Although the early April freezing temperatures that dropped below 20 °F probably had little effect on black cutworm eggs (see last week's article), reports from the field suggest that alfalfa weevil larvae may have been hit hard by the cold temperatures. Kyle Jensen (Lewis), Mark Carlton (Albia), and Virgil Schmitt (Muscatine), all extension field crops specialists, stated in an April 23 teleconference that no live alfalfa weevil larvae have been found in fields that they inspected. Most plants were brown and dead from the freeze, so any larvae that had hatched would be in the terminals and exposed to the cold.
Iowa State University
Rice, Marlin E., "Alfalfa weevil and the hard freeze" (2007). Integrated Crop Management News. 1089.
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