ofpesticides.

The USER is always responsible for the effects of pesticideresidues on his livestock and crops, as well as problems thatcould arise from drift or movement of the pesticide from thepesticide user’s property to that of others. Always read andfollow carefully the instructions on the container label.

POLICY STATEMENT FOR MAKING PEST MANAGEMENT SUGGESTIONS

Integrated Pest Management Guidefor Texas Forage Crops

system but in a different way than dothe pyrethroids. Repeated use of insec-ticides from any one group often quick-ly leads to insect pests which are resis-tant to that group.

Biological ControlInsect and mite infestations are

often held below damaging levels byweather, inadequate food sources andnatural enemies such as disease organ-isms, predators and parasites. It isimportant to recognize the impact ofthese natural control factors and,where possible, encourage their action.

Biological control is the use ofpredators, parasites and disease organ-isms to control pests. Important natur-al enemies in forage crops includeminute pirate bugs, damsel bugs, big-eyed bugs, assassin bugs, lady beetles,lacewing larvae, syrphid fly larvae, spi-ders, ground beetles and a variety oftiny wasps that parasitize the eggs, lar-vae and pupae of many forage croppests.

Biological control includes the con-servation, importation and augmenta-tion of the natural enemies of thepests. Biological control, an environ-mentally sound method of pest control,is a component of integrated pest man-agement in forage crops. The TexasA&M University System is fully com-mitted to the development of pestmanagement tactics which use biologi-cal control.

Existing populations of natural ene-mies are conserved by avoiding the useof insecticides until they are needed toprevent the development of economical-ly damaging pest infestations. Wheninsecticides are needed, their impactcan be minimized by choosing productsthat are more toxic to the target pestthan to the natural enemy. Classicalbiological control is the importation ofnatural enemies from other countries.This method has been effective onexotic pests which have entered Texaswithout their natural enemies, and tocompliment existing natural enemies ofnative pests.

Augmentation involves the purchaseand release of natural enemies on aperiodic basis. The most notable com-mercially available natural enemiesinclude the egg parasite, Trichogram-

ma, and the lady beetle and lacewingpredator groups. Although the controlof caterpillar larvae by the release ofcommercially reared Trichogrammawasps is theoretically possible,researchers have not been able to con-sistently achieve the level of parasitismnecessary to reduce infestations beloweconomically damaging levels. MultipleTrichogramma releases of parasitizedeggs at high rates ranging from 50,000to 150,000 per acre were used in thesestudies. There are currently no eco-nomic thresholds established for aug-mentative releases of Trichogramma forcaterpillar control. Parasite mortalityfrom insecticides used to control otherpests in or around parasite releaseareas is a major factor adversely affect-ing the success of augmentative releas-es.

Research studies have shown thatreleasing large numbers of lacewing lar-vae (30,000 and more per acre) canreduce bollworm infestations in cottonto below damaging levels. However,these release rates are currently cost-prohibitive because of high productioncosts for rearing lacewings. Introduc-ing lacewing eggs has been less success-ful. There is little information on theefficacy of introducing lacewings orlady beetles in any of their life stages inforage crops.

Because definitive information onaugmentation (when to apply, whatdensity to apply, etc.) is lacking, ento-mologists with the Texas AgriculturalExtension Service cannot provideguidelines for the application of aug-mentation as a management tool in for-age crops.

Endangered SpeciesRegulations

The Endangered Species Act isdesigned to protect and assist therecovery of animals and plants that arein danger of becoming extinct. Inresponse to the Endangered SpeciesAct, many pesticide labels now carryrestrictions limiting the use of productsor application methods in designatedbiologically sensitive areas. Theserestrictions are subject to change.Refer to the Environmental Hazards orEndangered Species discussion sectionsof product labels and/or call your localcounty Extension agent or Fish and

Wildlife Service personnel to determinewhat restrictions apply to your area.Regardless of the law, it is importantthat pesticide users be good neighborsby being aware of how their actionsmay affect people and the environment.

Worker ProtectionStandard

The Worker Protection Standard(WPS) is a set of new federal regula-tions that applies to all pesticides usedin agricultural plant production. If youemploy any person to produce a plantor plant product for sale and apply anytype of pesticide to that crop, WPSapplies to you. As of January 1, 1995,you must comply with all WPS regula-tions. The WPS requires you to pro-vide three basic types of pesticide pro-tection to your employees. You must:

■ inform employees about expo-sure,

■ protect employees from exposure,and

■ mitigate pesticide exposures thatemployees might receive.

In 1995 all agricultural pesticideswill bear a Worker Protection Standardstatement on the label. It will appearin the “DIRECTIONS FOR USE” partof the label. For more detailed informa-tion, consult EPA publication 735-B-93-001 (GPO #055-000-0442-1) TheWorker Protection Standard forAgricultural Pesticides – How toComply: What Employers Need toKnow, or call Texas Department ofAgriculture, Pesticide WorkerProtection Program, (512) 463-7717.

Protection of Bees andOther Pollinators fromInsecticides

Pollination is extremely importantin the production of many seed crops.This is especially true of legumes suchas alfalfa, clover and vetch. Most grassyplants are wind- or self-pollinated anddo not require the assistance of insectpollinators. Where pollen-collectinginsects are required for flower fertiliza-tion, the producer, insecticide applica-tor and beekeeper should cooperateclosely to minimize losses of bees. Thefollowing guidelines will prevent orreduce bee losses:

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1. Apply insecticides before bees aremoved into the fields for pollina-tion.

2. Use insecticides only when pestinfestations exceed action levels.Then, use materials least toxic tobees.

3. Make all applications late in theevening (6 to 7 p.m.) when bees arenot visiting the field. EVENINGAPPLICATIONS AFTER BEESHAVE LEFT THE FIELD ARELESS HAZARDOUS THANEARLY MORNING APPLICA-TIONS.

4. Use spray or granular formulationsrather than dust.

5. Where it is necessary to use one ofthe insecticides in Groups 1 or 2 inthe following list, notify the bee-keeper so that he can make neces-sary arrangements to protect thebees.

6. Avoid drifting or spraying an insecti-cide directly on bee colonies. Heavylosses generally occur in these situa-tions. On hot evenings, bees oftencluster on the fronts of the hives.Pesticide drift or direct spray at thistime generally results in heavy mor-tality.

Phytotoxicity PrecautionsSome insecticides discolor the

foliage of certain forage sorghum vari-eties. Stunting and foliage burn haveresulted from the use of specific chemi-cals on certain sorghum hybrids.Before application, growers shouldclosely check the insecticide label andcontact the manufacturer and the seedcompany regarding possible phytotoxiceffects.

ALFALFA ANDCLOVER PESTS

A large variety of insects are foundin alfalfa and clover. Some are onlyvisitors or may be feeding on otherplants scattered in the alfalfa or cloverfields. Others are present in smallnumbers but do not cause economicdamage. Many are beneficial.Beneficial insects include the insectpollinators, parasites and predators.However, several insect pests are injuri-ous. These pests feed on the leaves,stems, crowns, seed pods and flowers,resulting in economic loss.

Resistant CultivarsOne of the best ways to avoid

insect-related losses to hay and foragecrops is to plant cultivars which areresistant to insect damage. Many culti-vars are available which have bothinsect and disease resistance. The rela-tive levels of resistance in many of thecommercially available alfalfa cultivarsare provided in the following table.When selecting an alfalfa cultivar foruse on your farm, be sure to selectfrom the fall dormancy group appro-priate for your area. If you are unsureabout which fall dormancy group toselect from, contact your countyExtension agent or talk to a reputableseed salesman in your area.

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Insecticides Grouped According to Relative Hazards to Honeybees

Insecticides RemarksGroup 1. Highly Toxic

carbaryl (Sevin® 80S, Sevin® XLR Plus)carbofuran (Furadan®)chlorpyrifos (Lorsban®)dimethoate (Cygon®, Dimethoate®)malathion (wettable powder or ULV)methidathion methomyl (Lannate®)methyl Parathion permethrin (Ambush®, Pounce®)phosmet (Imidan®)

Group 2. Moderately Toxicdisulfoton (Di-Syston®)malathion (EC)phorate (Thimet®)

Group 3. Relatively Non-ToxicBacillus thuringiensis

(Agree®, Dipel®, Condor®, Design®, Javelin®, Xentari®)

hydramethylnon (Amdro®)

This group includes materials that kill bees on contact duringapplication or for several days afterward. With some exceptions,bees should be removed from the area if these materials areused on plants being visited by the bees. If bees cannot beremoved, applications should be made in the evening after allbees have completed foraging. Ultra low-volume malathion appli-cations should be avoided after blooms appear. Foliar applica-tions of granular formulations pose an intermediate hazard butshould not be applied when bees are working in the field. Soil-applied granular insecticides pose little hazard.

Do not apply when bees are working in the field. Apply in lateevening.

These materials are least toxic to bees. Applications should bemade in late evening when bees are not foraging.

Characteristics of Available Alfalfa Varieties*Variety Company FD BW VW FW An PRR SAA PA BAA SN RKN APH

5151 Pioneer 1 R — R — — R LR — MR — —5262 Pioneer 2 HR LR MR — R R R — MR — —A-54 Embro Seed 2 MR — — — MR MR — — — — —Agate Public 2 HR — HR MR R — — — — — —Alfagraze America’s Alfalfa 2 MR — R MR LR — — — — — —Alpine Oasis/Spangler 2 R R R R R R — — MR — —Baker Public 2 HR — R LR — HR HR — — — —Clipper Interstate/Payco Seeds 2 HR R HR R R — R — MR — —DK 122 DeKalb Plant Genetics 2 HR R R HR HR MR R — — — —Evolution Jacques 2 HR R HR HR HR — R — — — RFlagship 75 Peterson Seed 2 HR R HR R HR — MR — — — —Garst 636 ICI Seed 2 HR R R MR R — R — — — —Milk Maker II PGI/MBS 2 R — MR — R LR R — R — —Nordic ICI Seeds 2 HR R R R HR MR HR — — — MRPacesetter Research Seeds/

Brown/Servos 2 HR R R HR HR — — — — — —Profit Ciba Seeds/Wensman

Seed 2 HR R HR MR R — MR — MR — —Quantum Renk Seed 2 HR HR HR HR HR — HR — — — RVernal Public 2 R — MR — — — — — — MR —Viking 1 Northrup King 2 R HR HR R R — MR MR — — —WL 225 W-L Research 2 HR R HR MR HR R R — LR MR —Wrangler Public 2 R LR R LR HR HR HR — — — —98 Olds Seed Co. 3 HR R R HR R R R — — — —120 DeKalb Plant Genetics 3 HR — R LR R — R — R — —2833 Ciba Seeds 3 HR R HR HR HR MR R — — — —2841 Ciba Seeds 3 HR R R R R HR R — — — —2980 Olds Seed Co. 3 HR R R R HR R R — — — R5246 Pioneer 3 HR R HR HR HR R R — MR — MR5252 Pioneer 3 HR HR HR R HR MR R — LR — HR5311 Pioneer 3 HR MR HR — R R HR — MR — —9323 Research Seeds/Shissler 3 HR R HR R HR — — — MR — RAccolade Chemgrow 3 R HR R R R — R — — — —Achieva Agway/Allied 3 R R HR HR HR R R — MR R —Allegiance Keltgen/Lynks 3 R R R HR R LR R — R — —AgriBoss Cropmate 3 HR MR HR HR HR — HR — MR — —Arrow American’s Alfalfa 3 HR R HR MR HR — R — MR — —Attainer Hoffman 3 HR HR HR HR HR R R — MR — LRBenchmark Research Seeds/

