Alfalfa insect management – and more! – March 6

There’s a formula in our K-State Research and Extension Alfalfa Weevil publication for calculating degree days as a predictor of alfalfa weevil development. It requires a record of the daily high temperature (anytime it exceeds 48 degrees) then adding it to the lowest temperature for the day (or 48 degrees…whichever is higher), dividing it by two then subtracting 48. Doing so will give an idea as to when the weevil hatch might begin so you can start scouting.

Or…you can keep two things in mind: alfalfa weevil development progresses at temperatures above 48 degrees Fahrenheit and the Kansas Mesonet alfalfa weevil growing degree day tool ( can do the calculation for you. In fact, that Mesonet growing degree calculator for alfalfa weevils already has us well ahead of typical development for this time of year, meaning it’s time to start planning for weevil management.

To assist alfalfa managers with that management for the coming season, K-State Research and Extension Field Crops Entomologist Dr. Jeff Whitworth will be our guest for a discussion focusing on alfalfa pest management on Wednesday, March 6, at the Woolsoncroft Event Center (1615 Branch St.) in Seneca. Drop by for coffee at 10:15 a.m. with the program beginning at 10:30 a.m. with a discussion of an area alfalfa weevil monitoring program. Dr. Whitworth will then talk multiple alfalfa pests (weevils, aphids, etc.…) with a brief overview of weevil development followed by product selection considerations and application best management practices. He’ll finish the morning with a question-and-answer session open to discussing surrounding insect pests of all field crop insect pests (corn, soybean, etc…) before we finish around noon with a light lunch.

RSVPs are requested to help with a meal count. You can do so via email to me at or by calling the Meadowlark Extension District Seneca Office at 785-336-2184. In case of inclement weather, please call the Seneca Office to determine the status of the meeting. Hope to see you there for any/all our morning’s topics!

Alfalfa Weevil Management – Be Ready

Alfalfa weevils develop based on growing degree days. That’s days above 48 degrees Fahrenheit with growing degrees accumulating faster with higher average daily temperatures above 48. According to the Kansas Mesonet alfalfa weevil growing degree day tool at (it calculates the growing degree day accumulations at the state’s Mesonet stations), most of Northeast Kansas is well ahead of normal. If our current weather pattern remains, it could be an early year for alfalfa weevil pressure.

While it’s not likely hatch and feeding has yet occurred, the southern areas of the Meadowlark Extension District will likely see it happen sooner than later. Scout alfalfa fields appropriately and have a management plan in place should treatment be necessary. One good resource is efficacy trials done by KSU entomologists comparing products. It can be found at:

If you can, consider attending our Alfalfa Insect Management discussion with KSU Entomologist Dr. Jeff Whitworth March 6 in Seneca. Drop me a line for more information.

David Hallauer54 Posts

David Hallauer is the Meadowlark Extension District agent in the areas of horticulture and crops and soils.


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