Agroecological characterization of Xiphinema index in Spain1

Abstract

The agroecological characteristics of Xiphinema index were determined by studying its spatial and temporal distribution in different environmental conditions in Spain. The host range, life cycle in the Mediterranean continental climate and its relationships with grapevine fanleaf nepovirus are also reported. X. index is widespread in grape-growing areas in a wide range of soil textures and pH, even at high percentage of carbonates. However, it seems to prefer sandy-loam and sandy-clay loam soils, and populations decrease when soil carbonates increase. Its spatial distribution is random but it has a tendency to be found in the deepest clay horizons, where soil moisture is retained. Availability of moisture seems to be the limiting factor for nematode development. Grapevine and fig are the main host plants but X. index is also associated with fruit trees, ornamental crops, vegetable crops, woodlands and other uncultivated soils. Its life cycle in central Spain, where temperature ranges from <0°C until March to above 40°C from May—June until September, takes 6–8 weeks to complete. X. index was found in 14% of all vineyards sampled and in 50% of the fanleaf virus-infected vineyards. Transmission tests using bait plants were successful and the detection of the virus by means of ELISA test in a mimimun of five nematodes was achieved. Fanleaf-like symptoms often occurred in the absence of the virus, as demonstrated by ELISA.