Ag Venture 3 HR R HR HR HR — — — — — RBig 10 Great Lakes 3 HR — HR R R LR R — — — —Blazer XL Cenex/Land O’Lakes 3 R R HR HR HR HR R — R — RBolt ML Research Seeds/Jung 3 R R HR HR HR — — — MR — RBreak-thru Custom Farm Seed 3 HR R HR MR HR R HR — MR — —Bronco Jung/AgAmerica 3 HR R HR HR HR R R — — — —Centurion Agway/Allied 3 HR R R R R MR R — — — —Champ Research Seeds/Brown 3 R MR HR — MR — HR — HR — —Class Union Seeds 3 HR R R HR HR R R — MR — RColumbo PGI/MBS 3 R HR HR R R R HR — MR MR —Comet Moews 3 HR R R MR R — MR — — — —Crown Cargill 3 R R R HR R MR R — R — —Crown II Cargill 3 HR R HR HR HR MR R — — — —Dart AgriPro 3 HR R HR R HR — R — — — —DK 125 DeKalb Plant Genetics 3 HR R R HR R MR R — — — —Elevation Jacques 3 R MR R — MR — R — HR — —

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FD - Fall dormancy Bw - Bacterial wilt PRR - Phytophthora root rot SN - stem nematode LR - 6-14% of plants resistant 1 - most dormant Vw - Verticillium wilt SAA - spotted alfalfa aphid RKN - root knot nematode MR - 15-30% of plants resistant9 - least dormant Fw - Fusarium wilt PA - pea aphid APH - aphanomycetes root rot R - 31-50% of plants resistant† - new varieties An - anthracnose BAA - blue alfalfa aphid HR - 51% or more of plants resistant


Encore Research Seeds/Spangler 3 HR R HR HR HR — — — — — R

Envy Peterson Seed 3 HR R HR HR R — R — MR — MRFuture Ray Bros. Seed 3 HR MR MR LR R — R — MR — —GH777 Golden Harvest 3 HR R HR R HR — — — MR — RGH787 Golden Harvest 3 HR R R HR HR R R — — — RGenesis Pfister 3 HR R HR HR HR — HR — — — MRGreen Field Peterson Seed 3 HR R HR HR HR — HR — — — RHusky PGI/MBS 3 R — R MR MR — R — — — —Hyland Oasis 3 HR R HR R HR R HR MR MR — MRICI 645 ICI Seeds 3 HR R R HR HR — R — — — —Impact Peterson Seed 3 HR R HR MR R — R — MR — —K93 Kussmaul 3 R R R — R — R — MR — LRMagnum III-Wet Dairyland Seed 3 — MR R MR R MR HR MR — — MRMajestic Agway/Allied 3 HR HR HR HR R S — — R — —Mercury Moews 3 R — HR MR HR LR — — — — —Milkmaker PGI/MBS 3 R — HR MR MR — R — — — —MultiKing 1 Northrup King 3 HR R HR R R MR MR — MR — —Multi-plier Jacques 3 HR R HR HR HR MR R — — — —Multistar FFR 3 HR R HR HR HR R — — R — —Oneida VR N.Y.S.I.C. 3 R HR HR MR MR — — — — — —Perry Public 3 R — R LR MR — — — — — —Renegade Geerston 3 R LR MR — R R R — — — —RFV-20001 Custom Farm Seed 3 HR R HR HR HR R R — R — LRRoyalty Cargill 3 HR R HR HR HR R R — MR MR LRSpark Brunner 3 HR R R R R — R — — — —Starmaster Doeblers 3 R R R MR R — R — — — —Sure Cenex/Land O’Lakes 3 HR R HR HR R LR HR — — — —Surpass ABI 3 HR R HR MR R — R — — — —Thrive Great Lakes 3 HR R HR HR HR HR R — R — —Trident II Cargill 3 HR R R R HR LR MR — LR — MRUltra Seedtec 3 HR R HR HR R LR R — R — —Ultra Leaf 871 La Crosse Seed 3 HR HR HR HR HR — R — — — RVIP Research Seeds/Schuman 3 HR R R R R MR HR LR MR — —Webfoot Great Lakes 3 R — MR — R — — — — — —WL 317 W-L Research 3 HR R HR R HR R HR — R MR —Zenith ICI Seeds 3 HR R R HR HR HR R — MR — —555 Pioneer 4 HR — MR — — HR HR — — — —630 ICI Seeds 4 HR MR R MR R MR R MR MR — —631 ICI Seeds 4 HR R HR R HR R HR MR R — MR2852 Ciba Seeds/Hoffman 4 HR R R HR R MR R — — — —5333 Pioneer 4 HR MR HR HR R R HR — LR — —5364 Pioneer 4 R MR R MR MR HR HR — R — —5373 Pioneer 4 HR R HR HR MR R HR — — — LR5454 Pioneer 4 R MR HR HR HR R R — MR — LR5472 Pioneer 4 HR MR HR MR MR R HR — R — —Action Research Seeds/Spangler 4 R MR R HR R MR R — — — —AF 21 Asgrow 4 HR R R HR R R R — MR MR —AF 31 Asgrow 4 HR R HR HR HR R HR — MR — —Agressor America’s Alfalfa 4 HR R HR HR HR MR HR — MR — MRAgri-Mate Cropmate 4 R R HR R R MR R — MR — —AlfaLeaf Plains Alfalfa 4 HR R R R HR R R — — MR —Allegro Keltgen/Lynks 4 HR R R HR HR — HR — MR — RAllstar Beachley-Hardy 4 HR R HR HR HR LR R — R MR —Apollo America’s Alfalfa 4 R — R LR R MR MR — MR — —

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Apollo II America’s Alfalfa 4 R MR R MR HR MR — — MR — —Apollo Supreme America’s Alfalfa 4 HR R HR HR R — HR — — — —Arc Public 4 LR — MR HR — — HR — LR LR —Asset Allied Seed 4 HR R R R HR R R — — — MRChief Jacques 4 HR R R R HR R R — MR MR —Cimarron VR Great Plains Research 4 HR R HR HR R HR HR MR R MR MRCommandor Northrup King 4 R MR R HR R MR — — MR — —Crystal PGI/MBS 4 HR R HR R HR LR R MR MR — LRCutter Interstate/Payco Seeds 4 R R HR R HR R R — MR — MRDK 133 DeKalb Plant Genetics 4 HR R HR HR HR R R — MR — RDynasty Dairyland Seed 4 HR R R MR R R — — — — —Eagle Asgrow 4 HR MR R R MR R R LR R — —Echo Callahan 4 R R R MR R R HR — MR — —Edge Research Seeds/Servos 4 R R R HR R R R — — — —Empress Blaney/Gutwein 4 HR R HR R HR R HR — R MR —Enterprise Mershman Seeds 4 HR R HR R HR HR HR — — — —Epic Mike Peterson 4 R — MR — R — HR — HR — —Fortress Northrup King 4 R R R R HR HR R — HR — —GH 737 Golden Harvest 4 R R R MR HR R R — MR MR —GH 747 Golden Harvest 4 HR MR R HR HR — HR — MR — —GH 755 Golden Harvest 4 HR R HR HR HR R R R R — —Good as Gold Johnson/Top Farm/

Hoegemeyer 4 HR R HR R HR R HR MR — — LRGourmet Hay Blaney/Gutwein 4 HR R HR HR R MR HR R R MR —Jade NC+ Hybrids 4 HR R R R HR MR — — — — —Jewell Wilbur-Ellis 4 HR R R R HR R R — — — MRLegacy Genesis 4 HR R HR R HR HR R — — — —Legend Cenex/Land O’Lakes 4 HR R HR HR HR LR R — MR — —Magnum III Dairyland Seed 4 R MR R MR R MR R MR MR — LRNew Era 90 Stine 4 HR R HR HR HR MR R — R R —Ogallala 633 Germain’s 4 HR R R HR HR HR R — MR — MROvatron1 Callahan 4 HR HR HR HR HR MR R — MR — RPeak Research Seeds/Royal 4 R LR R — MR — HR — HR — —Persist Kaltenberg/Doeblers 4 HR R HR R HR R — MR MR — MRPrecedent Doeblers/Wyffels 4 HR R R R HR R R — — — RPremier Wyffels/Wetsel 4 HR R HR HR HR MR HR — MR MR —Prism Beachley-Hardy/Wilson 4 HR R R HR HR — — — — — MRPro-Cut L. Herried Seed 4 HR R HR R HR R R — MR MR —Pro-Cut 2 L. Herried Seed 4 HR R R R HR R R — — — MRProGro 424 Casterline Seeds 4 HR R HR R HR R R MR — — MRPromise ICI Seeds/Hoffman 4 HR R HR HR HR MR R — MR MR —Quest Renk Seed 4 HR R HR R HR MR R — R MR —RamRod Bio-Plant Research 4 R R R MR R R — — — — —Resistar FFR 4 R HR HR R HR MR — — R — —Reward Drussel/Patriot 4 HR R HR R HR R R MR MR — LRRiley Public 4 HR LR — MR — HR HR — — — —Sabre Kinder/Allied 4 HR HR HR HR R S HR — MR — —Stine 9227 Stine 4 HR R HR HR HR R — — — — MRTarget II Bio-Plant Research 4 HR R R R R R — — — — —Terminator La Crosse 4 HR R HR R R — — — MR — —Vemema Public 4 MR MR — LR LR MR — — HR — —Verta+ NC+ Hybrids 4 HR R R HR R LR R — — — —Voyager Bio-Plant Research 4 HR MR R MR R MR — — — — —Voyager II1 Ziller/Lemke/Bio-Plant 4 HR R HR R HR R HR MR MR MR MR

