for Arborists, Landscape Managers & Nursery Managers

Commercial Horticulture September 13, 2013Coordinator 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) 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- Scale update- Redheaded sawfly- Hercules beetles- Bagworms- Crapemyrtle aphids- Hemlocks with yellowing needles- Leafhoppers- Scarab beetle grubs- Lawn fertilizer law- Home and Garden Information Center

Plant of the WeekAnnouncementsDegree Days

A New Address for IPMnet

Integrated Pest Management for

Commercial Horticultureextension.umd.edu/ipm

Wet Summer Ending in Very Dry PeriodIn August, we reported that it was one very wet summer. Now, since the beginning of September, the rain has mostly stopped. Areas did get some rain yesterday. Several nursery owners and landscapers are reporting that the soil is bone dry. The extremely wet summer caused soil moisture levels to be high resulting in root rots in several plants. Now that we are in a sunny, dry period many of the plants with compromised root systems are showing scorching symptoms. We are getting many reports of large oak trees and hickory trees in wooded landscapes that are showing branch dieback and in some cases whole trees dying. Many of these declining trees are dying from going through over 7 years of dry summer periods, followed by a wet summer. The stress on these trees make them susceptible to secondary borers such as the two-lined chestnut borer and various root rot organisms and canker diseases. In naturally wooded lots, the big trees are normally replaced by the younger trees. Unfortunately, in many landscapes the owner had the young replacement seedling removed and just maintained the large trees which has cut off the supply of young vigorous trees to replace the older declining trees. In these cases, all that can be done is either remove dying branches or in some cases take the declining trees down.

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Scale Updates

White Prunicola Scale (WPS, armored scale): Monitoring WPS in Laytonsville on Wednesday September 11, found varying life stages (many females that have not produced eggs, few females with eggs, and many CRAWLERS). The Degree Days per weatherchannel.com were 3019 DD. If degree day accumulations in your area near or at 3019 DD, you should closely monitor plants infested with WPS.

If you customer has cherry laurel in their landscape check it now for the presence of white prunicola scale. We have been seeing this armored scale increasing in populations on cherry laurels over the last 3 years. This is the third generation for this season. Nancy Harding has been monitoring this scale this season and she is finding crawlers active this week. If you are going to obtain control now is a good time to take action. Applications of one of the two Insect Growth Regulators (IGRs), Distance or Talus, should go on now for the most effective control and least impact on beneficial organisms.Control: When crawlers are out, apply pyriproxyfen (Distance) or buprofezin (Talus) mixed with 0.5 - 1%

Indian Wax Scale: We received a report from a nursery with Indian wax scale. There is only one generation a year. At this time of year, look for the red overwintering female underneath the thick, waxy covering. Be sure to check plants next year for crawlers in early to mid June.

Redheaded SawflyRedheaded sawflies are out and feeding on pines in September. Jeff Schwartz, Ashton Manor Environmental, found them active in Bowie and Bob Nixon, Master Gardener, found them on a mugo pine in Howard County.Control: If possible, prune off tip growth on which they are feeding and destroy. Horticultural oil or spinosad (Conserve) sprayed onto the larvae are two options for control.

Hercules BeetlesKerry Kelley, Homestead Gardens, found three hercules beetles on empty carts recently. Every so often we get a report of one. Years ago, we had a nursery grower who found about a dozen at one time. Hercules beetles feed on decaying plant material.

A female hercules beetle. Color varies due to moisture level - beetles are black when wet and lighten up and become mottled as they dry out

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Crapemyrtle AphidsMark Quesenberry, Damascus Enterprises, Inc., noted that he has been fighting quite the infestation crapemyrtle aphids for the past two months on two properties spraying between Talstar and Permethrin G with little control. Two weeks ago he did a foliar application of Merit. Mark noted that this week when he checked one of the properties, there were only a few aphids on four large trees.

