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Weekly Field Crops Pest Report 2011

August 21, 2011, Volume 10 Number 15

  1. View from the Field
  2. Weather Outlook
  3. Western Bean Cutworm Update
  4. Storing Corn or Soybeans? Remember Stored Grains Pests
  5. White Mold in Soybeans
  6. Clipboard Checklist
  7. Contact Information

View from the Field

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Mike Hunter and Mike Stanyard report some soybean fields are now exceeding the average of > 80% of plants containing 250 or more soybean aphid threshold guideline. These fields contain wingless and winged aphids and the very small white dwarf types. It is a good indication that at least some of the aphids came in on our recent weather fronts. Recall that soybeans are vulnerable to impacts of soybean aphids up through their late pod fill stages (up to R5).

There have also been reports of Phytophthora root and stem rot and white mold on soybeans. Phytophthora can affect soybeans from germinating seedlings to mature plants. You may see wilted plants or stunting of plants with brown-purple lesion on the stem just above the soil line. This disease over-winters as oospores and mycelium in the soil and surface residue. Heavy soils with poor drainage come help promote this disease. In growing seasons with high rainfall can also cause the disease to proliferate. Research also indicates that soil compaction increases the risk of Phytophthora. There are no economic thresholds for phytophthora root and stem rot on soybeans at this time. Some of the management options are: fungicide seed treatments, crop rotation, clean tillage to remove crop residue and resistant or tolerant varieties.

White mold of soybeans has been described as a "high yield" disease, favoring well-managed high-density fields with the greatest yield potential. White mold infection occurs during the reproductive phase of soybean plant growth. growth. Ascospores deposited on flower petals germinate when free water is present on plant surfaces, utilizing the petal as a nutrient base. Infection progresses with the growth of mycelium into plant eventually infecting stems and petioles, and disrupting vascular tissues, stems, and pods. As nutrients are exhausted, fungal mycelia aggregate into sclerotia that form both inside and outside the plant stem. These sclerotia then fall to the ground where they can survive for years depending on environmental conditions.

We conducted 2 field meetings in pasture fly management this week. One in Columbia County (grass fed beef) and one in Dutchess County (dairy). Face fly and horn fly populations were moderate to high at both locations. Some producers stated they had had trouble with pinkeye. This disease can be transmitted by face flies. Stable flies at both farms were low.

Weather Outlook

August 18, 2011

Jessica Rennells, Northeast Region Climate Center, Cornell University

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Temperatures ranged within 3 degrees of normal this past week. Precipitation ranged from less than half an inch to over 3 inches. The base 50 growing degree days ranged from 100 to 125 for most of the state.

Today's (8.18.11) temperatures will be in the mid 70's to mid 80's with a chance of showers and thunderstorms. Tonight will be in the mid 50's to low 60's.

Friday will in the mid 70's to mid 80's with an increased chance of showers and thunderstorms. Lows will be in the 50's and low 60's.

Saturday will be mostly sunny with highs in the low to mid 80's with a few lingering showers possible in eastern NY. Lows will be in the upper 50's and low 60's.

Sunday will be in the upper 70's to low 80's with a chance for showers and thunderstorms. Lows will be in the low to mid 60's.

Monday temperatures will be in the mid to upper 70's with a chance for showers and thunderstorms. Overnight temperatures will be in the low to mid 60's.

Tuesday will be mostly sunny, a cold front will bring cooler highs, throughout the 70's and lows will be in the upper 50's and low 60's.

Wednesday's highs will be in low to mid 70's with lows in the mid to upper 50's.

The five-day precipitation amounts will range from a quarter an inch to one and a half inches. The highest amounts are expected in the southern Hudson Valley and Eastern Plateau. The 8-14 day outlook is showing below normal temperatures for the southern half of the state and above normal precipitation for all of NY. The three month outlook (Aug/Sept/Oct) is calling for above normal temperatures for the whole state.

Here is the average first frost map for the northeastern US:

first frost date for NE US

Western Bean Cutworm Update

Keith Waldron
NYS IPM

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Total Western Bean Cutworm (WBC) moth counts have dropped significantly the past two weeks from peak flight the week of August 2. To date this year WBC moths have been captured in Broome, Cattaraugus, Cayuga, Chautauqua, Chemung, Clinton, Cortland, Delaware, Erie, Essex, Genesee, Jefferson, Lewis, Livingston, Madison, Monroe, Oneida, Onondaga, Ontario, Orleans, Otsego, Schuyler, Seneca, Steuben, Tioga, Tompkins, Wayne, Wyoming, Yates. Moth counts have ranged from a low of zero to a high of 156 in Attica (Wyoming County). Interestingly, WBC moths have not been reported captured in Chenango, Herkimer, Montgomery, Niagara, Oswego, Schoharie, St. Lawrence, Suffolk, Sullivan counties this year.

Our collected WBC moth numbers are by and large substantially below those of Midwestern states where economic populations levels and damage has been reported. WBC eggs hatch in 10 days or less and larvae are highly mobile. Should local areas have had WBC egg laying and successful hatch, larvae would be on their way or have potentially reached their preferred feeding site. In corn, larvae would be going for the ear zone. Once inside the ear there is nothing that can be done but to check fields before harvest for damage or to compare efficacy of Cry1F Bt to refuges or conventional corn. Recall that unlike other ear infesting caterpillars that are cannibalistic towards their own kind, more than one WBC larva could be found per ear. Larvae in dry bean fields would now be headed for the pods and can be difficult to find because they crawl around in the canopy to feed.

