Weekly Field Crops Pest Report 2009

View from the Field

Ken Wise
NYS IPM

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Black cutworm has been reported in several corn fields across the New York. Black cutworm adult moths must migrate north each spring, and they lay eggs primarily on grasses.  When there are grasses in the field overlapping a corn crop, infestation from this pest is more likely.  Two scenarios that can contribute to black cutworm population booms include a grass cover crop that is left covering a field until soon before corn planting, and weedy grasses that are not burned down prior to no-till planting. If the grassy weeds are controlled after an infestation of cutworm is already happening, the cutworms will leave the dying weeds and feed on the small corn plants.  Risk to a corn crop from black cutworm is increased by planting late. For more information on black cutworm biology and management, please review our online publication, Black Cutworm Management.

Soybean aphid (SBA) has been detected at generally low infestation levels in soybeans across the state. Some areas of central NY, Wayne and Yates counties, however, have reported numbers at the 250 SBA’s per plant threshold guideline. Remember SBAs populations can increase very quickly under favorable conditions. For more information see the article on SBA in this WPR issue.

Potato leafhopper (PLH) can be found in alfalfa across New York. PLH populations are not currently close to threshold levels, but can be expected to increase over the next several weeks. I would start monitoring your alfalfa fields every 7 to 10 days for the rest of the summer. For more information on how to scout for see June 10, 2009 Volume 8 Number Weekly Pest report: How to Sample for Potato Leafhopper in Alfalfa.

Wet, cool conditions continue to be favorable for slug problems, particularly in no-till or reduced tillage fields and fields with high residue. Eyespot disease has also been observed in reduced tillage corn.

Birds are the pest of the week. We are getting many reports of significant damage by birds (mostly crows) feeding on corn seedlings in the fields.

Weather Outlook

Drew Montreu
NOAA NE Climate Center, Cornell University

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Temperatures during the past week remained a couple of degrees below normal statewide, with a few isolated areas being as much as three or four degrees colder than normal. Precipitation was plentiful, with most areas receiving between 1 and 3 inches. Places in Southeast New York got more, with 3 to 4 inches falling, while areas in the North Country saw less than an inch.

Base 50 Growing Degree Days (GDD) last week accumulated mostly between 75 and 100. There were some pockets of higher values up to 125 in some of the lower elevations, such as the river valleys. For the season, most areas are between 500 to 600, with isolated pockets that are higher. The mountainous areas have seen less, with between 400 and 500 in the Catskills and Alleghenies and as few as 200-300 in the Adirondacks. Compared to last year, pretty much everywhere is behind to some degree. Areas in the southeast are only a couple of calendar days behind, while areas south of Lake Ontario and up into the North Country and Adirondacks are 7 to 10 or more calendar days behind. Everywhere else remains between 3 and 7 days behind last year. Compared to normal values, areas in the Southern Tier are a couple days ahead, with the Southeast as much as a week ahead. Areas north of I-90, however, are generally 3 to 7 calendar days behind, with some places on the Tug Hill as much as a 10 days behind. This corresponds to about 75 degree days on either side of normal, except for the North Country, which is 75 to 150 degree days behind.

In the weather, high pressure has been dominating most of the state the past few days after the rain-soaked weekend. A cold front will come through this evening and overnight after a hot day with some thunderstorms possible. Some hail and strong winds could be possible with those, especially over western and central New York. Heavy rain could also be a concern as the storms may be slow moving. Behind this front, high pressure will again build in for the start of the weekend, with dry conditions for most of Friday and into Saturday. Highs will generally range from the upper 70s to low 80s. Another front will come through with another round of storms possible on Sunday. After that the forecast becomes a little more difficult, but it appears that another area of low pressure may move in and only slowly drift eastward for the first part of next week. If that is the case, showers would be scattered across the state from Monday right through Wednesday with cooler than normal temperatures. For the next 5 days though, the heaviest precipitation should fall across western and far eastern portions of New York, where up to 1.5 inches may fall. Elsewhere should see between a half of an inch and one inch, with perhaps some locally heavier amounts in thunderstorms. The 8-14 day outlook has some questions marks in it as well, but the start of July looks like it may continue the trend of below average temperatures with near average precipitation.

Time to scout for soybean aphids

Keith Waldron
NYS IPM

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Most areas across the state are currently reporting few or no SBA's present, however, soybean aphid (SBA) populations appear to be on the increase in the central NY production areas of Wayne and Yates counties. Adjacent counties could also be affected. In some fields, current SBA numbers have increased as much as 10 fold in one week and are now at the 250 SBA's/ PLANT threshold. These affected soybean fields are currently at the V2-V3 growth stage about 8 inches tall. Beneficial insect populations in these fields unfortunately appear to be absent or only at very low numbers at this time. These conditions have prompted insecticide treatment.

Soybean aphid (SBA) problems have typically been relatively isolated across NY since their initial introduction in 2000-2001. Field monitoring for this pest is, however, recommended since at least some fields reach threshold numbers every year requiring treatment to avoid losses. No cause to panic... but now is the time to begin checking fields soybean aphid.

