干旱区生态环境知识资源中心

The storability of five new different formulations of Metarhizium acridum (two oil, one paste, one semi-solid and one powder) was investigated under ambient and low temperatures. Fourth-instar nymphs of the desert locust Schistocerca gregaria (Forskal) were used to evaluate their virulence. Under ambient conditions (23-38 degrees C), all the formulations maintained acceptable viability (66.1 +/- 2.30 to 71.8 +/- 0.88% germination) after 6 months of storage. After 10 months, only conidia from the powder formulation remained viable. In contrast, samples of the formulations kept under low temperatures (-1.2 to 15 degrees C) did not show significant loss of viability after 30 months of storage despite repeated power cuts, lasting sometimes several days. During this period, M. acridum conidia remained virulent to nymphs with 100% mortality 5 to 7 days after the treatment. These results show that all the formulations have greater stability when stored under low and even fluctuant temperature changes. Under ambient conditions, the formulations could remain effective for at least 6 months of storage.