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WAMPR FFR 4 R R R R R MR — — MR — —WL 320 W-L Research 4 R MR HR MR R R MR MR MR MR —WL 322 HQ W-L Research 4 HR R HR MR R HR HR R LR — —WL 323 W-L Research 4 HR R HR HR HR MR R — HR — RArcher America’s Alfalfa 5 MR HR MR R R HR HR R R R —Belmont Great Plains Research 5 HR R HR HR R HR HR MR R — —Crockett Northup King 5 HR — MR HR R HR S S — — —Deseret Public 5 MR — — — — — — — R — —Mede Union Seed 5 MR MR HR R R HR R R — R —Washoe Public 5 R — — LR R R R — R — —581 Pioneer 6 LR — HR — MR HR MR — R — —ABI 700 America’s Alfalfa 6 MR MR HR HR R HR HR HR R R —DK 169 DeKalb Plant Genetics 6 R MR R — MR HR R LR R — —Express Union Seed 6 MR MR HR R HR HR HR R R R —Lahontan Public 6 MR — LR — LR MR LR — R — —LM 455 Lohse Mill 6 R MR HR LR R HR HR MR R — —Lobo Seedtec 6 MR R HR R HR R R R HR R —Meteor Northrup King 6 R LR HR S R HR HR HR HR — —Pike Northrup King 6 MR — R — MR MR R — R — —Wilson Public 6 R — R — — MR R — MR — —5683 Pioneer 7 MR — R — R HR R MR R — —Dona Ana Public 7 MR — MR LR R R R — — — —Malone Public 7 R — HR R R R HR — MR — —Rio Great Plains Research 7 R — HR HR HR HR HR HR MR R MRSutter PGI/MBS 7 R MR HR — HR HR RR MR R HR —Valley+ NC+ Hybrids 7 MR — HR R R HR HR R — — —WL 457 W-L Research 7 MR LR HR LR HR HR HR HR HR — —13R Supreme America’s Alfalfa 8 MR MR R MR R R R MR MR R —5715 Pioneer 8 LR LR HR HR R HR R HR — — —5888 Pioneer 8 — — HR — R HR R R R — —Arroyo PGI/MBS 8 MR — HR LR HR HR HR MR HR — —Condor Northup King 8 — — HR — HR HR HR HR — — —DK 189 DeKalb Plant Genetics 8 MR MR HR HR R HR R R MR R —Falcon Lohse Mill 8 LR — HR — MR MR MR MR — — —GT 13R Plus America’s Alfalfa 8 R — MR LR R R MR LR R MR —Madera PGI/MBS 8 MR MR HR LR MR HR HR LR MR HR —Maricopa PBI/MBS 8 MR MR HR LR R HR HR R R HR —Moapa 69 Public 8 — — HR — — R — — — MR —Nitro Public 8 — — HR — R R HR — — — —Pierce Northrup King 8 LR — HR — R R HR R R — —WL 515 W-L Research 8 LR — R — R R R MR R — —WL 516 W-L Research 8 MR — HR LR HR HR HR HR MR — —WL 525 HQ1 W-L Research 8 MR — HR — HR HR HR HR R — —Yolo PGI/MBS 9 LR LR HR LR MR HR HR R MR HR —SW 14 S & W Seed 9 — LR HR — LR HR HR R — HR —5929 Pioneer 9 — — HR — R R HR HR — — —CUF 101 Public 9 — — HR — MR HR HR HR LR MR —Florida 77 Pioneer 9 — — HR MR — MR — — — R —Mecca PGI/MBS 9 LR — HR LR MR HR HR MR MR HR —Sundor Northrup King 9 — — HR — MR HR HR HR HR — —UC Cibola Public 9 — — HR — MR HR RL R — R —WL 605 W-L Research 9 — — HR LR HR HR HR HR MR — —

7


*Reprinted with permission of Hay and Forage Grower, 79000 International Drive, Minneapolis, MN 55425. January 1994.

Field ScoutingFields of alfalfa or clover grown for

hay or grazing should be checked week-ly during the growing season for insectactivity.

It is important to sample as much ofthe field as possible (at least 4 or 5spots in each field). Populations ofpests can vary across fields, and yourresults may be inaccurate if only asmall part of the field is checked.Most sampling should be done awayfrom field edges. Fields should be sam-pled when the hay is dry so that theinsects can easily be found.

Stem Sampling. In areas wherealfalfa weevil is the key pest in alfalfaduring spring, stem sampling is the pre-ferred sampling method. Stem sam-pling is made easier using a beat buck-et. A 30-stem sample should be taken,selecting stems at evenly spaced inter-vals through the field. For fields largerthan 30 acres, 2 or more stem samplesshould be taken. During sampling, thestems can be conveniently held in thebucket. After the 30-stem sample hasbeen collected, beat the stems vigorous-ly against the inside of the bucket for10 to 20 seconds. This dislodges themedium sized and large larvae and theycan easily be counted.

Sweep Net Sampling. A standard15-inch diameter sweep net is the basicsampling tool used in many Texas alfal-fa and clover fields. A sampling unitconsists of 10 consecutive (180-degree)sweeps taken while walking throughthe field. The net is swung from sideto side with each step. The net shouldbe held so that the lower half of theopening (7 to 8 inches) is drawnthrough the foliage. If foliage andstems are not obtained in the sample,the net is not being swung hard

enough and/or deep enough. Samplesmay differ somewhat among individu-als according to their reach.

Five samples (each consisting of 10sweeps), one taken in each quadrant ofthe field and one near the center of thefield, provide a good estimate of insectnumbers. Samples should be taken 30to 50 feet from each edge of the field.

A sweep net can be used to samplea field for aphids and other pests.Often aphids are too abundant tocount individually, but can be estimat-ed in 10s or 100s.

Sucking PestsPea Aphid. Pea aphids are the most

commonly seen aphids in Texas alfalfaand clover crops. The adults are brightgreen, long legged and about 1/8 inchlong. Adults may be winged or wing-less. In spring and summer, all aphidsare female, and each gives birth to 50to 100 young over a 10- to 12-day peri-od. Up to 20 generations may occurper year. When not held in check byweather, predators, parasites or dis-eases, pea aphids can produce hugepopulation increases. Pea aphids gener-ally cause the greatest amount of dam-age in the spring.

Resistant cultivars are very helpfulin reducing pea aphid damage (seetable pages 7-10). Use of an insecticideis justified when aphid populationsreach the action level (See table below).

Pea aphids prefer to congregate indense colonies along the stems, termi-nal shoots and leaves. Heavy infesta-tions cause plants to wilt and yellow.Honeydew is usually not abundant oninfested plants.

Spotted Alfalfa Aphid. The spot-ted alfalfa aphid is small (1/16 inch

long) and grayish-yellow with four tosix rows of raised dark spots on theback. This aphid is usually found onthe undersides of the lower leaves.However, as the population increases,aphids can be found on all parts of theplant. Spotted alfalfa aphids secretelarge amounts of honeydew whichinterfere with cutting and baling anddegrade hay quality. Spotted alfalfaaphids fall from alfalfa plants when dis-turbed.

As with pea aphids, spotted alfalfaaphids are all female. Each female pro-duces 100 offspring and up to 20 gen-erations may be produced per year.Winged females may travel up to 70miles with the wind.

Infestations can increase rapidlyunder favorable conditions. However,rain and high humidity often reducean infestation or create conditionsunfavorable for survival.

The spotted alfalfa aphid causes atoxic reaction in plants as it feeds.This reaction results in plant injuryand even death of seedling alfalfa. Onestablished stands, growth is severelystunted and yellow or chlorotic areasappear on the leaves. Veins of newlyformed leaves often become discolored,a symptom known as “veinbanding.”

Resistant cultivars offer varyingdegrees of protection from yield andstand losses due to spotted alfalfaaphid (see table, pages 4-7). In somecases insecticides may be needed (seetable, page 9).

Blue Alfalfa Aphid. The blue alfal-fa aphid was detected in alfalfa fieldsin West Texas in 1978, but as of thisprinting has been of little economicimportance. The pest closely resemblesthe pea aphid but is bluish-green ratherthan light green. The blue aphid tends

8

Action Levels for Aphid ControlHay height (inches) No. aphids per stem No. aphids per sweep

Pea Aphid <10 40 2001/

>10 70 300-400

Spotted Alfalfa Aphid <10 20 100-2001/

>10 40 200-400

Blue Alfalfa Aphid* <10 10-12 50>10 40-50 2001/

*Treat for blue alfalfa aphid if aphids are present in numbers approaching the thresholds and plants have taken on astunted, bluegreen appearance.

1/ Sweep sampling is generally not appropriate on short hay.

to congregate in clusters on the termi-nal growth while the pea aphid may befound over the entire plant. Blue aphidpopulations tend to build up in theearly spring, but decline when tempera-tures exceed 85 degrees F. Severestunting of plants and deformation ofleaves may result from blue aphid feed-ing on new alfalfa regrowth less than 6inches tall and when temperatures arebelow 75 degrees F. Leaf yellowingoccurs as plants die.

Resistance to this pest is available inseveral alfalfa cultivars (see table, pages4-7).

Three Cornered Alfalfa Hopper.Three cornered alfalfa hoppers arecommonly found in alfalfa and cloverfields. Adults and nymphs suck plantjuices by puncturing stems either ran-domly or in a circle that completely gir-dles a stem. Girdling is done primarilyby the nymphs. Girdled stems becomestunted and weakened just above thesoil surface.

In most of Texas, three corneredalfalfa hoppers are rarely an importantfactor in forage alfalfa production. InEast Texas, however, the girdling dam-age to the vascular tissue of the stemsresults in a condition which mimicsboron deficiency. Leaves on affectedstems take on a red color underneath,and a light yellow-green color on top.Individual damaged stems which devel-op these symptoms usually die.

Check crowns closely near the soilsurface for three cornered alfalfa hop-

9

Suggested Aphid Control on Alfalfa and Clover*(Pea, Spotted Alfalfa, Yellow Clover and Blue Alfalfa Aphids)

Insecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazingchlorpyrifos (see remarks)

(Lorsban® 4 lb) 1/2 pt 7 7dimethoate (see remarks)

(Dimethoate 400) 1/2 - 1 pt 10 10(Dimethoate 2.67 lb) 3/4 - 1 1/2 pt 10 10

disulfoton (see remarks)(Di-Syston® 15% G) 6.7 lb 28 28

malathion (see remarks)(Cythion® 5 lb) 1 1/2 - 2 pt 0 0(Cythion® 8 lb) 1 1/4 - 1 1/2 pt 0 0

methyl Parathion(Methyl Parathion 4 lb) 1 pt 15 15(Methyl Parathion 7.5 lb) 1/4 - 1/2 pt 15 15(Penncap-M®) 2 - 3 pt 15 15

*When weevil control is desired with the same application, see section on weevil control.Remarks

Chlorpyrifos. Do not make more than four applications per year or apply more than once per crop cutting. Not labeled for use on clover.

Dimethoate. Make only one application per cutting. Do not apply if the crop or weeds in treatment area are in bloom. Not labeled for use on clover.

Disulfoton. Make only one application per crop season.Malathion. When alfalfa is in bloom, spray only in the early morning or late evening to avoid bee kill.

Suggested Three Cornered Alfalfa Hopper Control in Alfalfa and CloverInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazingcarbaryl (see remarks)

(Sevin® 4 F) 1 qt 7 7(Sevin® 50 W) 2 lb 7 7(Sevin® 80 S) 1/4 lb 7 7(Sevin® XLR Plus) 1 qt 7 7

malathion (see remarks)(Cythion® 5 lb) 1 1/2 - 2 pt 0 0(Cythion® 8 lb) 1 1/4 - 1 1/2 pt 0 0

RemarksCarbaryl. Apply only once per cutting.Malathion. Do not apply to clover or alfalfa in bloom. Do not apply to seed clover or alfalfa.

per nymphs. Check several locations ineach field. The action level in alfalfaand clover crops grown for hay isreached when nymphs average 25 to30 per crown. In seed alfalfa andclover crops sample for three corneredalfalfa hopper adults with a sweep net.The action level is reached when sweepnet counts average 150 or more per100 sweeps.

Thrips. Thrips feed on alfalfablooms, buds and leaves. When popula-tions are large, leaves become distortedand silvered and blooms turn a mottledbrown. Thrips damage to alfalfa grownfor hay or forage is generally minimal.Use of insecticides for thrips controlhas never been shown to be economi-cally advantageous.

