Eggar moth

The genus Eriogaster belongs to the family Lasiocampidae (the Eggar moths) within the order Lepidoptera. These moths are recognized as significant pests of various deciduous trees and shrubs. The most well-known species include the small eggar (Eriogaster lanestris) and the small lappet (Eriogaster rimicola), which are capable of causing localized outbreaks in orchards and forest plantations.

This pest primarily attacks fruit-bearing crops such as apple, pear, plum, and cherry trees. Additionally, it causes damage to forest species like birch, linden, willow, and hawthorn. The larvae are voracious feeders, leading to severe defoliation during peak infestation years. This foliage loss weakens the host plants, rendering them susceptible to secondary pests and various pathogens.

The biology of these insects follows a univoltine life cycle. Adult moths typically emerge in late summer or autumn. Females lay eggs on branches, covering them with specialized abdominal hairs that provide insulation against winter temperatures. The eggs overwinter, and in the spring, the newly hatched larvae congregate in communal silk tents. These nests serve as a base for nocturnal feeding activities.

The damage is characterized by initial skeletonization of leaves, followed by complete defoliation as the larvae grow. Heavy infestations can lead to significant biomass reduction, growth retardation, and loss of fruit yield. Due to the presence of urticating hairs on the larvae, natural predation by birds is often limited, allowing the population to grow rapidly under favorable weather conditions.

Control measures combine physical and chemical approaches. Essential practices include:

• Manual removal and destruction of silk tents in early spring.
• Application of bio-insecticides based on Bacillus thuringiensis against young larvae.
• Usage of contact insecticides if thresholds are exceeded.
• Winter sanitation through pruning and removal of infested branches.