Hemlocks With Yellowing Older NeedlesTodd Armstrong, The Davey Tree Expert Company, Inc., has received reports from his clients who have hemlocks needles on small branches turning yellow. Their lab report notes that no insects or diseases were present and the cause was likely abiotic such as root or drought stress. Hemlocks do lose their older needles about every 3 - 5 years.

Trees are not the only places you’ll find bagworms. Tony Murdock, Fine Pruning, found this one on a wall. Photo: Tony Murdock, Fine Pruning

BagwormsRichard Chaffin, The Brickman Group, reported emergence of an adult male bagworm in Baltimore county on September 11. Debby Smith-Fiola, IPM Scout, reported that males had emerged from the bags in Keedysville and the females had not laid any eggs yet. Pick off bags of trees at this time of year. Some bags will be empty since males have emerged from them. The female does not fly and lays eggs in the bag before dying.

Adult male bagwormPhoto: Mark Dreiling, Retired, Bugwood.org

Yellowing on older hemlock needlesPhoto: Todd Armstrong, Davey Tree Experts, Inc.

LeafhoppersLeigh Cochrane, Master Gardener, sent in photos of marigolds and parsley with heavy damage from leafhoppers. A nursery grower is also seeing unusually heavy damage on trees this month. Is anyone else seeing heavy damage? Let us know at sgill@umd.edu.

Leafhoppper damage on marigoldPhoto: Leigh Cochrane, Master Gardener

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Lawn Fertilizer Law Information on Maryland’s Lawn Fertilizer Lawn including review sessions and testing dates and a pdf version of The Professional Lawn Care Manual are available at: http://mda.maryland.gov/fertilizer. Review Dates and Locations: There is no cost to attend, however, seating is limited and pre-registration is required. The review sessions are not designed as training sessions. Please do not attend the review session if you have not read the manual. EastonSeptember 18, 20139:30 – noonTalbot County Free Library100 West Dover StreetEaston, MD 21601

Carroll Community CollegeDecember 11, 2013(Review in the morning and test in the afternoon)

Testing Dates and Locations: Easton September 18, 12:30-2:30 pm and 3:00-5:00 pm (Easton)December 11 (Westminster)

Turfgrass Nutrient Management LawFor the last couple of weeks we have advertised that the turfgrass nutrient management law goes into effect on October 31, 2013. There are several training sessions and exams dates that have been set up in the State. Once you take and pass the exam MDA will require that you obtain Continuing Education Units (CEUs) by July 1 2014. MDA will be counting several of the University of Maryland Extension conferences for CEU credits. The conferences that will count toward CEU will be announced in upcoming IPM Alerts. The session that we will be holding on December 11, 2013 at the Carroll Community College will help prepare those that will be taking the test for the first time, but it will also count for CEU for those that have taken the test and passed and now need CEU credits.

The Home and Garden Information Center (HGIC) Has Answers for Your Customers“How long do I have to water those new shrubs?” “Why did that tree die?” “What are those gross looking green and black worms eating my mugo pine?” Homeowners have lots of questions about their plants that can eat into the time of busy green industry professionals.

Not to worry... University of Maryland Extension’s Home and Garden Information Center has REAL PEOPLE on hand ready to answer all types of homeowner questions related to gardens, landscapes, lawns, insects and wildlife. These trained and experienced staff members are Certified Professional Horticulturists, supported by Extension Specialists and the University’s resources.

So please help yourselves and your customers by directing them to HGIC. Homeowners can get answers by...Calling 1-800-342-2507; Mon.-Fri., 8am-1pm Sending questions through the website 24/7 (they are answered within 48 hours)Receiving the free, monthly e-newsletter

Scarab Beetle GrubsMark Schlossberg, ProLawn Plus, Inc., is reporting more scarab beetle grubs in turf in Phoenix on September 13.

Scarab beetle grubsPhoto: Mark Schlossberg, ProLawn Plus, Inc.

