Study the effect of some acids on the viability of Beauveria bassiana (Bals.) Vuill. and Metarhizium anisopliae and their growth ability on chitin agar

Abstract

This study aimed to evaluate the effects of three acids; Citric, Oxalic and Boric acids 0.05% on the viability of Beauveria bassiana and Metarhizium anisopliae spores after 1,2, 3 days of exposure 27±1 C° and the growth on chitin agar was obtained after 5 days at 26 ± 1C°.The results showed that the rate of viability of B. bassiana and M. anisopliae with boric acid was 312.3,209,150.3 colony/ml and 318,294.7,157.5 colony/ml respectively during three period time of in comparison with control and spore suspensions with the other acids. Spores of both fungi B. bassiana and M. anisopliae showed maximum rate of viability in the suspension supplied with citric acid which were 266 and 293.6 colony/ml, respectively after 1day of exposures to this acid in comparison with viability of control and other periods. Spores viability was lost with oxalic acid. On the other hand, control recorded highest rate of radial growth in the control was 1.92, 4.4 cm on the medium chitin agar after 3 days of incubation in comparison with other treatments. Both fungi showed best rate of radial growth 3.12, 1.88cm after 1and 3 days of exposure to citric acid, respectively in comparison with other treatments. There were no such growths on chitin agar after exposure the oxalic acid.