TPM/IPM Weekly Report

TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers Commercial Horticulture March 30, 2012 In This Issue... - Ambrosia beetles - Emerald ash borer - Six-spotted tiger beetles - Sapsucker damage - Pachysandra problem - Asian longhorned beetle - Lecanium scale - Bullet galls - Pollen count - Eastern tent caterpillars - Boxwood blight - Cold damage - Caterpillar on cherry laurel - Euonymus leafnotcher caterpillar - Japanese maple scale and San Jose scale - Powdery mildew - Boxwood psyllids - Aphids - Mining bees - Pine needle scale Weed of the Week Plant of the Week Phenology Degree Days Contacts for Experts Conferences Integrated Pest Management for Commercial Horticulture www.ipmnet.umd.edu Coordinator 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) Ambrosia Beetle Activity I (Stanton) have received samples from alcohol baited Lindgren traps in nurseries in Frederick County, Montgomery County and Hartford County and from Chestnut Society members in 4 counties. These traps were loaded with ambrosia beetles of many species. The one that is in each of the traps in large numbers and is of concern is Xylosandrus germanus. Marie Rojas called in last Friday to let me know that she found Xylosandrus germanus drilling into Cornus Venus TM in Darnestown, MD. Control: If you are planning to apply Peremthrin (Astro) or Bifenthrin (Onyx) to the trunk of susceptible trees, apply it now. 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 At the point where the sap ooze originates, you can just make out the rear of the beetle Photo: Marie Rojas

Control Options for Emerald Ash Borer Stanton Gill David Smitley, Michigan State University, spoke at the Invasive Species Training on March 21st on his work evaluating different control materials for emerald ash borer. David applied imidacloprid at 1 oz per every one inch of trunk diameter as a basal soil drench to trees under 8 diameter at breast height (dbh). They obtained good control for one year on these treated trees. For trees with dbh greater than 8, make two applications in the spring. The best control with this material has been a one year period. David also mentioned that dinotefuran will give season long control as trunk sprays or basal drenches. The longest control has been obtained using TREE-age (Emamectin Benzoate). Emamectin benzoate is owned by Syngenta company and they have an agreement with Arborjet for selling the product for professional arborists and horticulturists. Arborjet has released emamectin benzoate to Rainbow Tree Company. Smitley did trials making fall and spring applications. The results showed that emamectin benzoate trunk injections provided excellent protection for 3 years for 15-17 dbh trees. The label states 2 years of control. Smitley felt this was a conservative estimate since their research found that for trees under 20 dbh, three years of control is obtainable. Larger diameter trees may only obtain 2 years of control. An ISA journal article on David Smitley s research is available at http://joa.isa-arbor.com/request.asp?journalid=1&articleid=3166&type=2. Smitley pointed out that emamectin benzoate is effective in controlling lepidotperous species. It appears to control banded winged clearwing borer on ash treated with this product. This is not true for imidacloprid treated trees since this product is weak on lepidopterous species. Smitley conducted trials for control of mimosa webworm on honey locust trees using the emamectin benzoate and control was excellent. Six-spotted Tiger Beetles (Not Emerald Ash Borer) At this time of year, there is a metallic green beetle that is active. It is often found flying along open paths in wooded areas. It is the six-spotted tiger beetle, a predator. We receive photos of it through the season because people suspect it as an emerald ash borer (EAB) adult. Both are metallic green in color, but the tiger beetle is a larger and wider beetle than EAB. Look for the six white spots on the tiger beetle to help with identification. Emerald ash borer adult (left) and six-spotted tiger beetle adult (right) Sapsucker Damage Linda from Facilities Unlimited sent in a photo of sapsucker damage on Ilex Nellie Stevens. The damage occurred in the fall. Sapsucker activity can girdle the tree and cause dieback. Yellowing on Pachysandra Nadine Horenstein, John Shorb Landscaping, is seeing pachysandra at several sites with an unusual amount of yellowing on the foliage this season. Is anyone else seeing this yellowing occur? They are running soil tests and will be sending us photos. 2 Sapsucker damage Photo: Linda from Facilities Unlimited

