TPM/IPM Weekly Report

TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers Commercial Horticulture June 1, 2012 In This Issue... - Brown marmorated stink bugs - Main peachtree borer - Rust on amelanchier - Rust on ash - Oriental borer - Rose rosette disease - Twospotted spider mites - Clover comments - Tick information - Monarch caterpillars - Imprelis information - Brown patch in turf - Lecanium scale on callery pear - Lecanium scale on oak - Arborvitae tip blight - Clematis - EAB quarantine update - Japanese maple scale update Beneficial of the We Weed of the Week Plant of the Week Degree Days Phenology 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) Brown Marmorated Stink Bugs With the temperatures reaching into the 90s last weekend, adult brown marmorated stink bugs went wild. In black light traps in Westminster, very high numbers of adult bugs were captured on Saturday and Sunday. On a glass window the count was over 150 bugs on Monday afternoon. The adults are laying eggs on plants now, and eggs were found on tomato and pepper foliage on May 28. Brown marmorated stink bug nymphs (June 2, 2011) On June 12 and 13, 2012 there will be a meeting of entomologists in Carroll County. We will give you an update after the meeting on any new developments in control strategies. 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 Upcoming Programs June 7, 2012 MAA Pest Walk - Prince Frederick, Maryland June 8, 2012 Recertification Conference - Derwood, Maryland June 21, 2012 MNLA Field Day - D.R. Snell Nursery, Union Bridge See page 10 for links to conference details

Main Peachtree Borer Adult activity of the main peachtree borer increased heavily over the weekend. Now is the time to apply protectant sprays to the trunks of susceptible tree species. Rust on Amelanchier On a visit to a Maryland nursery we saw the most incredible rust infection caused by a Gymnosporangium sp. of fungi. The moisture levels must have been ideal for spread of the rust spores this spring. The spores produced on serviceberry or others in the rose family only infect the alternate hosts which include junipers or cedars. The spores produced on junipers and cedars infect only members of the rose family in early spring. Preventative sprays would have to be applied in early spring not much to do now. Rust on Ash From Glenn Gladders, Forest Health Specialist, Delaware Forest Service: On May 31, I visited a landowner in Smyrna, Delaware who was concerned about a white ash tree on the property. I diagnosed ash rust based on the presence of distinctive fruiting structures on the undersides of the leaves. Ash rust is a fungal disease caused by Puccinia sparganioides, which requires certain cord and/or marsh grasses as alternate hosts. This is an interesting and fortunately rarely serious disease that we have not seen much in Delaware since 2006. 2006 was a banner year, though, probably because of spring weather conditions favorable to disease development. Ash rust on white ash Photo: Glenn Gladders, Delaware Forest Service More rust: We are receiving quite a few reports of rust this spring. Gaye Williams sent photos of rust on pear. Oriental Beetle, Anomla orientalis I (Stanton) have not seen a sample of oriental beetles for many years, but we received samples from a container nursery in Maryland with larvae present. The larvae (grubs) feed on roots of woody plants and perennials in nurseries and on turf in the landscape. Adults can cause some damage to flowers, but flower damage does not seem to be significant. Control: Insecticides such as imidacloprid and bifenthrin can be used to control grubs. 2 Gymnosporangium sp. on pear Photo: Vanessa Orlando, MDA Oriental beetle larva and adult

