Weekly Field Crops Pest Report 2009

View from the Field

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Cereal leaf beetle (CLB) is the insect pest of the week. Brain Aldrich (Cayuga County CCE) reports a winter wheat field approaching an economic threshold for CLB. The economic threshold is three or more eggs and larvae per stem before the boot stage or one or more larvae per flag leaf after the boot stage. Mike Stanyard (NW NY Dairy and Field Crops Team) indicated that a few growers have sprayed for CLB. Mike states that in the fields he was scouting CLB were below threshold in winter wheat and oats. Mike has also seen some frost injury in newly emerged corn and soybeans. See last week’s pest report issue for management information on CLB.

Janice Degni (South Central NY Dairy and Field Crops Program) reports alfalfa weevil tip feeding activity. She states that the injury is still below an economic threshold. At SUNY Cobleskill this week I saw 1st to 2nd instar alfalfa weevil larvae in fields. Fields on south facing slopes had more larvae than other fields. It is because these fields warm more quickly allowing weevils to develop rapidly. Tip feeding on south facing fields was 20% and all other fields were at less than 5%. For information on how to monitor alfalfa weevil see the article below.

Yellow nutsedge has been a problem at the SUNY Cobleskill farm. As you can see in the pictures they have a lot of nutsedge in this corn field.

Much of the corn in this field also had frost injury as seen in the following photo. This corn will recover even though it was hit with the frost. This is because the growing point of corn before the V6 stage is still below the soil surface. This protects the active growing point from frost.

Weather Outlook

NOAA Northeast Climate Center, Cornell

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This past week saw temperatures slightly cooler than average, with most areas ending up about two to five degrees below normal. There were also a couple of widespread frosts earlier in the week. Precipitation was scarce in the western part of the state. The rest of the state was pretty uniform, getting between one and three inches.

Base 50 growing degree days accumulated less than 50 statewide over the past 7 days, with areas in the Southern Tier and in the North Country seeing less than 25. For the season, this puts almost all areas in the 100-200 growing degree day range. The only exception to that is in the northern Adirondacks, where there have been fewer than 100.  Comparing these to last year, these values are within 75 growing degree days, with more this year in the and fewer this year in the north , with the dividing line running roughly along I-90. Compared to normal values, most areas are up to 75 growing degree days above normal, with slightly below normal values along Lake Ontario and in the North Country.

Looking into the next week, a series of high pressures will dominate the weather on most days, meaning little in the way of precipitation is expected. The best chances for any rain will be on Friday, when a weak cold front comes through, and towards the middle of next week. I think most areas will stay dry on Friday though. Temperatures will be hot today, with widespread 80s. After that front goes through, highs Friday, Saturday and Sunday should be in the mid 70s. Highs will generally be near 70 on Monday, with low 70s on Tuesday and Wednesday. Low temperatures will be pretty consistent, with most morning lows generally in the upper 40s in the north, ranging through the 50s for the rest of the state. For the next week, there does not appear to be a threat of any more frosts or freezes. The long range forecast looks like temperatures will return to below normal levels, with precipitation also staying below normal.

Insect Pests and Corn Crop Establishment in Conservation Tillage

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Overall, IPM and soil conservation are compatible priorities for field crop production.  Both depend upon our knowledge of the biological cycles of crops, pests, and soil microorganisms.  Both have the goal of protecting soil and water resources while still maintaining or improving farm economic returns.  However, there are circumstances in which a unique ecosystem created by soil residue or cover crops can give pests an extra foot-hold in spring.  A proactive approach can mitigate any potential negative pest impacts from increased soil cover in a conservation tillage field.

Two insect pests in particular can be a greater threat to our field crops in soil conservation systems, seedcorn maggot and black cutworm. 

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.

Adult flies of the seedcorn maggot lay eggs in areas of high organic matter on or near the soil surface.  The hatching maggots find their way to the nearby corn seed.  The decaying surface organic matter in a no-till or reduced till field can substantially increase the risk of high populations of seedcorn maggot.  Reduced tillage keeps soil temperatures lower early in the season.  Cool soil temperatures mean seedlings emerge more slowly, thus giving the maggots a longer time to feed.  Later planting can help minimize the seedcorn maggot risk, as can removal of debris from rows and closing of the seed slot.  Insecticidal seed treatments are effective in controlling seedcorn maggots under most circumstances.  For more information on the seedcorn maggot, visit Early Season Insect Pests of Corn.

