Abstract

The white grub, Hylamorpha elegans Burm., is a serious pest on cereals and pastures in Chile. In laboratory and greenhouse studies, the pathogenicity of two Metarhizium anisopliae var. anisopliae (Metsh.) isolates: Qu-M270 and Qu-M802 on H. elegans larvae was evaluated. The first evaluation was carried out by immersion of third instar larvae in increasing suspensions, 0 to 10(8) conidia mL-1 of each isolate. The area under an accumulated mortality curve was calculated, observing differences (P = 0.032) between the isolates, with Qu-M270 being 50% superior to Qu-M802. The LC50 and LC90 for Qu-M270 were 10(4.7) and 10(7.5) conidia mL-1, respectively. The greenhouse evaluation was carried out in pots with pasteurized soil and 10 larvae of H. elegans, on which four suspensions (0 to 10(14) conidia ha-1) were pulverized. After thirty days, there were no significant differences in the mortality between doses of 10(13) and 10(14) conidia ha-1 (P < 0.05), with 95 and 94% of larval mortality, respectively, but there was a difference at 10(12) conidia ha-1 (P = 0.045) with 74% mortality. It is concluded that Qu-M270 was more effective in the control of H. elegans larvae.