The alfalfa weevil is the most important insect pest of alfalfa in Colorado. The use of resistant varieties and timing of cutting can help manage moderate weevil problems. Beneficial insects and diseases can combine with good crop management practices to minimize the need for chemical controls. Insecticide treatments should be used only when justified by the presence of economically significant numbers of alfalfa weevils. Alfalfa weevil insecticide treatments can be very hazardous to honey bees in Colorado.A number of insect pests attack alfalfa in Colorado. One of the most important is the alfalfa weevil Hypera postica, which has been a problem in most alfalfaproducing areas of the state since the early 1900s. Losses from this insect vary from year to year, but in some seasons they can be large enough to justify the application of an insecticide.

Address: Campus Delivery 4040, Fort Collins, Colorado 80523-4040
Telephone: (970) 491-6281
Website: http://www.ext.colostate.edu/pubs/insect/05500.html