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Weekly Field Crops Pest Report 2010

August 6, 2010              Volume 9 Number 15

1. View from the Field

2. Weather Outlook August 5, 2010

3. What pest problems to consider when planting winter wheat?

4. Corn Silks and Beetles

5. Western Bean Cutworm

6. Clipboard Checklist

7. Contact Information

View from the Field

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Potato leafhopper (PLH) populations at the Cornell Research Farm in Valatie have declined dramatically. Early last week I would collect 200to 300 PLH in three samples. This week I collected 2 PLH in 3 samples. The alfalfa has turned yellow to a crusty brown because the of previous high infestation levels. SUNY Cobleskill PLH populations have remained low all season. I have seen very few adult corn rootworm beetles this season. The western bean cutworm traps in Cornell Research Farm in Valatie and at SUNY Cobleskill were empty this week. Extension Educators are reporting spider mites and white mold infestations in soybeans in central NY. Downy mildew has also been observed in the upper canopy of soybean fields.

Western bean cutworm (WBC) moths continue to be caught in traps across NY. Highest captures this past week in Livingston county. Peak moth flights have already occurred in Ohio and Ontario. WBC captures in NY are expected to decline next week.

Weather Outlook August 5, 2010

NOAA Northeast Regional Climate Center

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Last week temperatures were within 3 degrees of normal.  Precipitation ranged from a tenth of an inch to one inch, though most of the state had half an inch or less.

The base 50 Growing Degree Days range from 100 to 150.  The state is ahead of last year by two weeks to over three weeks. Compared to normal, the state is ahead by 10 to 22 days. 

Today (Thursday) highs will be in the low to upper 80s witha chance for showers and thunderstorms. Tonight's temperatures will range from the mid 50s to low 60s. Friday will be sunny with highs ranging throughout the 70s.  Friday night will be in  upper 40s to low 50s. Saturday will be sunny with highs in the mid to upper 70s and lows ranging from the upper 40s to mid 50s.

Sunday we'll have continued sunshine with highs in the low80s.  Overnight temperatures will be throughout the 50s. Monday highs will be in the low to mid 80s and lows in lower 60s?.   There will be a chance for scattered showers, more likely for northern NY. Tuesday's temperatures will be in the low 80s and with lows in low to mid 60s?.  There's a slight chance for scattered showers across the state. Wednesday's highs will be in the upper 70s and low80s and lows will be in the low to mid 60s.  More chance for scattered showers.

The five day precipitation amounts will range from a quarter to three quarters of an inch.  The 8-14 day outlook is showing neither above or below normal temperatures, but above normal precipitation.

What pest problems to consider when planting winter wheat?

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Time to plant winter wheat is just around the corner. There are several factors to consider when planting winter wheat. The first is to never plant wheat in the same field two years in a row. By rotating you reduce the risk of several diseases like eyespot foot rot, powdery mildew, leaf rust, Stagonosporanodorum blotch, glume blotch and more. The second item to consider is what winter wheat variety to plant. Of course you will look at potential grain yield, grain test weight and straw quality. It is also important to consider resistance to diseases in the varieties you select. Diseases of particular concern are wheat spindle streak mosaic virus, soil borne mosaic virus, yellow dwarf virus (formally called ?barley yellow dwarf virus?), powdery mildew, leaf& stem rust and/or other disease problems your farm has had in previous years.  For a list of potential wheat varieties consult your Cornell Guide for Integrated Field Crop Management. Next, remember to plant AFTER the Hessian fly free date. By doing so, not only are you avoiding infestations of Hessian fly but also certain aphids that can transmit yellow dwarf virus. The following figure shows the Hessian Fly Free Dates in NYS:

The use of certified wheat seed should be considered. When seed is certified you can be confident of the quality and it is void of diseases and weed seed. Next is to remember to always use a fungicide seed treatment to protect the crop from certain seed and seedling related diseases. Another core consideration is having a sound fertility program. When a plant is healthy it can complete with weeds and may tolerate more insect pest pressure and still maintain good yield.

Corn Silks and Beetles

Ken Wise

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Every year I see two kinds of insects feeding on corn silks: corn rootworm beetles and Japanese beetles.  I have been asked many times ?Does this feeding by beetles reduce pollination of corn?? Generally, these beetles do not affect pollination of corn. Corn rootworm (CRW) beetles prefer to eat pollen. The corn plant can produce enough pollen to pollinate the ear of corn and still have plenty left over for the corn rootworm beetles.

In New York, the feeding of the adult CRW beetles on silks can occasionally be a problem. Clipping of the silks can prevent pollination, resulting in poorly filled ears. If 10 or more adults are found per plant at silking, less than 50 percent of corn silks are brown, and silks <0.5 inch long, treatments to control adults may be warranted, and pollination has not yet occurred, apply an insecticide (see: Cornell Guide for Integrated Field Crop Management,Table 3.6.1).

The good thing is that even a damaged silk can still receive pollen and will fertilize the ear. Reduced fertilization can only occur when the silk is clipped to less than a 1/2 inch long before pollination.

Japanese beetles also like to feed on the silks of corn. I have seen up to 8or 9 on one ear of corn. The thing with Japanese beetles is that they prefer to feed on browning silks. When the silk has turned brown the ear of corn has already been pollinated. Japanese beetles also clump in certain areas of the field. Many times this is along edges and not the rest of the field.

Japanese Beetles on Feeding on Silks

Western Bean Cutworm

Keith Waldron

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Western bean cutworm moth catches continued again last week across NY. Western bean cutworm moths have now been collected in 26 of 30counties participating in the monitoring network. Most traps had zero to low numbers of moths captured, however, Livingston county traps had higher numbers of moths caught: Caledonia (43) and Avon (14). Peak moth flights have already occurred in Ohio and Ontario. WBC captures in NY are expected to decline next week.

Western bean cutworm egg masses were detected on sweet corn in Eden valley (Erie county) July 20. WBC moths are attracted to pre-tassel corn. As corn moves into grain fill stages WBC moths are more attracted to dry beans.

In corn, WBC larvae feed on the tassels and ultimately move to feed on ears. Larvae can bore through the husks or enter the ear near the sillk region.

Unlike other caterpillars that feed on corn ears (corn earworm, European corn borer, etc.) WBC larvae are not cannibalistic and could have multiple larvae per ear. First instar WBC larvae are brown with a black head and markings down their back. Mature larvae are smooth, hairless, and light tan to pink. At first glance, WBC larvae are distinguished by two distinctive dark brown stripes immediately behind the head. (see photo).

WBC larvae

In dry beans, WBC scouting needs to focus on checking beans for pod feeding to target the larvae that are actually doing the damage.

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, R stage pest issues (corn rootworm, European corn borer, armyworm, foliar diseases, nutritional deficiencies)
  • Check no-till fields/fields with high residue or weeds for slug/snail damage
  • Monitor for weeds, note presence of "who", "how many" and "where"
  • Monitor tasseling corn fields for presence of corn rootworm beetles.

Small Grains:

  • Monitor spring grains for crop stage (heading, grain fill), insect problems 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, 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 page.
  • Consider installing biting flytraps to reduce horse, deer and stable fly populations.


  • 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


  • 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.

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