for Arborists, Landscape Managers & Nursery Managers

Commercial Horticulture July 1, 2011Coordinator 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)

In This Issue...

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

TPM/IPM Weekly Report

- Weather update- Japanese beetles- Euonymus scale- San Jose scale- Oscure scale and gloomy scale- White prunicola scale- Imperlis information- Tobacco budworm- Broadnecked root borer- Gypsy moth- Downy mildew- Mimosa webworm- Honeylocust spider mites- Catalpa sphinx moths- Fungus gnat larvae- Clearwing moths

Beneficial Pic of the WeekWeed of the WeekPlant of the WeekPhenologyDegree daysConferences

Integrated Pest Management for

Commercial Horticulture

www.ipmnet.umd.edu

Weather UpdateIt is will reach the low 90 °F temperature range this weekend and it is bone dry out there. Ginny Rosekranz reports that the Eastern Shore is still hot and dry and is now over 10 inches below normal rainfall. Make sure you keep plants watered well during this hot and dry period. Otherwise plant material will be showing dieback later in July. Other than that, relax like the cat in the picture this fourth of July and enjoy the summer.

Japanese BeetlesBeth Clark reported on June 22nd that she found Japanese beetles in Owings Mills. We are only seeing a few individuals here at the research center in Ellicott City so far this season.

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Euonymus ScaleWe examined euonymus scale from Frederick County last Friday and there were many settled 1st instars and some crawlers present.Control: Distance or Talus with 0.5% horticultural oil.

San Jose ScaleWe received a sample of San Jose scale from Harford County on an ornamental plum. Most were 2nd and 3rd instar females on the plant. Watch for crawlers of the second generation as we move into July. This scale is common on plum, pyracantha and several rosaceous plants. The female covers are round with a raised center. There are three generations.

Obscure Scale And Gloomy ScaleObscure scale tends to be found on pin oak and willow oaks. Crawlers should be out in early July. We are mainly seeing females right now in central Maryland.

Gloomy scale is common on maples, especially red maples. The crawlers should also be out in early July. If you have a sample send in twig samples to 11975 Homewood Road, Ellicott City, MD 21042. We will look at them and let you know what life stages are present.

Gloomy scale on mapleObscure scalePhoto: James Solomon, USDA Forest Service, Bugwood.org

White Prunicola ScaleThis armored scale is mainly on Prunus species, especially cherry. It is also on lilac. The crawlers should be out in early July.

Euonymus scale on Euonymus kiautschovicus ‘Paulii’

San Jose scale on almondPhoto: United States National Collection of Scale Insects Photographs Archive, USDA Agricultural Research Service, Bugwood.org

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Broadnecked root borerPhoto: Dan Yates, Bartlett Tree Experts

Imprelis InformationJohn Akehurst, Akehurst Landscaping, sent us a link for an article from Penn State on their observations on Imprelis injury to trees at http://extension.psu.edu/greenindustry/giec/news/2011/some-observations-on-imprelis-injury-to-trees

Caterpillar Attacking PetuniasTodd Franklin, The Brickman Group, sent in photo of caterpillars feeding on petunias. It is the tobacco budworm, Heliothis virescens. They love petunias and they are very active in summer. Todd noted that he found this caterpillar on a few in pots. They were only on the petunias and had chewed all the petals off of them. He did not see any damage to any of the other annuals that were in the same pot.

Broadnecked Root Borer (Prionus laticollis)Dan Yates, Bartlett Tree Experts, found a beetle at a property in Warfordsburg, PA (near Hancock, MD) along the western fork of the Potomac River, not far from the C&O Canal trails. While performing a root collar excavation around a white oak near the corner of the house, Dan found a giant long-horned beetle. Based on the photo, Dan Gilrein, Cornell University, identified it as the broadnecked root borer. Dan Gilrein noted that he is evaluating a pheromone for this beetle and that this beetle has been a damaging pest in one fruit orchard in New York and he sometimes also sees it in landscape plants (oak, rhodies, others). Disease, drought, mechanical injury, and poor soil conditions increase tree susceptibility. Therefore, follow cultural practices that will keep trees thrifty and vigorous.

