for Arborists, Landscape Managers & Nursery Managers

Commercial Horticulture June 17, 2016Coordinator 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. Please

include location.

TPM/IPM Weekly Report

- Japanese beetles- Bagworm control- Powdery mildew- Calico scale- Gloomy scale- Good guys on trees- Bears in Maryland- Fruit insect control- Gypsy moths- Lacewing activity- Millipedes

Beneficial of the WeekWeed of the WeekPlant of the WeekPhenologyDegree DaysAnnouncements

IPMnetIntegrated Pest Management for

Commercial Horticulture

extension.umd.edu/ipm

Japanese BeetlesBy: Stanton Gill

It will be a banner year for Japanese beetle adults in 2016. This prediction is tied into the wet periods that we had in June and mid-July 2015 when we had regular rain incidences. Egg hatch and larval survival was very high last year. We will see many adults feeding on purple leaf plums, birches, grapes, cherries, crape myrtles, roses and many other favored plants in the next couple of weeks.

On Monday, Ginny Rosenkranz, UME, emailed me that she observed her first adult Japanese beetle out feeding on her rose plant in Salisbury. Although we are generally about 7 - 10 days behind the Salisbury area in central Maryland, reports of beetles are coming from central Maryland. A Japanese beetle adult was found in Frederick on June 14. Dan Felice, Synatek Solutions, found beetles on poor looking turf in Frederick County on June 16. He noted that

Japanese beetles are in the area; this cluster of adults was found in Frederick on June 16Photo: Dan Felice, Synatek Solutions

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Recent weather conditions have been favorable for powdery mildew infectionPhoto: Brad Williams, UMBC

Bagworm ControlBy: Stanton Gill

We had several people report that bagworms had hatched last week. Cindy King, Kingstown Farm Home, found bagworms on a customer’s weeping purple beech. Cindy checked the evergreens and did not find any bagworms on them.

The control options in mid-June are many. Bacillus thuringiensis (Bt) is very effective on early instar bagworms, but use a sticker with the application. Another very safe choice is spinosad sold under several names including Conserve. These two materials have minimal impact on beneficial organisms (when used according to the label), but effectively control bagworms. Acelepryn and Mainspring would both control bagworms, but at a much, much higher cost. Again, both materials have the least impact on beneficial organisms, but control the caterpillar. An older class of chemistry, acephate, will control bagworms, but there is a wider spectrum of what it will also kill.

More often found infesting conifers, bagworms also feed on deciduous trees like this purple weeping beechPhoto: Cindy King, Kingsown Farm Home

Powdery MildewWe are seeing and receiving reports of powdery mildew on plants such as flowering dogwood, crape myrtle, crabapple, and Monarda. Brad Williams, UMBC, reported that he is starting to see powdery mildew on crape myrtles on campus this week. On flowering dogwood, severe infections can cause older leaves to turn purplish red. The warm days and cool nights promote infection. Pruning and adequate spacing of plants can increase air circulation to help reduce powdery mildew infection. When buying new plants, check to see if resistant cultivars are available. If necessary, fungicides can be used, but they should be applied when infections first appear with repeated applications according to the label.

they were all over this lawn of fine fescues and that it was a “No Mow” seed mix that was not doing well. Amanda Ramey, National Park Service, reported seeing her first Japanese beetle of the season on linden at Fort McHenry NMHS in Baltimore City on June 16.

We are conducting a trial at nurseries to test out new systemic insecticides applied as both soil drenches and foliar sprays. Last year, we tested out the newly labeled Btg sold under the name beetleGone from Phyllom Company of California. At the high rate (128 oz/100 gallons of water) it was effective for 3 – 4 days in protecting foliage. If you use it this year, we suggest mixing in a spreader/sticker.

Special request: Let me know if you are seeing pupating grubs in the turf areas and also let me know as soon as you see emergence of adult Japanese beetles. Contact me at 410-868-9400 or sgill@umd.edu.

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Calico scale adult female with eggsUSDA Agricultural Research Service, Bugwood.org

Calico scale crawlers and newly settled crawlers on honey-locust leavesPhoto: Nancy Harding

Calico Scale, Eulecanium cerasorum (Cockerell) CRAWLERS and newly settled crawlers (1st instar) (see photo) were found on honeylocust (Gleditsia tricanthos var. inermis) in College Park on June 16. This soft scale can be a pest to all stone fruit and ornamental fruit trees, as well and other hardwood trees such as dogwood, elm, zelkova, honeylocust, sweetgum, magnolia, maple, pyracantha, buckeye, and tuliptree.

