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Weekly Field Crops Pest Report 2009

July 10, 2009                      Volume 8 Number 12

1. View from the Field

2. Weather Outlook July 9, 2009

3. Aphid Mummies in Alfalfa and Soybean

4. Soybean Defoliators: Do They Do Damage?

5. Dung Beetles in Manure on Pasture

6. NYS Soybean Rust and Soybean Aphid Update

7. Clipboard Checklist

8. Mark Your Calendars

9. Contact Information

View from the Field

Ken Wise

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I am still finding low populations of potato leafhopper at the SUNY Cobleskill Farm this week. The alfalfa was 20 plus inches tall and I was getting 10 potato leafhopper per sample (10 sweeps of the net is equal to one sample). If the temperature starts to climb most like so will potato leafhopper populations.

Soybean aphid populations have generally been relatively low (< 40 SBA’s / plant) across much of NY. Some areas of central NY are reporting hot spots of SBA activity with populations well over the 250 SBA’s / plant threshold guideline. Producers are encouraged to monitor soybean fields for this insect pest.

There have been some reports of Japanese beetles in soybeans in Western NYS. Japanese beetles are leaf feeding insects. This pest feeds on a wide range of plants. Generally, Japanese beetles do not cause yield losses in soybeans because the beans can compensate very well. For more information on soybean defoliators see the article below.

Keith Waldron and I were in Jefferson and Lewis county conducting fly management workshops this week. We discussed house flies and stable flies management in and around the barns. We also talked about horn and face fly management on pasture. All of these fly species were present at relatively low numbers at both locations. The fly populations appear to be remaining low helped, in part, by recent cool temperatures. Excess moisture and warmer temperature expected over the next week will likely create conditions favorable to increasing fly populations on pasture and in the barns. In barns - clean potential fly breeding habitat areas (undisturbed moist organic matter, i.e. spilled feed, soiled bedding, etc.). For more information on barn fly management see issue June 25, 2009  Volume 8 Issue 10.

Weather Outlook July 9, 2009

Drew Montreu
NOAA NE Climate Center, Cornell University

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Temperatures during the past week were well below normal, with almost everywhere in the state 3 to 6 degrees colder than normal. Precipitation was lightest in the west, with one-half to one inch falling west of I-81, and generally 1 to 2 inches to the east. The Mohawk Valley and Albany region got even more, with 2 to 3 or more inches falling, mostly from heavy thunderstorms Tuesday.

Base 50 Growing Degree Days only accumulated between 75 and 100 for most areas. A few places got over 100, including just southeast of Lake Ontario, the far northeastern part of the state, and areas downstate. There were also some pockets that got less than 75 in the mountains. For the season, most areas are now between 700 and 900. The Hudson Valley is over 900, and further Downstate is over 1000. There have been slightly less than 700 in the Alleghenies, and as few as 400 to 500 in the Adirondacks. Compares to last year, the north and Finger Lakes are 7 to 10 calendar days behind, with Monroe and St. Lawrence Counties and the Tug Hill as much as 2 weeks behind. Most everywhere else is 3 to 7 days behind. Those areas more than a week behind correspond to over 150 growing degree days behind last year. Areas south of I-90 and in the East are generally up to 75 growing degree days behind normal, but southeast New York as much as 75 growing degree days above normal. Elsewhere is 75 to 150 growing degree days behind.

Sunny weather will be the rule today and tomorrow as the state sees a ridge of high pressure build in. On Saturday and Saturday Night, a cold front will cross the state with thunderstorms. With highs reaching up into the low 80s, some of those storms could be strong to severe, especially from I-81 west. Sunday should be mostly rain free, except for the far eastern parts of the state, where some showers may linger in the morning. Highs Sunday behind the front will be in the mid 70s. High pressure should keep showers out of most areas on Monday, with highs in the mid 70s and lows in the mid 50s. There will be a chance of showers on Tuesday as a low moves by to our south. Highs will be in the upper 70s, with lows in the low to mid 50s. Wednesday could have some showers as a warm front approaches, but highs should still reach up into the low 80s, with lows in the upper 50s. For the next 5 days, most areas can expect no more than half an inch of rain, though exactly how much falls will depend on how the storms Saturday evolve. For the next 8 to 14 days, the Climate Prediction Center is calling for below average temperatures and above average rain, but I tend to think things may end closer to normal than they were last week.

