Alternative strawberry production using solarization, metham sodium and beneficial soil microbes as plant protection methods

High-impact chemical biocides are no longer used in crop production systems due to environmental concerns and sustainable agricultural practices must involve the use of environmentally friendlier alternatives for controlling pests and diseases. We compared the effect of two disinfestation treatments, solarization and metham sodium, combined with the arbuscular mycorrhizal fungus Glomus intraradices, the saprophytic fungus Trichoderma aureoviride and the plant growth-promoting rhizobacteria Bacillus subtilis, in strawberry crop production. Also, the effects of high temperatures achieved during the solarization process on the viability of mycorrhizal inocula were evaluated under controlled conditions in a laboratory study. Moist inocula of the arbuscular mycorrhizal fungus G. intraradices were maintained for three hours for five consecutive days at 35, 40, 45, 50 and 55 °C, respectively. Our results show that soil solarization and metham-sodium disinfestation improved strawberry yield by 24% and 18%, respectively, compared with the fruit yield obtained in untreated soil, whereas application of T. aureoviride and B. subtilis did not affect plant production in the absence of a pathological agent. Solarization and metham-sodium application did not eliminate the natural populations of arbuscular mycorrhizal fungi and at the end of the experiment all plants, independently of the treatments, were mycorrhizal. After the heating treatments, under controlled conditions, the inoculum of G. intraradices submitted to 50 °C completely lost its mycorrhizal potential.