Small eggar

The Small eggar (Eriogaster lanestris) is a moth belonging to the family Lasiocampidae. It is a well-known pest in European orchards and forests, recognizable by its grey-brown wings with a distinct white central spot.

The larvae, or caterpillars, reach about 50 mm in length. They are heavily covered in long, dense hairs that serve as a protection mechanism. Contact with these hairs can cause skin irritation, so caution is required during physical handling.

The pupal stage occurs inside a dense, tough, brownish cocoon. The species is known for its ability to enter prolonged diapause, where the pupae can remain dormant in the soil for several years, making population management difficult.

The moth typically has one generation per year. Adult emergence occurs in early spring, often as soon as temperatures rise, allowing the species to adapt to cool, northern climates.

Females lay eggs in clusters on branches, covering them with hair from their own bodies for protection against cold weather and predators during the overwintering period.

The Small eggar primarily feeds on deciduous trees and shrubs, showing a strong preference for the Rosaceae family. Fruit trees such as apples, pears, plums, and cherries are most commonly affected.

In addition to orchard crops, the larvae are known to consume foliage of birches, lindens, and hawthorns. This polyphagous nature allows the pest to thrive in various environments, including hedgerows bordering agricultural land.

Young larvae initially feed in social groups, skeletonizing leaves, which significantly impacts the tree's photosynthetic capability. As they grow, they consume entire leaves, leaving only veins and petioles behind.

Severe infestations can lead to total defoliation of fruit trees. This damage drastically reduces the tree's health, impacting fruit yield for the current year and hindering bud development for the following season.

Weakened trees become susceptible to secondary stressors, including bark beetles, various fungal diseases, and winter kill, which can permanently damage or kill the host plant.

The most obvious sign of an infestation is the presence of silk-based "nests" or tents created by young caterpillars on the branches. These serve as shelters and feeding hubs.

Visual spotting of caterpillar groups is common during the spring months. The leaves on the tree will show significant bite marks, looking thin, tattered, or completely consumed, leading to "bare" branches.

Frass (caterpillar droppings) can often be found on the leaves below the nests or scattered on the ground around the base of the tree during peak feeding activity.

During the dormant season, one may find old, empty cocoons attached to twigs, which indicates that the population has been active in the area in previous seasons.

An unexpected browning or thinning of the tree crown in late spring, despite adequate watering, is another indicator of significant larval activity occurring higher in the tree canopy.

Mechanical control is highly effective for smaller infestations. Pruning and destroying branches containing the silk nests before the caterpillars disperse can significantly reduce the population.

Cultural practices include deep tilling of the soil around the base of the trees in late autumn. This practice can destroy cocoons that are overwintering in the soil or ground litter.

Biological control using Bacillus thuringiensis (Bt) products is recommended for early larval stages. These treatments target the caterpillars while sparing beneficial insect species in the garden.

Chemical insecticides should be reserved for severe outbreaks. Always ensure that the chosen product is labeled for fruit crops and adhere strictly to safety intervals regarding harvest times.

Maintaining orchard health through proper pruning, sanitation, and weed management reduces the attractiveness of the site to female moths looking for suitable egg-laying spots.