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Commercial Horticulture September 6, 2013Coordinator 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) 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
TPM/IPM Weekly Report
- Dog-day cicadas- Scale update- Montgomery County meeting- Rust on tall fescue- Grasshoppers- Fall webworm- Crapemyrtle aphid- Mimosa webworm- Emerald ash borer- Lawn fertilizer law
Beneficial of the WeekWeed of the WeekPlant of the WeekAnnouncementsDegree Days
A New Address for IPMnet
Integrated Pest Management for
Commercial Horticultureextension.umd.edu/ipm
Dog-day CicadasWe are getting a lot of reports of male cicadas singing (mating calls to females) in the trees in many parts of Maryland. This is the dog-day cicada that is active in late summer. Most people know the 17-year periodical cicada, Magicicada septendecim (Linnaeus), that completes its life cycle in 17 years, emerges in large numbers (broods) in large geographical areas and is out in the spring. The one we generally see every year in August through September is called the dog-day cicada, Tibicen spp.
The life cycle of the dog-day cicada (sometimes called the annual cicada) is 2 to 5 years. A female cicada uses an ovipositor to insert clusters of eggs into twigs and small branches. We generally have at least one brood emerging each summer. In 6 to 7 weeks, small nymphs hatch from the eggs and drop to the ground. They burrow into the soil, seeking tree roots. Adult dog-day cicadas can live for 5 to 6 weeks and your customers will see them dying on their driveways, sidewalks, and decks as we progress into September. There is nothing you need to do about this insect. Cicada killer wasps and birds do a pretty good job of reducing the populations each year.
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Rust on tall fescuePhotos: David Clement, HGIC
Scale UpdatesWhite Prunicola Scale (WPS, armored scale): Monitoring WPS in Laytonsville on Wednesday September 4, found the first signs of 3rd generation CRAWLERS. However the majority of scales have not produced eggs at this time. The Degree Days per weatherchannel.com were 2874 DD. We will continue to monitor and report for the optimal time for control measures (estimate next couple of weeks). Therefore, if the degree days in your area are near or at 2874 DD, you should closely monitor your plants infested with WPS for crawlers. Monitoring: The most common host plants that should be monitored are Prunus species, lilacs, and privets. You are looking for the white male and female “covers” on the bark of branches and trunks. Note that white peach scale looks very similar to white prunicola scale but they have different host plants.
Japanese Maple Scale (JMS, armored scale): Monitoring JMS in Laytonsville on Wednesday September 4 found the majority of the scales examined have reached 2nd instar stage (their overwintering stage). The Degree Days per weatherchannel.com were 2696 DD. Therefore, if the degree days in your area are near or at 2696 DD the efficacy of the use of IGRs will likely not be effective.
To aid in your monitoring and management of JMS see fact sheets:
Japanese Maple Scale - Woody Ornamental Host Plantshttps://www.extension.umd.edu/ipm/publications/landscape-publications
Japanese Maple Scale - A Pest of Landscape Trees and Shrubshttps://www.extension.umd.edu/sites/default/files/_docs/programs/ipmnet/JapaneseMapleScale-UMD-1.pdf
Montgomery County Working Group Meeting on Pesticide RegulationsThere will be a working group meeting on Monday, September 9, 2013 at 10:30 a.m. at the Montgomery County Council Office Building, 3rd Floor, 100 Maryland Avenue, Rockville, Maryland to discuss the potential of Montgomery County Government following the Takoma Park model of passing more restrictive pesticide regulations for applications to lawns and landscapes. This meeting is opened to the public and if your business wants to stay informed it might be worth attending.
Rust on Tall FescueRust symptoms on tall fescue turf, most likely caused by Puccinia coronata. Rust outbreaks are most common in late summer and early fall. Rust is a disease of slow growing turf, so factors that contribute to poor growth tend to favor rust development. These factors include summer heat and drought stress, low nitrogen fertility, compaction, and shade. Rust can also severely damage new spring-seeded lawns that lose vigor during heat and drought conditions.
Management is best achieved by maintaining a healthy and vigorous turf stand and well maintained turf typically out grows the damage from the disease. Avoiding early evening irrigation also will help limit disease spread by lessening the chance of extended dew periods. DMI and QoI (strobilurin) fungicides are very effective against rust, but on well-established turf, should be considered only as a remedial treatment when cultural practices fail to prevent an outbreak.
