Screening to antagonistic fungi for Botrytis cinerea biocontrol in Chilean forest nurseries

Abstract

Botrytis cinerea is one of the most important pathogens in Chilean forest nurseries. The disease control has been based on the use of fungicides; nevertheless, under certain conditions of disease pressure this practice has not been effective, besides its environmental problems due to its excessive use. The objective of this study was to select antagonistic fungi to B. cinerea, by means in vitro and nurseries assays, to determine its capacity as biocontrol agents of the «grey mould» disease in forest nurseries. The antagonistic potentials were obtained from the plants phyloplane, collected from forest nurseries. Seventy one fungi strains were evaluated in their capacity to reduce in vitro the pathogen colonization and sporulation by bioassays in Eucalyptus leaf discs. Selected strains were assayed under greenhouse conditions. Pinus radiata and E. globulus plants were sprayed with the pathogen (1x105 conidias/ml) and later treated with the antagonists (1x 107 conidias/ml), evaluating the disease incidence and severity. In the in vitro assays, four strains of Trichoderma, three of Clonostachys, four of Penicillium, one of Cladosporium and other eight unidentified fungi strains did not significantly reduce pathogen colonization and sporulation. In the greenhouses assays, the strain Clonostachys (A-10) was able to reduce, in both P. radiata and E. globules, the disease incidence and severity. These results allow concluding that antagonists selected have the potential to B. cinerea control in forest nurseries.