Oklahoma State University Stillwater, OK
Oklahoma Alfalfa Oklahoma Cooperative Extension Service Oklahoma Agricultural Experiment Station

The Oklahoma Alfalfa Weevil Model What It Is and How to Use It
If you can estimate the height of your alfalfa and count numbers of larvae in a 30-stem sample, then you have all you need for the Oklahoma Alfalfa Weevil Model to go to work for you. This model, which is located on the World Wide Web (http://www.mesonet.ou.edu/premium/agmodels.html?alfalfaweevil), is a tool which can help growers determine the need and proper timing for insecticide applications to avoid serious weevil damage.  The model, which was developed a number of years ago by Oklahoma State University entomologists and other researchers, requires degree-day totals (base 48 0 F) since January 1, the current height of your alfalfa, and the number of larvae in a 30-stem sample. The degree-day information is obtained from the Oklahoma Mesonet, the state's automated weather station network of 114 stations, while the alfalfa height and larvae counts are provided by the grower or scout. The user should read the Model Description section on the Web page to understand the proper scouting procedures. Once the scouting information is at hand, the grower can obtain the model's recommendation through use of the Interactive Spraying Recommendation Form. Simply click on the Mesonet site closest to your location, fill in the larvae numbers and alfalfa height, and click on "Submit".  The Web page features various sections, including current and seasonal model output, a colorized map of degree-day totals since January 1, and links to various alfalfa insect fact sheets as well as our Mesonet agricultural weather product home page (radar.metr.ou.edu/agwx/agwx.html), which growers are encouraged to review for other useful information.
J.D. Carlson, Agricultural Meteorologist Biosystems & Agricultural Engineering

 

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