TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers Commercial Horticulture June 15, 2012 In This Issue... - Brown marmorated stink bugs - Japanese beetles - Walnut twig beetle traps - Asian longhorned beetle traps - Minute pirate bug in traps - Nursery field day - Powdery mildew - Native caterpillar - Cottony maple scale - Lady bird beetles - Spider mites - Rusts - Mounds in turf - Problem on cherry - Squirrells and lecanium scale - Columbine leafminer - Colorado potato beetle Beneficial of the Week Weed of the Week Plant of the Week Degree Days Phenology Conferences Integrated Pest Management for Commercial Horticulture www.ipmnet.umd.edu 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 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 Bug Report Thanks to each of you who sent an e-mail to report activity of brown marmorated stink bugs this week. If you see eggs or nymphs this week send me an email at sgill@umd.edu. Here is a short summary of what people have sent in so far for the weekly IPM Alert: Eastern Shore (Salisbury area) eggs found and a couple of adults still active; St. Mary s City (St. Mary s County) some adults found on thornless blackberry fruit but no eggs or nymphs; Sunshine (Montgomery County) adults found feeding on raspberries but very light population; Westminster (Carroll County) 2 adults were found in sweet cherry clusters but very low population activity this season, egg hatch on a serviceberry; Barnesville area (upper Montgomery County) adults found and one egg cluster found but no nymphs yet; Manor Maryland (Baltimore County) some adults observed (2 3) but no eggs or nymphs found; Hamilton Virginia (Loudon County) hatched nymphs reported. Jim Persels, Master Gardener in Queen Anne s County, reported, At my place outside Centreville we are seeing only about 10-15% of the number of adults that we were seeing coming out of hibernation last year. However, I have talked to several people who live nearby who say they are seeing more than last year. Overall, everyone is reporting relatively light activity form BMSB, especially when you compare it to the 2011 season when they were everywhere and on everything.
Japanese Beetles We are starting to receive steady reports of Japanese beetle activity. Chris Rosier, The Davey Tree Expert Company, spotted Japanese beetles feeding on a Kousa dogwood on June 13 in Cockeysville. He also found them feeding on river birch and crape myrtle. From David Kinderdine, Velvet Touch Rose Care: In Potomac, I ve observed small quantities around the metro area thus far this season with the exception of one particular property located on the Potomac River in Potomac close to the WSSC plant. The beetles at this property are as bad as I ve ever seen. Thousands if not 10 s of thousands of beetles eating everything in sight. This client has approximately 500 Knock out roses. They are swarming the crape myrtles, Leyland cypress, magnolias, and just about anything green. I hope this is not any indication of what s ahead for Montgomery Co. Andrew Ristvey, Wye Research and Eduction Center, noted that it seems like it might be bad on the upper shore this year in Talbot and Queen Anne s counties. Heavy Japanese beetle damage on rose Photo: David Kinderdine, Velvet Touch Rose Care Here at the research center in Ellicott City, Japanese beetles are getting started as well and we are seeing higher numbers at this time of year compared to last year. Control: Adult Japanese beetles can be controlled by several insecticides (ex. clothianidin [Arena], imidacloprid). Walnut Twig Beetle Trapping We have walnut twig beetle traps that several of you have volunteered to place out in Maryland. So, far the samples I am receiving have all turned out to be negative for the presence of walnut twig borers. Thanks to all who are sending samples to the CMREC lab. Asian Longhorned Borer We have placed out four of the new Pennsylvania Department of Agriculture Asian longhorned beetle borer traps in the last couple of weeks. So far, no adults have been sent into our lab at CMREC. The adults should be in flight activity right now so if you find a large black beetle with white spots and antennae with white and black banding do not be shy about sending in a sample to CMREC or contact me at sgill@umd.edu Trap Counts Tony Murdock sent in insect specimens from the walnut twig borer and Asian longhorned borer traps from the Frederick area this week. Both trap counts were negative for walnut twig borer and ALB. On a side note, the one trap capture was composed of mainly jumping tree bugs. Jumping tree bug from trap 2
