Fate and activity of fungal biocontrol agents (BCAs) on strawberry
B. Jensen, B. Andersen, U. Thrane, D.F. Jensen, K.F. Nielsen and J. Larsen.
Journal of Plant Pathology Volume 90 (2, Supplement) August 2008, Book of Abstract, 9th International Congress of Plant Pathology, August 24-29, 2008 Torino, Italy,. 507 pages.
2008
บทคัดย่อ
Fungal BCAs against grey mould are being used at flowering in strawberries. The objective of an ongoing project is to study the fate and activity of selected BCAs from application until harvest and consumption. The activity of BCAs based on Trichoderma harzianum and Clonostachys rosea against the grey mould pathogen, Botrytis cinerea, was examined on flowers using strains with reporter genes encoding either GFP or DsRed fluorescence.Approximately 70% of both C. rosea and B. cinerea conidia germinated on flower tissue while only 20% of T. harzianum conidia germinated within 24 hours at 20°C. Dual inoculation of the fungi showed that C. rosea significantly reduced both B. cinerea and T. harzianum germination on flowers. In addition, C. rosea significantly reduced grey mould symptoms. The fate of BCAs after application to the flowering plants, approximately 104 CFU/flower, was studied in field trials. Quantification of the BCAs on berries developed from inoculated flowers showed that less than 160 CFU/berry of either T. harzianum or C. rosea were recovered one month later. High density (worst case) inoculation of berries with T. harzianum and C. rosea showed no increase in CFU density on the berries after four day incubation at 20°C. Sub-samples of these berries will be analysed for presence of microbial metabolites. Data on fate and activity of BCAs on strawberries both pre-harvest and post-harvest will aid risk assessment of BCAs by pointing out the kind of assessment studies needed to ensure safe use of BCAs.