Rose Rosette Disease By Penny Wolkow, UMD Diagnostic Lab We are receiving reports of rose rosette in the landscape again this year. Once thought to be a useful biocontrol for wild multiflora roses, the disease Rose Rosette has moved on to infecting cultivated ornamental roses. Depending on the cultivar, symptoms include witches broom with small distorted leaves, rapid elongation of new shoots, an overabundance of thorns, distorted buds and flowers, and a reddish coloration of the leaves and stems (See photo 1). Infected plants may die in a couple of years. Rose Rosette is thought to be caused by a virus that is spread by tiny eriophyid mites. These mites can be blown by wind currents, spreading easily from host to host. At this time, there is no effective control for the disease other than prevention by complete removal and destruction of infected plants. When planting new roses, stay at least 100 meters away from areas where multiflora roses may be, and avoid planting downwind from them. Space new plants so their canes and leaves won t come into contact with each other. Efforts to produce resistant cultivars are ongoing. There is no simple diagnostic test to confirm rose rosette disease in the UMD Diagnostic lab, we use a microscope to check symptomatic rose tissue for the presence of the mites in order to make a diagnosis. Complicating the diagnosis of this problem is the fact that similar symptoms, especially the witches broom, can be caused by contact with the herbicide glyphosate (see photo 2). Symptoms of glyphosate injury may not appear until spring if application occurred in late summer or fall. Many plants will eventually recover from inadvertent exposure to a low concentration of glyphosate. Photo 1. Rose Rosette on multiflora rose Photo: Dawn Dailey O Brien, Cornell University, Bugwood.org Photo 2. Glyphosate injury on rose. Photo: HGIC Diagnostics website Twospotted Spider Mites Debbie Ricigliano, HGIC, brought in a sample of laurel showing bronzing on the upper sides of leaves. There was a heavy population of spider mites on the undersides of the foliage. Twospotted spider mite activity is a bit early this spring with the hot, sunny weather which provides perfect conditions for spider mite development. Check the undersides of the leaves for the presence of mites and eggs. Control: Horticultural oil can be used when temperatures go down; Other materials include Abamectin (Avid), Bifenazate (Floramite), Spiromesifen (Judo for nursery use and Forbid for landscape use - both have translaminar action). Bronzing/stippling caused by twospotted spider mite feeding 3

Comments About Clover From: Richard Uva, Ph.D., Seaberry Farm, LLC: Clover seems to like it cool and moist and grows vigorously in early spring and in the fall. It can be hard to control with some herbicides and it has the tendency to creep from the alley into the tree row. Numerous studies in fruit orchards found that despite its ability to fix nitrogen it was actually too strong a competitor and it is not used (see the work of Ian Merwin). It is a popular forage for bees and in orchards eliminating clover is done to protect bees from insecticides that fall to the orchard floor when clover is in bloom. Andrew Senesac did some work on subterranean clover in the 1990s as an orchard ground cover. It is an annual clover that is not naturalized here. I don t recall what his conclusions were, but I don t think it was successful. From Marc Beaudoing, MNCPPC: We have lots of clover here at Pope Farm! Clover in a central Maryland nursery From: Norm Brady, Bartlett Tree Experts: I have been watching the spread of this N-fixing plant for 3 years. I have been trying to accumulate data on, what I consider, an interesting association. N fixing is an expensive process. Plants that fix N regulate the process. There is little benefit in expending energy to accumulate N in excess of a plant s requirements. The association I am interested in is basically territorial. As clover approaches trees it declines in density. This decline does not appear to be related to exposure to sunlight. Clover exhibits this same reluctance to enter the canopy area of deciduous trees prior to their leafing out in early spring. One would assume that N levels would be lower beneath the tree canopy so excess N is not likely to be a factor. What puzzles me is how clover knows it is within the tree canopy and why it finds this area unsatisfactory for growth or undesirable. This association is not prejudicial to species or evergreens vs deciduous. Nor does aspect appear to be a factor. Check any yard that is not being treated with herbicides and I think you will be able to see what I m describing. Tick Information Mark Schlossberg wrote in about an article published in The Baltimore Sun. The article covers the State Health Department s program to control blacklegged ticks using Bifenthrin insecticide. They recruited 185 volunteers from Carroll, Howard and Baltimore counties and it is the 2nd year of the program. Health officials are seeing if it reduces the incidence of Lyme disease. Richard Wingrove, Richard R. Wingrove, NOAA sent in information about a tick removal tool. He noted that I have used it and think it is very good. I have removed around a half dozen ticks off of myself and kids. It worked 100% of the time. If you want to try it out, go to http://www.tickinfo.com/protickremedy.htm for more information. Monarch Caterpillars Matt Katsuleres, UMD, sent us photos of a monarch butterfly caterpillar feeding on butterflyweed (Asclepias tuberosa) on May 29 in College Park. He found four of them on the plants. Monarch caterpillar Photo: Matt Katsuleres, UMD 4

