The objective of this research was to evaluate the pathogenicity of Metarhizium anisopliae isolates on Scaptocoris carvalhoi (BECKER 1967), and to determine the average Lethal Dose (LD50) and the average Lethal Time (LT50), under laboratory conditions. The bioassays were conducted at Embrapa Western Agriculture in Dourados, MS, Brazil, during the year 2003. Suspensions of four M. anisopliae isolates (Ma7, Ma69, Ma283, and Ma 342) were made at 10(4), 10(5), 10(6), 10(7) e 10(8) conidia mL-1 and 5mul of each concentration were inoculated topically on S. carvalhoi and corresponded to 50, 500 5,000, 50,000, and 500,000 conidia stinkbug-1, respectively. After inoculation, the insects (ten adults and five nymphs per plot) were placed into gerboxes and kept in growth chambers at 26±1ºC and 85% relative humidity, under darkness conditions. At the highest dose (500,000 conidia insect-1), a significant increase in stinkbug mortality was observed, regardless of the isolate. The lowest LD50 were observed with the Ma69 and the Ma7 isolates, and the highest with the Ma283 isolate. The LT50 ranged from 0.32 to 5.84 days, with no significant differences. The isolates Ma69 and Ma7 showed potential for S. carvalhoi control under field conditions.
Insecta; entomopathogenic fungus; biocontrol