What to look for:
Check the under surface of leaves for presence of very small aphids. If present, the aphids are usually seen in small clusters near the leaf veins. They are tiny, 1/16" long at their largest, with distinctive black cornicles (tail pipes).  Soybean aphids are the only aphids to successfully colonize soybean plants. These aphids may or may not have wings.

Infested fields may also be stunted, have areas leaf curling and the sticky "honey dew" residue associated with a high aphid population and relatively low numbers of natural enemies. A large colony of soybean aphids often includes white, shed skins and brownish carcasses killed by fungal pathogens. Plants with very high SBA populations can also attract ants that can be seen on and in the plant canopy.

Threshold guideline:
SBA threshold guideline is 250 soybean aphids per plant if populations are actively increasing on 80% or more of the plants prior to early pod fill (R4). The 250 SBA / plant action threshold is based on an average of aphids per plant over 20-30 plants sampled throughout the field. This threshold incorporates an approximate 7-day lead time between scouting and treatment to make spray arrangements and handle weather delays. Midwestern research has found that treating earlier than this threshold in most cases does not pay for itself. When scouting the early vegetative stages of soybeans for soybean aphid, it is just as important to watch for the aphid's natural enemies, including ladybugs, syrphid fly larvae, parasitic wasps, and fungal pathogens.
If fields are approaching threshold, a follow up field visit is recommended within a week, particularly following rain storms, to determine if SBA populations are increasing, assess potential impact of natural enemies and re-assess if rains have affected aphid numbers on plants.

Treatment:
Insecticides labeled in NY for treatment of SBA's are shown in Table 6.6.1 of the Cornell Guide for Integrated Field Crop Management. If fields are treated, re-evaluate fields for SBA numbers at least 7-10 days following treatment. Information from any treat / no treat side-by-side comparisons is always appreciated.

What Fields are at Risk for Corn Rootworm?

Ken Wise
NYS IPM

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 Corn rootworm populations can build in a cornfield from year to year. Fields that are not rotated and remain in corn for several years are most at risk from corn rootworm damage. A two to three year rotation out of corn or cucurbits such as pumpkins reduces the risk that a corn field will reach an action threshold for this pest. This spurs the question, “Do you scout a 1st year cornfield after sod for corn rootworm?” Yes, because any pollinating cornfield can attract corn rootworm. Even worse, late pollinating corn can attract many hungry corn rootworm beetles from fields where they did not get enough pollen. After the beetles eat their fill on late season pollen they will lay eggs in the soil. So yes, scout all cornfields for corn rootworm that will be planted to corn again next year. You do not need to scout fields that will be rotated out of corn next year. For more information on corn rootworm checkout our online publication: Corn Rootworm Management Guide.

Curb conditions that can favor dairy barn fly populations

Keith Waldron
NYS IPM

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Confined livestock facilities can contain perfect habitats for house and stable fly populations to develop. The good news is these conditions, when controlled, can help minimize 90% or so of the potential fly problem. A little management time each week will pay big dividends as the season progresses.

Sanitation, Sanitation, Sanitation! Staying ahead of fly populations begins with cultural practices that eliminate conditions favorable to fly breeding. House flies and stable flies both breed in areas where moist undisturbed organic matter such as spilled feed, moist hay, wet grain, and manure-soiled bedding are present. Another favorable breeding spot is a location that remains relatively undisturbed and offers protection from foot and hoof traffic. Frequent clean out of potential breeding sites and other activities that enhance dry conditions in animal areas will make the local environment inhospitable to successful buildup of fly populations.

With sound sanitation as the foundation for fly management, additional tactics can be brought to bear. A variety of biological control agents occur naturally in the typical dairy barn. These include various predators of house and stable fly eggs, larvae and adults. When sanitation, is used effectively, natural enemies can more easily keep up with what fly populations remain and can be quite effective at reducing their numbers. The key is to employ sanitation early and as often as practical as the first line of defense for mitigating fly populations. Common fly predators include predaceous mites, rove and Carcinops beetles, parasitoid wasps, and fly diseases. Parasitoids, the small wasps that attack fly pupae, are quite effective at reducing fly populations. These tiny wasps, however, can take up to three times longer to develop than the house fly. This is the reason their populations can use a “jump start” early in the season to reach the numbers needed to head off house fly problems. For those wishing to use parasitoids to enhance their biological control efforts the earlier in the season the better is recommended. There is still time to begin releasing the wasps in barns and calf housing areas. Parasitoids should be released close to their prey, i.e. in and around potential fly breeding habitat.

A number of insectaries advertise house fly parasitoid species for use in confined animal facilities. Our experience at Cornell has shown a need to obtain climatically adapted strains. The two parasitoid species we have had success with in NY are: Muscidifurax raptor and Musicifurax raptorellus.

