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Weekly Field Crops Pest Report 2011

September 30, 2011, Volume 10 Number 20

  1. View from the Field
  2. Weather Outlook
  3. A New Disease in New York: Soybean Vein Necrosis Virus
  4. Clipboard Checklist
  5. Contact Information

View from the Field

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A new soybean disease has been confirmed in New York this week. The pathogen is soybean vein necrosis virus (SVNV). See article below written by Dr. Gary Bergstrom.

Once again we have reached the end of the season for the NYS IPM Weekly Field Crops Pest Report. We would like to thank all the extension educators and field consultants for providing us with in-field observations each week for the report. Your data is critical to us providing information statewide each week on the status of pests in the field. We will be emailing an end of the season survey to determine what impact the report has had statewide. This survey helps us fine tune the report each year. Please make any suggestions on how we might be able to improve the report. Again thank you for all your help and observations.

Weather Outlook

September 29, 2011
Andrew Montreuil
NOAA NE Climate Center, Cornell University

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The recent wet weather, thanks in part to a stalled out area of low pressure to our west, will continue through the weekend as a new weather system absorbs the low and only slowly moves out of our area. Rounds of showers and thunderstorms are expected today, especially for central and northern New York. Rainfall amounts should generally be less than the past couple of days, though some localized areas could approach an inch or more. High temperatures today will be in the 60s for most of the state with lows tonight near 50. Friday looks like the driest day of the weekend, with most areas only seeing a few showers. The one expectation will be western New York, which could see a bit more widespread shower activity. High temperatures will be a little cooler than today, generally in the low to mid 60s except for Downstate which will stay near 70 at least.

Temperatures will begin to fall from west to east overnight Friday night with widespread showers moving back across the state. Temperatures will continue to fall through Saturday. By Saturday evening, areas in western and central New York may barely be above 40 degrees. Clouds and showers should keep temperatures from dropping too far Saturday night, with the coldest lows likely in mid to upper 30s across central and western New York. High temperatures for Sunday may not recover much, with many areas upstate not getting out of the 40s with more clouds and showers.

Finally, by Monday, the weather will begin to improve. The rain should move out and temperatures should rebound back towards more seasonable temperatures near or above 60. Dry, seasonable weather will continue into Tuesday and Wednesday. Low temperatures early next week should remain in the 40s and 50s.

Over the next five days, much of Upstate New York could see over an inch of rain, with some areas getting 2-3" depending on where the heaviest thunderstorms set up. The most likely areas for this to happen appear to be over central New York and the North Country. The 6-10 and 8-14 day outlooks are pointing to a much different weather pattern, with above average temperatures and below average precipitation likely.

A New Disease in New York: Soybean Vein Necrosis Virus (SVNV)

Dr. Gary Bergstrom,
Department of Plant Pathology and Plant-Microbe Biology

The presence of a new soybean disease was confirmed in New York this week. The pathogen is soybean vein necrosis virus (SVNV). It was first described in Tennessee in 2008, and in Arkansas, Illinois, Kansas, Kentucky, and Missouri in 2009. The symptomatic plants in New York came from a soybean field in Ontario County. Symptoms observed in the field were vein-clearing followed by 'scalded' reddish areas around the veins and a browning of the veins, especially on the lower leaf surface (see the photo below). Dr. Ioannis Tzanetakis of the University of Arkansas, a leading researcher on SVNV, positively identified RNA of SVNV in samples from Ontario County. In nearly the same time frame as our New York discovery, SVNV has been confirmed in Delaware and Maryland, and with pending diagnoses in Virginia and Pennsylvania. This morning I viewed photographs with symptoms from a field in Herkimer County that also appear to be caused by SVNV; the symptoms were predominantly on the upper, youngest leaves.

What is known about SVNV? The answer is not very much. It is thought to be transmitted from soybean to soybean by thrips (soybean thrips and perhaps others). Soybean thrips are observed in New York along with a number of other thrips species. The virus has been placed in the Tospovirus group of plant RNA viruses (stands for Tomato spotted wilt virus) which are transmitted by thrips. Finding it this year doesn't mean we will find it next year. We don't know if the virus can also be transmitted through seed or by any other means. We don't know if it will have an impact on yield. Potentially the virus may be transported long distances by thrips in one growing season or the virus may survive locally in weed hosts (no one has demonstrated this yet) and then be transmitted locally by thrips when their population increases within a season. Tospoviruses are circulative/propagative in their association with thrips, so if thrips survive our winters, SVNV might well survive in the living thrips. Insecticidal seed treatments may have a role to play in killing thrips on young soybean plants and reducing the incidence of early virus infection. Resistant varieties appear to be the main path to sustainable management and several investigators are assessing varieties in other parts of the country. There is no basis to recommend that farmers do anything substantially different now in their cropping practices just because we found this new virus. For now, I would classify its presence in NY only as a potential problem worth keeping an eye on. We encourage growers and consultants to inspect any still-green soybean plants for possible SVNV and to inform your local Cornell Cooperative Extension field crops educator if you find symptoms that are similar to soybean vein necrosis.

soybean vein necrosis virus

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, soybean, corn harvests

Field Corn:
* Note crop growth stage and condition potential for silage harvest?
* Foliar diseases, stalk rots and ear mold
* Check for European corn borer, Western bean cutworm, foliar diseases (such as Gray Leaf spot and Northern Corn leaf blight), vertebrate injury (birds / deer), slugs, weed escapes, herbicide injury, nutritional deficiencies, etc.
* Monitor weed populations noting presence of "who", "how many" and "where"

Alfalfa & Hay:
* Monitor alfalfa seedings for weeds, for potato leafhopper & diseases.
* Check established alfalfa stands for potato leafhopper, weed and disease problems.
* Check established alfalfa stands for signs of alfalfa snout beetle infestations in counties known to have this pest.
* Storage areas cleaned and ready to accept next harvest?

* Note crop growth stage and condition
* Evaluate stand for deer, weed assessment, white mold, foliar disease incidence, harvest timing

Dairy Cattle: Livestock Barn Fly Management:
* Monitor animals and facilities for house fly and stable fly populations
* Check facilities for favorable fly breeding conditions: (organic matter + moisture): leaks in watering systems, roof gutters for leaks and potential overspill, drainage,
* 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 * Continue fly monitoring: install "3X5" index card fly speck monitoring cards throughout barn
* Use, replenish, replace fly management materials: sticky fly tapes/ribbons, insecticide baits, natural enemies (parasitoids), fly population monitoring (3 x 5) spot cards
* Continue release of purchased natural enemies (fly attacking parasitoids)

Dairy Cattle: Pasture Fly Management:
* Monitor animals for presence of face flies, horn flies and stable flies. Action guidelines: face flies (average 10 per animal face), horn flies (average 50 / dairy, 200 / beef cattle per animal side), stable flies average 10 per animal (all four legs)
* Check feed bunk / water source locations for signs of stable fly breeding (moist undisturbed organic matter - spilled feed, round bales, etc.), minimize source of moist organic matter i.e. fly breeding areas in barn and in adjacent animal loafing yard
* Check paddocks for forage quality / quantity, rotate as appropriate
* Check paddocks for vegetation poisonous to livestock
* Consider use of fly traps to help reduce deer, horse and stable fly populations

* Pre-clean in and around grain storage bins in anticipation of soybean and grain corn harvests.
* Keep areas around storage bins and silos clean and mowed

* Note any repairs needed for recently used equipment: tractors, tillage implements, harvesting equipment, etc. as they are cleaned and serviced.
* 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.

Contact Information

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

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