The National Sunflower Association says cutworms were reported in the southwestern area of North Dakota feeding on canola. Now is a good time to scout field crops for cutworm feeding injury before economic feeding injury occurs. Crops are most susceptible during the early crop stages – seedling to 6-leaf stage.
Cutworm feeding can be noted by defoliation, or cut and wilted plants, leading to bare patches in the field. Few plants can be lost to cutworm feeding if the plant population is below the recommended established stand. The greater the plant population, the more damage can be tolerated without economic yield loss. When spraying insecticides for cutworm control, applications should be made in the evening when cutworms feed actively. Wet soil conditions will also improve insecticide efficacy, as cutworms feed near the soil surface. Rescue foliar treatments are warranted for sunflower when cutworms exceed the treatment threshold of 1 per square foot or 25-30% of plants cut. Insecticides are ideally targeted at the young larvae (less than ¾ inch) which are easier to kill than the large larvae (greater than 1 inch).
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