Weekly Field Crops Pest Report 2012

View from the Field

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Alfalfa weevil 1st larvae were found at the Cornell Research Farm in Valatie this week (4/25). First instar larvae hatch from eggs at 280 degree-days (base temp. 48F). The 280 degree-days are based on peak occurrence. This is about 50% of a population of weevil in a field. Newly hatched larvae are about 1/16 inches long and yellow to light green in color. The 1st instar larvae feed on the inside of the stem for a few days before exiting and moving to the fresh buds and leaflets on the ends of the stems. As the larvae develop they will feed on alfalfa leaflets.

While most of the clover looked very good at the Valatie farm this week there were sporadic dead plants throughout the field. I sent a few photos to Dr. Gary Bergstrom. He speculates that it might be crown rot. The plants at the farm were under high drought stress until this last weekend. The added stress might have weakened plants making them at higher risk for infection by crown and root rot pathogens.

Photo of clover with crown or root rot

Joe Lawrence reports that alfalfa snout beetles (ABS) have started to march in Lewis county. ASB adults are mottled gray, humpbacked, 1/2 inch long, do not fly, and are all females. Adults emerge in the spring to feed on new shoots from the alfalfa crown. Spring ASB emergence occurs about the time the shadbush (Amelanchier sp., aka Juneberry, Serviceberry) blooms. When adults emerge in the spring they migrate in mass numbers often in a northeast or northwest direction. 

Dr. Gary Bergstrom reports winter wheat growth stage is about 2 to 3 weeks ahead of schedule in many areas. Flowering may be around the 3rd week of May. It is important to know wheat growth stage and weather forecast at flowering time. If rain is predicted during flowering you have a higher risk of wheat infection by fusarium head blight (aka scab). There will be more on management of fusarium head blight in coming issues.

There are several reports of frosted crops across the state. Jeff Miller (Oneida County) has supplied up with a photo of a typical early morning view of frost on winter wheat.

I have also seen symptoms of alfalfa and clover tips that had been frosted and slightly damaged.

Weather Outlook

April 26, 2012
Jessica Rennells, Northeast Region Climate Center, Cornell University

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New York has seen an extremely mild winter, record heat in March, and overall dry conditions. Last week there were below normal temperatures for most of western NY and the Great Lakes Region. Central and eastern NY were up to 6 degrees above normal. We saw most of the month's precipitation in the last week. Most of NY had 1 to 2 inches, eastern areas and part of the Great Lakes region saw up to 3 inches of precipitation, as both rain and snow. Base 50 growing degree-days were less than 25 for most of the state.

Today's highs will be in the mid 50's to low 60's with rain showers later in the day as a frontal system moves in. Overnight temperatures will be in the 30's with chances for rain and some snow showers, though no accumulations are expected.

Friday will be gusty with temperatures in the mid 40's to low 50's with a slight chance for some sprinkles. Overnight temperatures will drop into the upper 20's and low 30's with widespread frost/freeze likely.

Much below normal temps for Sat – Mon.

Saturday's temperatures will be in the mid 40's to low 50's with partly sunny conditions. Lows will again be cold in the mid 20's to low 30's.

Sunday will be mostly sunny with highs in the upper 40's to mid 50's. Lows will be in the upper 20's to low 30's with clear skies, a hard freeze is likely.

Monday's highs will be in the mid 50's with mostly sunny conditions. Overnight temperatures will be in the 30's.

Tuesday will warm up with sunshine and temperatures in the low to mid 60's. Overnight temperatures will be in the low to mid 30's.

Wednesday will have temperatures in the upper 50's to mid 60's and a chance for scattered showers. Overnight temperatures will continue to warm and will be in the low to mid 40's.

The five-day precipitation amounts will range from a tenth of an inch to half an inch. The 8-14 day out look is showing below normal precipitation for central and eastern NY and a high probability for above normal temperatures.

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)

Soybean aphids in 2012?