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Grasshopper Life Cycle and ControlIn early September the weather has changed to hot and dry, at least for this week. Many weeds are drying up and grasshoppers are moving into container grown perennials and annuals. Some growers are reporting feeding damage on their plants in garden centers, nurseries and greenhouse operations growing plants outdoors. Grasshoppers cause some damage every year, but they become very destructive during dry periods. The main factor affecting grasshopper populations is weather. Fortunately, we have had a fairly wet summer and the populations of grasshoppers are not as high as the last couple of summers. Outbreaks, or exceptionally large populations, are usually preceded by several years of hot, dry summers and warm autumns. Dry weather increases the survival of nymphs and adults. Warm autumns allow grasshoppers more time to feed and lay eggs. The thing of concern with grasshoppers is that they have a high reproductive capacity. The female lays an average of 200 - 400 eggs per season. Female grasshoppers deposit their eggs below the soil surface in pod-like structures. Each egg pod consists of 20 to 120 elongated eggs cemented together. Egg pods are very resistant to moisture and cold and easily survive the winter if the soil is not disturbed. Grasshoppers deposit eggs in fallow fields, ditches, fencerows, and weedy areas. Fortunately, only one generation of grasshoppers is produced in most years.
Eggs hatch was late this year and occurred mainly in June and July. Many of the egg hatched late because the spring was cool and wet. Nymphs go through five or six developmental stages and become adults in 40 to 60 days, depending on weather and food supply. In September, you will find mainly adults feeding.
Biological Control Options: The good news is that grasshoppers have many natural enemies that help control their populations. A fungus, Entomophthora grylli, kills many grasshoppers when the weather is warm and humid as it was in the summer of 2013. Infected grasshoppers grasp onto plants in a death embrace with the front and middle legs, while the hind legs are extended. They die in this position. Fungal spores develop in and on the grasshopper’s body, then become airborne and infect other grasshoppers. This is a naturally occurring fungus and cannot be purchased in the marketplace. Another natural enemy is a protozoan, Nosema locustae. This product can be purchased and applied near nursery growing areas. Its spores have been incorporated with bran to make insecticide baits such as Semaspore®, Nolo Bait® or Grasshopper Attack® (These are a couple I found available on the Web and there may be others available). These baits kill some nymphs but almost no adults, though infected adults lay fewer eggs. Baits act too slowly and kill too few grasshoppers to be useful for immediate control. This method obviously would have to have been applied back in mid-summer and is not practical for the adults that are present in September.
Mechanical Control: One way to control grasshopper populations is to eliminate sites where they might deposit eggs. Grasshoppers prefer undisturbed areas for egg laying, so tilling weedy areas in late summer discourages females. If you have weedy areas near your growing plots try rototilling the area in September.Controlling summer weeds by cutting them down or applying herbicides in fallow areas during the summer leaves very little food sources for nymphs to feed on when eggs hatch. Eliminate tall grass and weeds from around any plants you wish to protect to make the area less attractive to grasshoppers and make it easier for birds to prey on grasshoppers.
Finally, insecticides can be applied to the foliage of your nursery and greenhouse plants to control the adults. Acephate or permethrin will provide about 7 to 10 days of control. Only choose this option if feeding is significant.
Grasshoppers are active in September, but the damage should be down this fall unless it becomes hot and dry.
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Fall WebwormsSeveral people are emailing in reports of a lot of activity of fall webworm this year. There are two races – red headed and black headed fall webworms that are active this summer. People are reporting high numbers on crabapples, mimosa trees, zelkovas, elms and many other tree species. There is nothing to do but prune out the webbing on high value trees.
Mimosa webworm damagePhotos: Steve Sullivan, The Brickman Group
Crapemyrtle AphidWe are getting calls and emails reporting that aphids on crapemyrtles are especially bad this year. The crape myrtle aphid, Tinocallis kahawaluokalani, is still very active in September. One arborist treated with dinotefuran back in mid-summer and treated again with TriStar and was reporting the aphid population did not decline. They tried insecticidal soap and horticultural oil and obtained better control. Let us know if you are finding control of the crape myrtle aphid difficult this year. In their on-line fact sheet, Clemson Cooperative Extension reports that the following varieties have shown to be somewhat resistant to the crapemyrtle aphid: `Acoma,’ `Apalache,’ `Biloxi,’ ‘Caddo,’ `Choctaw,’ ‘Comanche,’ `Fantasy,’ `Hopi,’ `Lipan,’ `Miami,’ `Muskogee,’ `Natchez,’ `Osage,’ `Pecos,’ `Sioux,’, ‘Tuscarora,’ `Tuskegee,’ `Wichita,’ `Yuma,’ `Tonto,’ and Zuni.’ For more information and photos on crape myrtle aphids from North Carolina State University, go to http://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/note31/note31.html
Mimosa WebwormSteve Sullivan, The Brickman Group, is receiving a lot of calls from his customers about mimosa webworm this year. Second generation larvae will finish up this month. If populations are high, larvae may web leaves throughout the entire crown of the tree causing it to look completely brown. This caterpillars disfigures foliage, but it does not kill the tree.
