for Arborists, Landscape Managers & Nursery Managers

Commercial Horticulture October 27, 2017Coordinator Weekly IPM Report: Stanton Gill, Extension Specialist, IPM for Nursery, Greenhouse and Managed Landscapes, sgill@umd.edu. 301-596-9413 (office) or 410-868-9400 (cell)

Regular Contributors: Pest and Beneficial Insect Information: Stanton Gill and Paula Shrewsbury (Extension Specialists) and Nancy Harding, Faculty Research AssistantDisease Information: Karen Rane (Plant Pathologist) and David Clement (Extension Specialist)Weed of the Week: Chuck Schuster (Extension Educator, Montgomery County)Cultural Information: Ginny Rosenkranz (Extension Educator, Wicomico/Worcester/Somerset Counties)Fertility Management: Andrew Ristvey (Extension Specialist, Wye Research & Education Center)Design, Layout and Editing: Suzanne Klick (Technician, CMREC)

In This Issue...

If you work for a commercial horticultural business in the area, you can report insect, disease, weed or cultural

plant problems found in the landscape or nursery to

sklick@umd.edu

TPM/IPM Weekly Report

- Last report of 2017- December conferences- Japanese maple scale trials- Biological control conference- New traveling methods for trucks- Damage from Dicamba- Grubs in turf- Sapsuckers- Deer disease

Beneficial of the WeekWeed of the WeekPlant of the WeekDegree DaysAnnouncements

Pest Predictive Calendar

IPMnetIntegrated Pest Management for

Commercial Horticulture

extension.umd.edu/ipm

The End is HereBy: Stanton Gill

It is the end of October and time to put the IPM Alerts to rest for the winter. Don’t worry, we will be back online in March of 2018 as the pests, diseases, and cultural problems gear up next spring. We will also put out periodic issues this winter as special events occur.

We will also need your help. We will send out an electronic survey in November. We need you to take a few minutes to fill out the survey. We need this input to determine if we are being effective with the IPM Alerts and if they are working for you.

This stewartia is showing its fall color here at the research center this week

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Japanese Maple Scale TrialsBy: Stanton Gill

During the summer, Brian Kunkel (University of Delaware Extension), Suzanne Klick, Heather Zindash, Chuck Schuster, and I conducted field trials to evaluate several new systemic insecticides and some well established systemic and contact materials for controlling Japanese maple scale in Maryland nurseries. Foliar and soil drench applications were made. Besides the Japanese maple scale we evaluated cottony camellia/Taxus scale on hollies to see which material worked best. We took data over several months. Now, we are busy summarizing the data for presentations this winter and the spring of 2018.

Meanwhile, one of my students from Montgomery College, Caroline Hooks, noticed that some Tennessee researchers reported on several materials they evaluated for Japanese maples scale control in February of 2016. I contacted Karla Addreso, the lead author. Karla and her fellow researchers published their results in the Journal of Environmental Horticulture in the June 2016 edition. Some of their results did not surprise me, but others did. They found two generations per season, similar to Maryland. In their trials they used cherry trees. They found the dormant horticultural oil (brand name Ultra-Pure) suppressed scale populations with 76% fewer live scale at 30 days post treatment in a 2014 trial. The control plants saw a 45% increase in live scales. It was a different situation with summer applications for crawlers. Summer applications of horticultural oil did not give effective control of crawlers in 2104. In the 2014 trial, soil applications of imidacloprid (applied as the brand name Discus) and dinotefuran (Safari 2 G) did not control JMS at a 30 day post treatment count. At 60 days, the dinotefruan treated plants had fewer live scales than non treated plants. No difference was observed between the imidacloprid treated trees and control at 60 days post treatment. At 90 days, dinotefuran failed to suppress rebounding populations. Only imidacloprid treated trees sustained JMS suppression at 90 and 120 days post treatment. In the second year, the cherry trees treated with imidacloprid were free of JMS scale.

In our trials on armored scale, we have not seen really great results on armored scale that feed on woody bark. We have been able to get good control with imidacloprid on armored scale feeding on needles such as hemlock elongate scale and cyrptomeria scale on spruce. Imidacloprid is slow moving and may just take a long time to show impact on an armored scale such as Japanese maple scale. Imidacloprid was not in our Maryland trials in 2017 but dinotefuran was included. We will see what our results show later this winter.

