Use of a Chilean native strain 'Sherwood' of Trichoderma virens on the biocontrol of Botrytis cinerea in lettuces grown by a float system.

摘要

The biological control activity of Trichoderma virens [Gliocladium virens] strain Sherwood on Botrytis cinerea was estimated under a lettuce-growing hydroponic float system and compared with the commercial formulation of T. harzianum strain T39 (Trichodex), and the usual fungicide mixture, benomyl+captan. Therefore, butterhead lettuce seedlings, cv. Esmeralda, were grown on a floating system with the Wye nutrient solution under an environmental controlled greenhouse at Panguilemo Experimental Station, Universidad de Talca, Chile. Plants were artificially inoculated with 106 conidia/ml of B. cinerea. Previously, the plants were sprayed with 109 conidia/ml of Sherwood strain, Trichodex or benomyl+captan, according to the planned treatments. The incidence of grey rot in lettuce plants was evaluated at harvest time, 40 days after transplanting. In addition, quality parameters like plant height, weight and number of commercial plants were also evaluated. Lettuces treated with T. virens strain Sherwood showed a significant lower incidence (P<0.01) of grey rot disease and a significant higher percentage of commercial plants (P<0.05) than the control ones. The Sherwood strain, Trichodex and the fungicide mixture benomyl+captan showed a control activity on B. cinerea, but no significant differences were found among those treatments. Nevertheless, when lettuce was treated with the special mixture of fungicides and the Sherwood strain, a significant higher percentage (P<0.05) of commercial plants was observed when compared with other treatments..