Adult females are found on twigs and trunks. In the spring/early summer, they can easily be spotted by their mottled dark brown-black and white color. After egg hatch, the female dies and slowly turns a reddish-brown. Newly hatched crawlers (1st instar) are oval-shaped that start off white to pink then turn yellow. They will move from the trunk and twigs to the leaves of the host plant where they will settle and feed near the leaf vein for the summer. In late summer, they move back to woody tissue where they molt and create a hard waxy coating; overwintering as 2nd instars. There is one generation per year. The accumulated degree days in College Park as of June 16 were 1005DD.

Montitor: Look for honeydew on leaves and branches produced by the scale feeding on the phloem sap of the host plant and black sooty mold resulting from a fungus that grows on the honeydew. Also look for lots of ant activity as it can be a sign of a scale infestation. Ants are the scale’s protective army guarding their arsenal of sweet tasty food. In heavy infestations, dieback and stunted leaves that turn yellow and drop prematurely may occur. If the accumulated degree days in your area are close to the degree days in College Park (1005DD), look for crawlers on susceptible plants.

Control: One control method would be a basal trunk application of dinotefuran (Safari or Transtect) or acetamiprid (TriStar). Another method is to use one of the Insect Growth Regulators (IGR) such as Distance or Talus mixed .05% horticultural oil. Research has shown that this soft scale can be challenging to control; therefore monitor after any control application for its effectiveness. If egg-hatch has not occurred in your location and infestation is low/moderate, scraping off the adult female scale has shown to provide control without pesticides. Check for signs of natural enemies as they can aid in controlling populations of scale outbreaks, such as ladybird beetles that feed on eggs, crawlers, young nymphs and adults, parasitic wasp species, and even some birds.

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Assassin bugs are good generalist predators and will help to keep pest populations downPhoto: Brett VanOrsdel, Classic Lawn Company

Good Guys on TreesBy: Stanton Gill

Brett VanOrsdel, Classic Landscape Company, sent a photo of an assassin bug egg mass on the trunk of a tree. There were also many black and red assassin bug nymphs still near the eggs. There was sooty mold present on the trunk of the tree indicating that the tree either had an aphid population or a soft scale popluation excreting honeydew on which the sooty mold is growing. If you run into a similar situation, be sure to use an IGR such as Distance or Talus if soft scale is active to minimize the impact on the beneficial organisms.

Gloomy ScaleMarty Adams, Bartlett Tree Experts, found a very heavy infestation of gloomy scale on red maple in Columbia on June 15. Marty noted that he could see more scale than bark. This armored scale is commonly found on maples, but it is also reported on several other woody plants including dogwood, sweet gum, poplar, catalpa, black locust, willow, and grape. The females are still in the 3rd instar stage. Crawlers should be out in early July. Control: Talus or Distance applied at crawler stage should give control.

The heaviest damage from gloomy scale is often reported on maples; dieback of terminal growth occurs on heavily infested treesPhotos: Marty Adams, Bartlett Tree Experts

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Gypsy moth caterpillars are in the late instar stage and will be pupating soon

New Wildlife in Central MarylandBy: Stanton Gill

Last week when friends were visiting my farm in Westminster they spotted a black bear in my woods. This week in Montgomery, Howard and Prince George’s counties there have been sighting of black bears. Black bears used to be widespread and now seem poised for a comeback. If you see black bears active in your area, let me know at sgill@umd.edu.

From the June 15, 2016 UMD Email Alert (per campus police department):Today we were notified of two bear sightings on our campus (College Park), both near the Elkton Hall area. Callers reported the information to the Natural Resources Police Department on June 12, 2016. We want to share with our campus community what you can do if you see a bear.

Safety Tips:Never feed bears.Don’t panic and don’t approach it.Back away slowly.If you are outside, go to the closest building and go inside.Most bears fear people and will leave when they see you.If a bear growls, snaps its jaws, slaps the ground or brush, or bluff charges: you are too close.

The damage on this apple was caused by oriental fruit moth feeding

Fruit Insect ControlBy: Stanton Gill

Oriental fruit moths and codling moths are starting their second generation of activity as we move into mid-June. If you are treating you customers’ fruit trees, now would be a good time to apply either Spinosad (Entrust and Spinosad for fruit trees) to the fruit and foliage to protect from the damage that the larval stage will inflict upon peaches and apples.

Gypsy MothsChris McComas, HGIC, found late instar gypsy moth caterpillars on a blue spruce in western Howard County on June 17. Over the years, we have had regular reports of gypsy moth infestations on blue spruce, even when they are not in the area feeding on oaks. When these caterpillar feeding in spruce pupate and emerge, the adult females tend to lay eggs on the spruce. It is too late to control larvae now. Monitor the trunks of trees later in the season for egg masses which should be removed and destroyed if accessible.

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Lacewing larvae are predaceous; adults feed on nectar, pollen and aphid honeydewPhoto: Jeff Lavrusky, The Brickman Group

This species releases a chemical that includes cyanide as a defense mechanism; avoid handling this millipedePhtoo: Erik Goerner, Maxalea, Inc.

