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Commercial Horticulture August 29, 2014Coordinator Weekly IPM Report: Stanton Gill, Extension Specialist, IPM for Nursery, Greenhouse and Managed Landscapes, [email protected]. 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 AssistantDisease 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
TPM/IPM Weekly Report
Rainscape/Stormwater Management ConferenceBy: Stanton GillThe two-day rainscape/stormwater management conference for the green industry that was held last week was very successful. I was surprised to learn how many landscapers are including rainscape features in many innovative ways. From this conference we see a rising potential niche for landscape companies that specialize in maintaining rainscapes, permeable paved areas and green roofs.
- Rainscape conference follow-up- Long range weather- Impatiens downy mildew- MDA pesticide container recycling- Crape myrtle and seven- son flower- Cut flower farm tour- Caterpillars- Hercules beetle- Beech blight aphid- Flatheaded appletree borer- Scale update
Beneficial of the WeekPlant of the WeekPhenologyDegree DaysAnnouncements
IPMnetIntegrated Pest Management for
Commercial Horticulture
extension.umd.edu/ipm
Participants who attended on August 21st at Robinson Nature Center in Columbia, MD, had a tour of the green roof and rain garden
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Long Range WeatherBy: Stanton GillWell, we have reached the middle of the growing season. People are starting to plan fall plantings and for the upcoming winter. Several people attending the stormwater management conference said they have heard we are in for another cold, snowy winter. The Farmer’s Almanac, which bases predictions on past patterns, is predicting another cold, bitter winter for 2014/2015. One commercial supplier told me that the snowplow equipment suppliers are seeing a spike in their August sales of snow removal equipment.
I spoke with a NOAA employee from the Silver Spring, Maryland office to see what the word is from NOAA. He told me that the weather is controlled by an oscillation pattern which means they cannot tell until we are in the oscillation pattern. Until the pattern starts in the late fall we cannot really accurately predict the long range.So far, the majority of people seem to feel we are in for another cold, long winter. Let’s see who wins.
The white sporangia are very evident on the undersides of leaves (left). This bed of garden impatiens is dying out due to infection from impatiens downy mildew (right).Photos: David Clement, HGIC
Maryland Department of Agriculture Pesticide Container Recycling
MDA has a brochure on the dates and details of the pesticide container recycling program which is available at: http://mda.maryland.gov/plants-pests/Documents/recycle.pdf
Impatiens Downy MildewBy: Karen Rane, UMDWe received our first landscape sample of impatiens downy mildew in the diagnostic lab this week. The disease is most likely occurring now due to wind-blown sporangia. Initial symptoms include slight mottling and curling of infected leaves, with a white "lawn" of sporangia visible on the underside of the symptomatic leaves. Defoliation will occur as the infection spreads up the plant. While fungicides provide good protection of plants during greenhouse production in the spring, we do not recommend fungicide applications to landscape impatiens this late in the growing season. Management of this disease in the landscape involves bagging and disposing of all infected plants and leaves, and avoid planting impatiens in the same spot next year.
We were asked to include a section in the weekly IPM Alerts and/or on our website on potential plants to be used in rainscapes and a discussion section on problems people are experiencing out in the field. We need your help if we are to be successful with this addition. If you have innovative rainscape, green roof, really good plant material or permeable paver methods you have used with great success and are willing to share this information send me a short write up, [email protected]. We will place this information in upcoming IPM Alerts and on-line.
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Crape Myrtle and Seven-son FlowerBy: Stanton GillLast winter creamed many crape myrtle plantings in landscapes and in some nurseries. The interesting thing is that last week while visiting a re-wholesale yard one of the sale persons commented that sales for crape myrtles have been very high in August. If you are planting this plant in your customers’ landscapes this summer and the winter turns to the extreme cold side the loss rate will be high.
