Japanese alder sawfly

The Japanese alder sawfly (Eriocampa mitsukurii) is an insect species belonging to the order Hymenoptera and the family Tenthredinidae. This specific pest is known for its selective feeding habits, primarily targeting alder trees (Alnus spp.), and is predominantly found in East Asian ecosystems.

The host range is largely limited to various species of the genus Alnus. Given their preference for these trees, they can become a significant nuisance in nurseries and wild forested areas, leading to extensive defoliation if left unmanaged during their peak development seasons.

The life cycle consists of complete metamorphosis. Female sawflies deposit eggs into the leaf tissue. Upon hatching, the larvae begin to feed voraciously on the foliage. After undergoing several larval instars, they migrate to the soil to pupate in the leaf litter, where they remain until the next life cycle iteration begins.

Symptoms of infestation include severe skeletonization of leaves, where only the vascular tissue remains. The direct impact of this damage is the reduction of the tree's photosynthetic capacity. Continued defoliation over several seasons can cause severe stress, leading to stunted growth and increased susceptibility to secondary infections.

Effective protection strategies require an integrated pest management (IPM) approach. Regular monitoring is essential to detect early larval activity. In cases of high infestation, applying approved insecticides or biological control agents, such as specific viral strains or bacteria that target sawfly larvae, can significantly suppress population levels.