Comparison of the virulence of some Iranian isolates of Beauveria bassiana to Eurygaster integriceps (Hem.: Scutelleridae) and production of the selected isolate

Abstract

The virulence of four Iranian isolates and one exotic isolate of Beauveria bassiana on the fifth instar nymphs and also five Iranian isolates and one exotic isolate of it on the adults of Eurygaster integriceps Puton was studied using dipping and topical micro-application techniques, respectively. Nymphs were highly susceptible to the isolates. Comparison of LC50 values showed no significant difference among the isolates to nymphs. In case of the adults, LD50 values of DEBI 002, DEBI 006 and DEBI 008 were comparatively lower than those of other isolates (0.05% Tween 80® solution treatment). Coincidentally, DEBI 002 showed the lowest LD50 value among the others (odorless kerosene treatment). In addition, DEBI 002 showed the lowest LT50 value to adults. In production phase, the effects of different liquid culture media (microbiological glucose, biochemical glucose, chemistry sucrose and sugar) supplemented with yeast extract and solid media (rice, wheat and barley) were studied on blastospore and conidial production, respectively. The highest total yield was obtained 0.801 × 107 blastospores/ml media after 4 days for microbiological glucose plus yeast extract. Maximum conidial production was achieved 1.17 × 109 conidia/gr substrate using rice as medium. Viability of produced conidia on different solid media showed no significant difference among treatments.

Keywords

• beauveria
• eurygaster integriceps
• virulence
• production
• liquid cultures
• solid media