Reduced dosages of methyl bromide applied under gas-impermeable plastic films for controlling soilborne pathogens of vegetable crops

Four experimental trials were carried out at Albenga (Northern Italy) to ev aluate the effectiveness of reduced dosages of methyl bromide (MB) applied under gas-impermeable films in controlling soilborne pathogens of vegetable crops. Forty and thirty g/m(2) of MB applied under different types of gas- impermeable films controlled Rhizoctonia solani on bean, lettuce and basil, Fusarium oxysporum f. sp. basilici on basil and Sclerotinia sclerotiorum o n lettuce. Such treatments greatly decreased survival of artificially intro duced pathogen inoculum in the soil, with Fusarium oxysporum f. sp. basilic i being the most difficult pathogen to control. Gas impermeable films permi tted increased retention of MB, thus resulting in higher C x T (concentrati on x time) product values and reduced emissions into the atmosphere, as ind irectly shown by measurements carried out by using a portable Fumiscope gas detector. (C) 1999 Elsevier Science Ltd. All rights reserved.