TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers Commercial Horticulture May 25, 2012 In This Issue... - Clover in Nurseries - IPMpro App - Main peach tree borer - Black vine weevil - Horned oak gall - Red thread in turf - Cottony maple scale - Japanese maple scale update - Powdery mildew - Correction from May 18th - Bagworms - Mounds in turf - Black swallowtail caterpillar - Tuliptree scale and lady bird beetles - Lady bird beetles - Educational resources 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) Clover in Nurseries Here is an interesting one. Clover seems to be popping up in many nurseries this spring and the nursery owners have not planted it. Over the last month I have visited 5 different nurseries in the state and seen white clover flourishing in nursery rows in the grass strips between the nursery stock. The weather must have been perfect for clover germination last year and now there is an abundance of white clover. This is not a bad plant to have in the nursery row since it fixes nitrogen from the atmosphere for use in the soil. If you are seeing a similar situation in your nursery please send me an email at Sgill@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 Upcoming Programs June 1, 2012 Recertification Conference - Wye Mills, Maryland 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 9 for links to conference details
First Mobile App for Landscape and Nursery Professionals Developed by a Team of Plant and Pest Experts from Seven Major Universities From: Dr. Amy Fulcher, Plant Scientist, 865-974-7152, amyfulcher@tennessee.edu Green Industry professionals often find themselves in the field needing immediate access to pest and plant disease information and plant care recommendations. Or, they need to be alerted when destructive pests emerge in their area. Thanks to a collaborative effort of horticulturists, entomologists and plant pathologists at seven land-grant universities, now there s an app for that. The University of Tennessee Institute of Agriculture, working with Clemson, North Carolina State University, University of Georgia, University of Kentucky, University of Maryland and Virginia Polytechnic Institute, have developed the first IPM mobile app for nursery growers, landscapers, arborists, Extension agents and students that includes the major horticultural practices and disease and insect recommendations. IPMPro will streamline pest management decision-making, employee training, and will make complying with state pesticide recordkeeping regulations easy. The mobile app is available for iphone, ipad, and Android. Built by horticulture and pest management experts in cooperation with growers and landscapers, IPMPro was built for USDA Plant Hardiness Zones 4 through 8, which include 22 states from west of the Mississippi River, east and north to Pennsylvania and New Jersey, and south to the Gulf Coast. IPMPro is like having an expert in the field with the user to: Receive text-like alerts for time-sensitive pest issues and plant care - alert date adjusted to location Consult images, pest life cycle, and management options for major pests of woody plants Reference how-to information and images of cultural practices Obtain pesticide recommendations for major diseases and insects Utilize built-in pesticide recordkeeping for documentation while outdoors Track pests and cultural practices in calendar view or a chronological list Assist in educating new employees and experienced professionals This is the first application of its kind developed in the United States, and it was made possible through funding by the UT Institute of Agriculture through its Extension and AgResearch units. For less than a subscription for non-interactive tools like books and magazines that professionals currently use, IPMPro is $24.99. For more information on the application, visit http://www.ipmproapp.com. Coming soon for homeowners - IPMLite. Members of the development team may be contacted and include: Amy Fulcher (Lead Developer), University of Tennessee Institute of Agriculture, Department of Plant Sciences Frank Hale, University of Tennessee Institute of Agriculture, Soil, Plant and Pest Center William Klingeman, University of Tennessee Institute of Agriculture, Plant Sciences Department Alan Windham, University of Tennessee Institute of Agriculture, Soil, Plant and Pest Center Kris Braman, University of Georgia, Department of Entomology Matthew Chappell, University of Georgia, Horticulture Department Jean Williams-Woodward (Lead Plant Pathology Developer), University of Georgia, Department of Plant Pathology Winston Dunwell, University of Kentucky Research & Education