December ConferencesThere will be a morning program for turf nutrient management recertification on December 7, 2017 at Carroll Community College. No pesticide recertification credits are available at this progam.

The conference for pesticide recertification will be held on December 15, 2017 at Howard Community College in Columbia. No turf nutrient management CEUs are available at this program.

The brochures and registration information are posted at http://extension.umd.edu/ipm/conferences.

During the trial, we found Japanese maple scales on the holly berries

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Grub damage in turfPhoto: Mark Schlossberg, ProLawn Plus, Inc.

Save The Date: Biological Control ConferenceStanton Gill

We are putting the final touches on the February 1, 2018 Biological Control Conference for nurseries, greenhouses and landscape companies. The conference will be held at Carroll Community College in Westminster, MD. This program will be a joint effort between University of Maryland Extension and the Maryland Nursery, Landscape, and Greenhouse Association.

We are excited to have some excellent speakers lined up with fresh new outlooks on biological control. When the final brochure is ready, we will send out an email announcement.

Not as many Japanese beetle adults noted this year, but grub activity seems to be highPhoto: Steve Sullivan, BrightView

Have You Seen Dicamba Damage in NurserisBy: Stanton Gill

We are interested in knowing if any nursery owners saw damage from dicamba drift in 2017. Please contact me at Sgill@umd.edu if you experienced damage in 2017.

New Traveling Methods for TrucksBy: Stanton Gill

Many nurseries use long distance trucking to ship plant material. There was an article in Monday’s edition of the Washington Post noting that travelers will see more trucks riding in close tandem on the highways, maintaining a distance of 30 – 50 feet apart. They are doing it this way to save fuel since the forward vehicle is cutting the wind. Evidently, with all of the new radar and visual detection sensors they can program a truck to maintain close proximity with some acceptable degree of safety. The article did mention that trucks are involved in 11% of the national rear end accident incidents and this new technology will hopefully reduce these accidents. Let’s hope the sensing equipment does not fail.

Grubs in Turf

Steve Sullivan, BrightView, saw grub damage on October 16 in Eldersburg. Steve noted “it was interesting since it was the fewest Japanese beetles I saw this year, but first year to get grub damage in the neighborhood. I think crows were digging after them in the one area.” Mark Schlossberg, ProLawn Plus, Inc., is finding grub damage in turf in Towson.

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Deer DiseaseBy: Stanton Gill

Deer populations in the metro area of the Baltimore-Washington corridor do incredible amounts of damage to plant material. Now a disease (Epizootic Hemorrhage Disease) which is transmitted by a biting midge is taking out large numbers of deer in Tennessee and nearby states. Henry Keegan sent in an article that noted this year’s outbreak of this disease is concerning hunters in Tennessee because of the damage it is doing to the white-tailed deer population. The virus does not spread to humans.

Look for yellow-bellied sapsucker damage on woody plants such as holliesPhoto: Kevin Nickle, ProLawn Plus, Inc.

Sapsuckers Active in October in MarylandBy: Stanton Gill

We continue to receive reports of yellow-bellied sapsucker damage which we usually don't see until later in November. Kevin Nickle, ProLawn Plus, Inc., is seeing it in his landscape now. The Cornell Lab of Ornithology website has details on this woodpecker.

Beneficial of the WeekBy: Paula Shrewsbury, University of Maryland

How do insects survive the winter?

We are not far from the onset of colder weather and winter which always starts me thinking about how many beneficial and other insects are able to survive the freezing cold of winter. The answer is “they do it in a diversity of ways”. Insects vary in the life stage in which they “overwinter”. They may overwinter as adults, pupae, immatures (larvae or nymphs), or eggs. For example, wheel bugs spend the winter in the egg stage (see image). Praying mantids are another predatory species that overwinter as eggs within the styrofoam-like oothecae that the female produces (see image). Lacewings (predators) overwinter in their larval stage and some species of butterflies (pollinators), wasps (predators), and bees (pollinators) overwinter as adults. There are multiple strategies used by various insects to get through the winter, some of which are physiological and others behavioral.

