–by Dr. Jeff Whitworth
Cattail caterpillars are a perennial cause of concern throughout south central and north central Kansas. They are usually found on cattails, thus the name. However, every year some sorghum fields are infested. These infestations are usually most intense around field borders, and most especially in sorghum fields near water, i.e., a creek or pond, etc. The adult is a tan or dusky white, heavy bodied moth, which looks somewhat like a southwestern corn borer moth. The females usually start depositing eggs just about at the whorl stage of sorghum. However, the cattail caterpillar is rarely found within the whorl like “ragworms”, i.e., corn earworms/fall armyworms/etc. are. The cattail caterpillar is mostly found on the leaves themselves but may add to the “ragging” up of the leaves after they unfurl from the whorl (fig. 1) due to their voracious leaf feeding. The cattail caterpillar is a relatively hairy but very distinctive larva with bright orange/white/and black body markings (figures 2 and 3). A relatively high percentage of the older, larger, more mature larvae have been found to be parasitized, thus stop feeding, become very sluggish, and eventually just die from these natural enemies of these caterpillars. There is no established treatment threshold.
Figure 1 “Ragging” up of the leaves (Tom Maxwell)
Figure 2 Cattail Caterpillar (Tom Maxwell)
Figure 3 Cattail Caterpillar feeding on the edge of the leaf (Tom Maxwell)