Nursery Field Day If you are looking for a fun and educational experience, then make sure you sign up for the June 21st Maryland Nursery and Landscape Association Summer Field Day. Rick and Rebecca Snell are opening up their 200 acre farm in Frederick County for this event. There will be a tour of Rick and Rebecca s operation. Paula Shrewsbury, Karen Rane and Stanton Gill will be giving updates on research on insect and disease problems at this field day. Andrew Ristvey and John Lea-Cox will update participants on water and nutrient management. It is a great time to network with Maryland nursery growers and talk about plants and solutions to plant problems. To register, go to http://mnlaonline.org/calendar_day.asp?date=6/21/2012&event=71. See you there. Hot Sunny Weather and Cool Nights Perfect for Powdery Mildew This season, we have reported powdery mildew on dogwoods and some of the worst powdery mildew seen in many years on euonymus. Now, you can add flowering phlox to the list. This disease first occurs on lower leaves and then moves up the plant. Fungicides can be used as a preventative, but not curative for this disease. Spacing plants to allow for good air circulation helps to reduce the incidence of this disease. There are resistant phlox cultivars available, but when environmental conditions are optimal, even these plants can become severely infected. Powdery mildew on phlox Native Caterpillar Active Damian Varga, Scientific Plant Service, brought in a sample of uglynest caterpillars, Archips cerasivorana, feeding on black cherry in Annapolis on June 11. This native caterpillar is in the Tortricidae family and is often found on hardwoods, especially cherry trees. The caterpillars are active in May and June and have one generation per year. Larvae pupate in the nest and adults start to emerge in midsummer. Control: It is pretty straight forward prune off damage branches with the webbing. There is color variation among the different caterpillar instars 3
Cottony Maple Scale Matt Shultz, Harrell s Professional Fertilizers, sent in photos of cottony maple scale on Cornus florida from Kent County. Trees infested by cottony maple scale are maple, dogwood, boxelder, honeylocust, linden, poplar, basswood, elm and many others. The crawlers are just starting to be active this week. Look for the flat, oval, brown and very tiny crawlers. The crawlers move to the underside of foliage where they feed throughout the summer. Adults emerge in late summer. Just before leaf drop, mated females move back to the branches and twigs and reinsert their mouthparts for overwintering. There is one generation a year. The insect feeding causes twig dieback. Severe infestations can kill major limbs and occasionally the entire tree, especially if the tree is stressed (drought). Control: At this time of year TriStar foliar spray or Talus or Distance. Cottony maple scale egg cases (top left), third instar females (top right) and a lady bird beetle larva that feeds on the scale Photos: Matt Shultz, Harrell s Professional Fertilizers Lady Bird Beetles Jim Taylor, Relms Landscaping, sent us a photo of two empty lady bird beetle pupal cases that he found on crape myrtle in Annapolis. Jim noted that the plants have severe stippling and are looking really yellow. There is also a little powdery mildew on the foliage. We did not see a sample, but mites or aphids are possibilities for the source of the damage and the food source for the lady bird beetles. Empty lady bird beetle pupal cases Photo: Jim Taylor, Relms Landscaping Spider Mites Chris from Integrated Plant Care, reported heavy spider mite damage on magnolia in Bethesda this week. Control: Mite growth regulators available include Hexygon, Ovation (nursery use), Tetrasan. Another miticide option is Forbid. The chemical in Forbid (landscape use) is translaminar and desiccates treated mites and eggs. It acts a little like a growth regulator and it also inhibits oviposition in adult females. Some of the other materials for mite control are Avid (landscape use), Akari (nursery use), Floramite, Conserve and Sanmite (nursery use). 4
Rusts It s been a good year for rust infection so far this season. Mark Schlossberg, ProLawn Plus, Inc., found heavy sporulation of one of the gymnosporangium rusts (most likely cedar-quince) on the fruit of serviceberry in Baltimore this week. Jessica Ickes, Chevy Chase Club, is finding rust on hypericum. Preventative fungicides are available for control of these rusts. Rust on hypericum Photos: Jessica Ickes, Chevy Chase Club Mounds in Turf We included photos in the May 25, 2012 IPM report of mounds in turf. Several entomologists responding to the request for possible causes of the damage thought it was caused by skunk or raccoon digging for earthworms. After the report, Jim DeRamus, Brookside Gardens, responded suggesting the following: Another possible explanation for the turf mounds is turtle egg laying. Here at Brookside the eastern painted turtles and snapping turtles have been busy laying eggs in the turf. When they are finished and pack the soil back it looks exactly like the photographs. We see these mounds particularly in the turf in full sun, probably due to the orientation of these turf slopes to the south. The beds are more shaded and may not provide the proper incubation temperature. Problem on Cherry Jon Nagelvoort, Arbor Landscapers, Inc., sent in photos of a recently planted cherry tree that is not doing well. Jon noted that the tree has a hardened resin from top to bottom that looks like glue. With the drought this spring, it s likely that the tree did not receive adequate water during this period and the resulting problems are most likely stress related especially if the soil is poor quality. In a situation like this one, monitor for signs of borer activity and disease development. 5 Cherry tree in decline Photos: Jon Nagelvoort, Arbor Landscapers, Inc.