Asian Longhorned Borer At the March 21st Invasive Species Training, Michael Smith from USDA-ARS lab in Delaware talked about Asian longhorned borer (ALB) developments. In his talk he covered the work on new traps to detect ALB. He noted that the problem is that none of the traps pull the ALB from long distances and apparently they have to be close to the insect to get it to go to the traps. Once at the trap, the beetles tend to cling to the trap and if they do not find a mate at the trap they fly off. Michael is working on materials to coat the trap to make it more slippery to get the beetles to fall into the collection cup. Next Monday, I (Stanton) will be going to Longwood Gardens for training on using a new ALB that the Pennsylvania Department of Agriculture developed and is testing in PA for detecting ALB. I will let you know if this trap is working for us later in the season. The ALB trap that Michael Smith In the fall of 2011, Asian longhorned borer was displayed at the meeting found in Ohio, just outside of Cincinnati. The Ohio Department of Agriculture is still delimitating how much area is infested, but it is estimated that it is large (possibly over 100 square miles). This information is not good news since this beetles kills maples and many other species of plants. If you find a large black beetle with white spots on its exoskeleton, please get the sample to us or MDA. Asian longhorned beetle adult Lecanium Scale (Parthenolecanium quercifex) Steve Sullivan, The Brickman Group, brought in a sample of willow oak with an infestation of lecanium scale. This scale overwinters as immatures on the twigs. Look for crawlers on leaf veins from mid-june through September. There is one generation per year. Control: Dinotefuran (Safari, Transtect) or imidacloprid (Merit) can be applied as a soil drench for lecanium scale. Use oil to control crawlers when activity begins in mid-june. Lecanium scale immatures along willow oak twig Bullet Galls on Oak There were also small bullet galls, caused by a cynipid wasp, Disholcaspis quercusmamma, on this willow oak sample. There is not much that can be done about bullet galls since they are well protected within the gall from insecticides. There are numerous species of parastitoids that attack the wasps that make these galls. Bullet oak gall developing on willow oak twig 3

Pollen Counts Up The NOAA weather reports high oak pollen counts this week. If you have allergies they may act up this week. Eastern Tent Caterpillars We have been getting reports of Eastern tent caterpillar activity over the last week: Chris McComas, UME Home & Garden Information Center, reported seeing many small tents getting started on roadside trees in western Howard County near Mt. Airy. Marie Rojas reported finding very small tents on cherry on March 24 in Montgomery County. She noted that there are much fewer than expected at this point in time. Jim DeRamus found tents starting to show up on crabapples in Wheaton around March 19. Sam Fisher, Woodacres Tree Specialists, saw some active tents on March 23 in Potomac, MD. Matt Anacker, A&A Tree, reported caterpillars active in Baltimore. David Keane, Howard County Recreation and Parks, is reporting caterpillar activity in Frederick. Damian Varga, Scientific Plant Service, found them just hatched this week in Anne Arundel County. Bob Mead, Mead Tree Experts, found them active in Montgomery Village in Montgomery County. Control: Physically destroy tents if possible. Bacillus thuringiensis (B.t.) works well for early instars. Other good caterpillar controls include Confirm (tebufenozide), Conserve (spinosad), or Acelepryn (chlorantraniliprole). Boxwood Blight Found In Ohio The Ohio Department of Agriculture (ODA) announced the discovery of boxwood blight at a nursery in Lake County in northeast Ohio. Boxwood blight is a disease caused by a fungus (Cylindrocladium pseudonaviculatum) that threatens the health and sustainability of boxwood plants. This is the first detection of boxwood blight in Ohio. As previously reported, boxwood blight was first detected in the United States in North Carolina in October 2011. It was confirmed in Maryland in December 2011. Plant pathologists in the United Kingdom first identified the disease in the mid-1990 s. It is unclear how the disease was introduced into the United States. To date, Ohio is the 10th state to identify boxwood blight. Cold Damage With the cold snap that occurred early this week, some plants across the region suffered damage. Debbie Ricigliano, Home and Garden Information Center, sent us photos of some of the damage. Eastern tent caterpillar nest Photo: Ginny Rosenkranz Cold damage on Deutzia gracilis Nikko Photo: Debbie Ricigliano, HGIC Cold damage on Hydrangea macrophylla Endless Summer Photo: Debbie Ricigliano, HGIC 4

Caterpillars on Cherry Laurel (Prunus laurocerasus) Steve Sullivan brought in a sample of cherry laurel that had caterillars feeding on the foliage and rolling the leaves with silk. They are leafroller caterpillars that are causing this damage. Control: If necessary, options include Orthene (acephate) or Acelepryn (chlorantraniliprole). Leafroller caterpillar on cherry laurel Euonymus Leafnotcher Caterpillar Damian Varga reported activity of the euonymus leafnotcher caterpillar in Anne Arundel County on March 30. He noted that he is surpised to see it causing so much damage since the euonymus plants had been sprayed earlier. So far in Maryland, this caterpillar has only been reported in Anne Arundel County. If you see it in other areas, please let MDA know. Control: Options include Conserve (spinosad) and Confirm (tebufenozide). Japanese Maple Scale, San Jose Scale and Tuliptree Scale Marie Rojas brought in a Knockout rose sample that had two armored scales on it. One was the Japanese maple scale (JMS) and the second was San Jose Scale. Both scales were 3rd instar females. Marie is also finding JMS on other plants including magnolias and stewartia. Ginny Rosenkranz, University of Maryland Extension, brought samples of rose and euonymus that were heavily infested with JMS. San Jose scale should be going to crawler stage in May. It may be earlier with the unusual season, but we will keep you posted. The Japanese maple scale usually goes to crawler in June. The last scale reported by Marie is tuliptree scale which is in the immature stage on Magnolia stellata. This scale does not go to the crawler stage until September. San Jose scale Control: Applications of 0.5-1% horticultural oil and pyriproxyfen (Distance) or buprofezin (Talus) can be made when crawlers are detected. Marie found a twice-stabbed lady beetle adult feeding on some Japanese maple scale. This predaceous beetle provides some biological control of this scale. Japanese maple scale on rose (left) and on euonymus (middle); a twicestabbed lady bird beetle feeding on JMS (right). 5

