Xanthomonas campestris pv. viticola on grapevine cutting tools and water: survival and disinfection.

Abstract

Bacterial canker (Xanthomonas campestris pv. viticola) (Xcv) is the most important disease of grapevine in northeast of Brazil. The survival of Xcv2Rif was evaluated from 0 to 42 h following the dipping of the harvest shears in a pathogen suspension. An in vitro test of Xcv sensitivity to sanitizing agents and initial tests on shears were performed with dodecyl dimethyl ammonium chloride (1,140 ppm), benzalkonium chloride (245 ppm), sodium dichloroisocyanurate (16.2 ppm), sodium hypochlorite (20,000 ppm), calcium hypochlorite (130 ppm), calcium oxychloride (97,500 ppm) and chlorine dioxide (41 ppm). The ability of dodecyl dimethyl ammonium chloride (1,140 ppm) and sodium hypochlorite (20,000 ppm) to disinfect shears was tested with 50 sequential cuts on vine leaves. The maintenance of the efficacy of the sanitizing agents was tested between 0 and 8 h following solution preparation. The ability of five sanitizing agents to disinfect Xcv-contaminated water was also tested. Xcv survived for 24 h on harvest shears. Sodium hypochlorite and dodecyl dimethyl ammonium chloride presented the largest growth inhibition zones to four Xcv isolates and were 100% effective in disinfecting contaminated harvest shears. These two sanitizing agents maintained their efficacy for 8 h. Xcv was spread by contaminated harvest shears until the 24th cut, in average. Water disinfection was successfully achieved with dodecyl dimethyl ammonium chloride (570 ppm), sodium hypochlorite (5,000 ppm) and benzalkonium chloride (122.5 ppm).