Imprelis Damage: What to Do With Trees in 2012? At the arborist pest walk in May there was a question on what are the best cultural practices for trees that were treated in 2011. DuPont sent companies a letter saying to give the trees good cultural practices but this was not defined. We asked Jeff Derr, Virginia Tech, for his comments on what might be the best care for surviving trees that were treated with Imprelis in 2011. Below is Jeff s answer: There is no cure for Imprelis injury. The focus should be on reducing plant stress from other sources so that the tree does not have to overcome multiple plant stresses. So, irrigate as needed to maintain suitable soil moisture for growth, use mulch to moderate soil temperature and maintain soil moisture (but avoid over-mulching), control any insect or disease pests, address poor drainage issues, avoid injury from mowers and weedeaters, and avoid damage to root systems (trenchers, etc.). The thought has been to avoid fertilization. Hold off pruning except to remove dead tissue or to remove diseased or insect-infested tissue that cannot be addressed otherwise. Hopefully with time the tree will out grow the effects. Brown Patch in Turf Mark Schlossberg, ProLawn Plus, Inc., sent in this photo of the mycelium of the turf brown patch fungus, Rhizoctonia solani, taken early in the morning. The hot, humid weather has been very favorable for this disease, but the shift to cooler temperatures will help reduce the disease. Brown patch in turf Photo: Mark Schlossberg, ProLawn Plus, Inc. Lecanium Scale on Ornamental Pear in Ohio Lorraine Graney, Bartlett Tree Research Laboratory, sent several photos of a heavy infestation of a lecanium scale found on callery pear. Is anyone in Maryland seeing a lecanium scale on callery pears? Lecanium scale crawlers Photos: Lorraine Graney, Bartlett Tree Research Lab Heavy infestation of lecanium scale on callery pear. There is honeydew dripping from the scale (shown by arrow). Photo: Arborist with Bartlett Tree Experts 5

Lecanium Scales on Oaks Lecanium scale is in the crawler stage on oaks in the Olney/Brookeville area this week. Control: Distance or Talus are two good materials to use for control. Soil applications of dinotefuran or imidacloprid are also options. Arborvitae Tip Blight Susan Trice, Master Gardener coordinator from Frederick County, sent in samples of arborvitae with brown tips. I (Dave Clement) found the tip blight disease caused by the fungus Pestalotiopsis funerea. This disease is usually just an opportunistic invader taking advantage of weakened tissue from winter injury or drought, other pathogens or insect stress. Management is usually just a light shearing or pruning to remove the infected tips. Copper based fungicides can also be used if severe. Arborvitae tip blight Photo: David Clement, HGIC Clematis Blight Clematis blight or clematis wilt is caused by the leaf spot fungus Phoma clematidina, formerly known as Ascochyta. The fungus causes a leaf spot that under favorable disease conditions spreads and grows down the leaf petiole and into the stem. When the pathogen infects the stem it causes a girdling canker that causes the plant to wilt first and then die back. Management strategies include ensuring good air movement and quick removal of blighted stems. Possibly a general fungicide such as a copper based product could slow the leaf spot phase of the disease. Clematis blight on clematis Photos: David Clement, HGIC 6

