kentucky pest news june 14, 2011

8/6/2019 Kentucky Pest News June 14, 2011

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Online at: www.uky.edu/KPN

Number 1272 June 14, 2011

CORN-Fungicide Application Timing on Corn

WHEAT-To Store or Not to Store This Year’s Soft Red

Wheat Crop-UK-IPM 16-Point Checklist for Controlling

Insects in Stored Wheat

CORN

Fungicide Application Timing on Corn By Paul Vincelli

Certain articles in the farm press seem to besuggesting that there is value in applyingfungicides twice: Once to early-stage corn (V4 toV8), and again at VT/R1. Some Kentucky farmersconsidering using this practice may be asking theirlocal County Extension Agents for advice on thisissue. For inquiries relating to crop production, it

is best for Agents to rely on science-basedinformation.

In research at land-grant universities, if there is abenefit of fungicide application, it typically ismore pronounced when applied at VT/R1 thanwhen applied early. Applying fungicide earlygenerally hasn’t showed the same level of diseasecontrol as when applied at early reproductivephases. (For more information, seehttp://www.ca.uky.edu/agcollege/plantpathology/extension/KPN%20Site%20Files/pdf/kpn1257.pdf .)

As far as applying fungicide twice, I haven’t seenany research that supports routine use of fungicides twice in field corn under ourconditions. Yes, it may make sense in certainfields in the Deep South with early outbreaks of southern rust. It generally doesn’t make sensehere in Kentucky.

SHADE TREES & ORNAMENTALS-Spruce Diseases and Disorders Are Appearing in

the Landscape-Cottony Scales

LANDSCAPE-More Creatures on the Move

DIAGNOSTIC LAB HIGHLIGHTS

WHEAT

To Store or Not to Store This Year’s Soft RedWheat Crop By Cory Walters, Sam McNeill and Doug Johnson

Each year producers decide whether to store or selltheir Soft Red Wheat (SRW) crop. Producerstypically choose the latter and sell their crop off of the combine. This year the Chicago wheat (SRW)futures contract is offering a large storageincentive. The relationship between July 2011

Chicago wheat futures and March 2012 Chicagowheat futures is a plus $1.04/bu (March = $8.63,July = $7.59). Meaning putting grain in storageAND selling a March 2012 futures contract willgain you an additional $1.04/bu. However, thereare other costs and risk associated with doing this.Storage decisions should be made based upon thecarry offered in the futures market, storageconstraints (coming from other crops), harvestconstraints, storage costs, opportunity costs of money, and other costs.

The largest direct cost is the opportunity cost of obtaining cash (money). Foregoing money andholding grain in storage will cost you the interestgained from paying back outstanding loans orputting money in an interest bearing account. Asan example, say you have an interest bearingaccount which pays 5% annually. Putting grain instorage in late June and delivering in February ona March futures contract adds up to 8 months. The

Lexington, KY 40546

http://www.uky.edu/KPN



http://www.ca.uky.edu/agcollege/plantpathology/extension/KPN%20Site%20Files/pdf/kpn1257.pdf








interest foregone in storing grain adds up to $0.25($7.59/bu*.05*(8 months /12 months)).

Basis is the other source of price risk.Improvements in basis between now and deliveryreturn more money to the producer. A weakening

of basis costs the producer money. Producersshould monitor basis regularly and take advantageof strong basis offers by signing a basis contract(which would be for February delivery if sellingon the March futures contract).