MillipedesErik Goerner, Maxalea Inc., sent in a photo of millipedes (Apheloria virginiensis) on a rotting stump in Pikesville on June 14. Millipedes mainly feed on organic matter. Some species can be a nuisance when they get inside of buildings.

Lacewing ActivitiyJeff Lavrusky, The Brickman Group, found a lacewing larvae feeding on aphids. Lacewings are one of the many generalist predators that help keep pest insects, especially aphids, low to help reduce damage to landscape and nursery plants. Also monitor for lacewing eggs which are white and laid on a silken stalk.

Beneficial of the WeekBy: Paula Shrewsbury

Banded thrips

When we hear a reference made to insects called thrips we often think of herbivorous thrips that can become pests of plants. Fortunately, not all thrips are herbivores. Some thrips, like banded or broad winged thrips (family Aeolothripidae), are predators of other insects. These thrips get their name because of the morphology of the wings. The front wings are relatively broad compared to other thrips, of which a common characteristic is narrow wings. In addition, the wings have two longitudinal veins that go from the base to tip of the wing, and the wings appear to be banded or mottled in their color pattern. The most common species of Aeolothripidae is the banded thrips, Aeolothrips fasciatus. The adults of banded thrips are yellow to dark brown in color and have three white bands on the wings. Adult banded wing thrips, although only 1.6 – 2.0 mm in length, are the big guys of the thrips world. Thrips are holometabolous insects. They have egg, larval, pre-pupal, pupal, and adult forms.

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Japanese knotweed flowers are in cluster at the junction of the leaf petiole and stemPhoto: Ginny Rosenkranz, UME

Note the characteristic 3 white bands across the wings of the predatory banded thripsPhoto: Whitney Cranshaw, Colorado State University, Bugwood.org

Banded thrips can be found on a diversity of plants, including those that have been found in nurseries during our research studies. Banded thrips are generalist predators and are known to feed on other thrips species, aphids, spider mites, white flies, and other small insects. Banded thrips are widely distributed and can be found not only in North America, but also Europe, Asia, Africa, and Hawaii. In addition to banded and broad winged thrips, there are several species of predatory thrips. Be sure to accurately identify any thrips you might think are causing problems on your plants. They may actually be eating pest insects that are present.

Weed of the WeekBy: Chuck Schuster

Everything is growing very fast at this time. Bittersweet has grown a lot in the last several weeks. All weeds seem to be enjoying the moisture and warmth. As expected, I am getting contacted with issues related to some of these prolific weeds. A local HOA has been dealing with Japanese knotweed and has been losing the battle with it. I am updating my previously posted weed of the week to make sure we are working with it in the proper way.

Japanese knotweed, Polygonum cuspidatum, is a native of Eastern Asia that was introduced into the United States in the late 1800’s as an ornamental. It is an herbaceous perennial that grows in an upright shrub form, reaching heights of ten feet and more. This invasive perennial is found in landscapes and abandoned areas. It tolerates full shade, high temperatures, salinity and even drought, but prefers moist sites. This weed is often transported to new sites in fill material. Know the source of the fill and ascertain that it is free of this plant prior to accepting it. This assessment is not an easy process. The rhizomes will be notable in the soil, but it only takes an inch or two of this plant’s rhizome to start a new infestation.

Leaves are arranged alternately on the stem and are five to six inches long and three to four inches wide. They are a broad oval or egg shaped with a pointed tip. Rhizomes that produce new plants help promote the thicket growing pattern of this plant. Stems are hollow, jointed and when mature will resemble bamboo. Each joint has a thin membranous sheath encircling the stem. Flowers are small and white and found in clusters of four to five inches in length at the junction of the leaf petiole and the stem.

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Leaving any portion of the rhizome behind generates a new plantPhoto: Ginny Rosenkranz, UME

Control can be obtained by grubbing out new plants, remembering that any portion of the rhizome left behind will generate a new plant. Keeping this plant mowed is useful as it does not allow the root system to build up since the upper stems and leaves are needed to send energy back to the roots. Cut stem applications work well in most temperatures unless the ground is frozen. Products that can be used include 25% glyphosate, triclopyr (Garlon) with a follow application on new seedlings. Foliar applications can be used for large areas using a 2% glyphosate or triclopyr with a surfactant. Mow the plant often to keep it under control and in mid July allow regrowth to have enough leaf material to absorb chemicals. Do not wait until late fall to use foliar application methods as it requires active growth and temperatures above 65 °F.

