for Arborists, Landscape Managers & Nursery Managers

Commercial Horticulture July 20, 2012Coordinator 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 Brian Clark (Extension Educator, Prince George’s County)Disease 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 (Regional 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

- Weather update- Yellownecked caterpillar- Bagworm- Japanese beetles- Brown marmorated stink bug- Spotted winged drosophila- Fall webworms- Storm damage- New material for insect control- Powdery mildew- Gypsy moth- D.C. pesticide law (pending)- App: IPMLite for homeowners

Weed of the WeekPlant of the WeekDegree DaysPhenologyConferences

Integrated Pest Management for

Commercial Horticulture

www.ipmnet.umd.edu

Heat, Heat, and More HeatEveryone likes to complain about weather, but this summer you would be very justified. We continue to break records with the number of days above 100 °F. We are receiving a lot of emails with photos of stressed plant material with dieback occurring on branches and browning of foliage. It is hard to keep up with watering in this stressful environment.

While I was out in Ohio the newspapers had reports of the drought in the mid-West. The articles are saying the mid-West is having the worst drought since the 1930s when the dust bowl occurred and the 1950s. The corn and soybean crops are basically shot in the mid-West. The long range forecast from several meteorologists is for more of the same for the mid-west and the East Coast.On the bright side, you should have lots of opportunity for planting replacement plant material in the fall if and when it cools down.

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An assassin bug nymph was also found on the same crabapple

Mark Schlossberg, ProLawn Plus, Inc., sent in this photo on July 18 in Owings Mills and noted that no damage was seen 7 days ago.

One of the many yellownecked caterpillars feeding on the crabapple

Yellownecked Caterpillar Yellownecked caterpillars defoliated a crabapple this week in Ellicott City. The tree looked fine on Friday, but there was a fair amount of feeding by Monday and the caterpillars defoliated over 50 percent of the tree by the end of the week when they moved off the tree to pupate. This native caterpillar feeds on various woody plants including cherry, peach, almond, crabapple, quince, maple, elm, butternut, walnut, oak, hickory, chestnut, beech, linden, witch-hazel, birch, locust, sumac, azalea, and boxwood. They are gregarious which means they feed in groups. Isolated trees are more often attacked. Look for larvae from July through October. There is only one generation a year in Maryland.Control: Prune out clusters of caterpillars on light infestations on small trees. Applications of Bacillus thuringiensis (Bt), Confirm, or Conserve should reduce populations.

BagwormWe have a report from a nursery owner saying they are seeing a fresh hatch of bagworms this week. The eggs can hatch over a fairly long time, but I (Stanton) don’t remember getting reports of hatching in mid-July. If anyone else is seeing recent hatch-out please contact me at sgill@umd.edu.

Japanese BeetlesI (Stanton) thought that adult Japanese beetles had peaked and were declining in activity this week but I was wrong. I spoke with a grower in Howard County who reported a lot of adult activity this week with traps that are totally full. Please continue to let me know what you are seeing with Japanese beetle activity in your area at sgill@umd.edu.

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Spotted Winged DrosophilaWe received reports of spotted winged drosophila attacking black raspberries near Easton on the Eastern Shore, Howard County, Montgomery County and Westminster this week. The infestations were so high you could see hundreds of adults swarming over the berries.

Storm DamageMark Schlossberg, ProLawn Plus, Inc., sent in a photo of storm damage in the Metro area.

Fall WebwormsRichard Chaffin, The Brickman Group, is seeing fall webworm tents in Bel Air this week. There are two generations a year. The second generation activity usually starts in August. Control: Bacillus thuringiensis (Bt), Confirm, or Conserve can be used for control. The webbed branches can be pruned off and the webbing and caterpillars destroyed.

Brown Marmorated Stink BugWe are getting reports of nymph activity this week and one grower called in to report seeing mating adults out on foliage. Bob Nixon, Master Gardener, observed at least 10 on his five Triple Crown blackberry plants in Howard County. He noted that there appeared to be early to mid-size instar stages present. Karen Wimsatt, Master Gardener, reported not seeing any so far this year even though the bugs wiped out their pepper and bean crops and damaged tomatoes the past few years in Stevensville. Let us know what you are seeing with BMSB in your area at sgill@umd.edu.

Mid-instar brown marmorated stink bug nymph on blackberryPhoto: Bob Nixon, Howard County Master

Spotted winged drosphila fly damage and adultPhotos: Hannah Burrack, North Carolina State Univ., Bugwood.org

Fall webworm tentsPhoto: Richard Chaffin, The Brickman Group

Storm damagePhoto: Mark Schlossberg, ProLawn Plus, Inc.

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New Material for Thrips, Mites and Whitefly Control – Stanton GillBack in 2006 we tested out a product from Novozyme Company (Denmark) that is an entomopathogenic fungi, Metarhizium anisopliae strain. We conducted the trials in 3 Maryland commercial greenhouses using low volume sprayers. We wanted to see if you can spread the conidia through a crop using low volume sprayers. We were able to get the conidia pretty well spread throughout the crop canopy using several brands of low volume sprayers. We then set up trials at the University of Maryland greenhouse to evaluate the material for thrips and twospotted spider mite control. Applications made at 7 day intervals gave very good control of both western flower thrips and two-spotted spider mites.

