The fungal pathogen Botrytis cinerea causes severe rots on tomato fruit during storage and shelf life. Biological control of postharvest diseases of fruit may be an effective alternative to chemical control. Yeasts are particularly suitable for postharvest use, proving to be highly effective in reducing the incidence of fungal pathogens. Yeast fungi isolated from the surface of solanaceous plants were evaluated for their activity in reducing the postharvest decay of tomato caused by B. cinerea. Of 300 isolates, 14 strains of Rhodotorula rubra and Candida pelliculosa were found to be strongly antagonistic to the pathogen in vitro and were selected for further storage experiment. The antagonists were evaluated for their effect on the biological control of postharvest grey mould. Artificially wounded fruits were treated by means of a novel technique: small sterile discs of filter paper imbibed separately in suspensions of each yeast and the pathogen were superposed onto each wound. After 1-week, 11 isolates were significantly effective in reducing the diameter of lesions by more than 60% compared to the control treated with B. cinerea alone. Total protection was obtained with the strain 231 of R. rubra on fruits challenged with pathogen spores. To our knowledge, R. rubra and C. pelliculosa have not been described as biocontrol agents against grey mould caused by B. cinerea. Our data demonstrate that the application of antagonistic yeasts represents a promising and environmentally friendly alternative to fungicide treatments to control postharvest grey mould of tomato.

No abstract

No abstract

No abstract

Trichoderma harzianum is a potential biocontrol agent against Sclerotinia sclerotiorum in soybean. Information is needed on the compatibility of this biocontrol agent and the post-emergent herbicides used in soybean cropping.Haloxyfop R Methyl (EC 10.4%), Glyphosate (SL 48%), Imazamox (WG 70%) and Imazethapyr (SL 10%) were evaluated for their effects on the mycelial growth of T. harzianum on in vitro agar plates. Glyphosate (2000 ppm), Imazethapyr (500 and 250 ppm) and Haloxyfop R Methyl (1000, 500 and 100 ppm) reduced the mycelial growth of T. harzianum . Imazamox had no effect at any concentration.Subsequently, all the herbicides were assessed for their effect on soil populations of T. harzianum . Greenhouse assays conducted with non-sterile soil inoculated with T. harzianum and a specific herbicide were sampled before pesticide application and after 30 days. The number of colony forming units per gram of soil (c.f.u./g of soil) was evaluated with a soil dilution technique using Trichoderma selective medium (TSM). No detrimental effect was revealed.