Aphid Mummies in Alfalfa and Soybean

Keith Waldron

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Walking fields is critical to early detection of crop problems. It's also a way to discover all sorts of interesting examples of ecology in action.  One such example, common in alfalfa this time of year, is the presence of what might appear to be bronzed colored aphids "resting" on alfalfa leaves.  "Resting aphids?" What are you really seeing? One type of biological control of pea aphids

Pea aphids [Acyrthosiphon pisum (Hemiptera: Aphididae)] tend to be found in low to modest numbers in NY alfalfa but are generally not an economic pest. These insects are a food source by many natural enemies such as lace wing and lady bird beetle larvae. The bronze colored "resting" aphids one may see on alfalfa leaves are aphid "mummies" the result of the aphid being parasitized by a type of tiny wasp. In NY, two types of wasps can be found: Praon pequodorum and Aphidius ervi both Hymenopterans in the family Braconidae.

Praon pequodorum is a native aphid parasitoid which includes the pea aphid in its host range. Aphidius ervi was introduced to the United States in the late 1950's and early 1960's for biological control of pea aphid. This species is now widely distributed in North American alfalfa, often achieving high levels of parasitism. A. ervi is the more common parasitoid we encounter attacking pea aphids in NY.

Who's who? Aphidius mummies are smooth. Praon mummies look like they have webbing around them, with the bronze colored aphid body sitting on top. See photo.

How did that happen?
When the female wasp finds a suitable host, she bends her abdomen under her legs and injects an egg in the aphid with her ovipositor. Aphids may continue feeding and reproducing for several days, until the egg hatches. When the egg hatches, the wasp larvae start to eat the aphid from the inside and the larva completes its life cycle in the aphid body. Effective parasitization is obvious when the aphid swells and hardens into a leathery, brown colored "mummy". The parasite completes it's life cycle by emerging as an adult through a round hole at the rear of the mummy. Mummies can usually be seen 14 - 21 days after the first introduction is made. Development time is dependent upon the temperature and other environmental factors. One female wasp lays about 350 eggs in a lifetime. Most of these eggs are laid in the first five days after introduction.
The life cycle of Apidius ervi described above is excerpted from "Biological Control of Aphids with Aphidius ervi" by Cathy Thomas (PA Dept Ag IPM Program). The Vegetable and Small Fruit Gazette, April 2001, Volume 5, No. 4.

Note: Species of Aphidius and Praon have also been found attacking soybean aphids in NY - watch for mummies....

Soybean Defoliators: Do They Do Damage?

Ken Wise

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Japanese beetle and Mexican bean beetle are the main defoliators of soybeans in NYS. While they are minor pests, defoliation of soybeans sends up many red flags by growers. The question normally is how much leaf defoliation is too much in soybeans? The good thing is that soybeans can withstand much defoliation without losing yield. The soybean defoliation threshold is 35 percent of leaf area eaten or missing from V1 to just before bloom. During blooming through pod-filling stages, the threshold is 20 percent defoliation. The following pictures are a guide that depict 10, 20, 30 and 40 percent defoliation

10 percent defoliation             20 percent defoliation

30 percent defoliation             40 percent defoliation
(Source: Purdue University Field Crops Pest Management Manual, 1/92)

Dung Beetles in Manure on Pasture

Ken Wise

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Face flies and horn flies, two key fly pests attacking cattle on pasture, both complete their egg, larval and pupal stages in cow manure. These two fly pests are, however, frequently not alone – about 450 arthropod species have been reported to inhabit cow pats. While conducting pasture fly field meetings in Jefferson and Lewis county this week we found fly larvae (maggots) as well as other beneficial arthropods inhabiting the manure pats - a lot of dung beetles. Why dig through manure to find dung beetles? Dung beetles are very important insects that help decompose cattle manure and aide in recycling nutrients in pastures. Dung beetles compete with other organisms like flies inside the cattle pat for resources within the manure, thus limiting pasture fly development. Dung beetles help recycle the manure back into the soil providing nutrients for the pasture grasses to continue to grow and produce forage. Having a good population of dung beetles is an indication of a healthy pasture.  There are three types of dung beetles that can occupy a dung pat:

Rollers (telecoprids)

Geotrupes species, form balls of manure which they push from the pat to bury as brood balls

Tunnelers (paracoprids)

Onthophagus species are tunnelers that consume the pat and burrow beneath it to bury brood balls. 

Dwellers (endocoprids)

Aphodius species, consume the manure as they tunnel within the dung pat and oviposit eggs in the manure or surrounding soil.  Most dung beetles found in NY are dwellers.

Keith Waldron showing producer dung beetles in manure on pasture

Some feed-through insecticides can have detrimental effects on manure inhabiting arthropods. These materials are not always completely metabolized in the body and are dispelled into the manure pat. To enhance dung beetle populations try to select fly control methods and products that help preserve dung beetles in your pastures.