I (Stanton) was in Columbus, Ohio for the OFA meetings and met up with Novozyme representatives. They received their EPA labeling in 2012 for using this entompathogenic fungi in greenhouse for mites, thrips and whitefly control. They also have a label for outdoor use. They are conducting trials in the New England area to evaluate this material for a low-risk control for black legged tick (also known as deer trick) that spreads Lyme disease.

I am pretty jazzed that they expanded their label for these pests and it should add to the arsenal for low risk materials to control thrips, spider mites and whitefly. It should fit nicely into an IPM approach. We will be setting up additional trials later this year and in 2013 using this product. If you are using it to control spider mites the high label rate is used. For controlling thrips a middle rate is used and the lowest rate is used for whitefly control. We will provide more on this material as we conduct additional trials.

Powdery MildewKelly Wilson reported powdery mildew on tree peonies in Arlington this week. Powdery mildew was also developing on Knockout roses in Washington D.C. We’ve had a few samples of yellow barberry with odd reddish brown blotches on the leaves, and extensive defoliation. This is powdery mildew! The fungus produces sparse mycelium in the discolored areas, visible with a hand lens. Several products are labeled for control of powdery mildew on ornamentals in the landscape, including sterol inhibitors such as Banner Maxx and Eagle, QoI products like Heritage and Insignia, chlorothalonil (Daconil and others) and combination products like Pageant and Spectro 90. Fungicides are most effective in managing powdery mildew when used preventively. Always follow all label instructions, as rates, timing and crops listed will differ between products.

Close-up of brown blotches due to powdery mildew on barberryPhoto: Karen Rane, UME

Defoliation due to powdery mildew, with new foliage beginning to developPhoto: Karen Rane, UME

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Gypsy MothKaren Wimsatt, Master Gardener, reported that several years ago they had a significant gypsy moth infestation and had to spray for three consecutive years. This week while cleaning out a woodpile they found two egg cases under the bark of a log. They destroyed the egg cases and will monitor for more to try and reduce future damage to the many oaks in the area.

Regal moth and its caterpillar called the hickory horned devil

DC Law on Pesticide UseIn Washington D.C., the Pesticide Education and Control Amendment Act of 2012, is now awaiting the signature of DC Mayor Vincent C. Gray. If signed by the mayor, this law includes restrictions on non-essential cosmetic pesticides such as weed ‘n feed and Roundup from all government-owned property in DC. It would be put into effect by the District Department of the Environment beginning in late 2013 or early 2014. In the meantime, the bill calls for further education of DC businesses and private homeowners, who will still be able to apply synthetic chemical products on their own properties that do not border waterways. This law eliminates synthetic chemical pesticides from all property within 25 feet of a waterway and also any privately owned schools and daycare facilities where children congregate.

Regal Moth or Royal MothThe regal moth (aka the royal walnut moth) was found one morning this week on a shrub by our building here at the research center. The caterpillar of this moth is the hickory horned devil which has menacing-looking horns but is harmless. Late instar caterpillars are green with the orange horns. Early instars are red to brown. The caterpillar feeds on various woody plants including hickory, cherry, ash and sweet gum and can also be found around this time of year.

IPMLite for HomeownersIPMLite enables users to:• Receive text-like alerts for time-sensitive pest issues and plant care - alert date adjusted to location so they are always aware of current pest issues• View images, pest lifecycle, and management options for major pests of woody plants• Reference how-to information and images of cultural practices• Track pests and cultural practices in calendar view or a chronological list

IPMLite, or Integrated Pest Management Lite, was developed through a collaborative effort of horticulturists, entomologists and plant pathologists at seven land-grant universities. The University of Tennessee Institute of Agriculture, working with Clemson University, University of Georgia, University of Kentucky, University of Maryland, North Carolina State University and Virginia Polytechnic Institute, developed the first Integrated Pest Management mobile app, IPMPro, for nursery growers, landscapers, arborists and educators that includes alerts, major horticultural practices, and disease and insect information, as well as pesticide recommendations and electronic recordkeeping for professionals. Now the developers are introducing IPMLite for the homeowner. IPMLite was built for the USDA Plant Hardiness Zones 4 through 8 (with capability for Zone 9a and 9b), which includes 20-plus states from west of the Mississippi River, east and north to Pennsylvania and New Jersey, and south to the Gulf Coast. IPMLite is $9.99 and IPMPro is $24.99 and are available through Apple (iPhone and iPad) and Android marketplaces. For more information, visit ipmproapp.com and ipmliteapp.com.

