Virulence of Beauveria bassiana against Sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae) at different time periods of application

摘要

The virulence of?Beauveria bassiana?to overwintering Sunn pest adults was determined in the laboratory using micro-application techniques. Five microliter of 2 × 103, 2 × 104, 2 × 105, 2 × 106, 1 × 107, 2 × 107, 1 × 108?conidia/ml-1?were used in ?November, January and March. Applications were made to the mesosternum of adults. Mortality was recorded every 2 days for 16 days. Isolates were efficacious to Sunn pest at the higher concentrations. The cumulative corrected mortality after 12 days varied from 2.3% (SPT22) at 2×103?conidia/ml-1, when treatment was conducted in November, to 100% (SPSR2) at 1×108?conidia/ml-1?in March. The LC50?for SPSR2 decreased from 1.1×107?to 3.7×103?conidia/ ml-1?when treatment was conducted in November and March, respectively. The 50% lethal time (LT50) varied from 17.07days for GHA (the commercial fungal isolate – in?BotaniGard), to 9.31 days for SPSR2 in November. The most efficacious isolate was SPSR2.