Entomology and Plant Pathology, Oklahoma State University
127 Noble Research Center, Stillwater, OK74078
Vol. 11, No. 21
Apr 20, 2012
Start Looking For Variegated Cutworms in Canola, PRONTO!
Tom A. Royer, Extension Entomologist
During the Oklahoma canola field days last week, at every stop I heard Heath Sanders say “we learn something new about canola every year”. This year is no exception on the insect front. After receiving phone calls from several people about caterpillars infesting canola, I traveled with Heath Sanders of Producers Cooperative Oil Mill and Josh Bushong, OSU Canola Extension Specialist to look at some canola fields in Kingfisher County around the Okarche area. What we found in two of the five fields we checked was unsettling; seed pods being consumed by variegated cutworm caterpillars. Similar reports are coming out of SW Oklahoma as well.
The variegated cutworm is a common cutworm pest of alfalfa and vegetable crops. It winters as a pupa in the soil, but can be active year-around in warmer climates. The caterpillar can be recognized by the 4 to 7 diamond shaped white/yellow spots on the top center of their back (Fig 1). The larva grows through 7 instars in 4-6 weeks. Variegated cutworm populations go through 3 to 4 generations per year in Oklahoma. Unlike most cutworms, the variegated cutworm is a “climbing cutworm” and is much less subterranean than its relatives.
Fig 1. Variegated cutworm. (Photo courtesy of Frank Peairs, Colorado State University and Bugwood, www.bugwood.org)