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Weekly Field Crops Pest Report 2012

June 8, 2012, Volume 11 Number 8

  1. View from the Field
  2. Weather Outlook
  3. Stay Informed with the NYS CCE Field Crops News Blog
  4. Dry Weather and Preemergence Corn Herbicides
  5. Clipboard Checklist
  6. Mark Your Calendars
  7. Contact Information

View from the Field

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True armyworms are hitting western NY hard this week. They have been found in small grains, mixed stands of alfalfa/grass and hay fields and have been confirmed statewide. Many fields have been over threshold and sprayed with an insecticide. As you can see from the photos below infestation levels and damage have been extreme!

armyworm infestation

(photo taken by Sharon Bachman)

armyworm in field

(photo taken by Sharon Bachman)

BIG WARNING: True Armyworm and the crop have to be on the insecticide label before using the product. That means in mixed stands the alfalfa, grass and true armyworm have to be on the label.

Armyworms in eastern New York are in earlier instars than in western New York. I could find ¼ inch to ½ inch larvae in field margins where there was grass, with less than 1 per square foot. I also found 10% damage to field corn at the Cornell Research farm in Valatie. Armyworm has been confirmed from Clinton County all the way down to Dutchess County this week in eastern NY.  Remember: True armyworm larvae appear smooth cylindrical pale green too brownish when they are still small. Mature larvae are smooth and marked with two orange, white-bordered strips on each side. True armyworm ranges in size from 1/8 inch to 1.5 inches long.

arnyworm in hand

True Armyworm (Mythimna unipuncta)

Note that true armyworm seems to have two scientific names: Pseudaletia unipuncta and the other is Mythimna unipuncta. On the web it is listed both ways.

To find armyworm you have to look under the residue on the surface of the field. They only feed at night… unless they are in very large infestation levels, when they feed and march during the day. In hay fields, move the grass to the side and look under the grass residue on the surface. They will be at the soil surface.

Paul Cerosaletti reports a cornfield was over threshold for black cutworm. He also found a population of cereal leaf beetle in oats in Delaware County. Cereal leaf beetle has not been a common pest in western NY. Aaron Gabriel also found a population of cereal leaf beetle in the upper Hudson valley. I found cereal leaf beetle on oats in a field next to the farm in Valatie. 

Potato leafhopper (PLH) on alfalfa has been reported statewide at low infestation levels. As the weather warms and starts to dry out PLH can become a problem in alfalfa.

Jefferson and Lewis County have had issues with preemergence herbicide in cornfields this year. Once the growers sprayed, they had extended periods of dry weather—thus; rain did not activate the herbicide to kill weeds. For more information see article below.

Weather Outlook

June 8, 2012
Jessica Rennells, Northeast Region Climate Center, Cornell University

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We were in a different weather pattern last week with below normal temperatures ranging from 3 to 6 degrees below normal for most of the state. Precipitation amounts ranged from 1 to 2 inches for most of the state, with some areas receiving between half and one inch.  The base 50 growing degree-days ranged from 25 to 75.

Today will partly sunny with temperatures in the mid to upper 70s, nearing 80.  Showers and thunderstorms are possible later in the day; isolated storms could be severe producing strong winds and hail.  Overnight temperatures will be throughout the 50s. Saturday will be partly sunny changing to mostly cloudy with showers and thunderstorms possible as a warm front moves across the state.  Highs will range from the low 70s to low 80s.  Lows will be in the upper 50s and low 60s. Sunday will be sunny with temperatures in the upper 70s and low 80s.  Some scattered showers are possible.  Overnight temperatures will be in the upper 50s and low 60s. Monday will be sunny with highs in the low to mid 80s.  Lows will be in the mid 50s to low 60s. Tuesday highs will be in the low to mid 80’s.  Lows will be in the upper 50s and low 60s. Wednesday there will be a chance for showers and thunderstorms with temperatures in the mid 70s to low 80s.  Lows will be in the low to mid 60s. Thursday’s temperatures will be in the mid to upper 70s.  Lows will be in the upper 50s and low 60s.

The five-day precipitation amounts will range from one quarter to three quarters of an inch. The 8-14 day outlook is showing above normal temperatures for the entire state and below normal precipitation for all but the lower the Hudson Valley & Catskill areas.  Areas in western NY are still abnormally dry, though the rest of the state is not in dry conditions.

National Weather Service Climate Prediction Service Maps of 8-14 day outlooks

National Weather Service Eastern Region Headquarters watch/warnings map

NRCC Drought Page which features the US Drought Monitor map (updated every Thursday)

Stay Informed with the NYS CCE Field Crops News Blog

Mary McKellar
Extension Support Specialist
Cornell University

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Are you looking for a way to stay up to date on field crops information in New York State?

Cornell University campus faculty and staff in collaboration with CCE field crops county extension agents have developed a news blog on current field crops information in NYS which can be accessed at the NYS CCE Field Crops News blog.

Blog postings will include news articles, seasonally relevant extension articles and announcements about emerging issues and programming opportunities related to field crops in NYS including a weekly weather outlook, county scouting reports, county based research information and the NYS IPM Weekly Pest Report.

In addition to being able to access the blog directly at the address above, viewers may find a news feed to the blog at An email subscription to the blog is also available and can be found on the home page of the blog. Subscribers will be emailed updates as new postings are made eliminating the need to keep checking the blog for new information.