Keith Waldron
NYS IPM

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Soybean aphid (SBA) problems have been relatively isolated across NY since the aphids were first detected here in 200-2001. Since their arrival, soybean aphids have tended to be a more problematic in odd numbered years. Based on this historical trend, 2011 had potential to be one of those years of risk for SBA issues, yet not much happened. In fact, SBA's were very hard to find in many areas of the state last season. Recall that soybean aphids overwinter on buckthorn, then migrate to soybeans in early summer, where their populations increase before they fly back to buckthorn for the winter. Many entomologists theorize that last years prolonged wet, cool spring may have reduced the numbers of aphids flying from their overwintering sites to soybean fields. Low initial populations delayed buildup of SBA populations over the season.

So what about 2012?
Historically, SBA populations have not been serious issues in even numbered years. This is likely to again be the case in 2012. Last season there were areas in central New York where SBA populations in late summer / early fall increased just prior to their movement to buckthorn, their overwintering host. Depending on the amount of egg laying and subsequent overwintering survival, these areas may be at risk this year for early season SBA activity. Statewide, however, we expect SBA issues to be minimal this season following the alternate year – (even year low risk) trend. However….. As a precaution it is always advised to watch soybean fields closely for this insect.  Soybeans should also be monitored for weed escapes, diseases and other arthropods such as spider mites. In years past, the first SBA's of the season have been found as early as V2 stage soybeans. Typically SBA populations do not build up until later growth stages. 

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.
 
We'll have more updates on soybean aphid as the season continues.

National Soybean Rust Outlook for 2012

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The relatively mild winter has provided more conducive conditions for overwintering of soybean rust.

As of early April, positive detections of rust on kudzu could be found in Florida, Alabama, Louisiana, Texas, and northeastern Mexico. Observations at historical locations (locations positive for soybean rust in previous years) are occurring much earlier than previously observed. For example, rust was found in Gadsen County, Florida on March 23rd, which is more than a month earlier than the previous earliest seasonal observation of April 24th. The soybean rust sites in northeastern Mexico have been observed on volunteer legumes, kudzu, and commercial fields earlier in the spring. At this point last season, soybean rust was only observed in extreme southern Florida and in northeastern Mexico. Compared to a similarly mild winter in 2007, soybean rust was found on kudzu in Florida, Georgia, and extreme southern Texas but had not spread to Louisiana or Alabama at this point in the season. Soybeans are still being planted in many areas, so it is far too early in the season for significant risk to commercial soybeans. However, the amount of overwintering could be a long term concern if cool, wet weather persists in the spring and early summer in soybean growing areas.

Black Cutworm Moth Captures and Potential

Ken Wise, NYS IPM

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There are more reports of record captures of black cutworm in areas southwest of New York. Both Indiana and Illinois are reporting very intense captures of black cutworm moths. By contrast, Pennsylvania has not reported any significant flights of black cutworm. They state they have not gotten storms out of the mid-Atlantic states yet.

It is suggested that the nightly freezing temperatures have little effect on the moths. The moths generally find protected areas to survive the night. We potentially could have gotten a flight of cutworm moths this last weekend with the storm we received. They look for weedy fields to lay their eggs. Note that insecticide seed treatments and Bt corn for cutworm can give protection to moderate populations of cutworm. If the population is severe a field can suffer loses.For more information on black cutworm please refer to our brochure: Black cutworm in field corn Management Guide.

Got Flies? Are Field Meetings in Eastern NYS for Dairy and Livestock IPM for You?

Ken Wise, NYS IPM

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You already knew that nuisance flies cause undue harm to dairy cattle and other livestock and can cause off-the-farm local concerns. Did you know Cornell University's Veterinary Entomology program has developed a highly effective integrated program to help producers minimize fly problems, protect animal health and net profitability? Did you know Cornell University has the only Veterinary Entomology program in the northeast?

Integrated Pest Management (IPM) for livestock pests becomes more important every year. The summer season can expose fly management issues on individual farms yet provides educational opportunities to avoid problems too. Have you seen more flies on farms even after insecticide use? This could likely indicate presence of insecticide resistance, an increasingly common problem on New York livestock farms. Add to this, fewer insecticides are currently on the market that are registered for livestock use. These issues and others have increased concerns over options available for fly control. What is one to do? An integrated approach is the only effective means to keep fly populations at manageable levels.
 