Some solutions to both seedcorn maggot and black cutworm in corn stands in which soil conservation is a high priority include knowing the life cycles of insects that pose increased threats and increasing scouting efforts in at-risk fields, particularly during stand establishment and early emergence. 

How Do You Monitor Alfalfa Weevil?

Ken Wise
NYS IPM

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Alfalfa weevil can be a problem for established alfalfa fields prior to and shortly after first harvest.  To avoid unnecessary losses associated with injury from this insect pest begin monitoring fields in mid to late April when growing degree days have reached about 280 GDD (base 48F). The monitoring process is very straight forward. Look for signs of weevil feeding as holes in leaves and leaf buds and assessing the percentage of leaves affected. Here's how:

Pick 50 alfalfa stems at random throughout the field.

Look for the small "shot holes" in the leaves that indicate that larvae are feeding.

Record the percentage of alfalfa stems that show the "shot hole" feeding damage in the top 3 inches of the canopy.

Alfalfa Weevil Tip Larval Feeding

Before the first cutting, if 40% of the stem tips show feeding damage, you are at the "action threshold". The good thing is that alfalfa weevil can generally be controlled by harvesting. If you reach an action threshold within a week of your normal 1st cutting date, early harvesting will help avoid economic, yield, and forage quality losses. Alfalfa weevils only have one generation per year and are typically not a problem after first harvest. Occasionally, weevil can damage alfalfa re-growth after harvest. This damage may be more evident in the windrow areas, and can be more noticeable under cool or droughty weather conditions. If you find that 50 percent of the new growth is damaged, with many small larvae present, a chemical control may be warranted. For more information on alfalfa weevil checkout our online publication: IPM for Alfalfa Weevil

2009 Asian Soybean Rust Status

Gary Bergstrom
Cornell University

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2009 soybean rust detections to date have been on kudzu in the Southeastern U.S. Currently in the gulf coast region (Alabama, Mississippi and the panhandle of Florida), soybean rust disease incidence and severity on kudzu has been reported as low to medium. However, continued rain in this area will create ideal conditions for rust to continue to develop and may lead to the production of a significant inoculum source. Sentinel plots in the Southeastern U.S. have been planted and scouting efforts have begun. Please visit us again for future updates on soybean rust in the U.S. Updated May 14, 2009

NYS Soybean Rust Information Center

National Soybean Rust Website

Growing Degree Days for NYS

Ken Wise
NYS IPM

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Growing degree Days for Peak (50%) Occurrence of Alfalfa Weevil growth stage:

(Note: for alfalfa weevil predictions use Base Temp of 48F)

CURRENT Accumulated Growing degree days (48F Base):

March 1 -   May 20, 2009

*Indicates missing data

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
* Review EPA Worker Protection Standard training and posting compliance needs
* Maintain crop records by field, including variety, planting date, pesticides used, nutrient inputs including manure, etc.
* Watch for winter annual and other early season weeds, any patches of herbicide resistant weeds?
* Storage areas cleaned and ready to accept upcoming hay harvest?
* Enjoy Memorial Day Weekend!

Corn:
* Determine plant populations, make notes on germination problems
* 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 actions

Small Grains:
* Monitor winter grains for crop stage, insect (cereal leaf beetle, armyworm) and disease problems
* Check wheat for powdery mildew and soil borne wheat mosaic virus (susceptible varieties such as Harus and Jensen)
* Evaluate crop for adequate stand and plant vigor

Alfalfa & Hay:
* Monitor alfalfa seedings for weeds, insects & diseases.
* Check established alfalfa stands for alfalfa weevil, weed and disease problems.
* Storage areas cleaned and ready to accept upcoming harvest?

Soybeans:
* Check emerging stands for plant populations, early season pest problems

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
* Begin fly monitoring: install "3X5" index card fly speck monitoring cards through out barn
* Order fly management materials: fly tapes, insecticide baits, natural enemies (parasitoids)

Storage:
* Check storage areas (bunk silos, etc.) for readiness to accept first cutting
* Check forage allocation and anticipate feed program adjustments as forages are used up from previous year
* Plan where forages should be stored for optimum allocation for feeding
* Keep areas around storage bins and silos clean and mowed

Equipment:
* Note any repairs needed for recently used equipment: tractors, tillage implements, planters, etc. as they are cleaned and serviced.
* Service corn planter as needed. alfalfa harvesting equipment, and tillage implements
* Soybean planter and alfalfa harvesting equipment ready?
* 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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June 4, 2009 -- Small Grains Management Field Day, Musgrave Farm, 1256 Poplar Ridge Rd, Aurora, NY

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