EVALUATIONS OF INSECTICIDE PERFORMANCE FOR CONTROL OF ALFALFA WEEVIL LARVAE, 2001

With the advent of alfalfa weevil control quickly upon us, I thought it might be appropriate to share results of last year’s insecticide efficacy trial. Populations in our trials this year just reached threshold levels this week and our tests have been sprayed. I have heard from several locations around the state and the same is true in many other locations. In addition, populations are not extremely high, which our egg sampling indicated would be the case. Growers should at least scout fields now to make treatment decisions soon. Fall-planted alfalfa may not experience significant numbers of weevils in the first year of growth; however, aphids (in particular spotted or cowpea aphids) could be a problem. So far, aphid populations have been sporadic across the state with lighter populations of spotted alfalfa aphids in moderate to high rainfall areas. Some parts of southwestern Oklahoma have experienced high (treatable) levels of these insects already. Favorable growing conditions and adequate rainfall will help keep aphid populations in check and favor alfalfa growth.