Soil Disinfestation Efficacy against Soil Fungal Pathogens in Strawberry Crops in Spain: An Overview

(1) Background: Strawberry cultivation is highly dependent on soil disinfestation for proper development. Since the definitive methyl bromide phase-out, other chemicals have been used as alternatives. This research provides an overview on the efficacies of soil disinfestation methods on controlling soil fungal diseases of strawberry. (2) Methods: The efficacy of several soil disinfestation methods on soil fungal pathogens (SFP: Fusarium spp. and Macrophominaphaseolina) was analyzed in experimental field trials during eleven growing seasons. (3) Results: Average efficiencies in reducing soil pathogen inocula for soil disinfestation techniques are given. Soil disinfestations with chloropicrin, allyl isothiocyanate, dazomet, 1,3-dichloropropene:chloropicrin, methyl iodide:chloropicrin, and dimethyl disulfide reduced Fusarium spp. and M. phaseolina soil inocula by more than 90 %. Combination of solarization with organic manures (biosolarization) reduced Fusarium spp. soil populations by 80 % and M. phaseolina by 79 %. Reductions in plant mortality and increases in fruit yields over the untreated controls did not differ between chemically fumigated and biosolarized plots. (4) Conclusions: Soil fungal pathogens are effectively controlled by chemical fumigation of soils in intensive strawberry crops in Spain. In the case of mixed infestations of SFP with nematodes, the most efficient treatment in suppressing soil-borne diseases was soil fumigation with 1,3-dichloropropene:chloropicrin, but other alternative chemicals, such as allyl isothiocyanate, dazomet, and dimethyl disulfide, provided high efficacies in reducing the SFP inocula. Soil biosolarization is proposed as an effective alternative to chemical soil fumigation for strawberry cultivation in Southern Spain when SFP inocula is not remarkably high.