We are still in the relatively early stage in our understanding of how to use biocontrol to full advantage in fly management programs. Should producers purchase a product from outside the NE, we would be very interested in their thoughts and feedback on how well it is working for them.

To help evaluate how well fly management efforts are working use some means, such as spot cards or fly sticky tapes, to monitor fly populations over time. The spot card method helps provide an objective means to gain information and feedback on the effectiveness of their overall fly management program. Spot cards are 3X5 index cards placed at 5-10 locations throughout the barn in areas where flies can be seen resting such as walls, rafters, poles, etc. Date and identify the location (number) of the card and install cards out of the reach of animals. Change the cards weekly. Our guideline has been 100 spots per card per week indicates a fly problem. Your threshold may be different – the important thing to consider is to have a reference point on which to compare populations over time. Search the area close to location of the card for fly breeding habitat. Clean as necessary. Watch and compare spot card counts the following week.

Reducing the number of adult (breeding) flies helps minimize the potential for fly population buildup. Two additional fly management tactics to curb fly numbers include use of sticky ribbons and tapes and insecticide baits. Sticky ribbons (including the wide roll types) and tapes offer an effective non-toxic means to capture adult flies. Place tapes in areas not at risk from high winds, turbulent air and dusty conditions. A count or estimate of flies caught per tape week / location will give help evaluate the effectiveness or need for additional fly control measures.

Insecticide : sugar bait stations can also be deployed to capture adult flies. For more information on IPM for barn fly management see: Integrated Management of Flies in and around Dairy and Livestock Barns and Pest Management Recommendations for Dairy Cattle.

Not sure what flies you are seeing in and around your dairy facility? See: Veterinary Entomology, Arthropod ID

NYS Soybean Rust Update

Gary Bergstrom
Cornell University

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The first detections of soybean rust on soybean in 2009 were made in Louisiana and Alabama on June 4th and 8th respectively. This is the earliest detection of soybean rust on soybean in both of these states. Limited periods of precipitation over the next several days will lead to spore deposition in the affected areas in the Florida panhandle, Georgia and the Gulf Coast. Scouting in sentinel plots in the Southeastern U.S. continues. Much of the New York State soybean acreage has been planted and begun to emerge. Please visit us again for future updates on soybean rust in the U.S. and New York State. Updated June 10, 2009

NY State Soybean Rust Hotline: 607-255-7850

NYS Soybean Rust Website

USDA Soybean Rust Website

Fusarium head blight (FHB) Update

Gary Bergstrom
Cornell University

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For information on current risk of Fusarium head blight in our area see: Fusarium Head Blight Risk Assessment Tool.

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, early to mid season pest issues
* Gaps in row? Check for seed corn maggot, wireworm, cutworm, armyworm, seedling blights, birds, seed placement issues
* Check no-till fields/fields with high residue or weeds for slug damage
* Monitor for weeds, note presence of "who", "how many" and "where"
* Adjust post emergence weed control action

Small Grains:
* Monitor winter grains for crop stage (heading, grain fill), insect problems (cereal leaf beetle, armyworm) and foliar / head diseases
* Evaluate crop for plant vigor, lodgin

Alfalfa & Hay:
* Monitor alfalfa seedings for weeds, insects & diseases.
* Check regrowth of established alfalfa stands for alfalfa weevil, potato leafhopper, weed and disease problems.
* Check windrows of recently harvested alfalfa for signs of alfalfa weevil feeding damage and weevil life stage (instar cocoon).
* Storage areas cleaned and ready to accept incoming harvest

Soybeans:
* Evaluate stand emergence - seedling blights, seed corn maggot, weed assessment, soybean aphid, volunteer glyphosphate resistant corn
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 waterers, 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

Storage:
* Check storage areas (bunk silos, etc.) for readiness to accept first cutting, upcoming wheat harvest
* Clean in and outside of storage bins and grain handling equipment
* Keep areas around storage bins and silos clean and mowed
* Check areas around storage bins and silos for vertebrate tunnelling

Equipment:
* Note any repairs needed for recently used equipment: tractors, tillage implements, planters, etc. as they are cleaned and serviced.
* Service corn and soybean planter, alfalfa harvesting equipment, and tillage implements 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.

Mark Your Calendars

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July 7, 2009 -- Cornell Seed Growers Field Day, Ithaca, NY
July 15, 2009 -- Weed Science Field Day, Thompson Research Farm, Freeville, NY (morning program)
July 15, 2009 -- NYSABA Summer, BBQ, Musgrave Farm, Aurora, NY 12:00 noon
July 15, 2009 -- Weed Science Field Day, Musgrave Farm, Aurora, NY (afternoon program)
July 23, 2009 -- Aurora Farm Field Day, Musgrave Farm, 1256 Poplar Ridge Rd, Aurora, NY
Aug. 10-14, 2009 -- Soil Health Training Workshop, Ithaca, NY

Contact Information

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

Keith Waldron: NYS Livestock and Field Crops IPM Coordinator
Phone: (315) 787 - 2432
Fax: (315) 787-2360