Storing wheat in Kentucky during the summerpresents several physical challenges that canimpact profit margins. Freshly harvested wheatshould be dried as soon as possible to preventsprouting and suppress insect activity. Keepingthe storage environment dry (relative humidity of

air space between wheat kernels below 65%) is themost cost effective way of controlling moldgrowth and the mycotoxins they can produce.With average day-night temperatures in July andAugust approaching 80 degrees or higher, therecommended wheat moisture that meets thiscondition is 12.5% or lower (Table 1). Figure thecost to dry wheat below the base/market level of 13.5% moisture at about 0.5, 2.3 and 3.3 cents perbushel for each point of moisture removed withunheated air drying, bin drying, and hightemperature drying, respectively. Drying costs

will vary with the price of energy, labor andequipment, but consider this a cost effective wayto control insect and mold activity. Moreover,drying costs are generally much less than othermethods that may need to be taken if theseproblems occur during storage, as shown in Table2. More information on drying and storing wheatis provided in Chapter 10 of ID-125(http://www.bae.uky.edu/Publications/IDs/ID-125.pdf ).

Though storing wheat can result in some economic

advantages to the producer, it requires good insectpest management. The presence of insects orinsect damage can defeat the entire advantage of holding the wheat past harvest time. We havedeveloped a “16-Point Checklist for ControllingInsects in Stored Wheat”, which is attached to thisarticle. The producer should understand that insectpest management in stored wheat is by-in-large apreventative effort. Additionally, many of the most

important techniques occur before and duringharvest, and are non-chemical. Though pesticidesmay be added to wheat that is being binned, due tothe heat of the grain and temperatures in the bin,they will not last long. Of even greater concern isthe lack of a control option as the grain is being

removed for delivery. This usually occurs late inthe winter when it is too cold to fumigate. So,preplan and proactively: reduce the initial insectpopulation, slow insect growth when possible, andmonitor the grain to detect developing problemsearly.

Table 1. Equilibrium moisture content (EMC) of soft red winter wheat at different temperature andrelative humidity levels. (Source: ASABEStandard D245.4.)

Table 2. Comparison of wheat marketingopportunities.

$/bu $/bu Carry

Jul-

11 $ 7.59 Mar-12 $ 8.63

$

1.04Prep $ 0.05

Drying 4 pts $ 0.10

Insecticides $ 0.05

Fumigation $ 0.10

Insurance $ 0.02

Interest (5.0%) $ 0.25

Sub-total $ 0.57

Returnafter Co

Total $ 7.59 $ 8.06$0.47

In summary, wheat storage can be profitable whenthe futures market is offering a large carry and theproducer follows wheat storage guidelines. Themarket can incentivize storage through offering aprice in the future that is greater than the cost of storing grain to that time. Storing grain requiresfollowing guidelines; see 16 point checklist, to

Relative Humidity (%)

Temperature 30 40 50 60 65 70 80

°F Equilibrium Grain Moisture Content (%)

50 9.6 10.7 11.8 12.9 13.4 14.1 15.5

60 9.3 10.4 11.4 12.5 13.1 13.7 15.1

70 9.0 10.1 11.1 12.2 12.8 13.4 14.8

80 8.7 9.8 10.8 11.9 12.5 13.1 14.5

90 8.5 9.6 10.6 11.6 12.2 12.8 14.2

http://www.bae.uky.edu/Publications/IDs/ID-125.pdf








minimize the chance of insect and moisture issues.Benefits from storage continuously change andshould be watched closely when deciding to takeadvantage of returns to storage through a storagehedge.

UK-IPM 16-Point Checklist for Controlling

Insects in Stored WheatBy Doug Johnson and Sam McNeill

Prior to Harvest

1. ☐ Clean all equipment thoroughly to

remove old grain, trash and debris thatmight contaminate the new crop

(combines, carts, trucks, receivingpits/hoppers, conveyers: use pressurizedair/water) (storage bins: use a broom,shovel, and vacuum)

2. ☐ Remove spilled grain around

pits/hoppers and storage bins to preventcontamination

3. ☐ Treat bin walls and flooring with an

approved residual insecticide(common names of currently approvedcompounds are Tempo and Reldan)Note: Most stored grain insects areresistant to malathion so it is NOTrecommended!