For more information about the NYS CCE Field Crops News blog, please contact Mary McKellar (

Dry Weather and Preemergence Corn Herbicides

Mike Hunter, Jefferson County CCE

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Based on the large volume of phone calls and requests for field visits to look at weed control issues in corn fields, I felt it was most appropriate to send this crop update to local corn growers.- Mike Hunter, Cornell Cooperative Extension of Jefferson County

Many corn fields were sprayed with preemergence herbicide followed by 7 to 10 days without rain to activate them.  Widespread field observations and reports indicate that the dry weather conditions in May have resulted in inadequate weed control in numerous corn fields throughout the region.  After any herbicide application is made you should check those fields to make certain that you have controlled the weeds.  If you have not checked your corn field since it has been sprayed, now is the time to do so.

In order for most preemergence herbicides to do their job they must be present in the soil solution where the weed seeds germinate.  Most weed seeds will germinate in the top one inch of the soil.  It requires about ½ inch of rainfall to sufficiently move the herbicide to the soil depth require for effective weed control.  This is the main reason for so many failed preemergence herbicide treatments this season. 

If you have emerged weeds in a corn field that received a preemergence herbicide application you can do one of two things. 

  1. You can wait and see if the recent rainfall will provide any “reachback” activity. Reachback is a term used to describe the potential for a preemergence herbicide to kill small emerged weeds. It involves the herbicide being moved into soil solution and taken up by the roots of the weeds. This type of herbicide activity is highly inconsistent but does exist. If it does not look like you will be getting any reachback activity then you need to take action and apply a postemergence herbicide before it is too late. Once the broadleaf weeds and annual grasses get much bigger than a couple of inches tall, the chance for any reachback is gone. Not all preemergence herbicides will be able to provide control in this manner. If you have applied products such as atrazine, Lumax, Lexar, Bicep Lite II Magnum, Cinch ATZ Lite, G-Max Lite, Bullet, Verdict, Capreno, Dual, Outlook (or other acteadmides) there is a chance for this to occur. Do not expect any reachback from Prowl, Pendimax (or other dinitroaninlines).
  2. You can decide to take action now and make a postemergence herbicide application. Assuming that all of these situations are conventional corn, there are many good choices available to control most any emerged weed in a corn field. Proper weed identification is necessary when choosing the herbicide. If you are dealing with emerged grasses it is very important to know what grass species are present.

Available on the Web: Corn Pest Management

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.
*Walk fields to check crop condition, growth, and emergence. Look for signs of vertebrate pests (birds, ground hogs, deer, etc.).
*Mow around farm buildings to minimize rodent and other pest habitat

Alfalfa and Grass Hay:
*Monitor alfalfa for crop condition, watch re-growth for alfalfa weevil, potato leafhopper, and diseases.
*Evaluate alfalfa seedings for weeds, insects (potato leafhopper) & diseases.

Small Grains:

*Monitor winter wheat for foliar & grain head diseases, Fusarium Head Blight incidence
*Monitor winter grain fields for crop growth stage, signs and symptoms of diseases, weed pressure, insects (cereal leaf beetle)

Field Corn:
*Post emergence: Determine corn plant populations, monitor for emergence problems, weeds, noting presence of "who", "how many" and "where"
*Early season corn pests: seedling blights, seed corn maggot, white grub, wireworm, black cutworm, slugs, birds
*Adjust post emergence weed control actions

*Post emergence: Determine plant populations, monitor for germination and emergence problems, monitor for weeds, noting presence of "who", "how many" and "where"
*Monitor for soybean aphid

*Check and mend fences as needed.
*Check crop growth
*Check for presence of undesirable plant species harmful to livestock.
*Review/Plan rotation system

*Arrange for custom weed / disease management or check your own application or cultivator equipment for readiness or need for repairs.
*Check nozzles, pumps, etc., recalibrate pesticide application equipment regularly before use.
*Calibrate manure spreaders - maintain records on amount spread per field

Cattle on Pasture:
*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

Dairy Cattle Barn Fly Management:
*Monitor animals and barn area for house fly, stable fly and other pest management needs including presence of rodents and birds.
*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
*Consider purchase and release of Muscidifurax raptor and/or M. raptorellus natural enemies of house and stable fly pupae.

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

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Tuesday, 3 July 2012
For Seed Growers, Seed Treatment Applicators, and other Seed Professionals
Place: NYSIP Foundation Seed Barn, 791 Dryden Rd., Rt. 366, Ithaca, NY
Time: 8:30 AM-12:00 noon (registration starts at 8:30 and the program runs fro 9:00 until noon)

Freeville, NY (10 miles Northeast of Ithaca, Fall Creek Road, Rt. 366 extension)
8:00 a.m. Registration
Coffee (beverage), doughnuts, and informational trial packet
8:30 a.m.-11:30 a.m. Vegetable Crop Weed Control (Bellinder)

Aurora, NY (Poplar Ridge Road, connects 90 and 34B)
12:00 – 1:30 p.m. NYSABA Pork BBQ lunch at Musgrave Research Farm.
1:30 p.m. Registration
2:00 - 5:00 p.m. Field Crop Weed Control (Hahn)
CCA and DEC Credits have been requested for field crop and vegetable crop field days

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