Chewing PestsAlfalfa Weevil. The alfalfa weevil

is primarily a pest of alfalfa, but mayalso attack several species of clover.The first and second alfalfa cuttingsare most heavily damaged. Uponhatching, larvae feed on leaf buds, atthe tip of the plant. Older larvae feedmostly on open leaflets, but they alsofeed on the terminal buds. Foliage isskeletonized by alfalfa weevil larvae andfrom a distance, fields appear grayish towhitish in color.

Adult weevils lay eggs inside alfalfastems in late fall, winter and earlyspring. Eggs are laid in groups of from1 to 40 per stem. Each female lays 600to 800 eggs. Activity ceases on colddays during winter. Fall-laid eggs beginto hatch in early spring; spring-laideggs hatch after being exposed to a fewweeks of warm temperatures. Eggshatch into small, light green, black-headed larvae. Young larvae are whiteand feed inside stems 3 to 4 days.Larvae which emerge from stems aresmall and yellowish green. Mature lar-vae are darker green with a singlewhite stripe down their backs. Larvaefeed for about 3 to 4 weeks on the ter-minal and upper leaves. The damagecaused by larvae increases with larvalgrowth. The most severe damage isdone by large larvae. The damagestunts the plant. High populations mayremove virtually all leaf tissue on thefirst cutting and cause delayed, lowyielding second cuttings.

In fields where infestations arisefrom both fall- and spring-laid eggs,

feeding damage is extended over aperiod of 6 to 8 weeks. The amountof crop damage done by alfalfa weevillarvae at any time depends on:

1. the size of the alfalfa plant;

2. the size of the larvae; and

3. the number of larvae per alfalfastem.

The following figure depicts losseswhich have been documented fromvarious levels of alfalfa weevil infesta-tion in Oklahoma.

When larvae are mature, they spinspherical cocoons about 1/4 inch indiameter either on the plants or withinthe curl of fallen dead leaves. Theypupate within these cocoons andemerge as adults in 1 to 2 weeks.After emergence, most young adultsleave the alfalfa field and go to nearbyprotected areas for a summer restingperiod, returning to the fields again inthe fall.

Crop production practices thatencourage dense, vigorous plant growthwill reduce weevil damage. The firstcrop should be cut as cleanly and close-ly as possible when most of the plantsare in the bud stage. This deprives lar-vae of food and shelter. Exposing thelarvae to the hot soil surface when thecrop is cut causes extensive mortality.When infested alfalfa is cut, the stubbleunder the windrows is subject to exces-sive damage. Care should be taken toscout for alfalfa weevil damage to theregrowth, especially in the strips whichwere under the windrows.

Grazing during the winter will aidin destruction of fall-laid eggs andremove egg laying sites for winter egglaying.

Close field inspections are necessaryto determine when the alfalfa weevilaction level has been reached. Theaction level (see table, page 11) shouldbe based on plant size, plant damageand numbers of weevil larvae. Whenconditions approaching the action levelare found, cutting or insecticide treat-ment should be considered. If weevilpopulations are above treatment actionlevels and larvae are small, sprays canbe delayed until the oldest larvae arehalf grown to allow as much egg hatchas possible. Using this strategy, care

should be taken toallow passage of thelabel-specified timebetween spraying andcutting or grazing(see table, page 11).This strategy mini-mizes the chances ofhaving to spray a cut-ting twice and allowsfor treatment of themaximum number oflarvae without expos-ing the crop to exces-sive damage.

Sampling can beaccomplished using

several methods. Under situations inwhich the alfalfa weevil is a seriousannual pest of alfalfa, the stem sam-pling (beat bucket) method is best.Using this method, 30 stems are collect-ed at random throughout a field.(Additional 30 stems may be neededon fields larger than 30 acres.) The30-stem sample is beaten vigorously ina 2- to 3-gallon bucket for 10 to 20 sec-onds. This shakes out large and medi-um sized larvae. Larvae can then beeasily counted.

Percent damaged terminals can beuseful. When using this method, besure larvae are still present beforespraying a field.

In fields in which spring regrowth isvery short or following cutting, count-ing the number of larvae per squarefoot is a good way to sample alfalfaweevil populations.

In areas which have only sporadicand occasionally severe alfalfa weevildamage, a sweep net can be used toquickly and effectively monitor weevilpopulations.

The following table provides actionlevels for each of these methods.

10

0

-400

-800

-1200

-1600

-2000

-2400

Yie

ld R

educ

tion

(lb/a

cre)

Y(2nd cutting yield)

Y(1st cutting yield)

Larvae/Stem1 2 3 4 5 6 7 8 9 10 11 12

YIELD REDUCTION (lb./acre)Y(2nd cutting yield) = 138.7x

Y(1st cutting yield) = 167.8x

Action Level for Alfalfa WeevilPlant height (inches) Larvae per terminal Larvae per sq ft Percent damaged Larvae per

terminals1/ sweep2-6 1 —- 30-40 —-7-14 1.5 —- 25-30 20Near cutting2/ 2.0 —- 50 40-50Stubble3/ (after cutting) 1 16 — —1/ With presence of 1 medium or large larva per stem.2/ In alfalfa within 1 to 2 weeks of cutting, it may be advisable to cut early rather than apply an insecticide.3/ Stubble treatment may be advisable if cloudy conditions and mild temperatures allow good weevil survival on stubble

under windrows.

Suggested Alfalfa Weevil Control on AlfalfaInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazingcarbaryl (see remarks)

(Sevin® 80S) 1 7/8 lb 7 7(Sevin® XLR Plus) 1 1/2 qt 7 7(Sevin® 4F) 1 1/2 qt 7 7(Sevin® 50W) 3 lb 7 7

carbofuran (see remarks) (Furadan® 4 lb.) 1 - 2 pt 14 - 28 14 - 28

chlorpyrifos (see remarks)(Lorsban® 4E) 1 - 2 pt 14 - 21 14 - 21

malathion (see remarks) (Cythion® 5 lb.) 1 1/2 - 2 pt 0 0(Malathion ULV 9.79 lb.) 16 oz 5 5(Cythion® 8 lb.) 1 1/4 - 1 1/2 pt 0 0

methyl ParathionMethyl Parathion (4 lb.) 1/2 - 1 pt 15 15Methyl Parathion (7.5 lb) 1/4 - 1/2 pt 15 15Penncap-M® 2 - 3 pt 15 15

permethrin (see remarks)Ambush® 6.4 - 12.8 oz 0 - 14Ambush® 25W 6.4 - 12.8 oz 0 - 14Pounce® 4 - 8 oz 0 - 14

phosmet (see remarks)(Imidan® 70 WP) 1/3 lb 7 7

RemarksCarbaryl. Not effective against aphids.Carbofuran. Do not apply more than twice per season or once per cutting. Apply no more than 1 pt per acre on second

application. Not labeled for use on clover. Apply only to pure stands of alfalfa. Not effective against aphids.Do not cut or graze within 14 days after using 1 pt of Furadan or within 28 days after using 2 pts of Furadan.

Chlorpyrifos. Do not make more than four applications per year or apply more than once per crop cutting. Do not graze within 14 days after application of 1 pt per acre, or within 21 days after application rates above 1 pt per acre.

Malathion. Do not apply when plants are in bloom. Do not use on seed alfalfa. For alfalfa weevil larvae only.Permethrin. When rates are .1 lb ai/acre or less (Ambush® 6.4 oz/acre, Pounce® 4 oz/acre), application can be made on

the day of harvest. When rates above .1 lb ai/acre are used, do not apply within 14 days of harvest. Apply no more than .2 lb ai/acre per cutting.

Phosmet. Do not apply more than once per cutting. Not effective against aphids.

11

Clover Head Weevil. The mostimportant pest of Texas crimson cloveris clover head weevil. It was firstobserved in Texas in light, scatteredinfestations during the spring of 1965.It now occurs in all eastern and north-eastern counties where crimson cloveris grown. Crimson clover is an annualcrop. Producers who depend on crim-son clover reseeding itself are subjectto weakened stands in years followingclover head weevil outbreaks. This wee-vil prefers clovers, particularly crimson,alsike and red. However, the adultshave been observed on alfalfa, blackmedic and snap beans.

Adults become active in early springand begin egg laying in late March orearly April. Each female deposits 200to 300 eggs in stalks or leaf stems ofhost plants during a 2- to 6-week peri-od. Eggs hatch in 5 to 8 days andemerging larvae feed primarily in theflorets. Larval populations normally

peak about April 15 to May 1. Full-grown larvae are about 1/2 inch long,legless and vary in color from lightgreen to yellowish. Mature larvae spina silken cocoon in the floral head ofhost plants where they spend severaldays before pupating. The pupal stagelasts 3 to 6 days. The life cyclerequires 22 to 28 days from egg toadult. Adults are inactive during theremainder of the summer. They hiber-nate in ground trash and bunch grassesin or near clover fields.

The principal damage is caused bylarvae feeding on developing flowersand seed pods. Damage is also causedby adults feeding on stems. This oftenresults in lodging of the flowers.

The action level is based on the his-tory or damage in the field in previousyears plus the presence of weevils atthe beginning of the bloom period.Apply treatment when clover hasreached a 25 to 50 percent bloom

stage. If a second application isrequired, apply 7 to 10 days after thefirst.

Grasshopper. Grasshoppers aremost damaging in dry years. Thesepests generally migrate into the fieldfrom adjoining fence rows, ditch banks,field margins or native pastures. Grass-hopper nymphs and adults are foliagefeeders and can cause extensive forageloss when populations are large. Grass-hoppers may devour all plant partsexcept stems. However, extensive dam-age is not common. Grasshoppers aremost damaging in dry years.

A few grasshopper species hatch infields, but most species hatch outsidefields in weedy ditches or outlands.For grasshopper populations whichdevelop outside fields, grasshopper con-trol should be initiated before the pestsmove out of hatching areas and intothe field.

12

Suggested Clover Head Weevil Control on CloverInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest GrazingMethyl Parathion

(Methyl Parathion 4 lb) 1 pt 15 15(Methyl Parathion 7.5 lb) 1/2 pt 15 15

Suggested Grasshopper Control on Alfalfa and CloverInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazingcarbaryl

(Sevin® 80S) 2/3 - 1 7/8 lb 7 7(Sevin® XLR Plus) 1/2 - 1 1/2 qt 7 7(Sevin® 4F) 1/2 - 1 1/2 qt 7 7(Sevin® 50W) 1 -3 lb 7 7

carbofuran (see remarks)(Furadan® 4F 4 lb) 1/4 - 1/2 pt 7 7

dimethoate (see remarks)(Dimethoate 400 4 lb.) 1/2 - 1 pt 10 10(Dimethoate 2.67 lb.) 3/4 - 1 1/2 pt 10 10

malathion (see remarks)(Cythion® 5 lb.) 1 1/2 - 2 pt 0 0(Malathion ULV 9.33 lb.) 8 oz 0 0(Cythion® 8 lb.) 1 1/4 - 1 1/2 pt 0 0

RemarksCarbofuran. Do not apply more than twice per season, once per cutting, with no more than 1 pt per acre on second

application. Treat alfalfa prior to bloom. Do not move bees into field within 7 days of application. Apply only to pure stands of alfalfa. Not labeled for use on clover.

