TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers Commercial Horticulture October 9, 2015 In This Issue... - Weather update - Tuliptree scale - Woolly alder aphid - Lady bird beetles - Galls on oak - Brown marmorated stink bug Beneficial of the Week Weed of the Week Plant of the Week Phenology Degree Days Announcements 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 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) Finally - Rain By: Stanton Gill, University of Maryland Extension Well, three weeks ago I mentioned that we had experienced an 11-week drought period and it was tough on plants in the landscape. In the last week the rains came and people sent e-mails reporting they received 4 of rain in a single day. The rains lasted several days and the amount of rainfall was significant and helped break the drought cylce. This rain is very fortunate. Fully hydrated trees transplant better and have a higher survival rate going into the winter cold. Save the Date December 10, 2015 Pest Management Conference Location: Carroll Community College, Westminster, MD
Tuliptree Scale By: Stanton Gill, University of Maryland Extension I received a sample of tuliptree scale from Prince George s County (Clinton area) this week. I popped off female covers and there were crawlers present. There were several settled first instars on the stems. We first reported crawlers in Adamstown on September 11 so they have been active in most areas for about a month and populations have already peaked. Control: There are a couple of options for control. Treating with one of the insect growth regulators such as Talus or Distance is one option. The other option is a basal trunk drench using dinotefuran (Safari or Transtect). Woolly Alder Aphid Mark Kallal, USDA-Beltsville, found some woolly alder aphids on alder trees in Beltsville. They look very similar to the woolly beech blight aphids mentioned in a previous report. These aphids infest leaves, twigs or bark. Feeding causes leaves to shrivel and drop early. Predators of this aphid include lacewings, lady bird beetles, hover flies and parasitic wasps. This aphid requires silver maple to complete its life cycle. Other control measures are usually not necessary. Woolly alder aphids are found in colonies Photo: Mark Kallal, USDA-Beltsville When not to spray: Mark Eppard, Bartlett Tree Experts, found and photographed these lady bird beetles swarming/feeding on fuzzy gray/black aphids on the stems of young elms The galls on this oak leaf are one of just the many species of galls found on oaks; many of the different oak galls are caused by tiny wasps Photo: Mark Schlossberg, ProLawn Plus, Inc. 2
Fall Activity of Brown Marmorated Stink Bug is Upon Us! By: Paula Shrewsbury, University of Maryland Extension This week, Wednesday specifically, thousands of BMSB began their fall activity! Every fall BMSB amass and begin their movement towards overwintering habitats. The interesting phenomenon is that BMSB almost all start moving and flying on the same day. In many cases they end up in buildings such as homes, barns, sheds, commercial buildings, etc. In more natural areas, BMSB migrate to rocky outcroppings at higher elevations. We (Raupp and Shrewsbury labs, UMD) have been monitoring BMSB activity at Sugarloaf Mountain in Dickerson and Weverton Cliffs in Harpers Ferry, WV for the last month. Up until this past Wednesday timed visual counts have been 0 or in the single digits. On Wednesday, BMSB counts were in the several hundreds on Sugarloaf Mountain. I also noticed a great increase on the outside of my house in Columbia on Wednesday too. The timing of this fall flight activity is similar to what we saw last year (1st week of October in 2014). So if you have not addressed physical barriers to exclude BMSB from you homes and businesses now is the time. Be sure vents are screened, door sweeps are in good shape, window screens don t have holes, and any other openings are sealed. Remember, BMSB have evolved over thousands of years to be effective at what they do. They will find and enter any hole left unsealed! Brown marmorated stink bugs found the attic vent! Photo: P. Shrewsbury, UMD Brown marmorated stink bugs looking in the screen door from the outside will they make it in? Photo by P. Shrewsbury, UMD Beneficial of the Week By: Paula Shrewsbury, University of Maryland Do native parasitoids attack the exotic brown marmorated stink bug? Since brown marmorated stink bug (BMSB), Halyomorpha halys (Pentatomidae), started their fall movement this week and might be on many people s mind, I thought it would be a good time to talk about natural enemies that kill them. BMSB is native to several Asian countries and was first detected in the U.S. in Pennsylvania around the mid-1990 s. This exotic stink bug has become a significant pest of many agricultural crops in addition to a nuisance pest. Because BMSB is an exotic herbivore I am often asked if there are any native natural enemies that attack it, and will they have an impact on BMSB populations. Well this is a question that myself and several students in my lab have been looking for the answer to! Specifically, who are the native natural enemies and what type of impact are they having on BMSB? We did extensive studies in woody plant ornamental nurseries to address these questions. We found 7 species of parasitic wasps (very tiny ones) attacking the eggs of BMSB and an assortment of generalist predators that feed on the eggs and other life stages of BMSB. I would like to discuss the egg parasitoids today. 3