Photos show color variation of tobacco budwormPhotos: Todd Franklin, The Brickman Group

Gypsy MothDan Yates also found a late instar gypsy moth caterpillar in Catoctin Mountain National Park last weekend.

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Downy mildew on basilPhotos: David Clement, HGIC

Downy Mildew on BasilDavid Clement, Home and Garden Information Center, received a basil sample infected with downy mildew. It is one of the first reports in Maryland so far this season. Remove disease foliage to reduce the spread of infection.

Honeylocust spider mites and eggs

Mimosa WebwormChuck Kinsey, The Brickman Group, brought in a honeylocust sample that had some damage from mimosa webworm. Anthony Tripoli sent a few photos of the caterpillar and damage that he found in Ellicott City on July 1. The first generation is causing the damage now. The second generation occurs in late July to early August.Monitoring: Look for webbing on tips of honeylocust branchesand the caterpillars feeding within this webbing.Control: Prune out infested webbed branches on small trees. Bt or Conserve can be used. Controlling the first generation larvae decreases damage from the next generation.

Mimosa webworm caterpillarPhoto: Anthony Tripoli

Honeylocust Spider MitesThe honeylocust sample brought in by Chuck Kinsey also had a high population of honeylocust mites on it. This native spider mite feeds only on the leaves of honeylocust (Gleditsia triacanthos). There are several generations a year in this area. Honeylocust that are growing in hot dry sites are most susceptible to injury from this pest.Monitoring: Examine foliage of honeylocust. Use a piece of paper on a notebook and tap the leaves sharply over the paper and look for the mites using a 10 -16 X magnifier.Control: With the high temperatures, it is not the best time to apply a miticide. If making a treatment, be sure to irrigate and make the application early in the morning. Materials for mite control include abamectin (Avid) fenpyroximate (Akari), bifenazate (Floramite), hexythiazox (Hexygon), spinosad (Conserve), pyridaben (Sanmite) and horticultural oil.

Mimosa webworm webbing

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Catalpa Sphinx Moth ActivityCraig Greco, Yardbirds, Inc., found a female catalpa sphinx laying eggs on foliage this week. Phil Normandy, Brookside Gardens, is finding catalpa sphinx moth caterpillars hatching and feeding on one tree. Phil also found egg clusters on the top leaf surfaces.

Catalpa sphinx moth caterpillar

Adult catalpa sphinx moth laying eggsPhoto: Craig Greco, Yardbirds, Inc.

Something Weird on LawnsAt this time of year a weird thing will occasionally happen where a group of insect larvae band together and move across lawns and sidewalks. They are sciarid fungus gnats and commonly trek across turf when it is time to pupate. Nothing to worry about, but they look like a small snake moving across the landscape. It’s a cool part of nature.

Hummingbird Clearwing and Snowberry Clearwing MothsAt this time of year, when monarda is in bloom, we see the hummingbird clearwing and snowberry clearwing moths here at the research center in Ellicott City. These moths, which look a lot like bumblebees, hover like hummingbirds as they nectar on flowers during the day.Control: No control is necessary.

Hummingbird clearwing moth

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Burcucumber plantPhoto: Bruce Ackley, The Ohio State Uni-versity, Bugwood.org

Beneficial Photo of the WeekOne of the species of lady bird beetles found this week was the spotted lady beetle which tends to be pinkish in color. This beetle divides its diet fairly evenly between aphids and pollen.