Center Stanton Gill, University of Maryland, Central Maryland UME Karen Rane, University of Maryland Plant Diagnostic Craig Adkins, North Carolina State University, Agricultural Resource Center Steven Frank, North Carolina State University, Department of Entomology Anthony LeBude, Horticultural Science, Mountain Horticultural Crops Research and Extension Center Joe Neal, North Carolina State University, Department of Horticultural Science Juang-Horng (J.C.) Chong (Lead Entomology Developer), Pee Dee Research and Education Center Sarah White (Lead Horticulture Developer), Clemson University, Department of Horticulture Jeff Derr, Virginia Polytechnic Institute, Hampton Roads Ag. Res. and Ext. Center 2
Main Peach Tree Borer The first couple of adult main peach tree borers were caught in a pheromone trap in Westminster on May 20. Looking back at previous records, this activity is about 15 18 days earlier than most years. The males will be mating with females and the females will start laying eggs about 2 weeks after mating. Treatments should go on in early June. Trees they infest include peach, plum and cherry. Females tend to lay eggs at the tree base so concentrate protectant sprays on this part of the plant. Black Vine Weevil We continue to receive samples of black vine weevil adults from Baltimore and Montgomery counties this week. Look for the leaf notching on the leaves for signs of this night-flying weevil. Horned Oak Gall Marty Adams, Bartlett Tree Experts, brought in a sample of shingle oak with horned oak galls along the stem. Pin oak is a common host of these galls as well. This gall is caused by a tiny wasp, Callirhytis cornigera. The life cycle is complex with alternating generations and two types of galls. An inconspicuous gall develops in the summer on leaves along the veins. The wasps that emerge from these leaf galls then lay eggs on the twigs. As these larvae develop they produce the conspicuous horned galls. One wasp larva emerges from each horn where it has spent up to two years. Go to http://bygl.osu.edu/content/horned-oak-galls-0 for more information on the life cycle. Infested trees have both types of galls present so chemical control is not very effective. There are many wasp parasitoids that help reduce these gall-making wasps, especially during the leaf-galling generation. Red Thread in Turf Erik Goerner, Maxalea, Inc., sent in a photo of a turf plot in Towson that was infected with red thread disease which is covering about 10 percent of the turf. Cool (65-70 F), wet weather provides optimum conditions for the development of red thread disease in the spring and fall. Red thread disease is caused by the fungal pathogen, Laetisaria fuciformis. Red thread can reduce turf density and lead to invasion by crabgrass and other weeds. In a Red thread close-up Photo: David Clement, HGIC 3 Horned oak gall on shingle oak; there is one horn that has developed on this gall Red thread in turf Photo: Erik Goerner, Maxalea, Inc. few weeks as the weather warms up, it should not be much of a problem. Management: Red thread tends to cause more damage to poorly nourished lawns. Maintaining adequate nitrogen levels will often reduce the problem. However, high nitrogen levels can create problems with other turf diseases. If the infection warrants treatment, fungicides include Bayleton, Banner MAXX, Chipco 26GT, Compass, Curalan, Daconil Ultres, Headway, Heritage and Insignia. For more details on red thread disease, view the University of Maryland Extension fact sheet at http://www.mdturfcouncil.org/admin/uploadfiles/tt-24-red-thread-and-pink-patch.pdf
Cottony Maple Scale Damian Varga, Plant Scientific Service, brought a sample of dogwood with cottony maple scale that was from Brooklyn Park (MD). This scale was still in the egg stage. Paul Wolf, Integrated Plant Care, is also seeing this scale on dogwood. Other preferred plant hosts include maple, elm, hawthorn, sycamore, and linden. The crawlers are yellow and usually hatch in June so look for them now on the undersides of leaves. Control: Talus or Distance with 1% oil. This scale can be controlled with soil applications of dinotefuran (Safari, Transtect), imidacloprid (Merit - landscape, Marathon - nursery), or Thiamethoxam (Flagship). Cottony maple scale Japanese Maple Scale Update: From Paula Shrewsbury: Crawlers continue to emerge on maples in College Park, MD. As of Wednesday, May 23rd our monitoring of Japanese maple scale (JMS) found ~40% of scales had eggs, 16% had no eggs, 11% had crawlers hatching and 33% were settled crawlers. The degree day monitor we have on campus reported 927 DD (Jan. 1st May 22th). Weather.com reports 940 DD