Management of grapevine fanleaf virus vectors

Abstract

Grapevine Fanleaf Virus (GFLV) is the main virus disease on grapevine. Yield and vigour decrease quickly due to viral diseases which considerably reduces the lifespan of a vineyard plot. Such situations can be avoided by applying some precautions in the period between uprooting and replanting, based on the latest research findings.

As fanleaf disease is due to viruses transmitted by nematodes, surviving vector nematode populations should be eliminated before replanting a plot. A fallow period of 5 to 7 years is often recommended, but is economically difficult to apply. Using systemic herbicides to kill the old vines before uprooting is a first step in reducing food resources for the remaining nematodes. We have developed a nematode sampling system to quantify vector nematode populations. The results show that nematode populations are highly variable, and allow modulation of the fallow period in relation to the recontamination risk.

Research is now focusing on plants that reduce nematode populations faster than by simply leaving the soil bare during the fallow period. After initial screening under greenhouse conditions, a national French project was started recently to assess, under field conditions (various soil and climatic conditions), the effect of different selected plants on the nematode populations. Equally, the rate of GFLV recontamination of the plots after replanting is being assessed over a long period of time.

Other improvements for managing plant-parasitic nematodes could be integrated, such as using resistant rootstock.