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 evaluate 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 on lettuce. Such treatments greatly decreased survival of artificially introduced pathogen inoculum in the soil, with Fusarium oxysporum f. sp. basilici being the most difficult pathogen to control. Gas impermeable films permitted increased retention of MB, thus resulting in higher C x T (concentration x time) product values and reduced emissions into the atmosphere, as indirectly shown by measurements carried out by using a portable Fumiscope gas detector. (C) 1999 Elsevier Science Ltd. All rights reserved.