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Weekly Field Crops Pest Report 2011

September 2, 2011, Volume 10 Number 17

  1. View from the Field
  2. Weather Outlook
  3. Western Bean Cutworm – What's happening, what's next?
  4. Fall Weed Survey - Invasive species and Plants affecting Livestock
  5. Fall IPM Alfalfa Assessment
  6. Clipboard Checklist
  7. Contact Information

View from the Field

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Joe Lawrence (CCE Lewis County) reports several company representatives are finding western bean cutworm (WBCW) larvae in field corn ears in the north country region of Lewis, St. Lawrence and Franklin counties. While the amounts found to date do not appear to be causing economic losses it may indicate areas to watch for potential WBCW overwintering.

Mike Stanyard (CCE Northwest NY) and Mike Hunter (CCE Jefferson County) report white mold infestations in soybeans.

Mike Hunter reports that soybean aphids are at high infestation levels in some fields. It should be noted that studies have consistently shown that there is no economic benefit to spray once beans are full seed set in the pod. Mike Stanyard has seen the white dwarf morph of the soybean aphid. White dwarfs are a smaller, lighter-colored version of the typical yellow-green soybean aphids. These aren't necessarily SBA "babies"— nor a different species. No one truly understands what provokes females to give birth to dwarfs. But it could be a response to stress or change: high temperatures, shorter day length, or lower nutritional quality. These dwarfs live half as long and make 70% fewer nymphs compared to the normal green morph. Do they injure soybeans less? Maybe—but at this point, it's speculation. Include counts White dwarf numbers are still included in overall counts of aphids. White dwarfs are more likely to show during R3 to R4, when host quality declines. They reproduce more slowly and are less likely to exceed economic threshold of 250 aphids per plant.

Mike Stanyard continues to detect Phytophthora root and stem rot in soybeans. For more information on Phytophthora root and stem rot please view the pest report on August 21.

Weather Outlook

September 1, 2011

Jessica Rennells, Northeast Region Climate Center, Cornell University

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Temperatures were within 3 degrees of normal this past week. Precipitation ranged from less than an inch in western NY to over 8 inches in southeastern NY due to Hurricane Irene. There has been devastating flooding in parts of eastern NY. The base 50 growing degree days ranged from 75 to 125 for most of the state.

Today's temperatures will be in the 70's and low 80's with a chance for scattered showers and thunderstorms, more likely in western NY. Tonight will be in the 50's and low 60's.

Friday high pressure will bring mostly sunny skies with temperatures in the mid 70's to mid 80's. Lows will be in the mid 50's to mid 60's with a slight chance for overnight showers.

Saturday's highs will be in low to mid 80's with showers and thunderstorms possible as a cold front moves in. Lows will be in the 60's.

Sunday will be in the upper 70's and low 80's with scattered showers and thunderstorms as the front in is still over NY. Lows will be in the 60's.

Monday will be cooler in the upper 60's and low 70's with scattered showers and thunderstorms possible as the cold front finally moves out. Lows will be in the 50's.

Tuesday will be sunny with temperatures in the upper 60's and low 70's. Overnight temperatures will be in the upper 40's to mid 50's.

Wednesday will again have highs in the upper 60's and low 70's. Lows will be in the upper 40's and low 50's.

The five-day precipitation amounts will range from half an inch to over an inch. The 8-14 day outlook is showing below normal temperatures and above normal precipitation.

Western Bean Cutworm Update:What's happening, what's next?

Keith Waldron
NYS IPM

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A very few Western Bean Cutworm moths are still being collected across NY. The majority of WBC egg laying, however, occurred when the peak WBC flight occurred the week of August 2. Surviving larvae would have been expected to have moved from the egg mass location to their preferred feeding areas – corn ears or dry bean pods.

Reports have come in this week that WBC larvae and feeding injury have been found in developing corn ears in some Lewis, St. Lawrence and Franklin county corn fields. While these WBC reports indicate larval presence, economic larval infestations have not been detected. We have not heard of any WBC issues in dry beans.

As you check corn and dry beans for maturity and potential harvest dates, search corn ears and dry bean pods for WBC larvae and or signs of larval feeding.