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Plant of the Week, Ginny RosenkranzHardy gardenias, Gardenia jasminoides, like’Kleim’s Hardy’, ‘Frost Proof’ and ‘Chuck Hayes’ will grow in many protected gardens and thrive all summer and winter. A small shrub, hardy gardenia is cold tolerant from USDA zone 7-10. The plants are grown for their creamy white, extremely fragrant blooms so it should be planted in full sun to light afternoon shade and near windows or screened in porches to take advantage of the beautiful perfume. ‘Kleim’s Hardy’ is a single flower while ‘Frost Proof’ and “Chuck Hayes’ have beautiful double flowers. The fragrant 2-inch flowers bloom from late spring through the heat of summer. Hardy gardenias need acidic, moist, rich, well-drained soil. In the heat of the summer they will need more irrigation to promote flowering and a healthy plant. They grow 4-6 feet tall and wide, creating a rounded mound and are covered with dark shiny green leaves that persist throughout the winter. Many pests feast on the hardy gardenia including whitefly, aphids and scale insect and root rot is a problem if grown too wet. Bud drop can occur when the plants are under watered.

Weed of the Week, Chuck SchusterGiant ragweed, Ambrosia trifida, is a tall erect summer annual that is now being found in some settings. It is a member of the Asteraceae, or sunflower family. Reaching a total height of up to sixteen feet, this plant has large three-lobed leaves, and on occasion, five lobed leaves. The lobes originate from the same point (palmate). It prefers fertile well drained soils. Giant ragweed has a taproot, is tall and erect with several branches. It has a hairy stem. The leaves are lobed, opposite, and found on a long petiole, and they are also hairy. Each leaf can be up to eight inches in width and six inches in length. The female flowers are small and green in color; the male flowers are found on the end of the upper stems and are a cylindrical spike. Seeds can remain viable in the soil for several years.

Giant ragweed does not tolerate close and frequent mowing which can be one cultural method for control. Preventing it from going to seed will assist in future years for control as well. Use of most three way products has been effective in turf, and use of non-selective translocated products will provide partial control in landscape and nursery settings. Early management is the key to controlling giant ragweed.

Giant ragweedJames H. Miller & Ted Bodner, Southern Weed Science Society, Bugwood.org

Hardy gardeniaPhoto: Ginny Rosenkranz, UME

Degree Days (As of July 12)*Baltimore, MD (BWI) 2325 Dulles Airport 2239 Frostburg, MD 1461 Martinsburg, WV 2119 National Arboretum 2663 Reagan National 2663 Salisbury 2389 *As of May 11, degree day calculations are from weather.com growing degree day calculations instead of NOAA min and max tem-peratures. To check degree day (DD) accumulations in your local area go to: http://www.weather.com/outdoors/agriculture/growing-degree-days/USMD0100

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

LOCATION

Eupatorium purpureum First bloom (July 16) Ellicott CityHibiscus moscheutos Full bloom (July 16) Ellicott City

Plants in Bloom

Thousand Cankers Bus Tour in Virginia - Saturday, September 8th, 2012On Saturday, September 8th, there will be a chartered bus tour to the recent Thousand Cankers Disease outbreak sites, near Richmond, Virginia. There, participants will have the unique opportunity to get hands-on experience identifying this disease, which is likely to be appearing in Maryland soon. The trip will also include lunch, and a visit to a local arboretum. Many of the details are still to be determined, but for now, please mark your calendar for September 8th. More details, including registration fee, will be available at a later date. If you have any questions, Contact Dave Robbins, Maryland Chapter of the Walnut Council, at 301-791-4010 or drobbins@dnr.state.md.us.

August 6, 2012 Cut Flower TourSites: M and M Plants, Dickerson, MD and Farmhouse Flowers and Plants, Brookeville, MDTime: 8:30 a.m. to 3:30 p.m.Sponsored by University of Maryland Extension in cooperation with Maryland Greenhouse Growers’ Association and the Association of Specialty Cut Flower Growers

For a brochure, go to http://ipmnet.umd.edu/conferences/index.htm

Stanton GillExtension Specialist

sgill@umd.edu

Paula Shrewsbury Extension Specialistpshrewsb@umd.edu

Ginny RosenkranzExtension Educatorrosnkrnz@umd.edu

Chuck SchusterExtension Educator

cfs@umd.edu

Karen Rane Plant Pathologistrane@umd.edu

Brian Clark Extension Educator bpclark@umd.edu

Andrew RistveyExtension Specialistaristvey@umd.edu

David ClementPlant Pathologist

hgic.umd.edu

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.

Upcoming Programs

PANTS 2012 (Pennsylvania Nursery Trade Show)July 31 to August 2, 2012Location: Greater Philadelphia Expo Center, Oaks, PAwww.pantshow.com/2012

OFA Perennial Production ConferenceSeptember 10 - 12, 2012Location: Grand Rapids, Michiganofa.org

IPPS Eastern Region Annual MeetingOctober 10 - 13, 2012Location: Brandywine Valley, Pennsylvaniahttp://www.ippseastern.com

2012 Pest Management ConferenceDecember 13, 2012Location: Carroll Community College, Westminster MD

Mark Your CalendarChesapeake Green 2013A Horticulture Symposium

February 14 and 15, 2013

at the

Maritime Institute, Linthicum Heights, MD

(near BWI)