Fox moth

Systematic position. The Fox moth (Macrothylacia rubi) is a member of the Lasiocampidae family within the order Lepidoptera. It is a robust, nocturnal moth whose larvae are significant defoliators, often overlooked until substantial damage to foliage has occurred in various woody plant species.

Host plants. The species is highly polyphagous, meaning it feeds on a wide array of plants. It frequently attacks fruit-bearing bushes like raspberries and blackberries, as well as deciduous trees, including oak, willow, birch, and various orchard trees. Its ability to adapt to diverse food sources makes it a versatile and potentially destructive pest.

Biology and life cycle. The Fox moth typically completes one generation per year. Adults emerge in early summer, and after mating, females deposit eggs on host plants. Larvae feed on leaves throughout the season. A unique aspect of their life cycle is their overwintering strategy; they hibernate as mature larvae in leaf litter or soil, resuming activity in the following spring to pupate within a cocoon.

Nature of damage and pest status. The damage is characterized by extensive chewing of leaf margins and entire leaf blades. In cases of high larval density, the plants suffer from severe defoliation. This loss of photosynthetic surface weakens the plant, reduces its vigor, and negatively impacts the fruit yield, making it particularly problematic for commercial berry and fruit growers.

Control measures. Integrated Pest Management (IPM) is recommended for controlling Macrothylacia.

• Manual removal of egg clusters or young larvae in small orchards.
• Encouraging natural predators such as birds and parasitic wasps.
• Application of targeted biological insecticides like Bacillus thuringiensis.
• Chemical control with authorized pesticides if economic thresholds are exceeded.

Effective management requires consistent monitoring of the plants from late spring to autumn. By identifying the early stages of infestation, growers can apply localized treatments, significantly reducing the need for broad-spectrum chemicals and ensuring the long-term health and productivity of the cultivated trees and shrubs.