Weekly Field Crops Pest Report 2010
April 23, 2010 Volume 9 Number 1
View from the Field
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
YOUR HELP IS NEEDED
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
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?
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!
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:
(Note: for alfalfa weevil predictions use Base Temp of 48F)
CURRENT Accumulated Growing degree days (48F Base)
March 1 - April 19, 2010
*Indicates missing data
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 http://newa.cornell.edu/, 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
United States Soybean Rust Commentary (updated:04/06/10)
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
*Walk fields to check tile flow, check and clear drainage outlets.
Look for line breaks.
*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:
*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!)
*Review/Plan rotation system
Keith Waldron: NYS Livestock and Field Crops IPM Coordinator
Ken Wise: Eastern NYS IPM Area Educator: Field Crops and Livestock