Squirrels and Lecanium Scale Norm Brady, Bartlett Tree Experts, observed the following: I was watching a pair of squirrels in my neighbor s silver maple yesterday. They were going almost to the terminus of several small branches- hanging in most cases upside down because the branches were too small to support their weight. I was waiting for pruned twigs to start falling. Instead I watched as they moved leaves out of their way to get at something on the twigs. Later in the day, I returned to the limbs they were on to see if they were damaged in any way and could see that instead they had been feeding on lecanium scale. I m thinking about using them for our lecanium scale suppression program- just kidding. Ever heard about squirrels supplementing their diets with scale? Judging from the amount of photosynthate (honeydew) excreted by this particular scale - one might assume to be nutritious. Columbine Leafminer Mark Schlossberg, ProLawn Plus, Inc., sent in a photo of columbine leafminer damage on columbine in Baltimore. Look for the serpentine trails on the foliage that are created by the fly larvae feeding within the leaf. More than one leafminer may be present within a leaf. Control: In most landscapes it is probably not worth trying to control this leafminer. The damage is noticeable, but usually the plant survives. Applications need to be applied before the leafminers show up in the foliage. Columbine leafminer damage Photo: Mark Schlossberg, ProLawn Plus, Inc. Colorado Potato Beetle (For Horsenettle Control?) A nursery grower sent us a photo of a Colorado potato larva feeding on horsenettle and thought it might make a good biological control (as long as there are no crop plants nearby, of course). 6
Beneficial of the Week, Paula Shrewsbury These suckers seem to be everywhere! It seems almost every nursery and landscape I am looking around in has a nice population of wheel bugs! At this time of year I am seeing mostly nymphs. Wheel bugs, Arilus cristatus, are true bugs (Heteroptera) in the family Reduviidae which include a group of predators known as assassin bugs. Assassin bugs are very important predators of a diverse array of pest insects in our ornamental systems. This particular assassin bug gets its common name, wheel bug, because of the spoke bearing, wheel-like structure on the pronotum (section behind The predatory wheel bug adult with its large sucking mouth part stuck into a Japanese beetle resulting in death of the beetle Photo: Nikolaus Anderson, UMD A wheel bug nymph feeding on its newly captured lunch Photo: P. Shrewsbury, UMD the head) of the adults. They are large bugs with adults reaching 1-1.5. Immature wheel bugs are smaller, their abdomens seem to curl up at the back end and often have a red/orange coloration. They have long thin antennae and legs with black and orange bands. Most importantly both adults and nymphs have a long, dangerous looking proboscis (mouthpart) that they use to suck the life out of their prey - literally. Wheel bug adults and immatures are generalist predators that feed on insects such as caterpillars, planthoppers, sawfly larvae, aphids, and beetles. The wheel bug approaches its prey, quickly grabs it with its front legs, and then impales the insect with its beak. Through its beak the wheel bug injects digestive enzymes which liquefy the body tissues of the prey making it possible for the predator to suck up its food. In the autumn female wheel bugs will lay clusters of 10-40 eggs on the bark of trees. The eggs hatch the following spring. Nymphs and then adults are active through most of the growing season adding to the complex of generalist predators that help to suppress herbivore insect populations. Weed of the Week, Chuck Schuster Pennsylvania smartweed, Polygonum pensylvanicum, is a summer annual weed for horticulture, nursery and agronomy crops throughout the United States. It is often found in moist to wet areas which will include near roof gutter downspouts, low areas, and with irrigation equipment. Pennsylvania smart weed can grow three feet tall, has leaves that are alternate, long and narrow (lanceolate) from two to six inches in length, and one to one and a quarter inch wide. Older leaves are slightly hairy (pubescent) as will the first true leaves. An interesting point to note is the leaf petiole attachment to the stem. The ocrea is a very thin membrane sheath Pennsylvania smartweed Photos: Chuck Schuster, UME 7 (2) (1)
