Selecao de isolados de Metarhizium anisopliae (Metsch.) Sorok. contra a cigarrinha da raiz da cana-de-acucar Mahanarva fimbriolata (Stal) (Hemiptera: Cercopidae) em laboratorio

The accumulated mulch on the soil resultant from the mechanized cutting of sugarcane promotes favorable temperature and moist to Mahanarva fimbriolata (Stangstroml), a pest that causes serious problems due to its widespread occurrence and high populations. Seventy nine isolates of Metarhizium anisopliae (Metsch.) Sorok. from different hosts and regions were tested for their pathogenicity. Ten spitlebugs were put in petri dishes (9 cm of diameter) containing sugarcane leaves sprayed with 1 ml of a suspension containing 5 x 10(7) conidia/ml. Five replicates were used per treatment. The petri dishes were kept at 25 +/- 1 degrees C, 70 +/- 10% RH and 12h photophase. Insects were monitored daily to calculate total cumulative mortality, as well as corrected and confirmed mortality for each treatment. The best tested isolates were: IBCB 348, IBCB 351, IBCB 363, IBCB 408, IBCB 410, IBCB 418, IBCB 425 and IBCB 482, which showed confirmed mortality equal or higher than 70%, six days after spraying.