NYS Soybean Rust and Soybean Aphid Update

Gary Bergstrom
Cornell University

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Sentinel plots in NYS are being established in Cayuga, Jefferson, Seneca, Washington and Wayne counties. Scouting in these plots should begin in the next few weeks. Another report of soybean rust on soybean in a sentinel plot was made on June 22nd in Acadia Parish in Louisiana. In 2009, soybean rust has been reported in the U.S. in Alabama, Florida, Georgia, Louisiana and Texas.Updated July 9, 2009
NY State Soybean Rust Hotline: 607-255-7850

NYS Soybean Rust Website

USDA Soybean Rust Website

Clipboard Checklist

Keith Waldron

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* Emergency contact information ("911", local hospital, Chem. Spill emergency contact, other?) posted in central posting area
* Maintain crop records by field, including variety, planting date, pesticides used, nutrient inputs including manure, etc.
* Watch for any patches of herbicide resistant weeds, weed escapes
* Storage areas cleaned and ready to accept hay, wheat harvest

* Monitor fields for plant vigor, growth stage, mid season pest issues (European corn borer, foliar diseases)
* Gaps in row? Check for seed corn maggot, wireworm, cutworm, armyworm, seedling blights, birds, seed placement issues
* Check no-till fields/fields with high residue or weeds for slug damage
* Monitor for weeds, note presence of "who", "how many" and "where"
* Adjust post emergence weed control action
Small Grains:
* Monitor winter grains for crop stage (heading, grain fill), insect problems (cereal leaf beetle, armyworm) and foliar / head diseases
* Evaluate crop for plant vigor, lodging, maturity / time till harvest
* Grain bins ready to accept upcoming harvest?

Alfalfa & Hay:
* Monitor alfalfa seedings for weeds, insects & diseases.
* Check regrowth of established alfalfa stands for potato leafhopper, weed and disease problems.
* Storage areas cleaned and ready to accept incoming harvest

* Evaluate stand growth and development - weed assessment, soybean aphid, volunteer glyphosphate resistant corn

Dairy Livestock Barn Fly Management:
* Sanitation, sanitation, sanitation - clean animal resting areas, feed troughs, minimize source of moist organic matter i.e. fly breeding areas in barn and in adjacent animal loafing yard
* Check waterers, drainage, roof gutters for leaks and potential overspill
* Continue fly monitoring: install "3X5" index card fly speck monitoring cards through out barn
* Install/refresh/replenish as needed: fly tapes, insecticide baits, natural enemies (parasitoids

* Check storage areas (bunk silos, etc.) for readiness to accept upcoming wheat harvest
* Clean in and outside of storage bins and grain handling equipment
* Keep areas around storage bins and silos clean and mowed
* Check areas around storage bins and silos for vertebrate tunneling
* Check temperature of recently baled hay in hay mow

* Note any repairs needed for recently used equipment: tractors, tillage implements, planters, sprayers, etc. as they are cleaned and serviced.
* Service hay harvesting equipment as needed.
* Calibrate manure spreaders - maintain records on amount spread per field

Emergency responder information on pesticide spills and accidents CHEMTREC:  800-424-9300
For pesticide information: National Pesticide Information Center: 800-858-7378
To Report Oil and Hazardous Material Spills in New York State: NYS Department of Environmental Conservation Spill Response:_800-457-7362 (in NYS)_518-457-7362 (outside NYS)
Poison Control Centers: Poison Control Centers nationwide: 800-222-1222. If you are unable to reach a Poison Control Center or obtain the information your doctor needs, the office of the NYS Pesticide Coordinator at Cornell University, 607-255-1866, may be able to assist you in obtaining such information.

Mark Your Calendars

Keith Waldron

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July 15, 2009 -- Weed Science Field Day, Thompson Research Farm, Freeville, NY (morning program)
July 15, 2009 -- NYSABA Summer, BBQ, Musgrave Farm, Aurora, NY 12:00 noon
July 15, 2009 -- Weed Science Field Day, Musgrave Farm, Aurora, NY (afternoon program)
July 23, 2009 -- Aurora Farm Field Day, Musgrave Farm, 1256 Poplar Ridge Rd, Aurora, NY
Aug. 10-14, 2009 -- Soil Health Training Workshop, Ithaca, NY

Contact Information

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Ken Wise: Eastern NYS IPM Area Educator: Field Crops and Livestock
Phone: (518) 434-1690
Fax: (518) 426-3316

Keith Waldron: NYS Livestock and Field Crops IPM Coordinator
Phone: (315) 787 - 2432
Fax: (315) 787-2360