Two of the parasitoids found attacking BMSB eggs are in the genera Trissolcus and one in the genera Telenomus (Family Scelionidae), one in the genera Ooencyrtus (Family Encyrtidae) and three were in the genera Anastatus (family Eupelmidae). First, I want to mention the Trissolcus species. Trissolcus are specialist egg parasitoids of bugs in the family Pentatomidae (ex. stink bugs). In Asia, there are Trissolcus spp. that provide biological control of BMSB so we predicted U.S. Trissolcus may also attack BMSB eggs. However, our studies found that our native Trissolcus accounted for less than 2% of all the parasitoids that emerged from BMSB. In fact, each of the other egg parasitoid species accounted for less than 1% of parasitoids that emerged from BMSB except for Anastatus. Of most interest was that over 95% of the parasitoids emerging from BMSB eggs were Anastatus reduvii the winner! Anastatus is a generalist parasitoid which attacks a wide range of insect eggs across different orders. Anastatus attacks eggs of not only stink bugs, but other Hemiptera such as assassin bugs, eggs of Lepidoptera such as orange striped oak worm, and even grasshopper and mantid eggs. A study conducted in 2012 and 2013 found average parasitism rates of 32% and 44%, respectively. Native Anastatus reduvii are definitely attacking and killing BMSB at relatively high rates! When observing BMSB on your plants, be sure to look for the egg masses in the spring and summer and note their color. Healthy eggs are a light, mint green color that get slightly darker as they mature. When eggs have been parasitized they turn very dark in color. Smile when you see those dark colored eggs. Two egg masses of BMSB: healthy light green eggs (left) and dark colored eggs with parasitic wasps developing inside them. The wasps feed on and kill the BMSB eggs (right). On the left an Anastatus parasitoid has just found the BMSB egg mass. On the right a Scelionid parasitoid adult has recently emerged from a BMSB egg. Photos: P.M. Shrewsbury, UMD Weed of the Week By: Chuck Schuster, University of Maryland Extension Indian mock strawberry, Duchesnea indica, is a shade loving perennial found in landscapes and turf throughout the southeastern United States. Each leaf is trifoliate, or made up of three leaflets, is longer than it is wide, up to three inches in length and up to one and one half inches wide. The leaflets are attached to the main petiole by way of a small petiolules. The petiole is hairy. Indian mock strawberry will spread by stolons, which are hairy. Flowers are on the ends of long stalks called peduncles. Flowers have five yellow pedals with large sepals below. The fruit is a fleshy berry similar to that of strawberries purchased or commercially raised. This is similar to wild strawberry, which has leaflets with pointed teeth on the 4 Indian mock strawberry is a shade loving perennial weed Photo: Clemson University
upper majority of the leaflet, and will have white flowers instead of the yellow flowers found on Indian mock strawberry. Control of this weed in turf can be obtained using 2, 4-D and Triclopyr and in landscape settings using a non selective product containing glyphosate. Plant of the Week By: Ginny Rosenkranz, University of Maryland Extension Nandina domestica Seika Obsession is a new cultivar from Southern Living Plant Collection for an upright, compact and very dense plant. Obsession is an improved selection of the dwarf nandina Gulf Stream, but with even brighter colored new foliage. New foliage emerges throughout the growing season so the bright red foliage is highlighted all spring, summer and fall, then with the advent of cold winter weather, all the foliage turns brilliant red. Its cultivar name of Seika in Japanese means sacred fire in honor of the colorful new growth. Like N. Gulf Stream, Obsession has small white flowers but needs very cold weather for the flowers to mature into berries. Like all nandina, Obsession is an evergreen plant, hardy from USDA zones 6-11, and does best in full sun to partial shade with the foliage coloration best in full sun. Growing only 24-30 inches tall and 20-24 inches wide, the dense compact growth creates a solid plant that fits into many landscape situations without the added worry of suckering or colonizing out of control. It prefers well drained soils with a light covering of mulch to maintain soil moisture, and once established will survive occasional droughts. Listed as deer resistant, the Nandina domestica New foliage of Nandina Seika Seika Obsession can be utilized in the landscape as a foundation plant, Obsession TM emerges throughout in colorful borders or hedges and even in containers. Like all Nandina, the season and needs very cold Nandina domestica Seika Obsession has no serious insect or disease weather to produce fruit Photo: Ginny Rosenkranz, UME pests. Degree Days (As of October 8) 2015 2014 2013 2015 2014 2013 Baltimore, MD (BWI) 3865 3508 3726 Dulles Airport 3798 3333 3697 Frostburg, MD 2650 2216 2311 Martinsburg, WV 3547 3347 3408 National Arboretum 4642 4325 4274 Reagan National 4642 4325 4274 Salisbury 3837 3895 4068 St. Mary s City 3974 3681 3847 To check degree day (DD) accumulations in your local area go to: http://www.yourweekendview.com/outlook/agriculture/growing-degree-days/. Note: degree days reported in this newsletter use a base temperature of 50 F, a start date of January 1st, and the date of monitoring as the end date. 5
Upcoming Conferences: 4 th Annual TreesMatter Symposium November 4, 2015 Early bird registration ends October 7, 2015 Location: Silver Spring Civic Center, Silver Spring, MD http://www.montgomeryparks.org/activities/things_to_do/ fall/trees_matter.shtm December 10, 2015 Pest Management Conference Details will be posted late September or early October A list of 2016 conferences will be posted soon 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.