News Release - USDA Updates Emerald Ash Borer Quarantine Policy Federal Order Focuses on Perimeter Areas WASHINGTON, May 31, 2012-- The U.S. Department of Agriculture s Animal and Plant Health Inspection Service (APHIS) today issued a Federal Order updating its Emerald Ash Borer (EAB) quarantine policy. The Federal Order allows unrestricted interstate movement of regulated articles within contiguous federal quarantine boundaries, with the exception of movements to protected areas within the existing quarantine area. The change will become effective on July 1, 2012. The protected areas include any area identified by a state as pest free for which the state has regulations to protect against the human assisted intrastate spread of EAB. APHIS s EAB program seeks to manage the invasive EAB using the best science and tools available, with emphasis on activities that are most effective in stopping/slowing the spread of EAB to new areas. APHIS is now modifying its policy to focus its regulatory efforts on the perimeter of quarantined areas. This will allow for the best use of available resources and reduce the complexity of the requirements for affected stakeholders. The policy change will allow EAB regulated articles to move freely within contiguous quarantined areas, except interstate movement into the protected areas. Movements of regulated materials from quarantined areas to protected areas must be done with a properly issued federal certificate or limited permit. Requirements for movement of regulated materials out of the federal quarantined area, regardless of destination, will remain unchanged. Companies and individuals should also check for and follow any relevant state EAB quarantine regulations. Regulated EAB material includes all ash wood with the bark and sapwood remaining, ash nursery stock, and all hardwood firewood. EAB is an invasive wood-boring beetle, native to China and eastern Asia, which targets ash trees. EAB probably arrived in North America hidden in wood packing materials commonly used to ship consumer and other goods. It was first detected in the United States in July 2002 and has since been found in 15 states. Everyday human activities can facilitate the long distance spread of EAB, and expand the extent and range of the infestation in North America. For this reason, APHIS continues to encourage homeowners, campers, vacationers, and outdoor enthusiasts not to move firewood. The movement of untreated wood products made of ash has been found to advance the spread of EAB. EAB is responsible for the death and decline of tens of millions of ash trees in the United States. To view an updated EAB quarantine map, go to http://www.aphis.usda.gov/plant_health/plant_pest_info/emerald_ash_b/downloads/eab_quarantine_map.pdf click here. For more information on APHIS s EAB program, please visit www.aphis.usda.gov. Japanese Maple Scale On May 29, we received a dogwood sample from Waldorf (977 DD). The dogwood had a great infestation of Japanese maple scale. We found several settled crawlers and mobile crawlers. Japanese maple scale has hatched as of May 31, 2012 (962 DD) in the Gaithersburg area. If you are in these areas it looks like a good time to apply either Talus or Distance. If you are in the Frederick area you probably will find the crawlers this week. Next week would be a good time to start applying either Talus or Distance. If anyone is out in the Allegany or Washington County area I would love to receive in a sample to see what the scale was doing in these areas. Send me, Stanton, an email at Sgill@umd.edu or a sample to CMREC (11975 Homewood Road, Ellicott City, MD 21042). 7

Beneficial of the Week What is that bug on your azaleas? It is red and black and commonly found on azaleas and, not surprisingly, known as the azalea plant bug or Rhinocapsus vanduzeei. It is a true bug (Hemiptera) and belongs to the family of bugs known as plant bugs (Miridae). Rhinocapsus also occurs on other plants in the Ericaceae family and raspberries. Rhinocapsus overwinters as eggs in the stems of azaleas. Egg hatch occurs around azalea bloom, and there is one generation per year. Adults are usually done by mid-july. Rhinocapsus is frequently observed but most people are not sure what they actually are doing on the azaleas. They seem to do a little of everything. Rhinocapsus are omnivores so they feed on prey, pollen and nectar. Rhinocapsus has been observed feeding on azalea lace bugs, whiteflies, leafhoppers, aphids, Weed of the Week, Chuck Schuster The weed for this week is meadow salsify, Tragopogon pratensis. Also know as showy goat s-beard or Jack-go-to-bed-at-noon. It is found throughout the United States in disturbed or poorly maintained areas. The seeds will germinate at temperatures from 55 to 70 F. This biennial will grow to about thirty inches in total height, and it develops from a taproot. During the first year it will form a basal rosette with grass-like leaves. During the second year, meadow salsify will grow in an erect form with leaves that are alternate and become shorter in length as they occur farther up on the stem. The leaves are long and narrow, almost grass-like and two to eleven inches in total length. Leaves appear to be recurved. The flowers appear on the top of the stalk, are yellow (similar to that of dandelion), two inches in diameter with ray type florets that have five small teeth. The seed head is a puff-ball which easily disseminates the seed in the wind. Azalea plant bug adult Photo: Bill Miller, The Azalea Works small flies, thrips, fall armyworm eggs and larvae, twospotted spider mite, azalea leafminer pupae, each other, and azalea pollen and flower parts. In addition, they have an annoying habit of trying to feed on people using their sucking mouthparts. There have been many reports by azalea enthusiasts of being bitten by this small (~3.5mm) bug. It is not clear if the bug feels the need to defend itself from large humans or if it is just hungry and exploring possible meals. Given all of this information I guess we would call Rhinocapsus a beneficial unless you are the one being bitten. Meadow salsify Photo: Mark Schlossberg, ProLawn Plus, Inc. It flowers from early June through mid July. Flowers open in the early morning and close by the afternoon. The stem will emit a milky sap when cut. Both the roots and leaves are edible. This is a broadleaf plant and can be controlled using most three way products in turf, and can be selectively controlled using most non selective post emergent products in landscapes. Plant of the Week, Ginny Rosenkranz Penstemon digitalis, beardtongue (also called smooth white penstemon) is an herbaceous perennial that is a native to the eastern United States. It will thrive in Maryland if it receives full sun and well drained loamy or sandy soils that are slightly acidic to slightly neutral (6.8-7.2) ph. The cultivar Husker Red was named the Perennial Plant of the Year in 1996 and has colorful reddish to maroon foliage all summer long, giving color to the perennial gardens even after the flowers are through. The plants can grow 2-3 feet tall with a spread of 1-2 feet. The leaves that can grow 4-5 inches long are arranged on strong thin stems opposite each other, then the next set is arranged in similar fashion but at 90 degrees, allowing optimum sun exposure. The basal leaves are elliptic or rounded while the stem leaves are lance-shaped or oblong. The white trumpet-shaped flowers, which 8