in College Park for the same time period. Data based on 2 years of JMS studies found first generation crawler activity lasts about 7-8 weeks and that PEAK 1st generation crawler activity occurs around 1150 DD. We are supposed to have warm weather this week. I predict in College Park DD accumulations will reach ~1150 DD / peak crawler activity. If you are in College Park or DD accumulations in your area are similar I recommend you put on your control applications of IGR for JMS. For optimal control of JMS determine DD accumulations in your area, visually monitor your plants for crawler activity, and proceed accordingly. See last week s IPM report (May 18, 2012) for more information on monitoring and control recommendations. From Stanton Gill: John Speaker brought in Ilex samples from a nursery in Wicomico county on May 22 and they are loaded with Japanese maple scale. The crawlers were just starting to emerge. There were mainly females with eggs, but crawlers are starting. It is supposed to reach 90 F by the weekend and we should see more crawlers by the weekend on the shore. They tend to be about 10 14 days ahead of most of Central Maryland. In Montgomery County, Marie Rojas is also only seeing eggs and no crawlers yet. I expect to see crawlers soon, but it is still a little early to treat in Central Maryland. Powdery Mildew Powdery mildew continues to be a problem on various plants in landscapes. Bonnie Flynn from Arlington sent in a photo of crape myrtle with such a heavy infection that leaves were becoming completely gray. The many sunny days and cool nights have been ideal for the spread of powdery mildew this spring. Powdery mildew on crape myrtle Photo: Bonnie Flynn 4
Bagworms Todd Armstrong, The Davey Tree Expert Company, Inc., reported bagworm hatch on May 14 in Baldwin. Marie Rojas, IPM Scout, reported hatch in Adamstown on May 24. Control: If the larvae are still small, Bt can be used. For later instars, options include Acelepryn, Confirm, and Conserve. Several of the recently hatched bagworms Photo: Todd Armstrong, Davey Tree Expert Company Mounds in Turf We had a landscaper submit these pictures of a mound in their customer s lawn. Nothing was found in the mound or in the holes. This mounding showed up in the last 2 weeks. We sent the photos to an ornamental list serve for comments. Below is a response with the likely cause of this situation: From David Shetlar, Purdue, University: I agree with Carlos Fernandez (Ohio State University) that this looks like skunk or raccoon digging for earthworms. In my experience, skunks tend to bite out the turf and make a more pointed hole while raccoons tend to mash down the earthworm castings and mash the turf with it. We get both critters doing considerable damage in home lawns that have great earthworm populations. Unfortunately, these folks are often advised by garden centers that they have white grubs and are then sold a grub treatment. Black Swallowtail Caterpillar Craig Greco, Yardbirds, Inc., sent in a photo of an early instar black swallowtail caterpillar, also called a parsleyworm. It becomes green, black, yellow, and white in later stages. This caterpillar feeds on dill, parsley, fennel and other members of the carrot family. Another common plant host is rue. It is a caterpillar that your customers might see in their herb garden. Black swallowtail caterpillar Photo: Craig Greco, Yardbirds, Inc. 5
Tuliptree Scale and Lady Bird Beetles This week, John Raver, The Brickman Group, brought magnolia samples with tuliptree scale that are mostly second instars that are starting to enlarge and start feeding. As they feed, they will excrete honeydew on which sooty mold will grow. The honeydew will also attract ants. There were several lady bird beetles on this sample. These lady bird beetle produce a waxy coating which makes them resemble mealybugs. Control: A foliar application of Distance or Talus; a drench of Imidacloprid (Merit in landscape, Marathon in nursery), dinotefuran (Safari, Transtect), or thiamethoxam (Flagship) A lady bird beetle larva with a waxy covering is feeding on tuliptree scale that is infesting a magnolia A view of the underside of the lady bird beetle larva Lady Bird Beetles Richard Chafin, The Brickman Group, brought a twig with lady bird beetle larvae that were starting to pupate. There are many species of lady bird beetles in the area and this is one that is found on woody plants. Chilocorus species pupate in their last larval skins, which are spiny. Chilocorus stigma is the twicestabbed lady bird beetle and it commonly feeds on scale insects. Lady bird beetle larvae starting to pupate Twicestabbed lady bird beetle adult Educational Resources Bill Miller, The Azalea Works, ordered a CD recently on tick morphology that he thought was pretty good. The CDs are free from Armed Forces Pest Management Board. Ordering information is available at http://www.afpmb.org/teaching-cds. He noted that they offer CDs on adult mosquito morphology, larval mosquito morphology, and tick morphology. 6