An alternative to crape myrtle is the seven-son flower, Heptacodium miconioides. Seven-son flower is just starting to bloom with white flowers in late August and will continue into September. After flowering the sepals turn bright red to purple and the plant has a great display until frost. This plant is a zone 5 plant and a planting I have at my farm in Westminster came through the winter without damage. I have not had any samples submitted to our CMREC lab with any insect problems on this plant over the years. Every plant eventually has an insect problem, but so far, this one has been relatively free of problems. This plant, trained as a small tree, is a good looking plant that fits in with an IPM approach of using pest resistant plant material.
Learn About Cut Flowers on September 9thIf you are interested in exploring commercial cut flower production we have a great field day set up for September 9, 2014 in Harford County, MD. The University of Maryland Extension is working with the Association of Specialty Cut Flower Growers in conducting an education tour and lectures on commercial cut flower topics at two Maryland cut flower operations. Several outstanding Maryland cut flower growers and suppliers of plant material will be giving short lectures at this field day. Karen Rane, Andrew Ristvey, Ginny Rosenkranz, David Clement, Chuck Schuster, and Stanton Gill will be covering topics on commercial cut flower production. You will get a chance to visit with two innovative commercial cut flower growers. Bill Harlan, Belvedre Farm, is doing field production and Charles, Richard and Matthew Bauer, Flowers by Bauers, are producing cut flowers such as snapdragons in the greenhouse using a hydroponic system.
To get more details, go to http://extension.umd.edu/ipm/conferences
Crape myrtle in full bloom Close-up of sepals on seven-son flower
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By feeding on Asclepias plants, monarch caterpillars accumulate toxic chemicals that make them distasteful to predatorsPhoto: Craig Greco, Yardbirds, Inc.
Caterpillars
Banded Tussock Moth CaterpillarConnie Bowers, Garden Makeover Company, found the banded tussock moth caterpillar on a Fothergilla gardenii shrub. These caterpillars are yellow-brown or gray-black. They feed on a variety of woody trees and shrubs, but are rarely found in significant numbers to warrant control.
Monarch CaterpillarCraig Greco, Yardbirds, Inc., sent in a photo of several monarch caterpillars feeding on milkweed. Look for this caterpillar on young leaves of milkweed (Asclepias) plants.
Hercules BeetleMark Nettleship, Country Springs Nursery, and Kevin Nickle, ProLawn Plus, Inc., are both reporting finds of female hercules beetles. The larvae of this beetle feed on rotted logs and have a 2-year life cycle in the logs. Adults are active in August and September.
Banded tussock caterpillars can be found resting on the topside of leavesPhoto: Connie Bowers, Garden Makeover Company
Here is one of the female hercules beetles found this week. The male has two large horns.Photo: Mark Nettleship, Country Springs Nursery
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Flatheaded appletree borers are most active on the bark on the sunny sides of treesPhoto: Richard Chaffin, The Brickman Group
Beech Blight AphidBy:Stanton GillI received an email with a video of what look like dancing white fluff on a beech. Today I received another email, this one from Daniel Macpeak with a picture of white fluff covering a beech. Evidently, this insect has become quite common this fall. It is a woolly aphid species known as the beech blight aphid, Grylloprociphilus imbricator (Fitch). This aphid raises the posterior end of its body and sways when it is disturbed. This action produces a dance-like effect that occurs throughout the colony. It looks like it is dancing in the wind and can be very entertaining. The person that sent in the video of swaying bodies did a great job of capturing the moment and I spent endless moments re-playing the video.
I have not seen samples of this aphid for several years now, but this year may be the comeback year. When it does appear, however, it is usually in dramatic fashion. The aphid itself is a light bluish color, but it amasses by the thousands on the twigs, small branches, and the undersides of foliage primarily of the American beech, Fagus grandifolia. Populations can become quite obvious in August, but by September and October, they can be spectacular. Infested beech trees can appear to have their smaller branches and twigs covered with snow. In this regard, they look remarkably similar to colonies of the woolly alder aphid, which, as the name implies, is a pest of certain alders.