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Hydrangea ‘Limelight’Photo: Ginny Rosenkranz, UME

2013 TREES MATTER SYMPOSIUM Trees and the Built Environment Sponsored by The Maryland-National Capital Park & Planning Commission, Montgomery Parks’ Horticulture, Forestry and Environmental Education Division

November 20, 2013 8:00-4:00 Silver Spring Civic Building, 1 Veterans Place, Silver Spring, MD 20910 Attend the second annual Trees Matter Conference to learn from some of the country’s leading experts about innovative efforts to plant, protect and preserve trees in urban and suburban settings.

Trees Matter 2013 is ideal for arborists, municipal employees, landscape industry professionals, designers, engineers, green industry employees and anyone interested in the latest research on trees. Approved for International Society of Arboriculture & Certified Professional Horticulturist CEU’S.

To register or for more information, please visit http://www.montgomeryparks.org Advanced registration is $59 by to October 18 and $79 after October 18. Register for course #252399 at www.parkpass.org

Featured Speakers:

David Milarch, Co-founder of Archangel Ancient Tree Archive, Champion Tree Project International. Kim Steiner, Professor of Forest Biology at the Pennsylvania State University Doug Tallamy, Professor in the Department of Entomology and Wildlife Ecology at the University of Delaware and author of “Bringing Nature Home; How Native Plants Sustain Wildlife in our Gardens” Susan Day, Assistant Professor in Urban Forestry and Director of the Urban Horticulture Center at Virginia Tech Guy Meillieur, Practicing Arborist, Aerial Consultant and Owner of Better Tree Care

Plant of the Week, Ginny RosenkranzHydrangea paniculata ‘Limelight’ is a deciduous shrub that blooms from mid-summer with large lime-colored cone-shaped flower panicles that can grow up to 12 inches long. The flowers start out creamy white then mature to a lime chartreuse color that becomes a pink or rose color before fading into a soft tan. Flowers are mostly sterile so they seldom go to seed, and they persist on the plants into the winter months. ‘Limelight’ is a more compact variety of the Hydrangea paniculata or Pee Gee Hydrangea, growing 6-8 feet tall and wide rather than the 6-15 feet the species grows. Plants grow best in slightly acidic soils, in full sun or partial shade and thrive in USDA zone 3-8. The shrub grows in a vase shape with the dark green foliage turning red in the fall. They can be planted in a mixed shrub border or hedge and can be a specimen accent plant as well. Aphids, rose chafers, oystershell scale, and twospotted spidermites can be insect pests while bacteria wilt, leaf spot, powdery mildew and rust are the diseases that can affect the plants.

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

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.

Degree Days (As of Sept 12)Baltimore, MD (BWI) 3328 Dulles Airport 3153 Frostburg, MD 2111 Martinsburg, WV 3074 National Arboretum 3783 Reagan National 3783 Salisbury 3627

To check degree day (DD) accumulations in your local area go to: http://www.weather.com/outdoors/agriculture/growing-degree-days/USMD0100

Note: degree days reported in this newsletter for various pests use the Weather.com web site, a base temperature of 50 °F, a start date of January 1st, and the date of monitoring as the end date.

November 7, 2013- Greenhouse Seminar at Chesapeake CollegeMaryland greenhouse growers and industry experts that are experienced in growing tougher to grow greenhouse crops will share some of their secrets on how to produce quality plants.

Several growers are moving fertility management to lower rates of nitrogen and potassium and higher rates of micronutrients. This produces better quality plants with lower fertilizer inputs. Dr. Cari Peters of Peter’s Lab will talk about this method at the conference. There will also speakers talking about new markets to investigate.

This conference will cover full private pesticide recertification credit and full credit for Category B interior ornamental) recertification.

Get a copy of the schedule and registration information at https://extension.umd.edu/ipm

Upcoming Programs

Go to https://www.extension.umd.edu/ipm/conferences