Nebraska Extension Crop Reports - Late April

Nebraska Extension Crop Reports - Late April

Michael Rethwisch, Extension Educator for Butler and Polk Counties: This week I sampled alfalfa for alfalfa weevil larvae in several counties. Most larvae were very small, indicating that the hatch was very recent, and more weevil larvae should be expected.

Many sites still had over-wintering adult weevils present, with some still mating, thus egg laying is not over.  The cool weather is expected to result in an extended larval emergence pattern. Aphids were not prevalent at this time.

None of these sites had reached the threshold for an insecticide treatment (five alfalfa weevils/sweep); however, populations are likely building and these locations should be scouted again in four to five days.

Table 1. Number of alfalfa weevils per sweep at several locations in central Nebraska April 24.
Location Number/
Sweep
Location Number/
Sweep
Kearney #1 0.7 Worms 2.2
Kearney #2 1.8 Clarks 1.8
Gibbon-Shelton 1.1 Osceola 0.9
Wood River-Alda 0.2 Osceola-Shelby 0.5
Chapman 1.3 Rising City 0.7