4. ☐ Treat the outside base of all bins with

an approved residual insecticide (Tempo)

5. ☐ Mow, spray or remove

weeds/grass/vegetation around storagebins

6. ☐ Seal floor and fans, unloading augers

or other openings with heavy plastic toprepare bin for fumigation

7. ☐ Fumigate area under perforated floors

using product labels for instruction(currently approved products areChloropicrin and Phosphine)

CAUTION: Fumigants are restricted-use

pesticides and require formal training for safe

control

See UK publications ENT-19 and ENT-47 for

more information on fumigation

8. ☐ Post written notice that bin has been

fumigated

9. ☐ Wait the required time before entering

the bin--depends on product used and airtemperature

Note: Safe wait time ranges from 2 - 3days at 70 degrees F to 4 - 5 days at 56degrees F

During Harvest

10. ☐ Apply approved insecticide on

unheated wheat as it's transferred intostorage(It is best to use a DIFFERENT productthan in Steps 3 & 4, thus Reldan issuggested)

11. ☐ Apply a "cap-out" treatment to the

wheat surface after the bin is full12. ☐ Dry wheat to 12.5 % moisture if it will

be held through JulyNote1: This keeps the air space between wheatkernels dry (~ 65% humdity) which retards insectactivity and mold growthNote: This moisture or "shrink" cost amounts to 4cents/bu when wheat is $7.00/bu (see Fig. 1)

After Harvest

13. ☐ Insert pit traps into stored grain to

track insect activity and check them once

a week during the summerCAUTION: See UK publication AEN-39 to review safe methods of inspecting stored grain

14. ☐ Check for leaks in the bin around

ladders, roof vents, temperature cables andother openings

15. ☐ Check wheat temperature and moisture

weekly after binning for stability

16. ☐ Fumigate wheat prior to sale if insect

populations reach economic thresh holds

CAUTION: Fumigants are restricted-use

pesticides and require formal training for safe control

See UK publications ENT-19 and ENT-47 for

more information on fumigation

See UK publication AEN-45 for more

information on aeration and inspection of stored

grain



SHADE TREES & ORNAMENTALS

Spruce Diseases and Disorders Are Appearing

in the LandscapeBy John Hartman and Julie Beale

During recent weeks, a significant number of samples of diseased and declining spruce treeshave been observed in the Plant DiseaseDiagnostic Laboratory. Symptoms have includedyellowing and browning of newly expandingneedles and shoots; yellowing, browning andshedding of last year=s needles; twig, branch andlimb dieback; and death of trees (Figure 1). Theremay be many different causes for the observedspruce problems, however, most of the problemsare likely related to the summer and fall 2010drought. A similar influx of spruce samples

occurred in 2007 after similar weather patternswere experienced. Below is a review of possiblecauses of landscape spruce symptoms.

Normal needle drop. Spruce and fir trees typicallyretain their needles for several years. In mostyears, needle drop is hardly noticeable withoutcareful examination of the inner branches where afew scattered needles may turn yellow and drop inlate spring or early summer of their third year. If spruce trees are not provided sufficient waterduring the dry part of the summer, normal needle

drop could be earlier and more sudden than usual.Normal needle drop is a seasonal occurrence andcan vary from tree to tree and from year to year.Sometimes these old, yellow needles can harborsaprophytic fungi, but these fungi are unlike theparasitic fungi that appear on younger needles.

Drought and inadequate rooting space. Droughtalone can cause spruce needle yellowing and lossfollowed by tree decline. Blue spruces areespecially affected. Sometimes spruce trees areplanted in the wrong place and as they get larger,

have inadequate space for optimal rootdevelopment. Inadequate rooting space in anurban environment essentially provides droughtconditions even when there is adequate rainfall.Drought stress is associated with loss of foliageand death of lower branches (Figure 2); cankerdisease may also kill lower branches in droughtstressed trees, as described below.

