Preparation and use of oil formulations of Beauveria bassiana and Metarhizium anisopliae against Spodoptera litura larvae

Abstract

In vitro, the compatibility of eight vegetable oils, used as components in formulation, was studied in conidia of entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae, based in three parameters that are been evaluated: germination rate, vegetative growth and conidiogenesis. Almond oil and gingelly oils at 1, 2 and 3% concentrations showed compatibility with B. bassiana as well as M. anisopliae. Mustard oil and eucalyptus oils at all three concentrations proved toxic to B. bassiana and M. anisopliae except at 1% concentration. Sunflower oil, olive oil, coconut oil and castor oils displayed compatibility with M. anisopliae and toxic to B. bassiana except olive oil and castor oil at 1% concentration. Conidiogenesis appear to be more affected than germination for the sample which displayed toxicity. Compatibility classification in to toxic, moderately toxic and compatible enabled assessment of the tested oils for use in formulations. Conidial formulations of B. bassiana and M. anisopliae with almond oil/olive oil/gingelly oil/castor oil were used for bioassaying against Spodoptera litura. All the four formulations displayed higher mortalities of the target pest compared to unformulated conidia.