In addition to being occasionally abundant and showy, this species is capable of producing vast amounts of honeydew. This aphid excrement is plant sap that has gone through the insect’s body where certain amino acids and other nutrients having been extracted. The rest is then expelled as waste onto the branches, foliage, understory plants, and the ground below. Certain fungi known as the sooty molds then colonize this honeydew and turn the substrate black. Because of the copious amounts of honeydew produced by this aphid, the production of sooty mold can become severe and spectacular in its own right.
Control is usually not needed, but it will be eye-catching for your customers. Let me know if you find it active in your area. I would like to see how widespread it is this year. Send an email to me at [email protected]
Flatheaded Appletree BorerAfter noticing dieback on a red oak, Richard Chaffin, The Brickman Group, found a flatheaded apple tree borer, on the bark of the tree on August 26 in Harford County. If you see adults, also look for D-shaped exit holes on the trunks. This borer is an opportunist that attacks weakened trees.Control: Keep trees healthy and vigorous to reduce problems with this borer. Keep trickle irrigation on susceptible trees, especially red maple, dogwood and oaks during the hot part of the summer. Applying a mulch layer will help conserve moisture. It is too late in the year for effective chemical control with permethrin or bifenthrin. Next year you can apply these materials in early May to prevent entry of newly hatching larvae.
The aphids are coating the branch marked by the arrowPhoto: Daniel Macpeak, Goldleaf Lawn Care
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Scale Update*By: Nancy Harding, UMD
White Prunicola Scale (WPS), Pseudaulacaspis prunicola (armored scale)Monitoring WPS for the 3rd generation of crawlers on Prunus subhirtella ‘Autumnalis’ in Laytonsville MD on Tuesday, August 26th, found mostly 3rd instars without eggs suggesting there will be a little time (maybe a week or so) before crawler activity. The Degree Days in Laytonsville as of August 26th were 2702 DD. We will continue to monitor WPS and report when the 3rd generation crawlers are active.Monitoring: Examine Prunus species (especially Japanese flowering cherry), privet and lilac for signs of WPS scales (ex. white covers on bark). If DD are higher than listed above where you are you should monitor for WPS crawler activity on host plants.Control: No control should be applied until you see crawler activity.
Japanese Maple Scale (JMS), Lopholeucaspis japonica (armored scale)Monitoring JMS on Ulmus americana in Laytonsivlle found mostly settled crawlers (1st instars) and 2nd instars indicating we are still in a window of time for applying controls. Based on our research and continued monitoring of JMS, crawler emergence period extends over 6-7 weeks. The Degree Day accumulation in Laytonsville as of August 26th was 2702 DD.Control: Applications of 0.5 - 1% horticultural oil combined with pyriproxyfen (Distance) or buprofezin (Talus) should be made when crawlers and settled crawlers are detected. This treatment should have about 2 - 3 week residual activity. At that time monitor your plants again to see if crawlers are still active. The twice-stabbed lady bird beetle and parasitic wasps provides some biological control of this scale.
For more information on the biology, management and host plants of JMS go to the following fact sheets:
Biology and Management: http://extension.umd.edu/sites/default/files/_docs/articles/FS-967%20Japanese%20Maple%20Scale.pdf
For the JMS Plant Host Fact Sheet (EBR 18), go to the IPMnet publications page.