Some insects survive winter’s cold through a process called supercooling. As temperatures drop in autumn and early winter many species of insects produce cryoprotectants, antifreeze-like compounds including glycerol and

An ootheca (egg case) of the Chinese praying mantis that was found on the vine of bittersweet in the winter. (image by M.J. Raupp, UMD)

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sorbitol, which prevent the formation of lethal ice crystals in bodies of overwintering insects. This “antifreeze” allows insects to survive even when ambient temperatures dip well below freezing. Woolly bear caterpillars and many of their relatives use this strategy.

Many insects will diapause (similar to hibernation in vertebrates) during the winter. Diapause is defined as an inactive stage of arrested development. Diapause results in the reduction of the insect’s metabolic rate to 1/10 or less its normal rate. This allows the insect to use its stored body fat to survive the cold winter. You may have noticed some insects aggressively feeding in the fall in an effort to store up on carbohydrates to help get them through the winter. In the spring, the onset of warmer temperatures will break or stop an insect’s diapause and they will continue to develop.

Migration to warmer climates is a strategy some insects use to escape the freezing temperatures. Monarch butterflies are one of the most magnificent examples of a beneficial that migrates.

Other insects tolerate the cold by hiding in protected, warmer locations. Ladybird beetles move up to rocky outcroppings and hide amongst the rocks. Some beetles (like pesty white grubs) burrow deeper in the soil below the frost line to escape. Other insects hide in leaf litter or under bark flakes of certain tree species. The nymphs of dragonflies and mayflies live in water of ponds and streams where they are active below any ice layer that forms.

The reasons insects, as a group, are so successful is their ability to adapt. So don’t worry too much about beneficial insects. Insects have been surviving freezing temperatures for a very long time.

Monarchs migrate south in the winter to escape the freezing temperatures of the northPhoto: M.J. Raupp, UMD

At this time of year you should see wheel bug egg masses on the trunk of trees. Wheel bugs will spend the winter in its egg stage. Photo: P.M. Shrewsbury, UMD

Weed of the WeekBy: Chuck Schuster, University of Maryland Extension

Weed control in lawns and landscapes is becoming a much watched and talked about subject. During the last 8 months, I have seen several apparent failures of applied products, complaints on products used and legislation on potentially banning certain types of products. As professionals in the industry, all need to look at some of the important things that need to be managed.

Water used as the carrier is an extremely important part of the application. What is the pH of the water source, what dissolved minerals are in the water and does the water contain solids that are mineral or soil in nature? Turbidity can cause some pre-emergent products to become non effective immediately. Water pH that is high, typically above 7.5, can reduce efficacy of some products which includes shortening product life on the plant. Test the water source at different times of the year, as water quality can change based upon the amount of water being drawn from wells. Usually public water sources are consistent.

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Drift and volatilization are very important at all times. All products have the potential of drifting if the product and equipment is not monitored properly. Volatilization, is an issue with a few herbicides, and these products are causing a great deal of discussion. While many of the concerns are from the agronomic side, it should be remembered that some of these products are also used in the turf care industry. Being mindful of the temperature changes predicted is sometimes not enough. Product safeners are available and in some cases recommended. Look at pressure, particle size, and boom height to avoid drift.

Herbicides are a needed tool in turf and landscape care. Being careful and using them properly is important to help the industry prevent the loss of many of these products because of legislation.

Plant of the WeekBy: Ginny Rosenkranz, University of Maryland Extension

Trillium cuneatum, wood lily, is a lovely native spring flowering herbaceous perennial. It only blooms for a short time, but in moist shady woods, they are a true harbinger of spring. As I always am looking forward to spring as soon as the temperatures turn cold, I decided to share my love of spring with this delicate looking, very hardy plant. Many varieties of trilliums have green leaves, but the wood lily or sweet Betsy trillium has green leaves that are mottled with darker forest green blotches. The plants grow best in USDA zones 5-8 and can be found from Pennsylvania south to Georgia. The three colorful leaves that resemble the coloring of toads (another common name is toadshade) emerge in the early spring and the dark burgundy red, slightly fragrant, 3-petal flower that is nestled down on top of the leaves blooms in late March to May. The leaves are actually bracts and the flowers can be on a stem (pedicellate) or be snuggled close to the bracts (sessile). Trillium cuneatum is a slow grower and expands its territory with underground rhizomes. Seeds are viable and ants and wasps spread them, but they too are slow to grow as well. Plants need shade, but in order to bloom they need a bit of spring sunshine, so the shade of deciduous trees is preferred. As mentioned before, the soil needs to be organically rich with compost, with a neutral pH, and moist but well drained, with addition of mulch each fall or spring. There are no serous insects or disease pests, but by living in a moist shady area, slugs and snails can be problematic and leaf spot, smut and rust can infect the foliage.

