Plant Pathology Common Pests Forest tent caterpillar | Forest tent caterpillar |
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Class: Insecta The forest tent caterpillar (Malacosoma disstria) is the larva of a North American moth. It has been recognized as an important defoliator of a wide variety of deciduous hardwood trees throughout its range for many years. This forest tent caterpillars spin silken mats on the trunks and large branches where they congregate to molt or rest from feeding. Forest tent caterpillars are just over 2 inches (5 cm) in length, black or dark brown or gray with blue and faint yellow longitudinal stripes. Each abdominal segment bears a white spot. The caterpillars have long setae, giving them a furry look. The adult moth that emerges after pupation is yellow or tan with a thick, short, furry body. The wingspan is about 1.5 inches (3 cm). Control: Larvacides applied in early spring can be effective, but once the caterpillars emerge little can be done. They can be removed from trees by hand and killed by dropping them into a bucket of soapy water. (The soap reduces the water's surface tension. Caterpillars placed in non-soapy water can literally crawl across the surface to escape). Dusk is a good time to attack caterpillars as they are gregarious and form dense groups on tree trunks and structures at the end of the day. |
