حساسية بيض عثة درنات البطاطا البطاطس Phthorimaea operculella لعزلات محلية من الفطر الممرض Beauveria bassiana

Abstract EN

The pathogenicity of three local isolates of the entomopathogenic fungus Beauveria bassiana (Bals.) Vuill were evaluated on eggs of potato tuber moth P.

operculella (Zeller).

Fungal isolates were obtained from Latakia (isolate B), ICARDA (spt 273, isolate C) and Damascus (isolate D).

Three concentrations 104, 105, and 106 conidia/ml were used for each isolate and sprayed on eggs.

Eggs in the control was sprayed with sterilized water.

The germination rate was evaluated 24h after incubation in the dark.

All tests were done under laboratory conditions of temperature 28±2◦C and relative humidity 40±5%.

Results showed significant differences in germination rate, where the average was 67, 55, and 47% for isolates B, D and C, respectively.

Susceptibility tests showed significant differences in averages of hatching rate between the control and spraying spore suspension of the isolates B, C and D (1×10 6 conidia/ml) which led to 18.3%, 26.6% and 38.3% hatching rate for the three isolates, respectively, in contrast to 66.6% for the control.

Findings indicated that eggs of P.

operculella seemed sensitive to local isolates of B.

bassiana at various levels, and further studies on the efficiency of different fungal isolates for controlling eggs of this pest under natural conditions are still needed