Oak eggar

The oak eggar (Latin Lasiocampa quercus) is a member of the moth family Lasiocampidae. Known for its distinctive appearance in both adult and larval stages, it is categorized as a significant pest of various deciduous trees and shrubbery in both forestry and horticulture.

The larvae are polyphagous, meaning they feed on a wide range of host plants. Their primary targets include oak, birch, willow, and alder trees. However, they are also frequently encountered in orchards, where they cause damage to apple, pear, and plum trees, significantly impacting tree health if populations remain unchecked.

The life cycle of the oak eggar typically spans one year. Adults are active in mid-summer, after which eggs are deposited on the host plant. The species overwinters as a young larva, usually hiding in leaf litter or deep crevices of the bark to survive cold temperatures. As spring arrives, they resume feeding, grow rapidly, and eventually spin cocoons to pupate.

The damage caused by these caterpillars is primarily defoliation. Young larvae start by skeletonizing leaves, while older caterpillars are capable of consuming entire leaves, leaving only the midribs. Severe infestations result in significant loss of foliage, which weakens the host plant, stunts growth, and makes trees more susceptible to secondary diseases and environmental stress.

Effective control measures require a combination of monitoring and intervention. It is crucial to inspect trees for egg batches and early-stage larvae during the spring. When populations exceed the economic threshold, targeted insecticide applications are recommended during the early larval development phase. Furthermore, promoting natural predators like parasitic wasps and birds can help regulate population numbers naturally in a garden environment.