Incurvum lappet moth

Systematic position: The Incurvum lappet moth (Malacosoma incurvum) belongs to the order Lepidoptera and the family Lasiocampidae. It is closely related to other tent caterpillars, sharing similar morphological traits and reproductive strategies characteristic of this insect family.

Host plants: This pest primarily infests deciduous trees and shrubs. Common host plants include willow, poplar, oak, and various fruit trees such as apple and plum species. Their feeding behavior often leads to significant defoliation of these plants during late spring and early summer.

Biology and life cycle: The lifecycle consists of four stages: egg, larva (caterpillar), pupa, and adult moth. Eggs are deposited in characteristic ring-like masses around small twigs during the summer. Larvae emerge in the following spring, live colonially, and construct silken "tents" or nests. They feed together until reaching the final instar, after which they pupate inside tough, silken cocoons.

Damage and economic impact: The primary damage is caused by the caterpillars' voracious feeding on foliage. Younger larvae skeletonize leaves, while mature caterpillars consume the entire leaf surface, leaving only the veins. Severe outbreaks cause extensive defoliation, which severely stresses the trees, inhibits growth, reduces fruit production, and leaves the trees vulnerable to secondary pests and environmental stressors.

Control measures: Integrated pest management (IPM) is crucial for controlling this species. Effective strategies include:

• Pruning and destroying twigs containing egg masses during the winter dormancy period.
• Physical removal and destruction of silken nests containing larvae during the spring.
• Application of biological insecticides containing Bacillus thuringiensis when larvae are in early growth stages.
• Use of contact or systemic insecticides if monitoring indicates that the population threshold has been exceeded.