that encircles the stem at an enlarged stem node arising from the petiole (1). Leaves often have a purple spot in the middle of the leaf (2). Stems are branched and swollen at the nodes. The flowers are pink and in clusters on spikes at the end of stems. The fruit is black. Seeds require cold weather for spring only germination. Control of Pennsylvania smartweed includes improved drainage, turf mowed to produce a thick dense stand and post emergent herbicides that include glyphosate products. It is becoming resistant to many pre emergent herbicides. Plant of the Week, Ginny Rosenkranz Purple coneflower (Echinacea purpurea) has become the darling of plant breeders who seem to glory in creating yellow, orange and red-purple coneflowers. Echinacea Pow Wow Wild Berry is a new seeded variety that is more compact, more branched and very full of bright rose-purple cone flowers with orange centers. It was also the Perennial Plant of the Year for 2010. They only grow 1 ½ - 3 feet tall and 1-2 feet wide from June until August. They are very tolerant of many soil types, from well drained clay soils to rocky soils to dry sandy soils and are very drought tolerant once they are established. They prefer a neutral soil ph. Purple coneflowers need full sun and are fairly deer resistant depending on the population of deer. The flowers of Pow Wow Wild Berry are 3-4 inches across and attract many butterflies and birds to the garden. They are hardy from USDA zone 3-8. Mildew, leaf spots and Botrytis are the diseases that can affect purple coneflowers. Japanese beetles seem to be the most common insect pest. 8 Echinacea PowWow Wild Berry Photo: Ginny Rosenkranz, UME Degree Days (As of June 14)* Baltimore, MD (BWI) 1255 Dulles Airport 1223 Frostburg, MD 729 Martinsburg, WV 1159 National Arboretum 1506 Reagan National 1506 Salisbury 1331 *As of May 11, degree day calculations are from weather.com growing degree day calculations instead of NOAA min and max temperatures. To check degree day (DD) accumulations in your local area go to: http://www.weather.com/outdoors/agriculture/growingdegree-days/usmd0100 PLANT PLANT STAGE (Bud with color, First bloom, Full bloom, First leaf) Actaea pachypoda Misty Blue First bloom (June 10) Silver Run Albizia julibrissin First bloom (June 12) Annapolis Asclepias tuberosa and A. incarnata Full bloom (June 11) Ellicott City Asilbe Granat Full bloom (June 10) Silver Run Buddlea hemsleyana First bloom (June 10) Silver Run Clethra acuminata First bloom (June 10) Silver Run Cyrilla racemeflora Bud swell (June 10) Silver Run Diervilla sessilifolia Full bloom (June 10) Silver Run Elliottia racemosa Bud swell (June 10) Silver Run Leptodermis oblonga Full bloom (June 10) Silver Run Lyonia ligustrina Full bloom (June 10) Silver Run Marshalia grandiflora Full bloom (June 10) Silver Run Monarda Jacob Kline First bloom (June 10) Silver Run Oxydendum arboreum Bud swell (June 10) Silver Run Rhododendron Millennium Bud swell (June 10) Silver Run Spiraea virginiana Full bloom (June 10) Silver Run Stewartia pseudocamelia Full bloom (June 10) Silver Run Thermopsis caroliniana Full bloom (June 10) Silver Run Yucca filamentosa Golden Sword Full bloom (June 11) Ellicott City LOCATION
Upcoming Programs 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 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 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 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 rosnkrnz@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.