Soil fumigation with chloropicrin in Italy: experimental results on melon, eggplant and tomato

Starting in 1999, seven experimental trials were carried out in Italy in order to evaluate the efficacy of chloropicrin (CP) (Tripicrin, a.i. 99% by wt) as alternative to methyl bromide for soil disinfestation. CP applied by shank injection at 30-40 g/m2 provided a satisfactory and consistent control of Fusarium wilt on melon and Verticillium wilt on eggplant, particularly in sandy soils. On melon against Fusarium wilt and on tomato against F. radicis lycopersici and Fusarium and Verticillium wilts CP at 40 or 60 g/m2 applied by drip irrigation at the concentration of 400 to 700 microliters/l or 850 microliters/l provided the best results. CP applied at 80 g/m2 with 60 mm of water (corresponding to 850 microliters/l) did not increase the efficacy of the soil fumigation treatment and, on tomato, was phytotoxic, causing sudden collapse of plants immediately after the transplant. The comparison of chloropicrin drip application under polyethylene, widely used in the past for methyl bromide soil fumigation, or under virtually gas impermeable film (VIF), to reduce atmosphere emissions, showed an increase of CP efficacy under VIF only reducing the dosages below 40 or 30 g/m2.