Dimethoate. Make only one application per cutting. Do not apply if crop or weeds in treatment area are in bloom. Not labeled for use on clover.

Malathion. Do not apply to alfalfa or clover in bloom.

Eliminate weedy field margins(roadsides and fence rows) to aid inreducing grasshopper numbers. Theseareas are favored habitat for egg layingand early nymphal feeding in manyspecies.

Chemical treatment of fields andfield margins is suggested in early sum-mer where grasshopper nymphs areabundant. The action level for fieldinfestations is an average of 10 or moregrasshoppers per square yard. Spot

and/or border treatments can be effec-tive.

Blister Beetle. Several species ofblister beetles may be found in alfalfafields during the growing season. Thebeetles range from 1/2 inch to morethan 1 inch long and are black, gray,reddish or brown in color. Somespecies are striped. Adult blister beetlesare narrow, cylindrical, rather soft-bod-ied beetles. The heads of blister beetlesare wider than the neck areas. This fea-

ture separates them from the otherbeetles commonly found in alfalfa.Adults feed primarily on blooms ofalfalfa and many other plants. Adultscan become very abundant from Junethrough September.

Blister beetles produce cantharidin,a blistering agent. This blisteringagent, when eaten, causes livestock tocolic and sometimes die as the liningof the digestive system is damaged bythe toxin. Animal reaction depends on

13

Suggested Grasshopper Control on Pasture, Range and Non-croplandBefore Grasshoppers Move to Fields

Insecticide (listed alphabetically) - Concentrate per acre Labeled application sitestoxicant per gallon or pound acephate (see remarks)

(Orthene® 75 S) 1/8 - 1/6 lb pasture, range and wasteland(Orthene® 75 S) 1/3 lb non-cropland (Orthene® 75 WSP) 1/8 - 1/6 lb pasture, range and wasteland(Orthene® 75 WSP) 1/3 lb non-cropland

carbaryl (see remarks)(Sevin® 4F) 1/2 - 1 1/2 qt pasture, range, non-cropland(Sevin® 4-oil ULV) 1/2 - 1 1/2 lb pasture, range, non-cropland(Sevin® 50 W) 1 - 3 lb rangeland, wastelands, non-cropland(Sevin® 80 S) 2/3 - 1 7/8 lb pasture, rangeland, non-cropland(Sevin® XLR Plus) 1/2 - 1 1/2 lb pasture, rangeland(Sevin® XLR Plus) 1/2 - 1 lb non-cropland

esfenvalerate(Asana® XL) 2.9 - 5.8 oz non-cropland

malathion (see remarks)(Cythion® 5 lb) 1 1/2 - 2 pt pasture, range(Cythion® 5 lb) 1 1/2 - 3 pt non-cropland(Cythion® 8 lb) 1 1/4 pt pasture, range(Cythion® 8 lb) 1 - 2 pt non-cropland (Malathion ULV 9.79 lb) 8 12 oz pasture, range, non-cropland

methyl parathion (see remarks) (Penncap-M®) 2 - 3 pt pasture and rangeland

naled (see remarks)(Dibrom® 8 lb) 1/2 - 3/4 pt rangeland

phosmet (see remarks)(Imidan® 70 WP) 2 1/8 - 2 3/4 lb alfalfa field margins

RemarksAcephate. For pasture range and wasteland: Do not apply when lactating dairy animals are present and do not

feed or graze lactating dairy animals on treated foliage. Within 21 days of treatment, remove meat animals at least 1 day before slaughter. One application per season. For non-crop areas (field borders, fence rows, roadsides, ditch banks and barrow pits): Do not graze or feed vegetation from treated area.

Carbaryl. Zero days preharvest interval for aerial application. Fourteen days preharvest interval for ground applications on pastures and non-cropland. Non-cropland is wasteland, right-of-ways, hedge rows, ditchbanks and roadsides.

Malathion. Dilute in water or diesel fuel oil. Zero days preharvest or grazing interval. Methyl parathion. Do not apply within 15 days of harvest or grazing.Naled. Grazing animals may be present during treatment. Do not graze lactating dairy animals on treated

area.Phosmet. Do not harvest or graze treated area.

the number of beetles consumed.Horses and poultry are very sensitiveto cantharidin, but all livestock are atrisk.

Hay and feed producers shouldinspect alfalfa fields for the presence ofblister beetles before hay is cut, espe-cially during the months of Junethrough September when the beetlesmost commonly move into fields.Blooming alfalfa fields can attract largenumbers of blister beetles. Fields shouldbe scouted for blister beetles starting 2weeks before cutting and throughoutthe baling process. Special attentionshould be paid to blooming fields.Adult beetles are mobile and somespecies are prone to congregate in onespot or a few small spots within a field.Infested areas should be left unharvest-ed or sprayed with an insecticide spottreatment.

Do not sell hay for livestock feedif blister beetles are present. The

cantharidin is highly toxic to all typesof livestock. Swathers with crimperdevices may crush beetles into the hayand increase the risk of livestock poi-soning. Cutting without a crimperallows living beetles to leave the wind-row before hay is baled. Cutting hayat or before 5 percent bloom greatlyreduces the risk of blister beetle conta-mination.

Finding only a few blister beetlesmay justify a treatment since the bee-tles are very toxic to livestock.

Pay attention to the harvest intervalon the insecticide you use.

Common Caterpillar PestsSeveral species of caterpillar larvae

feed on the tender stems and leaves ofalfalfa. These pests are quite similar inappearance and in the amount of dam-age they cause. Because of this similar-ity, one action level for the primaryfoliage feeding caterpillars in alfalfa is

used. It is important, however, to beable to identify these worms sinceinsecticides which work against oneworm may be ineffective against anoth-er.

The action level for caterpillars inalfalfa is seven worms per sweep, ortwo worms per square foot.

Alfalfa Caterpillar. The alfalfacaterpillar is the larval stage of a yellowor white butterfly that has a 2-inchwing span and black margins on thewings. The butterflies are seen flyingthrough the fields in late spring andsummer. Female butterflies lay 200 to500 eggs singly on the undersides ofalfalfa leaves. The eggs hatch in a fewdays, and the larvae feed on the leavesfor 12 to 15 days before pupating.Mature larvae attach themselves tostems and pupate. The pupa is uncov-ered by a cocoon, is attached head upto the stem and lasts 5 to 7 days beforethe adult emerges. Mature larvae are

14

Suggested Blister Beetle Control on AlfalfaInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazingcarbaryl(Sevin® 80S) 2/3 - 1 1/4 lbs 7 7 (Sevin® XLR Plus) 1/2 - 1 qt 7 7(Sevin® 50W) 1 - 2 lbs 7 7(Sevin® 4F) 1/2 - 1 qts 7 7

Suggested Alfalfa Caterpillar Control on AlfalfaInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or per pound Harvest GrazingBacillus thuringiensis (see remarks)

(Agree®, Dipel®, Javelin®, Xentari®) 0 0carbaryl (see remarks)

(Sevin® 80S) 1/4 lb 7 7(Sevin® XLR Plus) 1 qt 7 7(Sevin® 50 W) 2 lb 7 7(Sevin® 4F) 1 qt 7 7

methomyl(Lannate® 90% SP) 1/4 - 1/2 lb 0 7(Lannate® LV) 1 - 1 1/2 pt 0 7

methyl Parathion(Methyl Parathion 4 lb) 1 pt 15 15(Methyl Parathion 7.5 lb) 1/2 pt 15 15

Remarks Bacillus thuringiensis. Application rates must be taken from the individual product labels due to the variation in

formulations.Carbaryl. Apply only once per cutting.Methomyl. Do not apply when bees are in the field. Not registered on clover.

about 1 1/2 inches long and are dark,velvety green with white stripes alongeach side. They have large, roundedheads. Larvae feed on foliage andnumbers usually increase when notheld in check by diseases, beneficialinsects and spiders or weather.

The alfalfa caterpillar usuallybecomes a pest after the third alfalfahay cutting and is usually most abun-dant in mid to late summer (see actionlevel, page 14). Crop damage can some-times be avoided by early cutting.

Alfalfa caterpillar is normally themost damaging caterpillar on alfalfa inTexas. It is easily controlled withinsecticides, however.

Armyworm. Armyworms are theimmature stages of dull-colored, noctur-nal moths. Armyworm larvae range incolor from pale green to brown orblack and are striped with white to yel-lowish lines from head to tail.

The fall and beet armyworms arecommonly found on alfalfa and clovercrops and may develop into damagingnumbers that require chemical control(see action level, page 15). The yellow-striped armyworm is an occasional pestin alfalfa. The armyworms are markedwith an inverted “y” marking on thehead. Infestations of armyworms areusually most severe in mid to late sum-mer. Armyworms lay their eggs inmasses of several hundred eggs whichhatch in 2 to 3 days. The larvae feed ingroups when they are young, and dis-perse as they mature. Full grown larvaeare 1 1/2 inches long. The larvae feedfor about 3 weeks before falling to thesoil, burrowing (not deeper than 1inch), constructing a loose pupal celland pupating. Armyworms are normal-ly the most difficult worms to controlin alfalfa. Increased insecticide ratesand/or tank mixes of insecticides maybe required.

Corn Earworm. Corn earwormmoths are tan in color, about 3/4 inchlong, with a wing span of 1 to 1 1/2inches. Young larvae are greenishwith black heads. Fully developedworms are about 1 1/2 inches longand range in color from pale green orpinkish to brown.

After emerging, feeding on nectarand mating, adult female moths lay anaverage of 1,000 spherical eggs singlyon the new growth. The eggs hatch inabout 3 days and the larvae feed andgrow for 2 to 3 weeks. Full grown lar-vae drop to the ground, burrow 3 to 5inches into the soil and pupate. Thepupal stage normally lasts 10 to 12days.

Earworm larvae feed on numerousplants. In alfalfa and clover, larvaeprefer the leaves, but they will feed onother plant parts. Earworms may bepresent in alfalfa hay crops throughthe growing season, but usually aremost abundant from July throughSeptember. (See action level, page 15).

15

Suggested Armyworm Control on AlfalfaInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest GrazingBacillus thuringiensis (see remarks)

(Agree®, Dipel®, Javelin®, Xentari®) 0 0chlorpyrifos (see remarks)

(Lorsban® 4E) 1 - 2 pt 14-21 14-21methomyl (see remarks)

(Lannate® 90% SP) 1/4 - 1 lb 0 7(Lannate® LV lb) 3/4 - 3 pt 0 7

Remarks Bacillus thuringiensis. Application rates must be taken from the individual product labels due to the variation in

formulations.Chlorpyrifos. Do not make more than four applications per year or apply more than once per crop cutting. Do

not cut or graze within 14 days after application of 1 pt per acre or within 21 days after application at rates above 1 pt per acre.

Methomyl. Do not apply during bloom or when bees are present in field. Not registered for use on clover.

