Soybean leaf consumption by Nomuraea rileyi (Fungi: Deuteromycotina)-infected Plathypena scabra (Lepidoptera: Noctuidae) larvae

To determine the impact of Nomuraea rileyi on consumption by the green cloverworm, Plathypena scabra, larvae were reared from eggs obtained from field-collected moths, inoculated with conidia, and placed individually in separate plastic vials with a piece of surface-sterilized soybean leaflet. No significant differences in consumption rates were found between N. rileyi-inoculated and control larvae until after 144 hr post-treatment. After this period, consumption by larvae inoculated as first, second, third, or fourth instars was significantly less than that of control larvae because of mortality. First or second instars inoculated with N. rileyi conidia had significantly longer subsequent stadia than did control larvae. The average LT₅₀ of all inoculated instar groups was 6.5 days, and there was little evidence of significantly different N. rileyi susceptibility among instar groups. In general during the N. rileyi infection period leading to their deaths, inoculated P. scabra larvae had consumption patterns that were very similar to those of healthy larvae.