TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers Commercial Horticulture October 28, 2016 In This Issue... - Leafminer on sweet bay magnolia - Green roof issues - Last report - November 4th Beneficial of the Week Weed of the Week Plant of the Week Phenology Degree Days Announcements 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 Nancy Harding, Faculty Research Assistant 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 (Extension Specialist, Wye Research & Education Center) Design, Layout and Editing: Suzanne Klick (Technician, CMREC) Sweet Bay Magnolia Problems By: Stanton Gill IPMnet Integrated Pest Management for Commercial Horticulture extension.umd.edu/ipm 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. Please include location. Last week while visiting a Maryland nursery the owner brought me some container grown sweet bay magnolia. There were tracks of leafminer in the leaves but there were also round circles in the foliage. I asked David Clement, Plant Pathologist, to see if a virus was causing the round spotting. He dissected the leaves and found that the leafminers were pupating in the This leafminer infestation on sweet bay magnolia caused serpentine mines and splotches that looked similar to virus symptoms round circle areas on the leaves. Leafminer on sweet bay magnolia is not a big deal in a landscape. In a nursey the damage may prevent a customer from purchasing the plant. It is so late in the season and the foliage will drop in the next week or two so control is not necessary at this point.
Green Roof - Problems? By: Stanton Gill The schools in Montgomery County have been installing green roofs over the last couple of years. There are now 28 schools with green roofs in Montgomery County. When they first were installed there were few problems until now. We had larvae samples summited to our CRMEC lab this week. The larvae were being found in at least 7 of the schools with a new green roof. The larvae are the oriental beetle, Anomala orientalis. We have seen this beetle infesting container stock plants in herbaceous nurseries over the last 2 decades. The roof top planting with the high organic content substrate is a natural place for the female oriental beetle to lay eggs. The larvae are feeding on the succulent planting on the green roof and causing major damage. There are very few materials that can be used on green roofs for grub control. Back in August we suggested trying the new commercially available product called grubgone. This product contains a bacteria called Bacillus thuringienis galleriae. Unfortunately, the company that manufactures this product had production problems this summer and did not have the material available. We suggested an alternative using entomopathogenic nematodes, Heterorhabditis bacteriophora, and the applications were made in early October when the temperatures finally dropped to reasonable levels and the rain started up to ensure the survival of the nematodes. Meanwhile, birds have moved into feed on the grubs. Unfortunately, as the birds feed on the grubs they pull up the young sedum plants and leave them with exposed roots above the substrate. Green roofs continue to be very valuable, but we need to realize they will continue to NOT be bug free. We are Headed for the Home Stretch By: Stanton Gill Bristles and hairs on the tip of the underside of the abdomen on scarab beetle grubs are used in species identification; this beetle is an Oriental beetle November 4th will be the last regular IPM Alert we send out for the 2016 season. Don t worry we will send out special alerts about conferences and any pest alerts during the rest of the fall and winter. Also, we will be asking you to help us out by filling out our survey on how useful the IPM Alerts have been for your in your work in 2016. This survey will come out after the last IPM alert on November 4th. This image was included in last week s report without an indentification. These barrel-shaped eggs were laid by a wheel bug. 2
Beneficial of the Week By: Paula Shrewsbury Wheel bugs are making babies as the cold weather approaches. In the last few weeks several people have asked about and/or sent in pictures of wheel bug adults. Wheel bugs, Arilus cristatus, are true bugs (Hemiptera: 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 and other plant systems. This particular assassin bug gets it common name, wheel bug, because of the spoke bearing, wheel-like structure on the pronotum (section behind the head) of the adults. They are large bugs with adults reaching 1-1.5 in length. Immature wheel bugs are smaller, their abdomens seem to curl up at the back end and often have a red/orange coloration of their abdomen. Wheel bugs 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, plant hoppers, sawfly larvae, aphids, Japanese and other beetles, and stink bugs. The wheel bug approaches its prey slowly; when close it quickly grabs the prey with its front legs, and then impales the insect with its long beak. Through its beak the wheel bug injects digestive enzymes which liquefy the body tissues of the prey making it possible for this predator to suck up its food. Wheel bugs also use their long proboscis to defend themselves when they are threatened so beware if you are considering handling one of these animals. There is one generation per year of wheel bugs. At this time of year you are likely to see wheel bug adults, mating wheel bug adults, and egg masses of wheel bugs. The female wheel bug lay clusters of 10-40 eggs on the bark of trees. The egg stage is how wheel bugs will spend the winter and 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. So if you see wheel bug eggs in your landscapes and nurseries, smile and know that you will have prominent warriors in the spring to help overtake plant feeding insects. Weed of the Week By: Chuck Schuster A predatory wheel bug adult with its large sucking mouth part stuck into a brown marmorated stink bug adult resulting in stink bug death. Photo: M. Raupp, UMD At this time of year you should see wheel bug egg masses on the trunk of trees. Wheel bugs will spend the winter in its egg stage. Photo: P. Shrewsbury, UMD This plant seemed to be prolific this summer and early fall. Common lespedeza, Kummerowia striata (syn. Lespedeza striata), also known as Japanese clover, is a summer weed found in in the eastern United States in turf and landscapes settings. It prefers compacted dry soils with low ph. This low growing, prostrate weed will 3