Suggested Corn Earworm Control on Alfalfa and CloverInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazingcarbaryl

(Sevin® 80S) 1 1/4 - 1 7/8 lb 7 7(Sevin® XLR Plus) 1 - 1 1/2 qt 7 7(Sevin® 50W) 2-3 lb 7 7(Sevin® 4F) 1 - 1 1/2 qt 7 7

RemarksCarbaryl. Apply only once per cutting.

Occasional CaterpillarPests

Army Cutworm. There is only onegeneration per year of the army cut-worm. Female moths lay eggs in the fallon the soil surface. Moisture isrequired for the eggs to hatch. Younglarvae pass the winter hibernating inthe soil. As the weather warms duringthe day in late winter and spring, theyoung larvae resume their feeding andgrowth. Mature larvae are about 1 1/2inches long and pale greenish-grey tobrown. The back has pale stripes and isfinely mottled with white and brown.

Larvae feed on a variety of plants,although alfalfa and winter wheat arethe principal crops damaged. The armycutworm feeds entirely above the soilsurface. Larvae prefer to feed on plantleaves and only eat stems and other

plant parts when food is scarce. Feed-ing occurs from late afternoon untildaylight the following morning. Thelarvae hide under clods and in the soilduring hours of bright sunshine. Ondark, cloudy days, the larvae often feedboth day and night. They can often befound by looking under alfalfa crownsand under field debris. Army cutwormscan cause heavy damage to newlyplanted stands of alfalfa. Most armycutworm damage occurs in earlyspring, before the first cutting. Failureof a field to make spring growth is anindication armyworm damage may beoccurring.

The action level is three to four lar-vae 1/2 inch or less in length persquare foot, or two to three larvaemore than 1/2 inch in length persquare foot.

Webworm. Webworms are larvalstages of small, buff-yellow to brownmoths with 1-inch wing spans. Thealfalfa webworm, the garden webwormand the beet webworm feed on alfalfa,clover, cowpeas, peas and similar cropsas well as several weed species, espe-cially pigweed. The larvae of all threespecies create webs in the tops ofplants and feed within the webs, com-pletely skeletonizing the leaves. Flimsywebs near the plant terminals arenoticeable in alfalfa and clover cropsinfested with these insects. Webwormsoccasionally cause serious damage toalfalfa, particularly to the second andthird cuttings, primarily in East Texas.

On alfalfa hay crops, early harvest issuggested if the infested crop is nearthe cutting stage. The action level forinsecticide use is reached when thecrop is more than 2 weeks from cuttingand 25 to 30 percent of plant terminalsare infested.

16

Suggested Army Cutworm Control on AlfalfaInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazingcarbaryl

(Sevin® 80S) 1/4 - 1 7/8 lb 7 7(Sevin® XLR Plus) 1 - 1 1/2 qt 7 7(Sevin® 50W) 2-3 lb 7 7

chlorpyrifos (see remarks)(Lorsban® 4 lb) 1 - 2 pt 14-21 14-21

permethrin (see remarks)(Ambush®) 3.2 - 12.8 oz 0 - 14(Ambush® 25 W) 3.2 - 12.8 oz 0 - 14(Pounce® 3.2 EC) 2 - 8 oz 0 - 14

RemarksChlorpyrifos. Do not make more than 4 applications per year or apply more than once per crop cutting. Do not graze

within 14 days after application of 1 pt per acre or within 21 days at rates above 1 pt per acre.Permethrin. For rates less than .1 lb/ac (Ambush® 6.4 oz, Pounce® 4 oz), zero days cutting restriction. For rates above

.1 lb/ac, 14 days cutting restriction.

Suggested Webworm Control on Alfalfa and Clover(Alfalfa Webworm, Beet Webworm, Garden Webworm)

Insecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazingcarbaryl (see remarks)

(Sevin® 80S) 1 1/4- 1 7/8 lb 7 7(Sevin® XLR Plus) 1 - 1 1/2 qt 7 7(Sevin® 4 F) 1 - 1 1/2 qt 7 7(Sevin® 50 W) 2 - 3 lb 7 7

methyl parathion(Methyl Parathion 4 lb) 1 pt 15 15(Methyl Parathion 7.5 lb) 1/2 pt 15 15

RemarksCarbaryl. Apply only once per cutting. Pre-harvest interval is zero days on clover.

VETCH PESTS

Sucking PestsPea aphids, thrips and lygus bugs are

sucking insect pests of vetch.

A discussion of pea aphid biology isgiven on page 8 under alfalfa.

Thrips are tiny insects (1/15 inchlong) with bodies which are muchlonger than they are wide. They aregenerally yellow to light brown in color,mostly tan. Thrips have tiny suckingmouthparts. Adults have feather-likewings and readily fly. The commonlyoccurring species complete a life cyclein about 16 days (egg to adult) withadult females producing 50 or moreeggs during their 35-day life.

Lygus bugs are oval shaped, 1/4inch long bugs which are relatively flat

in profile. They vary from dark brownto light tan, light yellow and lightgreen. All lygus bugs have a distinctivelight colored triangle in the middle ofthe back. The life cycle lasts from 20 to30 days. Lygus bugs feed on the flowerbuds of many plants. They readilymove to new host plants. When flowerbuds are fed on, they often abort andfall from the plant.

The action level for these insects isshown in the following table.

Chewing PestsVetch Bruchid. The vetch bruchid

or “vetch weevil” is one of the mostdamaging pests for the vetch seed pro-ducer. Adults are about 1/8 inch longand black with irregular white patcheson the wing covers. Larvae are grub-like in appearance, 1/8 inch long and

are white to cream colored. Adultsfeed upon developing flower buds andpollen, but the primary damage iscaused by larvae. Larvae consume thecontents of the seed and may causeseed yield loses of from 10 to 74 per-cent. Bruchids do not reproduce instored vetch seed, although they maybe found occasionally inside the seedhulls.

The action level for vetch bruchidcontrol is 10 to 25 percent fallenblooms with bruchids present. Asweep net is preferred over individualplant inspection for detection ofbruchids. Check fields 6 to 8 daysafter treatment; if bruchids are stillpresent, repeat application.

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Pest Action Level – Pea Aphid, Thrips and Lygus BugPea Aphid When visible signs of plant wilting are observed, accompanied by foliage yellowing, honeydew and

increasing aphid numbers.

Thrips When seed production is a goal and excessive blasting and shedding of blooms is observed.

Lygus Bug When seed production is a goal and lygus average two per sweep in bud and early bloom stages.

Suggested Aphid, Thrips and Lygus Bug Control on VetchInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazingmalathion

(Cythion® 5 lb) 1 1/2 - 2 pt 7 7methyl parathion

Methyl parathion (4 lb) 1 pt 15 15

Suggested Bruchid Control on VetchInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazingmalathion

(Cythion® 5 lb) 1 1/2 - 2 pt 7 7methyl parathion

(Methyl parathion 4 lb) 1 pt 15 15

Armyworm and Cutworm. Army-worms and cutworms may occur indamaging levels in fields of vetch orvetch interplanted with a small graincrop. Their biologies are discussedunder the alfalfa and clover section.Armyworms and cutworms should becontrolled when visible foliage lossoccurs.

FORAGE SORGHUMPESTS

Soil Pest TreatmentMethods

Pre-plant Seed Treatment –Commercial Seed Treaters. Growerscan purchase commercially treated for-age sorghum seed, or take their farmgrown seed to a commercial seed treat-ment facility for treatment. Lindaneand Gaucho® are labeled insecticideswhich can be applied to foragesorghum seed by commercial seedtreaters to control soil pests. In addi-tion to its activity against soil insects,Gaucho® has activity on sucking pests.

Insecticides such as malathion andmethoxychlor are often applied to seedto control stored grain pests. Theseinsecticides are not effective for thecontrol of soil pests.

Pre-plant Seed Treatment – OnFarm. On-farm, pre-plant seed treat-ment can be accomplished by using a

concrete mixer, custom designed seedtreatment equipment or similar devices.Seed should be evenly coated withinsecticide. Sprinkle 1 pint of water oneach 100 pounds of seed and mix tocoat the seed evenly with moisture.Add the correct amount of insecticideto the seed as specified by the pesticidelabel and mix thoroughly. Lindane is

available for on-farm seed treatment.Follow recommendations on the insecti-cide label to achieve effective control.Lindane is phytotoxic on sorghum seedand will adversely affect germination.Do not treat seed with lindane morethan 3 to 4 weeks prior to planting.

Planter Box Seed Treatment.Some insecticides are formulated to beapplied to seed in the planter box.This direct seed treatment method iseffective only against certain pests andcertain population levels. Use this soilinsect control technique in strict accor-dance with recommendations on theinsecticide label.

Uniform distribution of insecticidein the planter box is important. Donot get insecticide on the skin or inthe eyes and do not breath insecticidedust.

At Planting Soil Insecticides.Insecticides can be applied to the soilat planting time using row-band or T-band techniques. These methods areless applicable where a bed planter is

used because insecticide incorporationwithin the root zone may defeat majorobjectives of bed planting—retainingsoil moisture in the bed. Where bedplanting is to be used, soil insecticidescan be incorporated in a band whenbeds are thrown up or when bed shap-ing is done.

With lister or conventional planters,mount spray or granular applicationequipment on the planter with the noz-zle or spout just behind the openingplow and in front of the coveringdevices. Adjust nozzles or spouts sothat the treatment band is about 7 to10 inches wide and the seed furrow, aswell as the covering soil, is treated.Usually, insecticide is adequately incor-porated during seed covering.Applying some insecticide productsdirectly in the seed furrow and indirect contact with the seed may affectgermination. For these products, row-banding the insecticide behind the cov-ering attachments is suggested.

For specific soil treatment sugges-tions, limitations, and rates of eachinsecticide labeled for use on foragesorghums, refer to the table for eachpest and the product label.

Postemergence. Insecticides can beused against some of the soil dwellingpests of forage sorghums as a postemer-gence or rescue treatment. These appli-cations are applied in a band directedat the base of the plant.

Soil PestsTrue and false wireworm, white

grub, corn rootworm, cutworm, seedcorn maggot and fire ants are commonsoil pests of forage sorghum in Texas.Non-crop plant residues are importantfood sources for soil pests. Crop rota-tion, cultivation and/or the use of her-bicides to reduce crop residues and

18

Suggested Armyworm and Cutworm Control on VetchInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazingmethyl parathion

(Methyl parathion 4 lb) 1 pt (see remarks)

RemarksMethyl Parathion. For rates below 2 pt/acre, do not apply within 15 days of harvest. For rates above 2 pt/acre, do not

apply within 20 days of harvest.

Suggested On-Farm (Pre-Plant or Planter Box) SeedTreatments

Insecticides - percent active ingredient RemarksLindane

Protox Seed Protectant - Drill Box Treatment Use according to label(lindane 12.5%, Captan 6.25% dust) directions.Triple Seed Protectant - (lindane 16.6%, Use according to labeldiazinon 11%, captan 35% dust) directions.

eliminate weeds are important practicesfor reducing soil pest problems. Properseedbed preparation that provides forrapid seedling emergence and establish-ment, and preplant soil inspection forthe presence of soil pest populationsare important in the management ofthese pests. If damaging pest numbersare present, approved seed treatmentsmay be used or insecticides may beapplied to the soil using row-band appli-cation methods. Preplant seed treat-ment or planter box seed treatmenthas proven effective in controllingwireworm, seed corn maggot and seedcorn beetle and may suppress whitegrubs. Moderate to large populations ofwhite grub and corn rootworm requireat-planting application of insecticides.

