Following the storm event, the week closed with below normal temperatures in place. Low temperatures dipped into the upper 20s to low 30s both Saturday and Sunday mornings. This prompted the first Freeze Warnings and Frost Advisories of the spring season to be issued by the National Weather Service. These headlines are issued when vegetation becomes susceptible to subfreezing temperatures and we’ve hit that point this year with some strawberries and fruit trees becoming vulnerable.
While there is some protection measures we can take for fruit crops, winter wheat and alfalfa is another story. Luckily, by most accounts, the extreme cold earlier in the week didn’t affect these crops. Connor Raymond, UK Grains Extension Associate, and Dr. Carrie Knott, UK Extension Grains Specialist, wrote an article on the subject titled, “Early Spring Freeze Effect on Kentucky’s What Crop”. As they mentioned, most of Kentucky wheat is currently in the Feekes 6-7 growth stage (jointing). Outside of a handful of counties in North Central KY and the Bluegrass, most of the major wheat producing counties across the state didn’t drop down to the 24-degree temperature threshold that is typically associated with injury at that stage.
Similarly, alfalfa should be alright too. Based on the following extension publication, AGR-236 Managing Frost Damaged Alfalfa Stands, injury is more likely when temperatures are below 26 degrees AND 300 growing degree days (base 50) have accumulated. We are running well behind that threshold this year. In fact, much of the state has yet to reach 200 GDD Base 50. Lexington Bluegrass AP currently sits at 140, Bowling Green Warren County AP at 188, and Paducah Barkley RGNL AP at 170.
While the threshold for FREEZE damage to alfalfa may not have been reached, many are now surpassing the 190 Degree Day threshold to start scouting for alfalfa weevil. Below is a look at the current map as of April 5, 2021, which can be accessed using the UK Ag Weather Center’s Insect Degree Day Maps. Dr. Ric Bessin, UK Extension Entomology Specialist, talked about the scouting process and insecticide applications in a recent article in Kentucky Pest News, here. The latest Kentucky Crop Progress and Condition Report, released this past Monday, mentions that the pest has been observed. Time to scout!