grow 15 to 18 inches in diameter. Leaves are in groups of three, oblong, and have a prominent mid vein with a slight fold or crease. Leaves are attached to the stem with a common petiole. Leaves will be up to three quarters of an inch in length, and one quarter to one half inch in width. The root system is a semi woody taproot, from which a branching stem will originate. Hairs on the stem grow in a downward angle. Flowers will be pink to purple in color. Often mistaken for black medic, check the leaf for a small spike on black medic. This weed grows best in thin turf and on dry compacted soil. One management option is to mow high and keep ph and fertility at appropriate levels. Use of post emergent herbicide applications should target common lespedeza when it is actively growing. This plant will also be found in sidewalk cracks, and well as compacted paths. Many selective and non selective products can be used depending on the setting. 2,4D can be used in turf, but never in a landscape setting. Do not mow for at least 24 hours after application. Glyphosate based products can works well in the landscape setting when the plant is actively growing. Use caution to avoid any contact with stem, shallow roots and exposure to foliage. Leaves of lespedeza are in groups of three and have prominet midveins Photo: John D. Byrd, Mississippi State University, Bugwood.org Lespedeza prefers compacted soil with low ph Rebekah D. Wallace, University of Georgia, Bugwood.org Plant of the Week By: Ginny Rosenkranz Nyssa sylvatica (black gum, black tupelo or pepperidge) is a native plant that is gradually showing up in nurseries and garden centers. It can grow 30-50 feet tall and about 30 feet wide in the USDA zones 3-9. Black gum thrives in full sun to partial shade in acidic, moist but well drained soils. It can tolerate some drought and also poorly drained soils. In the wild, the strong taproot makes it almost impossible to transplant established trees. The female tree blooms with a small greenish yellow flower on long stalks in mid spring. but needs a male for the blue black fruit to set in late September. Although the flowers are small, they are an excellent source of nectar for bees. The very sour fruit is enjoyed by many species of native birds and animals. The foliage of the black gum is dark green in the summer, but late summer the colors begin to change to flaming scarlet, florescent yellow, brilliant orange, and purple. Many of the trees in Maryland will show color, but Nyssa sylvatica will consistently give excellent brilliant fall color! Some of the more outstanding cultivars 4
include Wildfire with scarlet foliage, Forum with brilliant red veined in yellow, Jermyn s Flame with yellow, orange and red colors, Miss Scarlet with bright red foliage, Red Red Wine with bright red color of the new growth and fall color and Afterburner with red fall foliage. A new cultivar, Red Rage is disease resistant to leaf spot. Black gum is an excellent shade tree and can be used as a street tree as long as there is low urban pollution. This native tree is susceptible to cankers, leaf spots, rust, tupelo leafminer and scale. The leaves of Nyssa sylvatica, black gum, turn red to orange to yellow in the fall Photos: Ginny Rosenkranz, UME Degree Days (As of October 26) Annapolis Naval Academy (KNAK) 4360 Baltimore, MD (KBWI) 4111 College Park (KCGS) 3985 Dulles Airport (KIAD) 4152 Ellicott City (E3247) 4014 Fairfax, VA (D4092) 4385 Frederick (KFDK) 3850 Greater Cumberland Reg (KCBE) 3906 Gaithersburg (KGAI) 3800 Martinsburg, WV (C1672) 3886 Natl Arboretum.Reagan Natl (KDCA) 4796 Rockville (C2057) 4501 Salisbury/Ocean City (KSBY) 4137 St. Mary s City (St. Inigoes, MD-KNUI) 4496 Westminster (KDMW) 4118 Important Note: We are now using the Online Phenology and Degree-Day Models site. 2017 ADVANCED LANDSCAPE IPM PHC SHORT COURSE - JANUARY 3 6, 2017 We are pleased to announce the 2017 Advanced Landscape IPM PHC Short Course. This annual Short Course held in College Park, MD is a recertification short course for arborists, landscape supervisors, IPM monitors, advanced gardeners, and others responsible for urban plant management. For further information and registration materials please click on the following link http://landscapeipmphc. weebly.com/ or contact Kiley Gilbert, IPM Short Course Coordinator, Phone: 301-405-3911, E-mail: kgilber4@umd.edu 5
Commercial Horticulture Conferences New Location for 2016 December 2016 Conference Howard Community College in Columbia for December 16, 2016. Look for the schedule in late October. Advanced Landscape Plant IPM PHC Short Course January 3rd to January 6th Website: landscapeipmphc.weebly.com For registration information vist our website or contact: Kiley Gilbert, University of Maryland, Dept of Entomology Tel: 301-405-3911, Monday-Friday 8-4:30 Email: kgilber4@umd.edu CONTRIBUTORS: Stanton Gill Extension Specialist sgill@umd.edu 410-868-9400 (cell) Paula Shrewsbury Extension Specialist pshrewsb@umd.edu Karen Rane Plant Pathologist rane@umd.edu Chuck Schuster Extension Educator cfs@umd.edu David Clement Plant Pathologist clement@umd.edu Andrew Ristvey Extension Specialist aristvey@umd.edu Ginny Rosenkranz Extension Educator rosnkrnz@umd.edu Nancy Harding Faculty Research Assistant 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.