Wireworm. True and false wire-worms are the immature stages of clickbeetles and darkling beetles. Wire-worms are generally shiny, slender,cylindrical and hard-bodied. Theyrange in color from yellow to brown.

Wireworms damage forage sorghumby destroying planted seed and, to alesser degree, by feeding on seedlingplant roots. Stand establishment andplant vigor are reduced.

Cultural practices that reduce non-crop plant materials in fields, and rota-tion to tap-rooted crops that are unfa-vorable for wireworm development, areimportant non-chemical control meth-ods.

Fields should be sampled for thepresence of wireworms prior to plant-ing. Eight to ten soil samples 1 footsquare by 4 inches deep should betaken from the rows and examinedthoroughly. If two or more wirewormlarvae per linear foot of row are detect-ed, control measures are warranted.

No postemergence rescue treat-ments for wireworm control are regis-tered. Therefore, pre-plant sampling forthese pests is important.

Seed treatments or planter boxtreatments are effective in controllingwireworms. See Seed TreatmentSections for procedures and suggestedinsecticide products.

White Grub. White grubs are thelarval stages of May and June beetles.Larvae are characteristically “C-shaped”with white bodies and tan to brownheads. Larvae vary in size according toage and species. The last abdominalsegment is transparent, and digestedmaterial can be seen inside the larvae.

Larvae damage plants by feeding onthe roots. Small seedlings often arekilled, resulting in stand loss. Theroots of larger plants can be severelypruned, resulting in stunting, plantlodging and increased susceptibility todrought and stalk rot.

The action level for white grub isbased on the number of grubs persquare foot of soil. Examine onesquare-foot soil sample for each 5 and10 acres before planting. An average ofone white grub per square foot is suffi-cient to cause significant stand loss.Where grub numbers are high (approx-imately two per square foot) row-bandtreatments are not sufficiently effective.

No products are labeled for use onforage sorghum for control of whitegrubs. Several products which arelabeled on sorghum may suppress whitegrubs, but none specifically list whitegrubs.

Corn Rootworm. Corn rootwormsare the larval stages of a complex ofleaf-feeding beetles. The southern corn

rootworm is the most important for-age sorghum pest in the rootwormcomplex. Rootworms are small, creamywhite larvae with brown heads. Theyburrow into the roots and crowns ofsorghum plants. Poor stands, reducedplant vigor and the occurrence of deadheart in young plants are characteristicof rootworm damage. Plant lodgingmay occur later in the season.

Seed treatments with lindane areeffective in controlling light infesta-tions of corn rootworm. See SeedTreatment Section for procedures.More severe infestations require an at-planting soil insecticide. The decisionto apply an at-planting insecticide isbased primarily on damage in previousyears.

Cutworm. A complex of cutwormscan damage forage sorghum. Cut-worms are the immature stages ofmoths that are active at night. Grassyand weedy fields attract the egg layingcutworm moths. Newly hatched cut-worms feed on sorghum seedlings andoften clip plants just above the ground.Some subterranean cutworms feed onthe seedling root system.

Larval feeding commonly occurs atnight. Damaged fields normally haveareas in which cut plants look likethey have been closely grazed.Cutworms usually damage foragesorghum only during the seedlingstage.

Cultivation, crop rotations whichinclude fallow fields, and the use ofherbicides to kill weeds are importantmethods for controlling cutworms inforage sorghum.

19

Suggested Corn Rootworm Control on Forage SorghumInsecticides (listed alphabetically) - Concentrate per acre Amount per acre on a toxicant per gallon or pound 40 inch row spacing (lbs/acre)chlorpyrifos (see remarks)

Lorsban® 15G 8 oz/1000 linear ft 6.5fonofos (see remarks)

Dyfonate II® 20G 6 oz/1000 linear ft 5

RemarksLorsban. Apply in a 6 - 8 inch band or T-band and incorporate into the top 1 inch of soil at planting.Dyfonate. Apply in a 7 inch wide band using a row-bander directly behind the seed furrow opener and in front of the

press wheels, or in a 7 inch wide band directly behind the press wheels using drag chains or spring tines to insure incorporation. Do not make in-furrow applications.

Aerial or ground application ofinsecticides effectively controls cut-worms in established forage sorghumstands.

Well defined action levels do notexist for cutworms on forage sorghums.Control decisions are a matter of indi-vidual judgment related to stand loss.Insecticides should be applied as adirected spray to the plants and adja-cent soil. Increasing total spray volumenormally improves control.

Lesser Cornstalk Borer. The less-er cornstalk borer is an occasional pestof forage sorghum, legume and smallgrain crops grown on sandy soils inTexas. The insects normally over-win-

ter as larvae, pupating in the late win-ter. In early spring, moths emerge andlay greenish-white eggs on seedlingsorghum. The eggs hatch in about 1week and the small bluish-green wormsbegin feeding on leaves or roots. With-in a few days, the larvae bore into thestalks near the soil level. Each larvaproduces a soil-covered, silken tube atthe site at which it bored into the stalk.Affected plants appear moisturestressed. The leaves roll inward andplants become stunted or die. Controlmay be warranted where stands arethreatened, or where damage hasoccurred from this pest in previousyears.

Fire Ants. Fire ants can become aproblem on minimum till or no-till for-age sorghum in the eastern half ofTexas. Damage to seed and seedlingsby fire ants is generally most severeduring dry years. Fire ant suppressioncan reduce damage. Baits such asAmdro® can be used on non-crop land(land which will be farmed, in themonths prior to planting) to suppressants. Other options to prevent fire antdamage are seed treatments (see pre-plant seed treatment sections) and T-band granular insecticide applicationsat planting.

20

Suggested Cutworm Control on Forage SorghumInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazingcarbaryl

(Sevin® 80S) 2 1/2 lb 0 0(Sevin® XLR Plus) 2 qt 0 0(Sevin® 50W) 4 lb 0 0(Sevin® 4F) 2 qt 0 0

Suggested Lesser Cornstalk Borer Control on Forage SorghumInsecticides (listed alphabetically) - Concentrate Amount per acre on a toxicant per gallon or pound 40 inch row spacing (lb/ac)chlorpyrifos (see remarks)

(Lorsban® 4 E) 1 - 2 pt/ac 1 - 2 pt(Lorsban® 15 G) 4 - 12 oz/1000 linear ft 3.3 - 9.8

fonofos (see remarks)(Dyfonate® II 20-G) 6 oz/1000 linear ft 5

RemarksChlorpyrifos. Lorsban® 4 E, apply in 8-12 inch band directed at bases of plants, postemergence. Lorsban 15G, apply in

6-8 inch T-band and incorporate into the top 1 inch of soil at planting.Fonofos. Apply in a 7 inch band using a row-bander behind furrow opener but in front of press wheel or behind

press wheel using drag chains or spring tines for incorporation. It is acceptable to allow some granules to fall into the seed furrow, but do not apply as an in-furrow treatment.

Suggested Fire Ant Suppression on Forage SorghumInsecticides (listed alphabetically) - Concentrate per acre Applicationtoxicant per gallon or poundchlorpyrifos (see remarks)

(Lorsban® 15G) 8 oz/1000 ft2 T-band at-plant

RemarksLorsban. Apply in a T-band at planting.

Above-ground PestsGreenbug. Greenbugs are aphids

that suck plant juices and inject toxininto forage sorghum plants. Greenbugsare pale green, approximately 1/16inch long and have a dark green stripeon the back. Females begin giving birthto live young at 7-18 days of age, repro-duce for about 20-30 days, and produce50-60 young each (all female).

Greenbugs can cause stand loss,stunting and plant death in foragesorghums. They are not as damaging inforage sorghum as in grain sorghum,however. Plant death in the seedlingstage may occur, and growers shouldinspect plants frequently from emer-gence until the plants are 6 to 10 inch-es tall and continue scouting throughharvest.

The action level from emergence toabout 6 to 10 inches is any visible dam-age (plants beginning to yellow) withgreenbug colonies present and probableexcessive stand loss. Maturing sorghummay infrequently have excessive leafloss requiring treatment.

Armyworm. Armyworms are theimmature stages of dull-colored, noctur-nal moths. Armyworm larvae range incolor from pale green to brown orblack and are often striped with whiteto yellowish lines from head to tail.They are characterized by having aninverted “Y” marking on the head.

Fall armyworm is the most commonof this group in forage sorghums.Armyworm populations often increasein late summer and early fall, but insec-ticides are not recommended because

economically important damage is veryrare.

Grasshopper. A number ofgrasshopper species are common pestsof forage sorghum. These pests gener-ally migrate into the field from adjoin-ing fence rows, ditch banks, field mar-gins or native pastures. All grasshop-pers, nymphs and adults, are foliagefeeders and can cause extensive forageloss if the pest population is large. Anaverage of six to seven grasshoppersper square yard can consume as muchforage as one cow per acre.

Grasshopper control in foragesorghum production should be initiat-ed before the pests move out of hatch-ing areas such as fence rows, ditchbanks, weedy fields, etc. Grasshoppersare most damaging during dry years.

21

Suggested Greenbug Control on Forage SorghumInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazing

Attention: Review all remarks below thoroughly.dimethoate (see remarks)

(Dimethoate® 4 lb) 1/2 - 1 pt 28 28(Dimethoate® 5 lb) 6.4 - 12.8 oz 28 28(Dimethoate® 2.67 lb.) 3/4 - 1 1/2 pt 28 28

disulfoton (see remarks)(Di-Syston® 15% G)

in-furrow 5 - 6.7 lb 45 45band 6.7 lb 45 45whorl 6.7 lb 45 45

(Di-Syston® 8 lb)furrow 3/4 - 1 pt 45 45band 1 pt 45 45side dress 1 pt 45 45foliar spray 1/4 - 1/2 pt 45 45

phorate (see remarks)(Thimet® 15% G) 6.5 - 8.7 lb 30 30(Thimet® 20% G) 4.9 - 6.5 lb 30 30

RemarksDifficulty in controlling greenbugs has been encountered in several counties of the Texas High Plains. Resistance to mostregistered materials exists in some localized areas, and extensive use of insecticides may expand the resistance problem.In areas where resistance exists, the initial insecticide application should be made at the higher labeled dosage rate. In areas where insecticide resistance has not been observed, effective use of reduced rates is dependent on proper appli-cation timing. Reduced rates are designed to suppress greenbug densities below injurious levels while causing less dam-age to beneficial species. Using insecticides to eliminate greenbugs completely is not desirable. To conserve beneficialspecies, a few aphids must be maintained as a food source.Dimethoate. Do not apply more than three times per season. Do not apply after heading. For ground application use

25 - 40 gallons of water per acre. For aerial application use 2 or more gallons of water per acre.Disulfoton. Do not apply directly to the seed. Do not apply foliar spray or granules more than three times per crop

season. See label for waiting period for different types of applications. Consult label for rates for various row spacings.

Phorate. Labeled for use at planting in a 7 inch band over the row, or placed 1 inch below and 2 inches to the side of the seed. Do not place in contact with the seed. May be applied postemergence as a side-dress. Application rates depend on row widths (consult label).