For images of WBC see the factsheet: Western Bean Cutworm
Loxagrotis albicosta Smith

Storing Corn or Soybeans? Remember Stored Grains Pests

Ken Wise
NYS IPM

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Have plans to store your soybean and grain corn harvest on farm? If so, now is the time to start CLEANING your storage bins. Sanitation is the key to keeping insect pests out of your stored grains. Soybean and Corn harvest is not as far off as you may think so knowing what you need to do is important. The following is a step by step method for IPM in stored grain:

  1. Clean grain handing equipment (augers, combines, wagons, scoops, and trucks).
  2. Clean inside the grain bin (remember to clean under the false floor). Mice, moths, weevils and much more can survive under the false floor.
  3. Clean around the outside of the grain bin. Remove all weeds, spilled grain and debris 6 to 10 feet from around the grain bin. This will remove all habitats that can support a grain bin pest problem.
  4. Seal all cracks and crevices. Cracks are prime locations for insects to enter grain bins.
  5. Cover fans when they are not being used. Insects can enter the grain bin this way also.
  6. Use a registered sanitizing insecticide spray in and around the structure after cleaning.
  7. Never store new grain with old grain.
  8. Dry the grain bin before adding new grain. Insect pests need moisture to survive.
  9. Level the surface after filling the grain bin. Moisture accumulates in a grain peak. Microbial activity in the wet area will heat up and attract secondary insect pests.
  10. Do not fill grain bin all the way to the top. Leave a few feet for aeration.
  11. Aerate the grain to at least the ambient temperature. The hotter the grain gets the faster insect pests can develop. Stored grain insect pests development slows when the temperature falls below 500 F.
  12. Monitor grain for insect pests every 20 days from spring till fall and every 30 days in the winter.
  13. If you discover an infestation of insect pests you may consider an insecticide application. Select a NYS registered product for your stored grain. READ THE LABEL.
  14. Keep areas around grain bins mowed to limit rodent hiding places.

Common Insect Pests of Stored Grain:

  • Granary weevil
  • Saw tooth grain beetle
  • Red flower beetle
  • Larger cabinet beetle
  • Lesser grain borer
  • Rice weevil
  • Indian-meal moth
  • Flat grain beetle

White Mold in Soybeans

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Highly productive, dense stands of soybeans favor white mold development. The fungus survives from year to year in the soil as hard black pellets called sclerotia. Sclerotia of white mold must be present to cause the disease, though a small number of sclerotia on the soil surface can lead to significant outbreaks if wet, cool conditions are present while plants are flowering. Under these favorable conditions, sclerotia will germinate and mushroom-like structures (apothecia) will form. The apothecia produce ascospores which spread by wind and splashing rain. Ascopsores require a nutrient source to grow, and soybean flowers serve as ideal locations. The fungus colonizes dead flowers and the characteristic thick white moldy covering on stems and pods develops (see photo below). Mixed in with the white mold on stems are the black sclerotia. Plants may wilt and die as a result of infection. If white mold infection occurs late in the season, yield loss will not be as severe. Temperatures over 90 degrees will typically stop disease development. During harvest, the sclerotia on stems and pods may end up in the soil or residue, or may stay with harvested seed. Fields where white mold has occurred in the recent past are where it will most likely occur, so these are the fields to scout the most closely for disease development.
The following photo shows the white mold infection on a plant that is starting to wilt.

white mold

Photo taken by Mike Stanyard

A key to white mold management is to find strategies to prevent the build-up of the pathogen in a field. Rotation to crops other than soybean for at least 1 year (ideally 2 or more years) is recommended. Additionally, weed management practices that reduce weeds that serve as alternate host for white mold (for example lambs quarters and pigweed) will help to decrease build-up of the pathogen. It is also essential to avoid the planting of contaminated or infected seed, and to avoid the movement of infected soil with equipment. A strategy for preventing movement of infected soil is to harvest fields infected with white mold last. Varieties of soybeans that are tolerant or moderately resistant to white mold should be selected. Yield protection by spraying fungicides has not been documented in New York.

Clipboard Checklist

Keith Waldron
NYS IPM

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General:
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

Corn:
Monitor fields for plant vigor, growth stage, R stage pest issues (corn rootworm, European corn borer, armyworm, western bean cutworm, foliar diseases, nutritional deficiencies)
Monitor for weeds, note presence of "who", "how many" and "where"

Small Grains:
Grain bins ready to accept upcoming harvest?

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

Soybeans:
Evaluate stand growth, development and condition
Monitor fields for soybean aphid, foliar diseases, white mold, natural enemies, weed escapes

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 water sources, 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)

Dairy Livestock Pasture Fly Management:

Monitor animals for presence of pasture fly pests. Treatment guidelines: Horn flies (50 per dairy animal side, 100 per side for beef cattle), face flies (10 per animal face), stable flies (10 per 4 legs). See our Livestock IPM homepage.
Consider installing biting fly traps to reduce horse, deer and stable fly populations.

Storage:
Keep areas around storage bins and silos clean and mowed
Check areas around storage bins and silos for vertebrate tunneling
Check temperature of recently binned grains and baled hay in hay mow

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

PESTICIDE EMERGENCY NUMBERS

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
Email: jkw5@cornell.edu

Ken Wise: Eastern NYS IPM Area Educator: Field Crops and Livestock
Phone: (518) 434-1690
Fax: (518) 426-3316
Email: klw24@cornell.edu