Powdery Mildew Paul Wolf, Integrated Tree Care, called in to make the first report of powdery mildew of the season on euonymus shrubs in Northwest Washington. He said the infestation was fairly heavy. Powdery mildew was also showing up on euonymus in Columbia this week. The bright sunny days and cool nights must have been perfect weather for this fungus. Boxwood Psyllid Rich Anacker, A&A Tree Experts, Inc., reported finding boxwood psyllid damage on plants in Stevenson (Baltimore County) on March 28. Boxwood psyllid nymphs feed within new foliage and produce a white wax within the cupped leaves. In most cases, control is not necessary. Aphids Aphids continue to be active on woody plants in the region. Rich Anacker found them on Knock Out roses in Baltimore on March 28 and Beth Clark, Bob Jackson Landscapes, Inc., also found aphids on Knock Out roses in Easton on March 23 and on spirea in Pikesville on March 28. Craig Greco, Yardbirds, Inc., found them on roses in Vienna, VA. Craig also found a lady bird beetle feeding on aphids on another woody plant. Monitor plants with aphids for predator activity. These predators can do a good job reducing the aphid population to where control is not necessary. Aphids on rose (left) and lady bird beetle feeding on aphids (right) Photos: Craig Greco, Yardbirds, Inc. 6

Mining Bees Rob Meier is reporting mining bee activity on the grounds of Montgomery Village Foundation. There were 75 to 100 mounds in one particular area. Chuck Schuster, University of Maryland Extension, is also receiving calls about these bees which are very beneficial for pollination and should not be killed. Mining bees are not aggressive and seldom, if ever, sting. Mining bees, or digger bees, are solitary bees that nest in burrows in the ground. Mining bees are about the size of honey bees or smaller. Look for mining bees where there is exposed soil and good drainage. Holes are about a 1/4 inch in diameter or smaller and are often surrounded by mounds of soil. Pine Needle Scale (Chionaspis pinifoliae) Tony Murdock, Fine Pruning, found pine needle scale on red pines last week. This scale is also often found on white pine, Japanese black pine, Scotch pine and mugo pine. This scale is similar to juniper scale which has crawlers that are active two weeks earlier. Look for yellowing of foliage and dieback of branches. This scale overwinters as females and eggs. The reddish nymphs are active in May and a second generation is active in July through August. Control: Talus or Distance mixed with 1% oil is a good control if the population is high enough to warrant an application. Termites in Mulch We have been receving reports of termite activity in mulch this month. An article with more information is available in the April 27, 2007 IPM Report (http://ipmnet.umd.edu/landscape/lndscpalerts/2007/07apr27l.pdf. Weed of the Week, Chuck Schuster Field violet, Viola rafinesquii Greene, is a winter annual found in turf and landscape settings throughout the northeastern United States. This plant is already flowering in turf this spring. With a light purple and white flower, the plant can reach heights of twelve inches in fertile soils. Leaves are alternate, occur on a petiole, and are oval in shape with a rounded and toothed margin. The plant starts as a rosette. Leaves are three quarters to one and one half inches in length and almost that much in width. Leaves on the upper portions of the plant may be longer than wide, up to three inches in length and less than three quarters of an inch in width. Leaves have hairs along the veins on the leaf undersides and on the stem. Flowers are on a long flower stalk. Most flowers are one half inch in diameter with five petals that are as long as the sepals. Field or wild pansy is similar, but leaves will not have hairs, and flowers are white and yellow. Wild pansy has a diffuse root system that may produce a faint wintergreen fragrance. Control can be obtained using combination products with MCPA, triclopyr and dicamba, and glyphosate products. While other products can be used in turf settings, the use of these products will not be safe in nursery or landscape settings. Be cautious when using glyphosate products in nursery settings and close to desirable plants in landscape settings. 7 Viola raninesquii Photo: Chuck Schuster, UME

