Asian Chestnut Gall Wasp

Also known as Chestnut Gall Wasp, Oriental Chestnut Gall Wasp

Asian chestnut gall wasps are tiny, glossy black insects that reproduce exclusively by thelytokous parthenogenesis, meaning populations consist entirely of females without need for males. In early summer, adult females deposit eggs inside developing chestnut buds, inducing spherical green-to-rose galls that disrupt twig growth and suppress flower production. Because larvae develop sheltered inside plant tissue, infestations severely weaken chestnut trees and can reduce commercial nut yields by up to eighty percent.