April 9, 2007
How Has the Recent Cold Weather Affected Alfalfa & Alfalfa Weevils?
by Jim Fawcett
Temperatures in the teens and low 20s will at least cause some tissue damage in established alfalfa fields, and could cause more serious damage to the buds and crowns. Tissue damage often causes the leaves to have a near white appearance. It will take a week or more to determine if the cold temperatures have caused any permanent damage to the alfalfa. If the re-growth is showing evidence of freeze damage, plants should be dug and crowns split to check for damage. Healthy taproots are creamy-white in color, with a firm texture. Freeze-injured taproots will begin to be watery, tan/brown in color and beginning to soften. See Steve Barnharts article on the agronomy website for more information: http://www.agronext.iastate.edu/showitem.php?id=39.
The good news is that the cold temperatures should have killed any early hatched alfalfa weevils. Eggs are more protected though, and probably survived. Most eggs have not yet hatched, so assuming they survived, the current cold weather will not likely have a large impact on the weevil population.
What about Black Cutworms?
There have been a few
captures of Black Cutworm moths in
FOR YOUR CALENDAR
Wednesday, June 20
Thursday, June 21 (9:00 a.m. 4:00 p.m. each day), Hay Expo 2007
Thursday, June 21,
If you have any questions, please feel free to contact the Iowa State University Extension Office.
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