Dryocosmus are a genus of gall wasp

Gall wasp

Gall wasps , also called Gallflies, are a family of the order Hymenoptera and are classified with the Apocrita suborder of wasps in the superfamily Cynipoidea...

s. They are cyclically parthenogenetic insects that induce gall

Gall

Galls or cecidia are outgrowths on the surface of lifeforms caused by invasion by other lifeforms, such as parasites or bacterial infection. Plant galls are abnormal outgrowths of plant tissues and can be caused by various parasites, from fungi and bacteria, to insects and mites...

s on plants in the family Fagaceae

Fagaceae

The family Fagaceae, or beech family, comprises about 900 species of both evergreen and deciduous trees and shrubs, which are characterized by alternate simple leaves with pinnate venation, unisexual flowers in the form of catkins, and fruit in the form of cup-like nuts. Fagaceous leaves are often...

.

According to recent studies, the genus includes some species previously considered as belonging to the genus Chilaspis, whereas Dryocosmus favus should be excluded of the genus. Dryocosmus and Chilaspis are closely related to the other oak gall wasp taxa (Aphelonyx, Plagiotrochus, Pseudoneuroterus, Trichagalma, and some Neuroterus

Neuroterus

Neuroterus is a genus of gall wasps. Some species produce galls that fall off the host plant and jump along the ground due to the movement of the larvae within.Species include:*Neuroterus albipes*Neuroterus anthracinus*Neuroterus aprilinus...

species)
Dryocosmus kuriphilus is an invasive species

Invasive species

"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....

 in Europe and North America (originating from Asia) that endangers the chestnut

Chestnut

Chestnut , some species called chinkapin or chinquapin, is a genus of eight or nine species of deciduous trees and shrubs in the beech family Fagaceae, native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce.-Species:The chestnut belongs to the...

trees.