American grapevine aphid
American vineaphids (Aphis illinoisensis) are only 2 to 2.5 mm in size, have a soft body, and are reddish-brownish to black in color. They ingest plant sap with their stylet-like proboscis. Grapevine aphids have two dorsal tubes (siphons) on their bodies. These serve to release a defensive secretion with wax cells when threatened, which smears the mouthparts of small attackers and thus protects the aphids.
The American vine aphid belongs to the tubular aphid family (Aphididae). The aphids overwinter as an egg on snowball(Viburnum prunifolium). In spring, they form colonies and reproduce over several generations by means of virgin reproduction (parthenogenesis), and then form a winged, sexually reproducing generation. This then flies onto the vine. In the fall, the winged females return to snowball and lay eggs for overwintering.
In viticulture, the American grapevine aphid is a significant pest in some areas. American grapevine aphids feed on the sap of the plant. When they occur in masses, significant damage to the host plant can result. By withdrawing plant sap from the leading tissue (phloem), the infested vine loses carbohydrates and nitrogen. In the long term, severely infested canes may show signs of emaciation and stunted growth. As a result, the grapes may drop off. The American grapevine aphid does not transmit viruses dangerous to grapevines.
Prevention and control
Control of American grapevine aphids is advisable only in cases of heavy infestation. They have a number of natural enemies. These include ladybugs, velvet mites, lacewing larvae, predatory bugs, predatory mites and spiders.
As a plant sap sucker, the American grapevine aphid can be controlled relatively easily with systemic plant protection products (see list of plant protection products approved in Austria) .
Last updated: 04.11.2021