The Ecology, Economics, and Management of Agrilus Beetles

Purpose of Review

The invasion of North America by the Asian beetle Agrilus planipennis has caused severe economic and ecological damage to ash (Fraxinus) tree populations. Agrilus planipennis has recently entered eastern Europe and is spreading there. Many other Agrilus species can potentially become invasive pests due to the cryptic nature of their immature stages that can be inconspicuously transported within infested plant material. We review the ecology, economic impacts, and management strategies of Agrilus worldwide and highlight research gaps.

Recent Findings

Much has been learned in recent decades about the basic biology and control tactics for a few Agrilus species, especially A. planipennis.

Summary

The genus Agrilus has over 3,341 described species, making it the largest genus in the Animal Kingdom. Most Agrilus are univoltine and have a narrow host range. Chemical, tactile, and visual cues of host plants are used by adult Agrilus to select suitable hosts for consumption by adults and larvae. Most Agrilus larvae develop within the cambial region, constructing galleries that effectively girdle the host plant. Mechanisms of host plant resistance are being explored. Diverse groups of natural enemies attack all life stages of Agrilus species, with some coevolved specialist parasitoids being introduced successfully to suppress A. planipennis in North America. Climate change, leading to warmer and drier conditions, will influence the distribution and population dynamics of many Agrilus species. Many research gaps still exist in the areas of biocontrol, host plant resistance, and sustainable management strategies for this important group of plant pests.