Limanska N. Crown gall of grape (diagnostics and spread on the South Ukraine).

In this work we investigated the crown gall disease spread on the Ukrainian vineyards, and optimized a PCR based method for diagnostics of crown gall. The crown gall of grape is spread on the South part of the Ukraine. Our investigations conducted during 2002 - 2005 years revealed that in some vineyards up to 40 % of some scion and rootstock cultivars were infected with pathogenic Agrobacterium vitis and A. tumefaciens. The percentage of diseased grapevines depended on cultivar susceptibility and the origin of planting material. For the first time in the Ukraine the pathogenic agrobacteria were detected in wooden shoots, roots, galls, bleeding sap and soil by PCR based technique that was optimized in our research. We revealed that both regular planting material and clones including imported planting material were infected with crown gall agent. Vineyards with high number of infected grapevines (40 %) reveal high number of soil samples contaminated with pathogenic A. vitis and A. tumefaciens (47,1 %). In one investigated vineyard (south black soils also known as south chernozem) eradication of the crown galled plants resulted in pathogen elimination within 6 months. However in other vineyards crown gall agent could be detected at least after 2 years upon infected plants eradication. In different seasons the numbers of soil samples containing tumorigenic agrobacteria in the investigated vineyard were not the same. Our results suggest the expediency of soil sampling for tumorigenic agrobacteria detection during several seasons to study the spread of the pathogens in the investigated plot.