Comparison of different chemical and non-chemical alternatives to Methyl Bromide for strawberry in Huelva (Spain)

Spain's Methyl Bromide (MB) Alternatives Project has been developing/demonstrating alternative fumigants for methyl bromide on strawberry in Huelva since 1997. Here, we describe our research carried out between 2008 and 2010. In all the trials 'Camarosa' was grown under high plastic tunnels between October and the end of May every year. Field trials with the same complete randomized block design and 10-12 treatments were performed annually in two locations of Huelva ("Occifresa"-Moguer and " Cumbres Malvinas"-Palos de la Frontera.). In 2007/08 and 2008/09 the following ten treatments were applied: untreated control; MB+ chloropicrin (50 : 50 w/w); sodium azide; dazomet + 1,3D(dichloropropene); 1,3D + chloropicrin (61 : 35 w/w); chloropicrin alone; DMDS(dimethyl disulphide) + chloropicrin; methyl iodide + chloropicrin (50 : 50 w/w); acrolein; and furfural. In 2009/10, non-chemical treatments (biosolarization) were included; in comparison with previous year, four additional treatments were applied: biosolarization with fresh poultry manure (25,000 kg/ha), biosolarization with Brassica pellets (2,000 kg/ha), sodium tethathiocarbamate and metam sodium shank-applied with Rotary Spader implement. Black root rot complex (Fusarium spp., Cylindrocarpon spp., Rhizoctonia spp., and Pythium spp.) and nematodes Meloidogyne hapla and Pratylenchus penetrans were the main phytosanitary problems related to the soil, and Macrophomina phaseolina was detected occasionally in the first two seasons. However, plant survival, fruit size and yields were optimal in both locations. In 2009/10 at "Occifresa"-Moguer a higher percentage of dead plants was evidenced, and at an earlier stage than the previous growing seasons, mainly caused by Macrophomina phaseolina and Fusarium oxysporum. DMDS+ chloropicrin, 1,3D + chloropicrin and chloropicrin alone were as effective as MB: chloropicrin. Biosolarization with fresh chicken manure (25,000 kg/ha) showed higher production than the untreated control.