Green slug moth

Systematic position. The green slug moth (Parasa chloris) is a member of the Limacodidae family within the order Lepidoptera. It is widely recognized for the peculiar appearance of its larvae, which resemble slugs rather than traditional caterpillars due to their fleshy, limbless, and flattened bodies.

Host plants. This species acts as a generalist feeder (polyphage) on various deciduous trees and shrubs. Common hosts include fruit trees such as apple, pear, and cherry, as well as landscape trees like oak, maple, and linden. It can be particularly problematic in nurseries where foliage health is critical for plant development.

Biology and life cycle. The adult moth features a distinctive green color on its wings. Females typically deposit eggs on the undersides of leaves. The larvae are the most recognizable stage, often displaying bright, warning-like colors and specialized stinging spines. These spines cause painful skin irritation upon contact. The insect typically spends the winter in a hardened, spherical cocoon located in soil or on tree bark.

Damage and economic significance. Early-stage larvae skeletonize the leaf tissue, leaving only the veins intact. As they mature, they consume the entire leaf blade, leading to heavy defoliation. Significant damage can cause reduced tree vigor, diminished fruit yield, and can potentially stunt the growth of young trees if an outbreak occurs during the peak growing season.

Protection and control measures. Effective management of the green slug moth involves several integrated strategies:

• Manual removal of caterpillars if the infestation is localized on small trees.
• Application of microbial insecticides, such as products containing Bacillus thuringiensis.
• Use of broad-spectrum or selective chemical insecticides during peak larval activity, following label instructions.
• Promoting the presence of natural predators, including parasitic wasps and predatory bugs.
• Maintaining soil health and clearing leaf litter to disrupt the overwintering stages of the pest.