TPM/IPM Weekly Report

Transcription

1 TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers Commercial Horticulture October 16, 2015 In This Issue... - New pest control options - Persimmon borer - White prunicola scale - Horntail wasp - Daddy-longlegs, aka harvestmen - Stinkhorn fungus - Milkweed bugs - Root decline on zoysia Beneficial of the Week Weed of the Week Plant of the Week Degree Days Announcements Coordinator Weekly IPM Report: Stanton Gill, Extension Specialist, IPM for Nursery, Greenhouse and Managed Landscapes, sgill@umd.edu (office) or (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) What s Are New Pest Control Options? By: Stanton Gill, University of Maryland Extension Last week I went out to Chicago to participate in the IR-4 meetings. Here are several things I have to share with you from the meetings. We worked with Pyllom in 2015 testing Bacillus thuringiensis galleriae for Japanese beetles. The company is now seeking to expand their label to include use for foliar applications to ash trees to control the adult emerald ash borer. The female EAB does a maturation feeding when she emerges and they are thinking they will control this stage of the life cycle. IPMnet Integrated Pest Management for Commercial Horticulture extension.umd.edu/ipm On the disease end, Jill Calabro, Nufarm Americas, mentioned they have two products; one is called Bloomtime which is a naturally occurring bacterial antagonist that suppresses fire blight in apples and pears. The product contains Pantoea agglomerans strain E-325 that has a competitive/exclusion impact on preventing fireblight disease on plants. Generally 2-3 application sare made early in the season at bloom. The other product is BlightBan, a strain of Pseudomonas fluorescens. Both should be applied with a spreader sticker to fire blight-susceptible plants to help suppress disease. 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 Save the Date December 10, 2015 Pest Management Conference Location: Carroll Community College, Westminster, MD

2 Persimmon Borer By: Stanton Gill, University of Maryland Extension Brian Dahl and his staff at Pope Farm Nursery found a couple of container grown persimmon trees that were succumbing to a borer that was actively collapsing young trees. At our CMREC labs we dug the larvae out of the small trees. It was the persimmon borer, Sannina uroceriformis, Walker. I had a similar sample 3 years ago from a plant nursery on the Eastern Shore of Maryland. The larvae have the typical, somewhat parallel lines of gold-colored crotchets on the prolegs. The adult is active in late June to early July and lays eggs on the trunk. The larvae feeds in cambial tissue of the tree and with small trees like the ones being grown, the tree is rapidly girdled. Since these persimmon trees are being grown as ornamental trees, then a nursery manager can apply bifenthrin (Onyx) to the main trunk next year in mid June. Note the typical gold crotchets of clearwing borers on the prolegs of this persimmon borer larva White Prunicola Scale White Males Covers Are Very Obvious at This Time of Year By: Stanton Gill, University of Maryland Extension Connie Bowers, Garden Makeover Company, sent in several samples of cherry laurel with the stems thoroughly covered in the white covers of the male white prunicola scale. The crawlers were active back in mid to late September and we mainly found settled 1st instars present. There were a few males in the prepupal and pupal stage, but these are mainly outliers that are emerging late in the season. Most of the females were spent, having laid their eggs in September which hatched into crawlers a couple of weeks ago. Since there were mainly 1st instars present, I would say it would be appropriate to apply Talus or Distance. I would add in a 0.5 to 1% of horticultural oil at this point. Adults and pupal stages of male white prunicola scale as well as female covers were present in high numbers on samples of cherry laurel brought to our office last week 2

3 Horntail Wasp Steve Castrogiovanni, Mead Tree and Turf, found a horntail wasp on hickory. Females lay eggs deep into the wood of trees. The larvae bore into the wood and live in the tree for up to two years, possibly more. They typically migrate to just under the bark before pupation. A female horntail wasp uses her long ovipositer to insert eggs under the bark of trees Photo: Steve Castrogiovanni, Mead Tree and Turf Daddy-longlegs/Harvestmen Daddy-longlegs, also called harvestmen, look a lot spiders, but they are not spiders. They belong to the Order called Opiliones. Unlike spiders, they do not produce silk or venom. They are found for a short time in the fall clustering around windows, eaves, and doors. They are also found in damp basements and garages. Harvestmen feed on spiders, decomposing vegetative matter, and live and dead insects. Daddy-longlegs only have one body segment (unlike spiders which have two) Stinkhorn Fungus Darlene Rasin, MD Transportation Authority, found a fungus that popped up in her dry lawn in Baltimore City recently. It is one of the stinkhorn fungi which do show up suddenly in lawns and landscapes. The stinkhorn fungi produce a strong unpleasant odor and break down old plant matter. Stinkhorn fungi show up unexpectedly in lawns and landscapes Photo: Darlene Rasi, MTA Milkweed Bugs Milkweed bugs continue to be active on milkweed into the fall. Tony Murdock, Fine Pruning, found nymphs on the seed head of common milkweed in Frederick on October 8. The University of Wisconsin has more information at their Bug of the Week page on milkweed bugs. Milkweed bug nymphs are still feeding on seedpods in October Photo: Tony Murdock Fine Pruning 3