Coreopsis ‘Moonbeam’ and ‘Zagreb’Photo: Ginny Rosenkranz, UME

Spotted lady bird beetle

Weed of the Week, Chuck SchusterBurcucumber, Sicyos angulatus, is a summer annual with an appropriate name. Found in many areas of the United States, it can be a problem in landscapes and nurseries. Looking very similar to cucumber in our gardens, it has a vining growth habit, producing tendrils to aid in climbing. Burcucumber will have a shallow fibrous root system, stems which are quite hairy, and stems will have a ridge that runs the length of the stem, often called a furrowed stem. Leaves are alternate, with three to five pointed lobes, serrated margins and can be up to eight inches in width and length. Leaves do not have hairs on the top surface and will be finely pubescent, most often along the lower veins. The whitish to green flowers, with both male and female occurring on the same plant, will have five sepals and five petals. The fruit will be similar to a small cucumber with stiff long bristles. Each fruit will produce one seed that is flattened and brown, with a slightly pointed end. It is similar to Japanese hops, but Japanese hops do not produce the tendrils that will be produced by burcucumber.

Control can be obtained using Tenacity in turf settings. Oxadiazon (Ronstar) can be used to control in landscape and nursery setting when applied as a pre-emergent.

Plant of the Week, Ginny RosenkranzCoreopsis is a native herbaceous perennial that is covered in blooms for at least a month in the heat of summer, and then continues to bloom sporadically throughout the summer until October. Coreopsis verticillata is also called threadleaf coreopsis after the long, slender leaves that are bright green. The 2-3 inch thin, palmately divided leaves are an adaptation allowing the plant to survive heat and drought. The plants are usually slow to emerge in the spring, waiting until the soils warm up to show any green foliage. They grow about 18-24 inches high and wide and thrive in full sun in almost any soil type as long as it is well drained. Coreopsis verticillata, once established into the landscape, is very drought tolerant and slightly salt tolerant. The flowers are 1 ½ - 2 inches in diameter, daisy-shaped and usually yellow, and are often seen with visiting butterflies. The yellow flowering cultivars include ‘Golden Showers’, ‘Golden Gain’, ‘Moonbeam’, ‘Zagreb’ and ‘Crème Brulee’. Newer cultivars introduce new colors to the market. ‘Route 66’ has yellow flowers with a ring of burgundy around the crown that bleeds out to the tips of the petals, and ‘Sienna Sunset’ has warm apricot flowers. ‘Moonbeam’ has been the landscape favorite for many years, but the

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PLANT PLANT STAGE (Bud with color, First bloom, Full bloom, First leaf)

LOCATION

Asclepias incarnata First bloom (June 25) ColumbiaMonarda didyma First bloom (June 24) Ellicott City

Degree Days (As of June 30)

Baltimore, MD (BWI) 1634 Dulles Airport 1570 Frostburg, MD 941 Martinsburg, WV 1409 National Arboretum 1781 Reagan National 1767 Salisbury 1731

newer cultivars are great competition. Dead heading the spent flowers at the end of June will ensure re-blooming throughout the summer and into the late fall. Aphids, beetles, vine weevils slugs, leaf hoppers and root knot nematodes can cause insect problems while crow, stem and root rot, grey mold, botrytis, mildew, leaf spots, INSV and rust are the disease problems that can affect coreopsis.

Coreopsis ‘Moonbeam’ flowersPhoto: Ginny Rosenkranz, UME

Stanton GillExtension Specialist

sgill@umd.edu

Paula Shrewsbury Extension Specialistpshrewsb@umd.edu

Ginny RosenkranzExtension Educatorrosenkrnz@umd.edu

Chuck SchusterExtension Educator

cfs@umd.edu

Karen Rane Plant Pathologistrane@umd.edu

Brian Clark Extension Educator bpclark@umd.edu

Andrew RistveyExtension Specialistaristvey@umd.edu

David ClementPlant Pathologist

hgic.umd.edu

The information given herein is supplied with the understanding that no discrimination is intended and no endorsement by University of Maryland Extension is implied.

CONTRIBUTORS:

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.

Thank you to the Maryland Arborist Association, the Landscape Contractors Association of MD, D.C. and VA, the Maryland Nursery and Landscape Association and FALCAN for your financial support in making these

weekly reports possible.

Upcoming Programs:

July 21, 2011PGMS Field Day and Trade ShowLocation: American University, Washington, D.C.Contact: 703-250-1368

August 1, 2011Cut Flower Tour in Southern MarylandLocations: Mechanicsville and Loveville, MDContact: 301-596-9413