Insect Management Handbook

Donus zoilus

Pest description and crop damage This is the largest weevil found in legume fields. Fully developed larvae are about 0.5 inch in length, green to yellow, and have a brown head and a white or pink line down the center of the back. Larvae feed on buds and leaves. Larvae rarely need chemical control in alfalfa.

Epicauta spp
Meloe spp.

Includes

Beet armyworm (Spodoptera exigua)
Bertha armyworm (Mamestra configurata)
Western yellowstriped armyworm (Spodoptera praefica)

Includes

Alfalfa aphid (Macrosiphum creelii)
Blue alfalfa aphid (Acyrthosiphon kondoi)
Pea aphid (Acyrthosiphon pisum)
Spotted alfalfa aphid (Therioaphis maculata)

Hypera postica

Pest description and crop damage Larvae are about 0.375 inch in length, yellow to green, with a white stripe down the back. They feed in and on the buds and leaves of alfalfa. For additional information on their biology and management, see: https://extension.usu.edu/crops/research/alfalfa-weevil .

Sampling and thresholds

Autographa californica and Trichoplusia ni

Colias eurytheme - also known as Orange Sulphur
Colias philodice - also known as Clouded Sulphur

Lygus lineolaris

Coleophora deauratella

Nymphalis antiopa