EFFECT OF BIOFUMIGATION WITH BRASSICA CARINATA AND SOIL SOLARIZATION ON PHYTOPHTHORA SPP. AND STRAWBERRY YIELD

Abstract

Biofumigation and soil solarization are nonchemical alternative methods for soilborne pathogen control. Biofumigation is based on the action of volatile compounds, essentially isothiocyanates, produced by the hydrolysis of Cruciferae. The aim of this work was to evaluate the use of biofumigation with Brassica carinata and soil solarization for reducing populations of Phytophthora spp. in the soil and enhancing strawberry production. Field experiments were conducted in a strawberry farm located in Moguer (Huelva, SW Spain), for two consecutive growing seasons from October to May (2005-2006 and 2006-2007). Plots, never treated with methyl bromide, were naturally infested by Phytophthora spp. Treatments were soil solarization (S), biofumigation+solarization (B+S), and the untreated control (C). Biofumigation with B. carinata (10 kg.m -2 at 10-cm depth) was done in July and plots were solarized and drip-irrigated from July to September, using clear 50-μm low density polyethylene mulch. B+S increased plant growth (foliar surface), fruit weight, and strawberry yield the most each year. Plant growth differences were observed relative to S and C, with foliar surface (cm 2 ) of B+S/S/C of 502/414/351, and 435/346/228 in January 2006 and 2007, respectively. Furthermore, S increased plant growth and strawberry yield relative to C. Fruit weight (g/fruit) of B+S/S/C was 25/22/17 and 23/20/17 in 2006 and 2007, respectively. In addition, both treatments reduced Phytophthora soil population relative to C. The current work, supported by Project ANDALGHORT Common Initiative Interreg Espana-Portugal, contributes to the development and optimization of biofumigation with Brassica and soil solarization as alternatives to the traditional use of chemicals in strawberry production.