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Suggested Grasshopper Control on Forage SorghumInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazingcarbaryl (see remarks)

(Sevin® 80S) 2/3 - 1 7/8 lb 0 0(Sevin® XLR Plus) 1/2 - 1 1/2 qt 0 0(Sevin® 50W) 1 - 3 lb 0 0(Sevin® 4F) 1/2 - 1 1/2 qt 0 0

dimethoate (see remarks)(Dimethoate 4 lb) 1 pt 28 28

malathion (see remarks)(Cythion® 5 lb) 1 1/2 - 2 pt 0 0(Cythion® 8 lb) 1 1/4 pt 0 0(Malathion ULV 9.79 lb) 8 - 12 oz 0 0

methyl parathion (see remarks)(Methyl Parathion 4 lb) 1 1/2 pt 15 15

RemarksCarbaryl. Use lower rates against nymphs on small plants and higher rates when grasshoppers are mature or crop has more

foliage.Dimethoate. Make no more than 3 applications. Do not apply after heading. For ground application, use 25 - 40 gallons water

per acre. For aerial, use at least 1 gallon of water per acre.Malathion. Cythion 5 lb. may be mixed 1 1/2 pt per gallon in diesel fuel. When mixed with diesel, apply only the 1 1/2 pt/ac

rate.Methyl parathion. Labeled use: Grass (Forage).

Suggested Grasshopper Control on Pasture, Range and Non-CroplandInsecticide (listed alphabetically) - Concentrate per acre Labeled application sitestoxicant per gallon or pound acephate (see remarks)

(Orthene® 75 S) 1/8 - 1/6 lb pasture, range and wasteland(Orthene® 75 S) 1/3 lb non cropland(Orthene® 75 WSP) 1/8 - 1/6 lb pasture, range and wasteland(Orthene® 75 WSP) 1/3 lbs non cropland

carbaryl (see remarks)(Sevin® 4-Oil ULV) 1/2 - 1 1/2 lb pasture, range, non-cropland(Sevin® 50 W) 1 - 3 lb rangeland, wastelands, non-cropland(Sevin® 80 S) 2/3 - 1 7/8 lb pasture, rangeland, non-cropland(Sevin® XLR Plus) 1/2 - 1 1/2 lb pasture, rangeland, non-cropland

esfenvalerate(Asana® XL) 2.9 - 5.8 oz non-cropland

malathion (see remarks)(Cythion® 5 lb) 1 1/2 - 2 pt pasture, range(Cythion® 5 lb) 1 1/2 - 3 pt non-cropland(Cythion® 8 lb) 1 1/4 pt pasture, range(Cythion® 8 lb) 1 - 2 pt non-cropland (Malathion ULV 9.79 lb) 8 - 12 oz pasture, range

methyl parathion (see remarks)(Penncap-M®) 2 - 3 pt pasture and rangeland

naled (see remarks)(Dibrom® 8 lb) 1/2 - 3/4 pt rangeland

RemarksAcephate. For pasture range and wasteland: Do not apply when lactating dairy animals are present and do not

feed or graze lactating dairy animals on treated foliage. Within 21 days of treatment, remove meat animals at least 1 day before slaughter. One application per season. For non-crop areas (field borders, fence rows, roadsides, ditch banks and borrow pits): Do not graze or feed vegetation from treated area.

Carbaryl. Zero days preharvest interval for aerial application. Fourteen days preharvest interval for ground applications on pastures and non-cropland. Non-cropland is defined as wasteland, right-of-ways, hedge rows, ditch banks and roadsides.

Malathion. Dilute in water or diesel fuel oil. Zero days preharvest or grazing interval. Methyl parathion. Do not apply within 15 days of grazing.Naled. Grazing animals may be present during treatment. Do not graze lactating dairy animals on treated area.

The action level is seven to tengrasshoppers per square yard accompa-nied by excessive leaf loss.

Chinch Bug. Chinch bugs occasion-ally damage forage sorghum in the east-ern half of Texas. The black-bodiedadult chinch bug has reddish-yellowlegs and fully developed wings. Thewhitish wings are marked with a trian-gular black spot at the middle of theouter margin. Immature chinch bugsresemble adults in shape but are red-dish in color with a white band acrossthe back.

Adult and immature chinch bugssuck plant juices and cause leaf redden-ing. Wilting and severe stunting ofplants attacked by chinch bugs are seenfrom the time of seedling emergenceuntil plants are 18 inches high.Chinch bugs are favored by hot, dryweather and large numbers of imma-tures often migrate from wild bunchgrasses or small grains to congregateand feed behind the lower leaf sheathsof sorghum plants.

The action level is reached whentwo or more adult chinch bugs arefound on 20 percent of the seedlings

less than 6 inches high. Make at leastfive random checks per field. On tallerplants, initiate control when immatureand adult bugs infest 75 percent of theplants. With ground application equip-ment, direct nozzles at the infested por-tion of the plants. To be most effective,apply insecticide in 20 to 30 gallons ofwater per acre.

PESTS OF PERMANENTAND IMPROVED

PASTURESGrasshoppers, fall armyworms and

true armyworms are the most commoninsect pests of pastures. In some areasof the state, desert termites havebecome a problem.

Grasshopper. Grasshoppers are themost important insect pest of nativepasture grasses. Ranchers should close-ly watch the development of grasshop-per populations in the hatching areasduring spring and early summer.Insecticides can be most effectivelyused in these sites before the grasshop-pers have dispersed over large areas.Hatching begins when daytime temper-

atures are 70 degrees F. or higher forseveral days and soil is moist.

Eight or more grasshoppers persquare yard is considered the actionlevel on rangeland and pastures.

See the table titled SuggestedGrasshopper Control on Pasture,Range and Non-cropland, page 22, forinsecticide suggestions in pastures andrangeland.

Armyworm. The fall armywormand true armyworm can be the mostdamaging insect pests of improvedpastures, temporary winter pastures,permanent pastures and small grains.These insects commonly occur inspring, late summer or fall and areoften associated with wet weather.These pests are easily controlled, butextensive damage may occur beforegrowers notice an infestation.Improved, temporary and permanentpastures, as well as small grains shouldbe watched closely; especially duringrainy periods in late summer and fall.

The action level is three or moresmall worms per square foot.

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Suggested Chinch Bug Control on Forage SorghumInsecticides (listed alphabetically) - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazingcarbaryl

(Sevin® 80S) 1 1/4 - 2 1/2 lb 0 0(Sevin® XLR Plus) 1 - 2 qt 0 0(Sevin® 50W) 2 - 4 lb 0 0(Sevin® 4F) 1 - 2 qt 0 0

Suggested Fall Armyworm Control in PasturesInsecticides (listed alphabetically - Concentrate per acre Days from last application to:toxicant per gallon or pound Harvest Grazingcarbaryl (see remarks)

(Sevin® 80S) 1 1/4 - 2 1/2 lb 0 - 14 0 - 14(Sevin® XLR Plus) 1 - 1 1/2 qt 0 - 14 0 - 14(Sevin® 50W) 2 - 3 lb 0 - 14 0 - 14(Sevin® 4F) 1 - 1 1/2 qt 0 - 14 0 - 14

malathion(Cythion 5 lb) 2 pt 0 0

methyl parathion(Methyl parathion 4 lb) 1 1/2 pt 15 15

RemarksCarbaryl. Zero days waiting required for harvest and grazing with aerial application, 14 days for ground application.

Desert Termite. Desert termitesinfest South and West Texas coastalbermuda pasture and bunch grassareas. Populations increase during yearswhen the summer months are dry.Highest above-ground populationsoccur from March through September.Few or no termites are present aboveground from December throughFebruary. Infestations occur in irregu-lar patterns and are mostly associatedwith areas which have high clay con-tent soils. Clay chimneys covering grassstems are built during the night orcooler parts of the day by the workerand soldier termites. Infested areashave a dark and unusual appearance asthe population increases. Rainfall willdecrease termite numbers but termitesbecome very active following rains. Ifdry weather continues and stand lossof the grass is occurring, a chemicalspot treatment may be warranted. Aspring-toothed harrow or light disc har-row may be used to break up chimneysand expose developing termites topredators, heat and drying conditions.

There are no specific insecticideslabeled for desert termite control inpastures, but several insecticideslabeled for other insects in pasturesmay help to reduce their populations.Malathion (5 pounds EC) has beenused at the rate of 1 quart applied in35 to 40 gallons of water. Two treat-ments, 1 week apart, should be appliedto the infested areas. A length of chainshould be dragged ahead of the sprayboom to break up the chimneys andexpose termites to the insecticide.This treatment may not be economical-ly feasible, however.

Red Imported Fire Ant. In Eastand Central Texas, red imported fireants can be a serious problem to forageproduction. The ants build mounds aslarge as 18 inches or more in diameter.Farm and pasture lands may becomeheavily infested with hundreds ofmounds per acre. In the hot summersun these mounds become hard, andfarm machinery is often broken whena mound is hit. In order to reducemachinery damage, farmers may be

forced to alter harvesting practices.Dragging a heavy bar to break upmounds between cuttings may berequired. Disc-type or Kountz cutterscan be used to cut forages in fire antinfested areas. They can withstand theimpact with large mounds withoutdamage.

See the publication, B-1536, FireAnts and Their Control, available atyour local county Extension office.This publication gives a completedescription of the biology, development,identification and control of this pest.

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Suggested Fire Ant Control in PasturesInsecticides (listed alphabetically) - Mix rate/ Use rate Methodtoxicant per gallon or pound 100 gal. water

acephate(Orthene® Turf, Tree &

Ornamental Spray 75%) 20 oz 1 gal/mound Indiv. mound treatmentcarbaryl

(Sevin® XLR) 1 1/2 qt 2 gal/mound Indiv. mound treatment(Sevin® 80S) 2 lb 2 gal/mound Indiv. mound treatment(Sevin® 50W) 3 lb 2 gal/mound Indiv. mound treatment

fenoxycarb(Logic® 1%) 1 - 1 1/2 lb/ac Broadcast, labeled only on

hydramethylnon horse pastures(Amdro® 0.88%) 1 1/2 lb/ac or Broadcast or indiv.

5 Tbsp/mound mound treatment

ACKNOWLEDGMENTThe author gratefully acknowledges the assistance and review of this document bythe following Texas Extension Entomologists: Drs. Bastian Drees, James Robinson,Pat Morrison, Roy Parker and J.W. Stewart. The assistance of Dr. Charles Ward ofNew Mexico State University and Richard Berberet of Oklahoma State Universityis also gratefully acknowledged.

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The information given herein is for educational purposes only. Reference to commercial products or trade namesis made with the understanding that no discrimination is intended and no endorsement by the CooperativeExtension Service is implied.

Educational programs of the Texas Agricultural Extension Service are open to all people without regard to race, color, sex, disability, religion, age,or national origin.Issued in furtherance of Cooperative Extension Work in Agriculture and Home Economics, Acts of Congress of May 8, 1914, as amended, andJune 30, 1914, in cooperation with the United States Department of Agriculture. Zerle L. Carpenter, Director, Texas Agricultural Extension Service,The Texas A&M University System.5M–3-96, Revision ENT, AGR 3-6-7

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