Cytospora canker. Cytospora canker, caused bythe fungus Leucostoma kunzei (imperfect stage,Cytospora kunzei), is commonly found on sprucetrees growing in Kentucky landscapes and is mostnoticeable on trees over 20 years old. Cankersmay begin at the base of small twigs and develop

into elliptic-shaped cankers. It is often noticedfirst on the lower branches with canker formationaccompanied by white resin (Figure 3) appearingon the infected branches or trunk. As the cankerenlarges, the branch is girdled and killed. Needleson affected branches can appear purple at first andthen turn brown as they die (Figure 4). Treesgrowing under stressful urban conditions,especially drought, are most vulnerable toCytospora canker. Wounding, mechanical injury,construction damage, and insect injury can alsocontribute to Cytospora canker.

Two needle cast diseases (at least). The fungi Rhizosphaera kalkhoffii and Stigmina lautti are thecauses of needle cast diseases observed on spruceduring recent years in Kentucky.

• Rhizosphaera needle cast symptomsconsist of yellowing first-year or olderneedles in summer. These needles laterturn brown and drop, perhaps 15 monthsafter initial infection. Thus, needlesdropping now could be the result of infections that occurred early last summer

before the drought. Needle cast diseasewas common in 2010 following the mostlywet season in 2009. Diseased needlescontain fungal signs in the form of dark spherical pycnidia which typically emergefrom the needle stomata and are thus linedup in rows (Figure 5). These rows of pycnidia protruding through the stomatacan be seen with the aid of a hand lens.Damage typically starts on the lowerbranches and moves up the tree. After 3to 4 years of severe infection the lowest

branches may begin to die. Colorado bluespruce, Picea pungens, is highlysusceptible to this disease. White spruce,P. glauca, is intermediate in susceptibilityand Norway spruce, P. abies, is relativelyresistant. Trees that are stressed fromdrought, poor planting practices, or otherfactors are more likely to suffer fromRhizosphaera needle cast.



• Stigmina needle cast has also beenobserved on shedding spruce needles inrecent years. Stigmina produces dark spore-bearing structures in the needlestomata (Figure 6), but under a hand lensor a dissecting microscope, they appear

“bushy” compared to the compactpycnidia of Rhizosphaera. Without somemagnification, the two diseases appear tobe very similar.

• Another spruce needle drop and twigblight disease is being investigated andmay be occurring in Kentucky and otherstates. Symptoms of the disease include2nd year needles turning yellow, thenpurple, and progressively dropping fromthe branches. Whole branches maydevelop a purplish cast. Dieback often

appears on branches throughout the treeand not mainly in the lower branches likeother needle casts. The cause is still notknown, but the disease may be associatedwith a fungus called Setomelanomma

holmii. It is likely that environmentalstress (drought again) can worsen thiscondition.

Spruce spider mite. Pale yellow to dusty tandiscoloration of needles can result from aninfestation of spruce spider mites. When viewed

with a hand lens pale stippling is visible onneedles. A light webbing is associated with heavymite infestations. If mites are suspected, hold awhite sheet of paper under a branch and sharplytap the branch. Look closely for small movingmites on the white paper. Seasonal needle dropcan be confused with needle loss due to spidermite damage.

Environmental and/or chemical injury toexpanding shoots. Sudden browning anddistortion of young needles and expanding shoots

of Norway and Colorado blue spruces, as well aswhite pine, may be related to herbicide exposurefrom certain lawn weed control applications. Thistype of symptom has been observed in Kentuckyand in numerous states in the Eastern andMidwestern US over the past 2-3 weeks. In mostcases, symptom appearance coincided with therapid onset of extremely high temperaturesbeginning in late May and was preceded by wet

conditions throughout the spring. Whethersymptoms are related to unusual weatherconditions, new weed control products or even aninteraction between the two has yet to bedetermined.

Improving the health of landscape spruce trees.Spruce health is enhanced by providing goodgrowing conditions.

♦ Provide one inch of water per week duringtimes of drought. Be sure the water isapplied over the root zone and avoidgetting the foliage wet.

♦ Mulch underneath the trees to retainmoisture. Grass competes very well andcan actually contribute to water stress intrees.