Plant of the WeekBy: Ginny Rosenkranz

Echinacea x purpurea ‘Evening Glow’ coneflower is a new reblooming native coneflower cultivar. In early summer, the plants start out with pale yellow flower petals that surround a dark central cone. As the large flowers mature, the petals change from yellow to apricot and then a soft rose pink color. The flowers are often bicolored as they mature. Once the flowers have all faded, they should be trimmed back to encourage new blooms in mid-summer. While in flower, hummingbirds, butterflies, and other pollinators visit frequently, adding color and movement to the garden. These later summer flowers will last until fall when the seeds of the flowers can be enjoyed by goldfinches. The plants need full sun for the best bloom and medium, well drained, slightly acidic soils in USDA zone 4-9. ‘Evening Glow’ grows 20-24 inches tall and wide on sturdy well branched stems and can be used as a border, in the herbaceous perennial bed, as a mass planting, or even in containers. The lightly fragrant flowers can also be used for cutting. Like the species, ‘Evening Glow’ is heat and drought tolerant and said to be deer resistant. When planting in the fall, be sure to give this Echinacea time to get roots well established before the ground freezes, and give them time to emerge from the chilly soil in the springtime, as they are lovers of hot summer soils.

Echinacea x purpurea ‘Evening Glow’ is a new reblooming coneflower cultivarPhotos: Ginny Rosenkranz, UME

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Degree Days (As of June 15)Annapolis Naval Academy (KNAK) 1003 Baltimore, MD (KBWI) 989 College Park (KCGS) 981 Dulles Airport (KIAD) 1011Ellicott City (E3247) 906 Fairfax, VA (D4092) 1150Frederick (KFDK) 849 Greater Cumberland Reg (KCBE) 945 Gaithersburg (KGAI) 880 Martinsburg, WV (C1672) 930Natl Arboretum.Reagan Natl (KDCA) 1233 Rockville (C2057) 1182 Salisbury/Ocean City (KSBY) 1004 St. Mary’s City (St. Inigoes, MD-KNUI) 1171 Westminster (KDMW) 1001 Important Note: We are now using the Online Phenology and Degree-Day Models site.

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

Once you know the GDD and / or plant phenological indicators (PPI, what plants are blooming) in your location, you can go to the Pest Predictive Calendar to determine what pests you can expect to be active soon in that location.

Biocontrol Conference for Nursery and Greenhouse GrowersWe are organizing a Biocontrol conference for August 18, 2016, so mark your calendar. We will put out a complete schedule of topics and speakers in June. The location will be Brookside Gardens in Wheaton, Maryland. We will be bringing in speakers from the Ontario Experiment Station, the Connecticut Experiment Station, BioWorks from Florida, local growers who have adopted biocontrol options, and several University of Maryland Extension faculty. Each will talk about their latest research in biological control options in the nursery, greenhouse and landscape. This program is co-sponsored with MNLGA and they will handle registration for this conference.

Drones and IPMIn the Monday issue of The Washington Post they had an article entitled “Even Cowboys Get the Drones.” The article talked about how drones are being used in Australia on the range to monitor cattle herds instead of using on-the-ground cowboys. This article ties into where we are taking the IPM program. On June 29, 2016 we are working with MNLGA in holding an evening session at Milkhouse Brewery in Mt. Airy, MD where we will have a talk on using drones in the horticulture industry. There will also be a live demonstration of drones at this site. The session will be held from 5:00 p.mn. until dark. Visit the MNLGA website to register for this interesting and hopefully, fun evening event.

PLANT PLANT STAGE (Bud with color, First bloom, Full bloom, First leaf)

LOCATION

Asclepias tuberosa First bloom Ellicott City (June 13)Stewartia pseudocamellia Full bloom Ellicott City (June 16)

Plant Phenology Indicators

Maryland Department of Agriculture: Pesticide Container Recycling Program

MDA has posted its schedule of collection sites for the 2016 Pesticide Container Recycling Program. Triple-rinsed (or equivalent) will be colleted on the scheduled days and times at the sites. See the brochure for details.

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

2016 Summer Conferences

MNLGA Nursery Field DayJune 23, 2016Location: Angelica Nurseries 11129 Locust Grove Road Kennedyville, Maryland 21645Contact: 410-823-8684Register online at MNLGA

Hops and DronesJune 29, 2016, 4:00 PM - 8:00 PMLocation: Milkhouse Brewery at Stillpoint Farm 8253 Dollyhyde Road Mt. Airy, MD 21771Contact: 410-823-8684, office@mnlga.orgRegister online at MNLGA

Maryland Christmas Tree Association Summer Meeting Saturday June 25, 2016 at Thomas Tree Farm, 3501 Ha-nover Pike, Manchester, MD For info: wayne@thomastreefarm.com

Hands-on Perennials Diagnostic WorkshopJuly 20, 2016Location: Perennial Farm 12017 Glen Arm Road Glen Arm, MD 21057Contact: 410-823-8684, office@mnlga.org

Biological Control for Greenhouses and NurseriesAugust 18, 2016Location: Brookside Gardens, 1800 Glenallan Avenue, Wheaton, MD 20902Contact: 410-823-8684, office@mnlga.org