Clonostachys rosea: effect of additives on its efficiency in inhibiting Botrytis cinerea sporulation on Eucalyptus globulus leaf discsABSTRACT
The present study was carried out to evaluate: the effects of additives and their mixtures, used in pesticide formulations, on the conidial germination of Clonostachys rosea, and the efficacy of Clonostachys strains A10 and A11, alone or in mixture of additives, in inhibiting Botrytis cinerea conidial sporulation on Eucalyptus globulus leaf discs at different temperatures. Conidial germination of Clonostachys strains in potassium and calcium carbonate (0.5, 1, 2 g L-1), cornstarch and sodium alginate (10, 15, 20 g L-1) was similar to that of the control with water (93.7% − 97.3%); for titanium dioxide (2, 4, 6 g L-1) and carboxymethylcellulose (0.5, 1, 2 g L-1), the inhibition was between 7% and 16%. Glycerol completely inhibited conidial germination. The viability of Clonostachys conidia was maintained in mixtures containing additives (potassium and calcium carbonate, titanium dioxide and carboxymethylcellulose). Clonostachys strains in the mixtures of additives suppressed Botrytis sporulation on eucalyptus leaf discs between 15°C and 25°C. At temperatures from 15°C to 25°C, Clonostachys suppressed Botrytis sporulation on leaf discs when compared to control but, at 10°C, the pathogen sporulation inhibition was significantly lower when compared to that from 15°C to 25°C. The obtained results suggest that: 1- potassium and calcium carbonate, cornstarch, sodium alginate, titanium dioxide, and carboxymethylcellulose can be used in formulations containing Clonostachys spores; 2- Clonostachys can be used between 15°C and 25°C but, below this range, other strategies should be adopted.
Keywords
Biocontrol agent; inhibition of Botrytis conidial germination; formulation additives;
Eucalyptus globulus