4 Root Decline of Zoysia By: Karen Rane, University of Maryland Extension Mark Schlossberg submitted photos last week of a zoysia lawn in Baltimore County showing patches of dead, brown turf. Dr. Joseph Roberts, UMD turfgrass pathologist, examined samples and determined that the problem was root decline caused by the fungus Gaeumannomyces graminis var. graminis. This pathogen grows along the roots, stolons and rhizomes of warm season turf species like zoysia, initially causing chlorotic patches up to several feet in diameter which progress to large areas of thinning and/or dead turf. High rainfall, high soil ph, soil compaction and nutrient deficient turfgrass all favor warm season turfgrass root decline. Therefore, cultural practices that promote healthy turf can go a long way in reducing turf loss due to G. graminis var. graminis. Dr. Roberts suggested the following: If possible, removing the infected sod could help to reduce the spread of the pathogen. Aerifcation to prevent soil compaction, ensuring adequate nutrition and proper mowing heights are effective in preventing the disease in future years. Avoid applying lime to infected areas as this pathogen is favored by high soil ph. Acidifying nitrogen sources, such as ammonium sulfate, can help to reduce ph. Applying a micronutrient package can also aid in disease reduction as Mg has been shown to reduce disease. Fungicides have limited curative activity on G. graminis var. graminis. It is best to use a fungicide as a preventative for controlling this pathogen in future years. Acropetal penetrants, such as the QoIs, DMIs, and benzimidazoles are best for control. Beneficial of the Week By: Paula Shrewsbury, University of Maryland What s up with exotic parasitoids and brown marmorated stink bug? Last week we started a discussion on brown marmorated stink bug (BMSB), Halyomorpha halys (Pentatomidae), and natural enemies that may be providing biological control of this exotic, invasive insect. Last week we discussed parasitoids that are native to the U.S. that were found associated with BMSB. The bottom-line of that story, based on our research, was that of several parasitoids found, there is one, Anastatus reduvii, which appears to be having a significant impact on BMSB in nurseries. This week I would like to talk about parastoids that are native to Asia, the natural range of BMSB. When exotic pest insects are introduced into the U.S. they usually arrive without any of their natural enemies. Without any biological pressure suppressing the exotic insects, populations quickly 4 Cultural practices that promote healthy turf can go a long way in reducing turf loss due to G. graminis var. graminis Photo: Mark Schlossberg, ProLawn Plus, Inc. A Trissolcus japonicus adult parasitoid adult which is 1-2 mm in size Photo: E. Talamas, USDA ARS, D3216-1