Over the last decade, Dr. Don Rutz and the Cornell Veterinary Entomology program has conducted a great deal of research developing new information to better manage livestock flies in and around confinement facilities and for animals on pasture. Some important areas of their research include:

• Insecticide resistance with house flies
• Biological control of house and stable flies
• Evaluation of physical control methods such as giant sticky traps in barns and several types of fly traps on pastures
• Ecology and importance of dung beetles in manure pats
• Management of cattle lice and mange mites

I would like to collaborate with local CCE personnel in Eastern NY to share the latest fly management information with producers by offering barn and pasture fly IPM workshops this summer. Ideally, these grower and large animal veterinarian oriented farm meetings would provide an overview of fly management issues and include a walk-a-bout to illustrate fly management "opportunities".

Sound interesting? If so, or if you would like more information please let us know by replying to this email. We are taking first come first serve requests.
 
For more information on livestock IPM see the Cornell Veterinary Entomology website.

I look forward to hearing from you.

Growing Degree Days

Ken Wise, NYS IPM

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CURRENT Accumulated Growing degree days (48F Base):

March 1 - May 2, 2011

*Indicates missing data

source: NEWA's Degree Day data page

Alfalfa Weevil Prediction Model
A website at NEWA can predict alfalfa weevil development in your area. Just select a weather station near you and it will give you the AW degree days.

Clipboard Checklist

Keith Waldron
NYS IPM

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General
*Walk fields to check tile flow, check and clear drainage outlets. Look for line breaks
*Note and record location of wet areas on field maps or aerial photo for future tiling considerations and crop decisions, check for areas of soil erosion
*Maintain crop records by field, including variety, planting date, pesticides used, nutrient inputs including manure, etc.
*Minimize field to field movement of soil and crop debris on equipment, particularly from field with known pest problems such as white mold and Phytophthora.
*Watch for early season weeds: winter annuals, chickweed, henbit, field penny cress, shepherd's purse, giant and common ragweed, purple deadnettle, lambsquarters, redroot pigweed, velvet leaf, Pennsylvania smartweed, common sunflower, quackgrass, foxtail

Alfalfa:
*Evaluate established legume stands for winter damage (thinning stand, frost heave), determine average alfalfa stand count adjust crop plans if necessary
*Monitor alfalfa for alfalfa weevil
*Monitor new seedings for Pythium blight and Phytopthora Rot Rot.
*Monitor alfalfa for Alfalfa Snout Beetle (In Oswego, Jefferson, Cayuga, Wayne, Lewis, St. Lawrence, Clinton, Essex, and Franklin counties)

Small Grains:
*Monitor winter grain fields for over wintering survival, weed issues, check growth stage, number of tillers
*Check stands for soilborne virus diseases, Wheat spindle streak mosaic and Soilborne wheat mosaic and powdery mildew symptoms, cereal leaf beetle, weed escapes, goose damage

Corn:
*Prepare land and plant corn as soon as conditions allow
*Pre-plant weed evaluation, timing cultivation and/or pre-plant weed management

Pastures:
*Check and mend fences as needed.
*Check crop growth
*Invasive species, plants harmful to livestock
*Review/Plan rotation system

Equipment:
*Remove / clean soil and crop debris from equipment
*Arrange for custom weed control or check your own application or cultivator equipment for repairs.
*Check nozzles, pumps, etc., recalibrate pesticide application equipment before use.
*Carry appropriate / necessary NYS DEC and EPA required documents: (pesticide applicators license, pesticide labels, MSDS sheets, etc.) with application equipment
*Calibrate planting equipment - maintain records on crop planting rate per field
*Calibrate manure spreaders - maintain records on amount spread per field

Storage:
* Check stored grain bins for temperature, moisture and signs of mold and insects. Aerate, core, transfer grain or treat as necessary
*Check forage allocation and anticipate feed program adjustments as forages from previous year are used up
*Plan where forages should be stored for optimum allocation next feeding season

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