Look for Trillium cunneatum in moist, shady woodsPhoto: Ginny Rosenkranz, UME

Degree Days (As of October 25)

Annapolis Naval Academy (KNAK) 4531 Baltimore, MD (KBWI) 4093 College Park (KCGS) 4001 Dulles Airport (KIAD) 4077Ellicott City (E247) 3931 Fairfax, VA (D4092) 4343Frederick (KFDK) 4035 Greater Cumberland Reg (KCBE) 3771 Gaithersburg (KGAI) 3895 Martinsburg, WV (C1672) 3785Natl Arboretum.Reagan Natl (KDCA) 4846 Rockville (C2057) 4486 Salisbury/Ocean City (KSBY) 4215 St. Mary’s City (St. Inigoes, MD-KNUI) 4506 Westminster (KDMW) 4247

Important Note: We are now using the Online Phenology and Degree-Day Models site. Use the following information to calculate GDD for your site: Select your location from the mapModel Category: All models Select Degree-day calculatorThresholds in: Fahrenheit F Lower: 50 Upper: 95Calculation type: simple average/growing dds Start: Jan 1

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Trees Matter SymposiumNovember 1, 2017Location: Silver Spring Civic Center, Silver Spring, MDFor more information

December Pest Management ConferenceDecember 15, 2017Location: Howard Community College, Columbia, MD

Advanced IPM Short CourseJanuary 8 - 11, 2018Location: University of Maryland, College Park, MD Contact: Short Course Assistant, 301-405-3911, umdentomology@umd.edu, http://landscapeipmphc.weebly.com/

FALCAN Pest Management ConferenceJanuary 19, 2018Location: Frederick Community College, Frederick, MD

Maryland Arborist AssociationJanuary 23-24, 2018 Location: Turf Valley, Ellicott City, MD

PGMS Green Industry Professional SeminarJanuary 26, 2018Location: Annandale, VA

Biological Control ConferenceFebruary 1, 2018 Location: Carroll Community College, Westminster, MD

Eastern Shore Pest Management ConferenceFebruary 7, 2018Location: The Fountains, Salisbury, MD

LCA Pesticide and Fertilizer Applicator Recertfication ConferenceFebruary 15, 2018Location: The Universities at Shady Grove - UMD

Chesapeake Green Horticulture ConferenceFebruary 20 and 21, 2018Location: Maritime Institute, Linthicum Heights, MD

Manor View Farm and Perennial Farm Education SeminarFebruary 23, 2018Location: Sheppard Pratt Conference Center, Towson, MD

Updates to conference information are posted at:http://extension.umd.edu/ipm/conferences

Upcoming Conferences

The information given herein is supplied with the understanding that no discrimination is intended and no endorsement by University of Maryland Extension is implied.

CONTRIBUTORS:

University of Maryland Extension programs are open to all citizens without regard to race, color, gender, disability, religion, age, sexual orientation, marital or parental status, or national origin.

Thank you to the Maryland Arborist Association, the Landscape Contractors Association of MD, D.C. and VA, the Maryland Nursery and Landscape Association, Professional Grounds Management Society, and FALCAN for your

financial support in making these weekly reports possible.

Photos are by Suzanne Klick or Stanton Gill unless stated otherwise.

Stanton GillExtension Specialist

sgill@umd.edu410-868-9400 (cell)

Paula Shrewsbury Extension Specialistpshrewsb@umd.edu

Ginny RosenkranzExtension Educatorrosnkrnz@umd.edu

Chuck SchusterExtension Educator

cfs@umd.edu

Karen Rane Plant Pathologistrane@umd.edu

Andrew RistveyExtension Specialistaristvey@umd.edu

David ClementPlant Pathologist

clement@umd.edu

Nancy HardingFaculty Research

Assistant

The Pest Predictive Calendar is a monitoring tool to assist in predicting when susceptible life stage(s) (stage you want to target for control measures) of pest insects are active by using plant phe-nological indicators (PPI) and growing degree days (GDD). This tool will lead to improved timing of management tactics and more effective pest management.

Check it out at Pest Predictive Calendar