*Degree data totals as per Weather Channel website (http://www.weather.com/outdoors/agriculture/growing-de-gree-days/USMD0045)
Look for the purple crawlers of JMS
Beneficial of the WeekBy: Paula Shrewsbury
Ambush bugs use camouflage to help them “ambush” unsuspecting prey!Ambush bugs are a group of predatory true bugs (Order: Heteroptera) that belong to the family Phymatidae. There are many species of ambush bugs that vary in their appearance and size, and the type of plant they use as their foraging habitat. At this time of year fall blooming flowers such as goldenrod and asters look amazing. If you look VERY closely into the flower heads you may see a highly camouflaged ambush bug sitting and waiting for its dinner to arrive. Adults and nymphs of ambush bugs are camouflaged to look like the flowers or foliage of the plants where they forage for prey. Their coloration is often mottled, and the outline of their body irregular, both characteristics that help them hide from unsuspecting prey. Ambush bugs are “sit and wait” predators. They use there camouflage and ability to sit very still for hours to hide from potential prey items. When the
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The yellow and brown patches of color and irregular outline of the body of this ambush bug helps it to camouflage very well within the golden rod flowers. Photo: M.J. Raupp, UMD
unsuspecting prey lands on the flower the ambush bug pounces on the prey grabbing it with its well-developed raptorial front legs. The ambush bug then injects enzymes into the prey. The paralyzing enzymes immobilze the prey and the digestive enzymes liquefy it allowing the ambush bug to slurp up its dinner using its sucking mouthparts. Ambush bugs feed on other insects as big as or bigger than themselves. They feed on a variety of insects that visit flowers such as the wasp pictured here, other bees or wasps, beetles, flies, and more. Although these bugs feed on other insects, some may not consider them “beneficial” because they sometimes feed on pollinating insects. However, it is all part of the circle of life which is amazing when you pay attention to it.
Look closely and you can see the ambush bug’s sucking beak inserted into the head of the wasp. The unsuspecting wasp landed on the flower to suck up some nectar and ended up with quite a surprise. Photo: M.J. Raupp, UMD
Stanton GillExtension Specialist
Paula Shrewsbury Extension [email protected]
Ginny RosenkranzExtension [email protected]
Chuck SchusterExtension Educator
Karen Rane Plant [email protected]
Andrew RistveyExtension [email protected]
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, 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.
Upcoming ConferencesCut Flower TourSeptember 9, 2014Location: Two Harford County operationshttp://extension.umd.edu/ipm/conferences
Reducing Lawn Fertilizer Use and Stormwater RunoffSeptember 17, 2014Location: University of Maryland Paint Branch Turfgrass Research and Education Facility, College Park, MDA brochure is available online
Degree Days (As of August 28) 2014 2013 2012 2014 2013 2012Baltimore, MD (BWI) 2776 2932 3438 Dulles Airport 2645 2943 3340Frostburg, MD 1767 1867 2190 Martinsburg, WV 2672 2718 3116 National Arboretum 3395 3349 3894 Reagan National 3395 3349 3894Salisbury 3048 3227 3567 St. Mary’s City 2874 3069 3623
To check degree day (DD) accumulations in your local area go to: http://www.weather.com/outdoors/agriculture/growing-degree-days/USMD0100. 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.
Plant of the WeekBy: Ginny Rosenkranz, UMEEutrochium purpureum subsp. maculatum, spotted Joe Pye weed, is a native plant that blooms in the late summer and is a major butterfly magnet. This subspecies is better suited to damp meadows, stream banks and coastal areas and is a perfect plant for rain gardens. Soil preference is average moisture and fertile soils that do not dry out. It is a clump forming herbaceous perennial that grows 5-7 feet tall with a spread of 2-4 feet and prefers full sun but can grow in partly sunny areas as well. The large dark green leaves expand to 8 inches in length. The leaves are coarsely serrated and arranged in whorls of 3-4 on purple spotted stems. The tiny rose pink flowers are perched on a domed terminals, creating a lovely buffet for pollinators. The fragrant flower clusters hold 5-7 florets and are vanilla scented. The flowers can start blooming in July and continue to bloom through September, then they give way to attractive seed heads which stay throughout the winter giving the garden interesting texture and food for winter birds. Hardy in USDA zones 4-8, Joe Pye weed can be used as the back border of a perennial bed, cottage garden, native meadow plantings and in rain gardens. Smaller cultivars should be chosen for small rain gardens. There are no serious pests for Eutrochium purpureum subsp. maculatum at this time, although the leaves will show scorching if the soil dries out.
