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Weekly Field Crops Pest Report 2010

August 27, 2010         Volume 9 Number 17

1. View from the Field

2. Weather Outlook

3. Western Bean Cutworm Update

4. Stop! Check for Corn Ear Rot

5. Winter Wheat, Aphids and Yellow Dwarf Virus

6. Storing Corn or Soybeans? Remember Stored Grains Pests!

7. Clipboard Checklist

8. Contact Information

View from the Field

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Western Bean Cutworm moth captures are down again this week. Some WBC larvae are beginning to be found in developing corn ears.

Soybean aphids have been very difficult to find this season, a trend that has been seen before in even numbered years. SBA populations are, however on the increase in some areas of the state, with fields in some areas actually exceeding the 250 SBA/plant threshold.  Fortunately, many of the affected soybean fields are in their late stages of pod fill and will soon grow out of their sensitive growth stage. The SBA populations are also being met with increasing numbers of natural enemies such as lady bugs and syrphid fly larvae. Winged SBA forms have been observed indicating those aphids will be moving to other soybean fields or to buckthorn their overwintering host plant.

This week while scouting the Cornell Research Farm in Valatie I discovered that most of the corn in one field was infected with gray leaf spot. Many of the plants were infected from the top to the bottom. Kati Waxman at Cornell University also thinks there might be northern corn leaf bight in the leaf photos I sent her. Below are the photos showing the diseases. We sent leaf samples to Gary Bergstrom and Kati Waxman for analysis.

Weather Outlook,
August 26, 2010

Jessica Rennells
NOAA Northeast Regional Climate Center, Cornell University

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Last week temperatures ranged from 3 degrees below to 3 degrees above normal.  Precipitation ranged from 1 to over 4 inches, most of which fell on Sunday.

The base 50 Growing Degree Days ranged from 75 to 125.  Almost the entire state is ahead of last year by over three weeks.  Compared to normal, the state is ahead by 2 to over 3 weeks.

Today‘s highs will be in the mid 60’s to mid 70’s.  Tonight’s temperatures will be in the upper 40’s and low 50’s.

Friday will be sunny with temperatures ranging from the upper 60’s to near 80.  Friday night will be in mid 40’s to low 50’s.

Saturday will be sunny with highs in the upper 70’s and low 80’s.  Lows will be in the low to mid 50’s.

Sunday will be sunny with highs in the mid to upper 80’s, some areas reaching 90. Overnight temperatures will be in the mid to upper 50’s.

Monday will be sunny with highs again in the mid to upper 80’s. Lows will be around 60.

Tuesday’s temperatures will be in the low to upper 80’s.  Lows will be in the low 60’s.

Wednesday’s highs will be in the upper 70’s to upper 80’s with lows in the low 60’s.  There will be a slight chance for scattered showers. 

The five day precipitation amounts will only be up to a quarter of an inch.   The 8-14 day outlook is showing above normal temperatures and neither above nor below normal precipitation.

The southern tip of the Hudson Valley still has abnormally dry conditions, but the rest of the state is no longer dry after the rain this week.

Western Bean Cutworm Update

Keith Waldron

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Western Bean Cutworm moth captures are down again this week with the majority of sites reporting no WBC moths observed. 726 WBC moths have been collected in NY so far this season. Reports have come in this week from northern and western NY that some WBC larvae are beginning to be found in developing corn ears. As more corn is evaluated for potential timing of harvest we expect to hear of more larval feeding reports.

WBC larvae are very tolerant of others of their own kind feeding in corn ears so it is not unusual to find several larvae in the same ear. We have not, to date, heard of WBC feeding damage in NY dry beans.

Field Scouting tips adapted from information supplied by Tracey Baute (OMAFRA, "Baute Blog").

WBC damage will not necessarily be in one specific area of the field. To improve the likelihood of finding an infestation, wander through field looking for signs of insect frass at the ear tips. Look for any signs of external entry holes from sides of the husk, though WBC do not always enter from the side of the ear. 

Signs of bird damage can also indicate that there was something in the ear that the bird went after.  (birds could be going after picnic beetles, corn borer or corn rootworm adults too.)

For hybrids without tightly closed husks at the ear tip and when there are signs of less silk or frass on the silk - open that husk to investigate.  Otherwise, just peel back random husks in the field if no external signs of damage exist. 

Once an ear with damage and or larvae is found, investigate the plants around that one including plants in directly adjacent rows. WBC larvae spread from their original egg masses and can crawl 12 feet down the row and 10 feet across potentially infesting many adjacent plants from just one eggmass.

If a WBC larvae is not present in the ear that has damage, you cannot fully confirm that the damage was caused by WBC, as it could also have been from ECB or corn earworm ... although WBC does tend to be the most destructive feeder.

