Tetraneura nigriabdominalis

Oriental grass root aphid

Description

This species of aphid comes from Asia and has spread in Europe and North America. On the top side of the leaf are formed follicle-like galls up to 2 cm in size. They are at first green or yellow-green, later on reddish or rose-red. The galls are stalked, elongate, pubescent (hairy), not shiny, and often with a pointed apex. Inside the galls, a spacious cavity is formed where the development of fundatrices and the 2^nd generation larvae takes place. Several galls are usually found on a single leaf. In the place of gall occurrence, the leaf is deformed and changes color from pale green to yellow. It attacks numerous species of elm (Ulmus ssp.) and often heavily infests them. It occurs on many places along with other representatives of this genus. It can be confused very easily with similar T. ulmi (which is widely distributed in Europe on Ulmus spp.) and which has shiny, hairless galls. Many times both species occurs on the same leaf. Further research is needed on the area of taxonomy and symptomatology of the genus Tetraneura.

Symptom

On the upper side of the leaf there are pocket galls up to 2 cm in size. They narrow at the point of contact with the leaf. The galls are hairy and dull.

Tree Species: Elm

Part of a plant- attacked: Leaf / Needle

Pest significance: Very harmful

Pest Category: Insects

Invasive Species: Yes

Present in EU: Yes