Soil Disinfection in Spanish Strawberry Nurseries - Three Years without Methyl Bromide

This work shows the effect of different chemical soil treatments used in strawberry nurseries on weed control and runner plant production, during the last three years after MB was banned, and raises the problems of the present fumigants. Fumigant treatments such as 1,3-dichloropropene: chloropicrin (DD: Pic), methyl isothiocyanate (MITC) generators such as metam-sodium (metham, MS) and dazomet and other products like methyl iodide (MI) and dimethyl disulfide (DMDS), were tested under different formulations, application systems and sealing conditions, using the 'Camarosa' cultivar. Two commercial nurseries situated in Castilla-Leon (north central Spain) were used and in each one an experimental design was composed of randomized blocks with four replications of nine fumigant treatments (plus non-fumigated control plots). Weed control and runner plant production estimations are shown for each treatment over the three crop seasons. Despite some inconsistency in the results, some of the chemical alternatives showed a good behaviour on weed control, like MS and the mixture DD: Pic. Runner plant production with MS and dazomet was non-significantly lower than with the other herbicide treatments. The current situation of soil fumigants is difficult; only dazomet (Basamid (R)) is authorized for a 10-year period, while the products that are mostly used, dichloropropene, chloropicrin and metam-sodium, are not included in the Annex 1 of the 91/414 CEE Directive and their future viability is complex. The rest of the tested and interesting chemical products, IM and DMDS among others, are not yet registered in Spain.