5 builds up and cause significant damage in the U.S. It makes sense that one of the first steps to managing an exotic pest is to examine the possibilities for biological control. This approach is usually referred to as Classical Biological Control. In the case of BMSB, USDA scientists traveled to Asia and searched for natural enemies that were attacking BMSB and likely providing suppression of the BMSB in that country. Several species of parasitoids that attacked the eggs of BMSB were brought back to the U.S. where they were placed in USDA quarantine facilities. For the past 4-5 years numerous studies have been conducted in quarantine on these parasitoids to: 1) determine if the parasitoid attacks BMSB at high enough levels to provide control if released; and 2) determine if the parasitoid is likely to have any detrimental impacts on any other species of insect, both herbivores and other natural enemies. Of the egg parasitoid species brought back to the U.S. the most promising species as it relates to biological control of BMSB is Trissolcus japonicus (Scelionidae), a tiny wasp that parasitizes eggs of BMSB and other stink bugs. However, studies are still underway to address question number 2 Will T. japonicus have a detrimental impact on other, native insects? These questions have to be answered before the USDA will approve for T. japonicas to be released into the environment. To date no releases of T. japonicas have been done in the U.S. This approach has been implemented, and parasitoids released, for many other exotic invasive species. Currently, myself and other scientists are involved in the release and evaluation of parasitoids that attack emerald ash borer (EAB). In 2014, there was an interesting twist to the T. japonicus BMSB story. In Beltsville MD, T. japonicus was found in the wild emerging from a BMSB egg mass. These wasps were sent to a lab for genetic analysis to determine if these wasps were related or from the same population as those in quarantine. They were not! What this situation suggests is that somehow T. japonicus was also accidently introduced into the U.S. It is not often the good guy is introduced accidently. In 2015, I and other entomologists began monitoring specifically for T. japonicus and found it in Beltsville again, Laytonsville and Adamstown, MD. In addition, it was found in VA and most recently in OR. Wow this was a surprise! Researchers will continue to monitor the exotic T. japonicus, native parasitoids and their impact on BMSB population. Hopefully, the combination of native and exotic parasitoids will lead to significant suppression of BMSB! Weed of the Week By: Chuck Schuster, University of Maryland Extension Greenbrier, Smilax spp, is a difficult to control woody weed of landscapes and nurseries. It is a native plant found throughout the United States. Greenbrier has an extensive root system made up of rhizomes and a stem with spines. This is a dioecious plant, meaning that there are male and female plants. The females bear fruit that ranges in color from a deep black, blue and red when ripe. Birds love this plant and thus help spread it. It is an important plant in the balance of the ecosystem, but as a climbing vine can create havoc in a landscape or nursery setting. Leaves are heart-shaped to oval, can grow to five inches long, and are leathery to the touch. Tendrils help support the climbing growth habit, which is what makes this plant useful for wildlife habitat. Seeds can remain viable for several years. Control of greenbrier is best done as early after emergence as possible. Remove mechanically taking all the root system. If the plant develops a dense root system, mechanical methods are less than satisfactory. Post emergent herbicides labeled for greenbrier are Campaign, a mixture of 2, 4D and glyphosate, and Finale (glufosinate). 5 This image demonstrates the extremely small size of Trissolcus japonicus Photo: A. Colavecchio, USDA ARS, D3224-1

6 Use caution as 2,4D can be a problem in landscape settings. Do not apply either of these products to greenbrier growing around stems, trunks or branches of desirable landscape plant materials. If necessary cut the vine of greenbrier as close to the ground as possible, and immediately apply concentrated solution of glyphosate to the cut stem. Use a 41% concentration if possible. Greenbriar leaves are heart-shaped and can grow to five inches long Photo: Chuck Schuster, UME Plant of the Week By: Ginny Rosenkranz, University of Maryland Extension Leucothoe fontanesiana Rainbow, rainbow drooping leucothoe, is a native evergreen shrub with graceful long arching rose red branches and grows 3-6 feet tall and wide. The leaves start out pinkish red with green and white, then mature to mottled red, green and white variegation that lasts all year long. In mid spring the plants have pendulous clusters of small bell-shaped white flowers that do have a fragrance. but it is often considered ill scented. Like many shade loving plants, rainbow leucothoe needs acidic, organically rich, moist, well drained soils. It is very picky and does not tolerate drought at all. On the other hand, Leucothoe fontanesiana and all its cultivars are extremely resistant to deer damage. Cold resistant from USDA zone 5-9 and fairly slow growing, Leucothoe Rainbow fits nicely in shady The foliage and stems of Leucothoe Rainbow range in shrub borders, in shady mass plantings, and as a great color from white to green to red. contrast to the darker evergreen rhododendron. Plants Photo: Ginny Rosenkranz, UME can be pruned in late winter or early spring. Leaf spot will damage the leaves and if severe enough, can kill the plant, especially if the growing conditions are not met. Degree Days (As of October 15) Baltimore, MD (BWI) Dulles Airport Frostburg, MD Martinsburg, WV National Arboretum Reagan National Salisbury St. Mary s City To check degree day (DD) accumulations in your local area go to: 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. 6

7 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 fall/trees_matter.shtm December 10, 2015 Pest Management Conference Location: Carroll Community College, Westminster, MD A list of 2016 conferences will be posted soon CONTRIBUTORS: Stanton Gill Extension Specialist sgill@umd.edu (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.