Purdue University entomologists have posted a WBC scouting video for corn late season.

Keep an eye on the quality of infested sites before harvest.  If ear rot starts to set in because of the damage caused by WBC, plan to harvest this field as early as possible.

As always, we look forward to hearing about your WBC field observations.

Stop! Check for Corn Ear Rot

Ken Wise

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Are you ready with the chopper or combine? STOP; check for corn ear rots first! Some kinds of fungi can create mycotoxins that are toxic to livestock. Taking a few minutes to check a field for certain ear rots can help you determine if you want to feed your field of corn to livestock. Pull back the husks on several plants and look for the presence mold growing on the ear of corn. The following are specific symptoms of certain ear rot diseases that can be found in NYS:

Fusarium Ear Rot appears as a white-to-pink or salmon-colored mold. This mold can begin with bird, deer or insect-damaged kernels. Fusarium ear rot may contain fumonisins which are mycotoxins that can be toxic to livestock.

Gibberella Ear Rot symptoms are pink to reddish colored mold. This disease starts near the tip of the ear and progresses down toward base of the ear. Gibberella can produce vomitoxin and zearalenone which is toxic to many kinds of livestock.

Diplodia Ear Rot symptoms appear as a thick white mold that usually starts near the base of the ear. This disease can also appear on the plant as raised black fruiting bodies on moldy husks or kernels. Diplodia does not produce any known toxins.

Cladosporium Ear and Kernel Rot symptoms appear as greenish black, blotched or streaked kernels scattered over the ear. This disease can also infect kernels that have been damaged by insects, birds, deer, hail, or frost. The disease can progress after the grain is harvested and stored.

Penicillium ear rot or blue eye symptoms range from a powder-like green or blue-green mold that is on and between the kernels and normally on the tip of the ear. If this disease progresses in storage it is referred to as blue eye because the germ is a bluish-green color. Penicillium ear rot can produce a mycotoxin called “ochratoxin”.

If you discover certain ear rot diseases make notes of the hybrid, tillage methods, rotation history, and planting date. By doing this you can avoid the disease occurrence in the future. The following is the effectiveness of specific management practices for corn ear rots:

Corn Disease
Resistant Variety
Crop Rotation
Clean Plow
Down of Residue
Ear Rots
1= highly effective, 2= moderately effective, 3=slightly effective, 4= not effective, 5 = not usually economical,
Reference: Purdue University Field Crops Pest Management Manual

While there isn't any practical solution for coping with ear rots this late in the current season proper fertilization, timely weed control and reductions in insect pest pressure can help reduce risk of disease. For example: European corn borer (ECB) resistant Bt corn is at lower risk for injury by this insect. Lower risk means fewer ECB tunnels into stalks and less potential for fungi to infect through wounds and cause stalk rot. Also avoid continuous planting of corn under conservation tillage where stalk rot can be prevalent. If you are harvesting corn grain make sure you clean the grain bins. Keeping the proper temperature, moisture content and good aeration in the grain bin can reduce storage molds from developing. It is important to have regular inspections of the stored grain. This is essential to minimize risk of developing insect and mold associated storage problems. Harvest silage at recommended maturity and moisture level, and pack silage tightly and exclude air rapidly. Consider using organic acid preservatives if you can't exclude air or reduce moisture. If you had a lot of stalk rot and were growing for grain consider chopping earlier for silage to minimize lodging and combine losses. There are kits you can purchase to test your corn for different toxins on your own farm. The following are places where you can also test your corn:

Dairy One Forage Lab in Ithaca: For more information, call the lab at 1-800-496-3344 extension 172. More information is available on the web at The Cornell College of Veterinary Medicine's Nutritional and Environmental Analytical Services Lab or from lab manager Joe Hillebrandt at 607-257-2345

Winter Wheat, Aphids and Yellow Dwarf Virus

Ken Wise

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Barley yellow dwarf virus, also know as yellow dwarf virus (YDV) in wheat is a serous disease across the country. This disease is transmitted by several species of aphids that infest wheat. When infected aphids feed on the plants they infect the wheat with the virus. Winter wheat that is infected in the fall does not show symptoms. Symptoms start to appear mid-spring as yellowing of leaves. One management strategy is to plant wheat after the Hessian fly free date in your region. This can limit the number of aphids entering the fall seeded winter wheat fields. Another management option is to plant a wheat variety that is resistant to YDV. 

Storing Corn or Soybeans? Remember Stored Grains Pests!

Ken Wise

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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 Pest 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
  • Angoumois grain moth
  • Confused flower beetle

(See: Maintaining Quality in On-Farm Stored Grain, IPM in Kentucky Farm Stored Grain and Improve Stored Grain Through IPM from Oklahoma State)

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, western bean cutworm, 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 pollinating 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, 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


  • 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.


  • 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, 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


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