Coloration is highly variable on fall webworm larvae
Emerald Ash Borer in GeorgiaUSDA has confirmed the first detection of emerald ash borer in Georgia. There are five species of ash that will be impacted.
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Lawn Fertilizer Law Information on Maryland’s Lawn Fertilizer Lawn including review sessions and testing dates and a pdf version of The Professional Lawn Care Manual are available at: http://mda.maryland.gov/fertilizer. Review Dates and Locations: There is no cost to attend, however, seating is limited and pre-registration is re-quired. The review sessions are not designed as training sessions. Please do not attend the review session if you have not read the manual.
Testing Dates and Locations: Easton Derwood September 18, 12:30-2:30 pm September 11, noon-2:00 pm September 18, 3:00-5:00 pm September 11, 2:30-4:30 pm
Montgomery CountySeptember 11, 20139:00 a.m. – 11:30 a.m.University of Maryland ExtensionAgricultural Farm History Park18410 Muncaster RoadDerwood, MD 20855
EastonSeptember 18, 20139:30 – noonTalbot County Free Library100 West Dover StreetEaston, MD 21601
Carroll Community CollegeDecember 11, 2013(Review in the morning and test in the afternoon)
Beneficial of the Week, Paula ShrewsburyCicada killers – are they as dangerous as they look?Fortunately, this rather large (~1 ½ - 2”) and somewhat intimidating looking wasp is only dangerous if you are a dog-day or annual cicada. Cicadas and cicada killer wasps, Sphecius speciosus, (Sphecidiae) have been active for a good few months now. The songs of the male cicadas are loud and the cicada killer wasps are abundant with males busy defending their territory. Cicada killers are not aggressive to humans. Cicada killers are solitary wasps (they do not have colonial nests like honeybees), although you are likely to find several “nests” or galleries in the ground in the same area. Nests are common in areas where soils are dry and somewhat sandy, and turf is often thin with bare spots. This is why golfers who spend time near sand traps are familiar with these large wasps. A single female wasp constructs a nest in the ground that contains a main gallery which may be up to a foot deep and have several chambers or brood cells running off of it. In each of the chambers the female will rear an individual baby or progeny. The female cicada will mate, and then she searches trees for cicadas. When she finds a cicada she stings it to paralyze it, straddles the cicada grabbing it with her legs, and returns the paralyzed cicada to her nest. She drags the paralyzed cicada into one of the brood chambers where she then lays an egg on the cicada. One of the very interesting aspects of cicada killer wasp biology is that if the adult female wants to produce female progeny she stocks the chamber with 2 cicadas, whereas she will leave only 1 cicada to produce a male. The egg hatches, the larva feeds, develops, and pupates over the remainder of the summer / fall and into the next spring. When the cicadas are active next July a new generation of adult wasps will emerge and begin the cycle again. It is often the male cicadas that are seen flying over the turf / sandy area. Males are territorial and will defend their territory and fend off other males who might try to
A cicada killer burrow which leads to underground chambers that are supplied with cicadas for immature cicada killer wasps to feed upon. Photo: Paula Shrewsbury, UMD
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Weed of the Week, Chuck SchusterGiant foxtail, Setaria faberi, is a weed growing tall at this time of year. This summer annual grows in clumps, has a fibrous root system and is found throughout the United States.
Leaf blades of giant foxtail can be up to sixteen inches in length and width is between one half and one inch. The leaf blade upon close examination will be found to have small hairs covering most of the upper surface and margin except near the leaf base. The inflorescence, (flower and seed head) of giant foxtail is where the plant gets its name. When fully mature, the seed head looks like the tail of the fox, and droops. It is cylindrical, with many spikelets; each spikelet will have between one and three bristles that are one quarter to one half inch long.
