U.S. agricultural experts expect the past several years of mild winters to increase the populations of many insect species, including alfalfa weevils.
The Purdue University scientists said many growers can expect the weevil to be a nuisance again this year.
"Now is the time for growers to get out and scout their fields for the alfalfa weevil in the larval stage," said Christian Krupke, a Purdue field crops pest management specialist. "With early feedings, the tips of the alfalfa leaves will have a repeating pattern on them from being chewed on before the shoot opened up."
When taking samples from a field, Krupke said it is best to walk in an M-shaped pattern and gather five stems from each touchpoint, totaling 25 stems. Each stem should be examined for evidence of feeding by the alfalfa weevil, maturity of the stem and stem length.
Most damage from the alfalfa weevil is done during the larval stage. A heavy infestation of larvae can consume enough foliage that an entire field may take on a grayish appearance.
The alfalfa weevil larva is a small, light green worm with a black head and three light stripes on its body.
Copyright 2007 by United Press International