–by Dr. Raymond Cloyd
We are receiving inquiries regarding the large milkweed bug, Oncopeltus fasciatus, nymphs and adults feeding on the seed pods of milkweed (Asclepias spp) plants (Figure 1).
Figure 1. Large Milkweed Bug Adults And Nymphs Feeding On Milkwee Seed Pod (Raymond Cloyd, KSU)
Large milkweed bug adults are 9/16 to 5/8 inches (10 to 18 mm) in length, with black and orange markings on the body (Figure 2).
Figure 2. Large Milkweed Bug Adult (Raymond Cloyd, KSU)
There are five nymphal instars before becoming adults. Females lay eggs on milkweed seed pods or in crevices between the seed pods. Females can lay up to 30 eggs per day and approximately 2,000 over her lifetime, which is about one month in the summer. The adults contain toxic compounds that are obtained from the plant fluids during feeding, which protects them from predators. Large milkweed bugs cause minimal damage to milkweed plants and are present for a short period. Large milkweed bugs overwinter as adults. There may be one to several generations per year in Kansas