Control of giant foxtail needs to start early in the season. Most pre emergent grass weed control will control giant foxtail. In landscapes consider using trifluralin (treflan) or a mix of trifluralin and isoxaben (snapshot) A lack of good control this year may be related to the change in precipitation patterns. In landscape beds with giant foxtail that has eluded early season control, post emergent control can be obtained easily using glyphosate products.
mate with “their” female. Because of the fear factor associated with these large wasps many people do not want them in their yards. There are a number of chemicals that are available that can be used to “dust” around the holes of the cicada killers. However, it is the texture, exposure, and drainage of your soil and thickness of your lawn that attracts a new crop of cicada-killers to your lawn each year. If you have the optimal habitat they will come. A more long term management strategy is to alter the habitat to make it less favorable for cicada killer wasps such as improving the density of the turf and soil quality. Keeping the soil moist will discourage females from building nests in these sites. Cicada killer wasps are natural enemies of annual cicadas, although I do not consider them directly beneficial since annual cicadas themselves are not “pests” of our plants.
For more information see: https://bugoftheweek.squarespace.com/blog/2013/1/4/the-killing-fields-dog-day-cicadas-itibicen-sppi-and-cicada-killer-wasps-isphecius-speciosusimissing-link-and-vid Cicada killer wasp adult perched on an
azalea while guarding his territory from other males. Photo: Paula Shrewsbury, UMD
Plant of the Week, Ginny RosenkranzCrocosmia or montbretia are landscape corms that provide summer color from June to August. They prefer to grow in full sun with moist soil, so an irrigation system is advantageous. They look and grow similar to the gladiolus in both flower and foliage with the most common color of red, yellow and orange. Crocosmia ‘Lucifer’ is a brilliant scarlet, C. ‘Norwich’ is a bright yellow and C. ‘Emily McKenzie’ is a bright orange and red flower. The flowers are tubular in shape and bloom along one side of the thin branching stems that grow 2-3 feet tall arching above the slender, dark green foliage which grows from the base of the corm. They
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Crocosmia ‘Norwich’ (left) and C. ‘Emily McKenzie’ (right)Photo: Ginny Rosenkranz, UME
provide color in perennial gardens and in containers, thriving in hot and humid weather, attracting butterflies and hummingbirds to the gardens. Although they grow well from USDA zone 5-9, it is best to dig up the corms (store them inside and don’t allow them to dry out) in the late fall in USDA zones 5-6. Spidermites can be a serious problem on the foliage and damage the flowers.
2013 TREES MATTER SYMPOSIUM Trees and the Built Environment Sponsored by The Maryland-National Capital Park & Planning Commission, Montgomery Parks’ Horticulture, Forestry and Environmental Education Division
November 20, 2013 8:00-4:00 Silver Spring Civic Building, 1 Veterans Place, Silver Spring, MD 20910 Attend the second annual Trees Matter Conference to learn from some of the country’s leading experts about innovative efforts to plant, protect and preserve trees in urban and suburban settings.
Trees Matter 2013 is ideal for arborists, municipal employees, landscape industry professionals, designers, engineers, green industry employees and anyone interested in the latest research on trees. Approved for International Society of Arboriculture & Certified Professional Horticulturist CEU’S.
To register or for more information, please visit http://www.montgomeryparks.org Advanced registration is $59 by to October 18 and $79 after October 18. Register for course #252399 at www.parkpass.org
Featured Speakers:
David Milarch, Co-founder of Archangel Ancient Tree Archive, Champion Tree Project International. Kim Steiner, Professor of Forest Biology at the Pennsylvania State University Doug Tallamy, Professor in the Department of Entomology and Wildlife Ecology at the University of Delaware and author of “Bringing Nature Home; How Native Plants Sustain Wildlife in our Gardens” Susan Day, Assistant Professor in Urban Forestry and Director of the Urban Horticulture Center at Virginia Tech Guy Meillieur, Practicing Arborist, Aerial Consultant and Owner of Better Tree Care
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.
Degree Days (As of Sept 5)Baltimore, MD (BWI) 3151 Dulles Airport 3153 Frostburg, MD 2005 Martinsburg, WV 2917 National Arboretum 3588 Reagan National 3588 Salisbury 3447
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 for various pests use the Weather.com web site, a base temperature of 50 °F, a start date of January 1st, and the date of monitoring as the end date.
November 7, 2013- Greenhouse Seminar at Chesapeake CollegeMaryland greenhouse growers and industry experts that are experienced in growing tougher to grow greenhouse crops will share some of their secrets on how to produce quality plants.
Several growers are moving fertility management to lower rates of nitrogen and potassium and higher rates of micronutrients. This produces better quality plants with lower fertilizer inputs. Dr. Cari Peters of Peter’s Lab will talk about this method at the conference. There will also speakers talking about new markets to investigate.
Get a copy of the schedule and registration information at https://extension.umd.edu/ipm
Upcoming Programs
Go to https://www.extension.umd.edu/ipm/conferences
