Effects of some cultural media and temperatures on viability of Beauveria bassiana (Bals.) Vuill. after different storage periods

Abstract

This study aimed to evaluate the effects of interaction between different storage conditions on the viability of Beauveria bassiana spores. The test interaction involved incubating fungus spores in four media; Nutrient broth (NB), Potato extract dextrose agar (PDA), mixture of Wheat bran and corn cobs powder (WC) at the ratio 3: 1 supplied with distilled water and distilled water only as control under different temperature degrees ; Refrigerator temperature degree 8-10 Cº, Freez temperature degree -20 Cº , Lab temperature degree 28 ± 2 Cº and Incubator temperature degree 35 ± 1 Cº after three periods of storage ; one , two and three months. The results showed that the best period in which spores maintained their viability was one month of storage under different temperature conditions in all media whereas the percentage of the viability was 56.4 – 85.1% , the viability percentage was best at refrigerator were was 70.8 – 85.1% , 51.3 – 76.9% and 33.1 – 55.7% after one , two and three months of storage respectively. The results also showed that the WC was the best medium to maintain the percentage of spore viability after three months of storage which was 55.7%. On the other hand, the spore viability showed sharp reduction after three months of storage in all media at different temperatures whereas the percentage of viability was 17.1 – 55.7 %, at the second month a percentage of viability was 36.2–76.9%.