Weed of the Week, Chuck Schuster The yellow flowering plant standing tall in some landscapes right now may be spiny sowthistle, Sonchus asper. This winter or summer annual is found throughout the United States in many different settings including landscapes and roadside areas. Spiny sowthistle can reach a total height of six feet (usually three to four feet). Starting from a basal rosette, it will form a taproot, and along with its thorny or prickly leaf margins is often mistaken for a member of the thistle family. The upright stem will emit a milky sap when damaged or cut. The leaves have a whitish covering, are deeply round-lobed, and are alternate on the stem. Leaves clasp the stem. Spiny sowthistle Photos: Chuck Schuster, UME Flowers will be formed in clusters at the end of stems, and are one half to one inch in diameter. Similar to a dandelion in shape and color, it will produce a seed that will be spread by air movement. It is similar to annual sowthistle, Sonchus oleraceus, but annual sowthistle has a very pointed lobes on the leaves and is less spiny than spiny sowthisle. One characteristic that distinguishes it from a true thistle is the milky sap that is released when cut. Control of spiny sowthistle needs to be done before bolting and seed production. This weed spreads primarily by seed. Dicamba can be used in settings where drift and volatilization are not a concern. Spot spraying with glyphosate products will be effective if done while the weed is in active growth stages. Plant of the Week, Ginny Rosenkranz Scabiosa columbaria, Pincushion Blue Butterfly, was the Perennial Plant of the Year in 2000 and is one of the longest blooming herbaceous perennials for summer color. Pincushion Blue Butterfly prefers full sun to part shade, cool evenings and moist, but well drained soils with a neutral ph. It is hardy through USDA zones 4-10. The plant is a rosette of ferny basal leaves with 2 foot tall, slender stems. It has 2 inch blue and lavender blue parasol flowers that many think look like an old fashioned pincushion. The basal leaves are lance-shaped while the leaves that climb the slender stem are lobed. The flowers will bloom from late spring through late fall if dead headed and fertilized. It is famous for attracting butterflies to the garden and the soft blue lavender colors makes a lovely counterpoint to the bright yellows, Pincushion flowers Photo: Ginny Rosenkranz, UME oranges and reds of many summer bloomers. Pincushion flowers are rich in nectar and are composed of many tiny flowers. It does well as a fresh cut and dried flower as well. Blue Butterfly is excellent in a sunny border, in containers as an edging plant and in the cutting garden. Pests include spider mites and slugs. Botrytis, stem rot leaf spot and anthracnose can be disease problems. 7
Degree Days (As of May 24)* Baltimore, MD (BWI) 783 Dulles Airport 781 Frostburg, MD 445 Martinsburg, WV 736 National Arboretum 990 Reagan National 990 Salisbury 849 *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) Aruncus Dioicus First bloom (May 21) Silver Run Clintonia umbellulata First bloom (May 21) Silver Run Cornus racemosa First bloom (May 21) Silver Run Euonymous americanus Full bloom (May 21) Silver Run Galax aphylla Full bloom (May 21) Silver Run Indigofera kirilowii First bloom (May 21) Silver Run Kalmia latifolia Full bloom (May 21) Silver Run Mitchella repens First bloom (May 21) Silver Run Phlox glaberrima ssp. triflora Full bloom (May 21) Silver Run Morris Berd Rhododendron Ben Morrison Full bloom (May 21) Silver Run Rhododendron viscosum First bloom (May 21) Silver Run Sisyrinchium angustifolium Full bloom (May 24) Columbia (blue eyed grass) Stewartia pseudocamellia Bud (May 25) Ellicott City Yucca filamentosa Golden Sword Bud (May 25) Ellicott City 8
Upcoming Programs Pesticide Recertification Conference June 1, 2012 Location: WyeREC, Wye Mills, Maryland http://ipmnet.umd.edu/ 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/ 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 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 Maryland Christmas Tree Association s Summer Meeting June 30, 2012 (Saturday) Location: Taylor Sines Woodlake Tree Farm, Oakland, MD Contact: 410-452-9793 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.