Autumn insecticide applications as a control measure against spring alfalfa weevil (Hypera postica) infestations

Alfalfa weevils, Hypera postica, are considered severe pests of alfalfa throughout the state of Kansas. They are univoltine and are only active during early spring and mid to late autumn. Several management tactics have been utilized against these destructive weevils but only the use of synthetic organic insecticides have provided acceptable protection for the first spring cutting of the alfalfa crop. A new tactic was implemented in the fall of 2011 by spraying insecticide as the adult weevils dispersed back into the alfalfa from their over-summering sites. Preliminary results of this first-ever autumn application are presented here.