often have a pink blush, are presented on the top of the stems in a panicle that is 4-6 inches above the foliage. Penstemon, which in Greek means 5 stamens, has 4 fertile stamens and one sterile stamen that has small tufts of fuzzy hairs on its end hence, the name beardtongue. Their flowers bloom April through June and attract many butterflies and birds. Plants should be deadheaded after bloom. They can be used in sunny perennial borders, rain gardens, as a specimen planting or in foundation plantings. They are drought tolerant and deer resistant. Plants are cold hardy in USDA zones 3-8. The insect pests include vine weevils, aphids and spider mites while the diseases include root rot, leaf spots, powdery mildew and rust. Penstemon in flower Photos: Ginny Rosenkranz Degree Days (As of May 31)* Baltimore, MD (BWI) 973 Dulles Airport 962 Frostburg, MD 579 Martinsburg, WV 913 National Arboretum 1189 Reagan National 1189 Salisbury 1037 *As of May 11, degree day calculations are from weather.com growing degree day calculations instead of NOAA min and max temperatures. Plant Phenology: What s in bloom PLANT PLANT STAGE (Bud with color, First LOCATION bloom, Full bloom, First leaf) Asclepias tuberosa First bloom (May 25) Ellicott City Ascelpias incarnata First bloom (May 30) Ellicott City Astilbe Granaat First bloom (May 31) Silver Run Buddlea hemsleyana First bloom (May 31) Silver Run Cimicifuga racemosa Full bloom (May 31) Silver Run Elliottia racemosa Bud swell (May 31) Silver Run Hydrophyllum virginianum Full bloom (May 31) Silver Run Indigofera kirilowii Full bloom (May 31) Silver Run Lyonia ligustrina First bloom (May 31) Silver Run Penstemon digitalis Husker Red Full bloom (May 31) Silver Run Spigelia marilandica Full bloom (May 31) Silver Run Spiraea virginiana First bloom (May 31) Silver Run Stewartia pseudocamellia First bloom (May 31) Columbia, Ellicott City Thermopsis caroliniana Full bloom (May 31) Silver Run Viburnum nudum Winterthur Full bloom (May 31) Silver Run Yucca filamentosa Golden Sword Bud (May 31) Ellicott City 9

Upcoming Programs MAA Pest Walk - Southern Maryland June 7, 2012 Location: College of Southern Maryland, Prince Frederick, Maryland http://www.mdarborist.com/ Pesticide Recertification Conference June 8, 2012 Location: Montgomery County Extension office, Derwood, Maryland Contact: 301-590-9638 http://ipmnet.umd.edu/ MNLA Field Day June 21, 2012 Location: D.R. Snell Nursery, Union Bridge, MD http://mnlaonline.org/ Maryland Christmas Tree Association s Summer Meeting June 30, 2012 (Saturday) Location: Taylor Sines Woodlake Tree Farm, Oakland, MD Contact: 410-452-9793 OFA Short Course July 14-17, 2012 Location: Columbus, Ohio ofa.org PANTS 2012 (Pennsylvania Nursery Trade Show) July 31 to August 2, 2012 Location: Greater Philadelphia Expo Center, Oaks, PA www.pantshow.com/2012 OFA Perennial Production Conference September 10-12, 2012 Location: Grand Rapids, Michigan ofa.org IPPS Eastern Region Annual Meeting October 10-13, 2012 Location: Brandywine Valley, Pennsylvania http://www.ippseastern.com 2012 Perennial Plant Symposium July 4-10, 2012 Location: Boston, Massachusetts perennialplant.org CONTRIBUTORS: 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, 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. 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.