Plant of the Week, Ginny Rosenkranz Euphorbia x martinii Ascot Rainbow spurge, is a primitive plant with variegated creamy yellow, lime green and red bracts that are often mistaken for flowers. The grey, green and gold lanceolate leaves grow up to 3 inches long, have a white midrib and are arranged on a purple stem in an alternate pattern. In the early spring and fall, the cool weather brings out a rosy tint of color on the leaves. The colorful bracts bloom from March to April and appear on top of the plants. All Euphorbia have a milky white sap that can be a skin irritant, so gloves should be worn when working with and around the plants. Euphorbias do best in full sun, but need part shade in the late afternoon. Although they need moist but well drained neutral soils, once established they can be very heat and drought tolerant. They grow in USDA zone 6-8. Crown 8 Euphorbia Ascot Rainbow Photo: Ginny Rosenkranz, UME rot and mildew can be problems. Plants grow up to 20 inches tall and will stay upright from early spring to late fall. A versatile plant, Euphorbia Ascot Rainbow can be planted in the landscape as an edging or border plant or in a container. Plant Phenology: What s in bloom PLANT PLANT STAGE (Bud with color, First LOCATION bloom, Full bloom, First leaf) Amelanchier canadensis Full bloom (March 29) Columbia Viburnum carlesii First bloom (March 23) Clinton Podophyllum peltaum (mayapple) First leaf (March 24) Columbia Cercis canadensis First bloom (March 22) Full bloom (March 26) Columbia Degree Days (As of March 29) Baltimore, MD (BWI) 207 Dulles Airport 217 Frostburg, MD 134 Martinsburg, WV 193 National Arboretum 250 Reagan National 278 Salisbury 378 Who can you contact for help with plant problems? Diseases: Karen Rane: rane@umd.edu, 301-405-1611 Go to www.plantclinic.umd.edu for information on how and where to submit suspected disease samples to her lab. Insects: Stanton Gill: sgill@umd.edu, 410-868-9400 (cell) or 301-596-9413 (office) Paula Shrewsbury: pshrewsb@umd.edu, 301-405-7664 Brian Clark: bpclark@umd.edu, 301-868-8780 (Brian covers Prince George s County) Weeds: Chuck Schuster: cfs@umd.edu, 301-590-2807 Soil Substrates Plant Fertility: Andrew Ristvey: aristvey@umd.edu, 410-827-8056 Horticulture: Ginny Rosenkranz: rosnkrnz@umd.edu, 410-749-6141 ext 106 (Wicomico, Worcester and Somerset counties)

NURSERY and GREENHOUSE Grower Nutrient Management Plan Certification Training Wednesday, April 11, 2012, 9am - 3pm. Attend this session if you need to become certified to write and update your own Nutrient Management plan. Location: Wye Research and Education Center, 124 Wye Narrows Drive, Queenstown, MD 21658 For registration information, please contact Debby Dant 410-827-8056 X115, ddant@umd.edu. For program information, contact Andrew Ristvey, aristvey@umd.edu or John Lea-Cox, jlc@umd.edu. NOTE: There is no cost for this program, but you need to confirm attendance since Extension will provide lunch. Upcoming Programs 2012 Interstate Ornamental Plant Mngt Conference April 4, 2012 Location: Maritime Institute, Linthicum Heights, MD Contact: Avis Koeiman, 301-405-3913 May 23, 2012 9:30-3:15 Invasive Species Identification and Management Seminar Location: 12055 Government Center Parkway, Fairfax, VA Cost: Free, but registration is required. To register please go to: http://ffxpest.eventbrite.com Contact: Jack Baggett 703-324-5542, John.baggett@ fairfaxcounty.gov ASCFG Mid-Atlantic Regional Meeting June 18, 2012 Roost Flowers and Design Location: Virginia Beach, Virginia ascfg.org CONTRIBUTORS: 2012 Perennial Plant Symposium July 4-10, 2012 Location: Boston, Massachusetts perennialplant.org OFA Short Course July 14-17, 2012 Location: Columbus, Ohio ofa.org OFA Perennial Production Conference September 10-12, 2012 Location: Grand Rapids, Michigan ofa.org Stanton Gill Extension Specialist sgill@umd.edu Paula Shrewsbury Extension Specialist pshrewsb@umd.edu Karen Rane Plant Pathologist rane@umd.edu Chuck Schuster Extension Educator cfs@umd.edu Ginny Rosenkranz Extension Educator rosenkrnz@umd.edu David Clement Plant Pathologist hgic.umd.edu Andrew Ristvey Extension Specialist aristvey@umd.edu Brian Clark Extension Educator bpclark@umd.edu Thank you to the Maryland Arborist Association, the Landscape Contractors Association of MD, D.C. and VA, the Maryland Nursery and Landscape Association and FALCAN for your financial support in making these weekly reports possible. Photos are by Suzanne Klick or Stanton Gill unless stated otherwise. The information given herein is supplied with the understanding that no discrimination is intended and no endorsement by University of Maryland Extension is implied. 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.