♦ Prune out diseased and dying branches

(only under dry conditions) and removethem from the area. Pruning tools shouldbe sterilized with 70% alcohol betweencuts.

♦ If needle cast disease has been diagnosed,a spring treatment with a chlorothalonil-based fungicide may provide protection.Timing of the treatment should coincidewith needle emergence and be repeated asnecessary until full needle emergence hasoccurred.

♦ Avoid unnecessary trunk or branch

injuries.

Figure 1. Spruce with lower branches

dead due to drought and Cytospora

canker disease.



Figure 3. Resin exudation forms a white

crust on the surface of Cytospora-

infected spruce stems.

Figure 4. Recently-killed branch on a Colorado

blue spruce.

Figure 2. Spruce with heavy loss of foliagein the lower branches due to a combination

of disease and inadequate soil moisture.

Figure 5. Close-up of Rhizosphaera needle cast showing

fungal fruiting structures in a line.



Cottony ScalesBy Lee Townsend

White fluffy eggsacs of the cottonymaple scale andcottony camelliascale really stand

out on foliage.Cottony maple

scales commonlyinfest silver maplebut can feed onother maples,

boxelder, basswood, birch, elm, and linden. Theyspend the winter in an immature stage on twigs orbranches and complete development in June whenthe egg sacs appear. Eggs hatch during June andJuly and crawlers move to the lower surface of leaves where they settle feed on sap for the rest of

the summer. Just before leaf drop, the smallinsects will move back to twigs and branches tospend the winter. There is one generation eachyear.

The cottony camellia scale can infest camellia,holly (source of most of our samples) yew,euonymus, and maple. The scales overwinter on

twigs or evergreen leaves. In the spring, the adultfemales lay cottony egg masses on the underside of leaves. Crawlers (young scales) feed on theunderside of leaves. Cottony camellia scales producelarge amounts of honeydew, a sweet, sticky materialwhich may attract ants or become covered with a

heavy growth of dark sooty mold.

Scales tend to thrive on stressed plants. Followinga recommended fertility program and wateringregime will promote plant health. However, over-fertilization favors scale buildup. If practical,improve plant sites to reduce stress and promotegrowth. Severely prune back heavily infestedbranches and protect new growth with insecticideapplications.

LANDSCAPE

More Creatures on the MoveBy Lee Townsend and Mike Potter

First, it wasearthworms,now it ismillipedes.

Hundreds of themsuddenlyappearingaround ahome andlandscape.What isgoing on?

Reasons for the activity are not clear but two mainthoughts are 1) seasonal dispersal fromoverwintering sites in fallen logs and other sheltersto more open grassy sites, 2) and / or searching formates.

Millipedes play an important role in breakingdown decaying organic matter as they feed. As aresult, they accumulate in areas where there issome moisture coupled with mulch, fallen leaves,or a significant thatch layer. Hordes of thesesegmented worms can be disconcerting when they

Figure 6. Close-up of Stigmina needle cast disease

showing fungal spore production from the infected

needle. Note that fungal fruiting is not as uniform and

dark as Rhizosphaera needle cast. (P. Bachi photo)

Figure 7. Dark cover of female

cottony maple scale with

attached egg sac. Figure 8. Flatbacked millipede - note 2

pairs of legs per body segment (B.

Newton photo).



are outside but anxiety levels really rise when theywander indoors via gaps under doors are otheropenings into structures. Millipedes usually diesoon after entering the relatively dry atmospherein buildings so there is not a real danger of thembecoming anything more than accidental invaders.

It is better to sweep up and discard these errantarthropods than to spray insecticides widelyindoors. Try to identify entry sites and close denyfurther access.

General management tips –

• Minimize moisture and remove debris -The most effective, long-term measure forreducing entry of millipedes (and manyother pests) is to minimize moisture andhiding places, especially near the

foundation. Leaves, grass clippings, heavyaccumulations of mulch, boards, stones,boxes, and similar items laying on theground beside the foundation should beremoved, since these often attract andharbor pests. Items that cannot beremoved should be elevated off theground.

