The role of an oil-based formulation for protecting the biocontrol fungus beauveria bassiana from some chemical fungicides under labortory conditions

Abstract EN

The lab study included evaluation of oil formulation to protect the conidia of Beauveria bassiana from two fungicides; beltanol and basten50 and four insecticides; decis, quality 5, dynamec and supredimethoate after mixing and incubated for 1 and 9 days at relative humidity (RH) 0.0, 6, 33 and 75% and temperatures; 25 and 35 °C.

Vitality percentage of conidia in aqueous suspension was negatively affected by recommended doses of the pesticides either the fungicides in which the vitality % of conidia kept at the lowest level (0.0% ) over their exposure periods (1 and 9 Days) to the 25 and 35 °C under RH 0.0 and 6% .

Not only that, but the insecticides had a negative effect under the same environmental conditions in which conidia recorded a vitality ranged 0.0-34.5% .

On the other hand, vitality of the formulated conidia was more degraded under influence of extreme drought conditions (RH 0.0 and 6% ) after mixing with a both fungicides over 9 days of exposing to the 35°C and was recorded 70 and 83.3% for 9 days of exposing to the 35 °C under RH 33% in compared with vitality of the fungicide-free formulated conidia.

All the formulated conidia whether treated or untreated with chemical pesticides maintained their vitality in completely (100% ) at all temperatures under RH 75% .

These results have confirmed that it was not benefitted to use the oils only in protecting conidia from adverse physical and chemical environmental conditions, unless appropriate moisture was available, even at a low level (RH 33% ).