Comparative effectiveness of entomopathogenic nematodes against the pupae of mustard beetle,Phaedon cochleariae F. (Chrysomelidae: Coleoptera)

Steinernema carpocapsae,steinernema feltiae (steinernematids),heterorhabditis indica and heterorhabditis bacteriophora (steinernematids) were tested to control the pupae of phaedon cochleariae under different laboratory bioassays in sterile sand. results showed a significant difference in mortality percentage among nematode isolates. all nematode isolates were found more effective when exposure time was increased up to 4 days. s. carpocapsae and s. feltiae showed better mortality at 25°c. both heterorhabditids caused maximum mortality as compared to steinernematids at 30°c. when different moisture levels were tested in the sand arena,a medium level of moisture (12%) caused maximum pupal mortality in all isolates. however,highest concentration of each isolate (200 ijs per ml) proved to be most appropriate for maximum insect death. similarly,both heterorhabditis nematodes killed all beetle pupae as compared to the other two steinernematids. infectivity test showed that s. carpocapsae produced the maximum number of infective juveniles in pupae at 25°c as compared to other nematodes. infectivity of h. indica was better at 30°c in pupae of phaedon cochleariae followed by h. bacteriophora,s. carpocapsae and s. feltiae. this study suggests some useful basic findings in developing biocides with suitable virulent entomopathogenic nematodes for controlling pupae of p. cochleariae. copyright 2012 zoological society of pakistan.