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. 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 or ear stalk.

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 corn 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.

What’s next for WBC?
Our NY WBC populations to date have largely come from moths emigrating into NY from more western states and Ontario, Canada. Circumstantial evidence suggests some amount of WBC overwintering in NY may be likely but has yet to be confirmed. After a WBC larva finishes feeding and completes development this season, it will drop to the ground and burrow beneath the soil, where it constructs an overwintering cell. Western bean cutworms spend the winter in the prepupal stage. If overwintering is successful, western bean cutworms would pupate the following year around May and emerge as adult moth later during the summer.

As always, we look forward to hearing about your WBC field observations. Thanks – (jkw5@cornell.edu)

Fall Weed Survey - Invasive species and Plants affecting Livestock

Keith Waldron
NYS IPM

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As we enter the harvest season take some time to update your field records. It is a great time to take stock of what field issues can be found and note them in individual field records to enhance future management decisions. Note particularly good and bad areas with the field such as differences in crop height, plant populations, drainage, yield, etc. Updates on pest presence or damage can also be noted at this time.

An easily visible pest group to document this time of year are weeds. What species? Where are they found? How many are there? What management type (annual, perennial, biennial, grass or broadleaf species? Knowing this information helps to refine weed management decisions and develop next years cropping plans.
 
While visiting fields to conduct the fall weed survey note presence of troublesome perennial species like Canada thistle and milkweed and potentially invasive species such as spiderwort, Japanese knotweed, leafy spurge, multiflora rose and spotted knapweed growing in or around production and fallow fields, pastures, in fence lines or in windbreaks. Many websites have information on invasive plant species. For information on invasive species in NYS see the website for the New York Invasive Species Clearinghouse / Cornell Cooperative Extension Invasive Species Education Program (CCE ISP) and the USDA's National Invasive Species Information Center for Plants.

If you raise livestock, fall is also a good time to assess pastures and other grazed areas for presence of common weed species known to be harmful to animals. These species include horsetail (Equisetum spp), poke weed, St. Johnswort, tall buttercup, jimson weed, common milkweed and among others. A listing of some common plants poisonous to livestock can be found in the publication Common Weeds Poisonous to Grazing Livestock.

To learn more about Plants Poisonous to Livestock and other Animals, see Cornell University's Department of Animal Science page on Plants Poisonous to Livestock and other Animals.

Fall IPM Alfalfa Assessment

Ken Wise
NYS IPM

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Fall stand counts are an indication of the health of your alfalfa crop. There are a number of pests and crop management issues that can reduce a stand count in alfalfa. The following are guidelines for stand counts in NYS:

 

 

Crowns per square foot

Harvest Year

Optimum Stand

Adequate Stand

New Spring Seeding

25-40

12-20

1st hay year

12-20

6-10

2nd hay year

8-12

4-6

3rd and older

4-8

2-5

Fall scouting before the first hard frost can also reveal pest problems. If you find yellow to brown plants it may indicate several different disease problems. These could range from a wide variety of disease problems including, verticillum wilt, leaf spots, fusarium wilt, anthracnose and more. An inspection of the root system can also indicated disease problems. Yellow, reddish-brown to black discolored or damaged roots may indicate disease problems such as phytopthora root rot or verticillium wilt. In northern NY counties where alfalfa snout beetles (ASB) have been a problem prematurely senescing, stunted or yellow alfalfa fields may indicate an ASB infestation. Fields should be evaluated for presence of the root feeding larval stage.

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, soybean, corn harvests
 
Field Corn:
* Note crop growth stage and condition
* Check for European corn borer, Western bean cutworm, foliar diseases, vertebrate injury (birds / deer), weed escapes, herbicide injury, nutritional deficiencies, etc.
* Monitor weed populations noting presence of "who", "how many" and "where"
* Check herbicide resistant corn fields for herbicide resistant soybean
 
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?
 
Soybeans:
* Note crop growth stage and condition
* Evaluate stand for soybean aphid, spider mites, deer, weed assessment, 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 through out 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
 
Storage:
* 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
 
Equipment:
* 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

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