The spread of Xanthomonas campestris pv. viticola (Xcv), causal agent of grapevine bacterial canker, occurs among other ways, through infected plants and grapevine cuttings. It was studied how to obtain propagation material free of Xcv testing the effectiveness of treatments of cuttings using thermotherapy, bactericides and sanitizers. The Xcv isolates were tested for pathogenicity and in vitro sensitivity to bactericides and sanitizers at different concentrations. The eradication of Xcv on cuttings was tested in experiments with thermotherapy (50ºC for 30 and 40 min; 53ºC for 5 and 10 min); bactericides [oxytetracycline+copper sulphate (150+2000, 165+2200, 180+2400 and 195+2600 mg L-1 of H2O) and oxytetracycline (600, 700, 800 and 900 mg L-1)] and sanitizers [dodecyldimethyl ammonium chloride (600, 1200, 1800, 2400 and 3000 µl L-1) sodium hypochlorite (5000, 10000, 20000, 30000 and 40000 µl L-1) and benzalkonium chloride (125, 167, 250, 334 and 500 µl L-1)]. We evaluated the incubation period, the incidence and severity of disease. The bactericidal oxytetracycline and sanitizers dodecyldimethyl ammonium chloride and sodium hypochlorite provided the largest zones of inhibition, in vitro. However, despite the several treatments tested we cannot recommend an efficient condition of temperature/time, and concentrations of bactericides and sanitizers capable of eradicating Xcv from infected grapevine cuttings, thus confirming their great importance for the spread of grapevine bacterial canker.
Vitis sp.; thermotherapy; bactericide; sanitizing; eradication
