–by Jeff Whitworth — Field Crops
The only alfalfa weevils observed this week were relatively mature larvae (see fig. 1) and thus most feeding damage should be about finished. All alfalfa fields monitored had been treated, with one exception. This year’s overall alfalfa weevil infestations seemed considerably reduced compared to most of the past years. This, coupled with good growing conditions, allowed plants to keep up with alfalfa weevil feeding resulting in less defoliation then usual as seen in fig. 2 (The plant on the left was typical of an untreated field which was adjacent to a treated field from which the plant on the right was removed from).
Figure 1 Alfalfa weevil larvae (picture by Cody Wyckoff)
Figure 2 Alfalfa defoliation Left: untreated field Right treated field (Cody Wyckoff)