Cotton bollworms, also known as corn earworms, continue to be present at treatment levels in fields across AR, with some having crossed into the MO Bootheel. Bollworm numbers may not be reflected in traps, as population and pheromone levels are high enough to render them ineffective. In his latest update, Pest Patrol entomologist Dr. Gus Lorenz reports that most soybean and cotton fields across AR will need foliar insecticide applications, and that growers should prepare for the possibility that this bollworm flight lasts until first frost.

Late-planted soybeans are most vulnerable to bollworm infestations, while soybeans that bloom before the July-August moth flight tend to avoid moth egg lay. According to the University of Arkansas Cooperative Extension Service, smaller larvae stick to blooms and new leaves, but larger larvae will feed on any part of the plant.

When scouting, look for smaller nymphs that are off-white, and larger caterpillars that are yellow, green, brown or black in color, with markings on their backs. In cotton, check the entire plant for eggs and larvae, as well as signs of damage to fruiting forms. Eggs are cream colored and flat at the base. Mature larvae can reach 1.5” long and be light green to light brown on the upper body.

When bollworm pressure reaches the state-determined economic threshold, we suggest Besiege®, a broad-spectrum insecticide that provides fast knockdown and fights off destructive lepidopteran pests like corn earworm across a broad range of crops.

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