• Don't allow water to accumulate near thefoundation or in the crawl space. Watershould be diverted away from the

foundation wall with properly functioninggutters, down spouts and splash blocks.Leaking faucets, water pipes and airconditioning units should be repaired, andlawn sprinklers should be adjusted tominimize puddling. Homes with poordrainage may need to have tiles or drainsinstalled, or the ground sloped to so thatsurface water drains away from thebuilding. Humidity in crawl spaces andbasements should be reduced by providingadequate ventilation, sump pumps,

polyethylene soil covers, etc.

• Since millipedes often thrive in the moist,dense thatch layer of poorly maintainedturf, de-thatching the lawn and keepingthe grass mowed close should make thelawn less suitable for millipedes. Over-watering or watering during the eveningmay also contribute to millipede problems.

• Seal Pest Entry Points - Seal cracks andopenings in the outside foundation wall,and around the bottoms of doors andbasement windows. Install tight-fittingdoor sweeps or thresholds at the base of

all exterior entry doors, and apply caulk along the bottom outside edge and sides of door thresholds. Seal expansion jointswhere outdoor patios, sunrooms andsidewalks abut the foundation. Expansion joints and gaps should also be scaledalong the bottom of basement walls on theinterior to reduce entry of pests andmoisture from outdoors.

• Insecticides - Application of insecticidesalong baseboards and other interior living

areas of the home are of little use incontrolling millipedes. Most wanderingmillipedes which end up in kitchens,living rooms, etc. soon die from a lack of moisture. Removal with a vacuum orbroom is all that is needed. Insecticidesmay help to reduce inward invasion of these and other pests when appliedoutdoors, along the bottom of exteriordoors, around crawl space entrances,foundation vents and utility openings, andup underneath siding. It also may be

useful to treat along the ground beside thefoundation in mulch and ornamental plantbeds, and a few feet up the base of thefoundation wall. Heavy accumulations of mulch and leaf litter should first be rakedback to expose pest hiding areas.Insecticide treatment may also bewarranted along the interior foundationwalls of damp crawl spaces and unfinishedbasements. Various insecticides sold inhardware/lawn and garden shops areeffective, including Sevin and synthetic

pyrethroids (e.g., Spectracide Bug Stop,Ortho Home Defense System). Treatmentcan be accomplished with a compressedair "pump up" or hose end sprayer. Dustformulations (e.g., silica get,diatomaceous earth) also work well fortreating cracks, weep holes, and similaropenings in the foundation.



DIAGNOSTIC LAB HIGHLIGHTSBy Julie Beale and Paul Bachi

Agronomic samples this week have includedphosphorus deficiency in corn; target spot,Pythium root rot and temporary phosphorus

deficiency on tobacco.

On fruits and vegetables, we have seenanthracnose, black rot, Phomopsis cane and leaf spot, downy mildew and phylloxera injury ongrape; leaf curl, brown rot, bacterial leaf spot andplum curculio injury on peach; bitter rot andfrogeye leaf spot on apple; common bacterialblight on bean; Sclerotinia stem rot on cabbage;bacterial spot/leaf blighting (both Xanthomonas and Pseudomonas) on pepper; bacterial canker,early blight, Septoria leaf spot and timber rot on

tomato; and Pythium root rot on watermelon.

On ornamentals and turf, we have seen scab oncrabapple; Gloeosporium leaf spot on birch;Botryosphaeria canker on blackgum; Phloeosporaleaf spot on mulberry; anthracnose andVerticillium wilt on maple; leaf blister on oak;Verticillium wilt on redbud; black spot and rosemosaic virus on rose; and dollar spot on turfgrass.

Note: Trade names are used to simplify the information

presented in this newsletter. No endorsement by the

Cooperative Extension Service is intended, nor is

criticism implied of similar products that are not

named.

kentucky pest news june 14, 2011

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