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Weekly Field Crops Pest Report 2010

April 23, 2010         Volume 9 Number 1

1. View from the Field

2. What Lady Beetles are out there?

3. Alfalfa Weevils March Early!

4. National Asian Soybean Rust Report

5. Clipboard Checklist

6. Contact Information

View from the Field

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We are back for our 9th year of the NYS IPM Weekly Field Crops Pest Report. As with past years we provide you with weekly pest alerts and potential threats. Each week we will send the report electronically to the Cornell Field Crops list-server


Local, timely pest observations are a very important aspect of the weekly pest report. If you see particular field crop or livestock pest issues of interest or concern feel free to drop the editors an email or call. Our contact information appears at the end of each issue. Your observations help us alert the rest of the state to potential problems that may arise. We encourage our readers to use the material provided in the weekly report in their extension programming, newsletters, local newspapers and farm visits. 

Scouting Report 4.23.10
I monitor the Cornell U. alfalfa plots and corn/alfalfa fields at SUNY Cobleskill weekly. The alfalfa is 5 to 7 inches tall and looks good at this time. This week I did discover alfalfa weevil adults in alfalfa on south facing slopes.  At the Cornell Research Farm in Valatie I discovered one 1st instar alfalfa weevil larvae. Alfalfa weevil activity has begun in the central finger lakes region. For more information on alfalfa weevil see the article below.

Other insect pests found this week in alfalfa were clover root curculio, a very small blue weevil called the cloverstem weevil, pea aphids and tarnished plant bug. Alfalfa snout beetle emergence reportedly began last week in Lewis and Jefferson county. 

There are also several weed species growing between alfalfa plants at the Cornell Research Farm in Valatie. The following species were present white cockle, Shepherd's purse, dandelions, and mustards. Only the dandelions and Shepherd's purse were flowering. While scouting triticale last week at the Valatie farm I found plants with snow mold and Stagonospora nodorum Blotch.

What Lady Beetles are out there?

Ken Wise

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Many of you know that I like lady beetles and have done some research on them in the past. This summer I will be tracking lady beetle populations in alfalfa fields weekly. I am taking 200 sweeps/alfalfa field (no matter the size of the field) with a 15inch sweep net and recording the number of lady beetles by species. If you would like to join me in this endeavor and at least record what lady beetles you are seeing in the field just send me an email. You don't have to do the 200 sweeps per field as this takes some time. I have a 2 page ID guide I have put together if you would like one?

Multicolored Asian lady beetle

Remember we are looking for the 9-spotted ladybeetle. This is our state insect that seems to have become extinct in NY. Dr. John Losey from Cornell has developed the Lost Lady Bug Project. This project documents species of ladybeetles across the country.  This is also a good project to be involved with!

Alfalfa Weevils March Early!

Ken Wise

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Where do they come from?. Those light brown weevils found in alfalfa this time of year that are 3/16? long, have a band of darker brown down the center of their back with a long snout?

Adult Alfalfa Weevil

Alfalfa weevils overwinter as adults along the edge of alfalfa fields under grasses, leaf litter, logs and other residue. As the weather starts to warm in the spring, weevils move back into their favorite habitat, Alfalfa! They will feed on alfalfa leaflets and then lay eggs into new stem tissue in the plant. To find the eggs look for tiny pinholes in the stem where the female weevil has chewed a small hole and lays her eggs in the hollow stem cavity. The eggs are small and bright yellow, although they darken as they near maturity. Each female can lay up 25 eggs/stem and as many as 500 to 2000eggs per season.  The eggs generally hatch in one to two weeks.

Calculating alfalfa weevil activity. You can predict when those eggs will hatch and larval feeding damage would begin using information from an alfalfa weevil growing degree day model.

To make the calculation you'll need access to maximum and minimum temperature data from March 1 through the current day. Take the high and low temperature of each day and divide it by 2 and subtract 48 degrees F. This will give you the number of heat units for an individual day. If it is a negative number then there were no heat units that day for alfalfa weevil to develop.

(High Temperature + Low Temperature / 2) - 48 F = AW heat units.

Keep a running tally of the accumulated heat units from day to day. Compare the total GDDs and compare this number against the expected alfalfa weevil growth stage from the following table.

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

Stage or Event
Accumulated growing degree days (48F base temperature)
Eggs hatch
Instar 1
Instar 2
Instar 3
Instar 4
Adult Emergence
(Note: for alfalfa weevil predictions use Base Temp of 48F)

CURRENT Accumulated Growing degree days (48F Base)

March 1 -   April 19, 2010

Base 48 F
Base 50 F
*Indicates missing data
source: NEWA

Producers with alfalfa in areas close to the NYS IPM Program's Network for Environment and Weather Applications (NEWA) weather stations can access alfalfa weevil prediction information directly from our website. To access the information from the NEWA website go to, look under the "Pest Forecasts" section on the menu bar and drop down to "Alfalfa Weevil". Select you closest weather station and get a report.

Check next's week's pest report for more management information on alfalfa weevil.

National Asian Soybean Rust Report

Gary C. Bergstrom
Cornell University

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United States Soybean Rust Commentary (updated:04/06/10)
On February 12th, rust was reported on soybean in Mexico in the state of Tamaulipas in Gonzalez and Mante municipalities.

On February 10th, rust was reported on kudzu in Mobile county Alabama.

On January 19th, Georgia reported that rust can no longer be found in Miller and Lowndes counties, which were positive previously.

In 2010, soybean rust was reported on kudzu in one county in Alabama, two counties in Georgia, four counties in Louisiana, and one county in Florida in the US. Soybean rust has also been reported in Mexico on soybean in the state of Tamaulipas in Gonzalez and Mante municipalities. In Mexico soybean rust has also been reported on jicama in the state of Tamaulipas, Altamira municipality and in the state of Veracruz-Llave in Pauco and Papantla municipalities. In2010, soybean rust has been found in eight counties in US and five municipalities in Mexico.

In 2009, soybean rust was found in 16 states and over 576 counties in the United States, and in three states and nine municipalities in Mexico

NYS Soybean Rust Information Center

National Soybean Rust Website

Clipboard Checklist

Keith Waldron

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*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
*Maintain crop records by field, including variety, planting date, pesticides used, nutrient inputs including manure, etc.

*Watch for early season weeds: winter annuals, chickweed, henbit, field penny cress, shepherd's purse, giant ragweed, lambsquarters, Pennsylvania smartweed, common sunflower

*Store snow shovel, "summerize" sno-blower?

Alfalfa and Small Grains:
Monitor alfalfa for Alfalfa Snout Beetle (In Oswego, Jefferson, Cayuga, Wayne, Lewis, St. Lawrence, Clinton, Essex, and Franklin counties)
*Monitor alfalfa for alfalfa weevil as weather continues to warm
*Evaluate established legume stands for winter damage (thinning stand, frost heave), determine average alfalfa stand count, adjust crop plans if necessary
*Monitor winter grain fields for over wintering survival, virus disease symptoms, goose damage

Pre-plant weed evaluation

*Prepare land for corn if it is dry enough and begin planting the last week of April if it is dry (even if it is cold!)

Check and mend fences as needed.
*Check crop growth

*Review/Plan rotation system

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.
*Calibrate planting equipment - maintain records on crop planting rate per field
*Calibrate manure spreaders - maintain records on amount spread per field

*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

Ken Wise: Eastern NYS IPM Area Educator: Field Crops and Livestock
Phone: (518) 434-1690
Fax: (518) 426-3316