Elm zigzag sawfly

The elm zigzag sawfly (Aproceros leucopoda) is an invasive insect species belonging to the order Hymenoptera and the family Argidae. Originally native to East Asia, it has become a significant pest in Europe, where it causes substantial defoliation of various elm species (Ulmus genus).

The primary host plants are elm trees. The larvae are specialized leaf-eaters, consuming the foliage of elms throughout their larval development. This feeding behavior poses a significant risk to the health and structural integrity of elm trees in both urban landscaping and forest ecosystems.

The biological cycle of the elm zigzag sawfly is marked by high reproductive potential. The species is characterized by parthenogenesis, meaning females can produce offspring without mating. This allows the population to multiply rapidly, with the insect completing multiple generations within a single growing season under suitable climatic conditions.

Damage caused by this pest is distinct and easily identifiable. Young larvae create a zigzag pattern while feeding on the leaf lamina. As they grow, they proceed to skeletonize the leaves completely, leaving only the primary veins. Severe infestations often lead to premature defoliation, which severely weakens the tree and hampers its overall development.

Management and control strategies against the elm zigzag sawfly include several important practices:

• Continuous monitoring of elm populations to detect the presence of the zigzag feeding patterns early.
• Application of selective systemic insecticides during the peak activity period of the young larvae.
• Use of biological control agents, including entomopathogenic fungi and naturally occurring parasitoids.
• Implementation of cultural practices such as removing leaf litter to reduce the overwintering population of the pest.