FITNESS OF A GENETICALLY IMPROVED ENTOMOPATHOGENIC NEMATODE

A strain of Steinernema carpocapsae (G-13) selectively bred for improved host-finding was compared against two wild-type strains, the commercially available All strain and the Foundation strain from which the G-13 strain was derived, for changes in fitness. Selection did not affect pathogenicity, mobility, sex ratio, or morphology. However, the G-13 strain showed a gain of fitness with regard to host penetration and reproductive potential and a loss of fitness for storage stability. Acquiring enhanced host-finding abilities does not appear to be correlated with a serious reduction in overall fitness, and the potential of the selected G-13 strain for inundative biological control appears unlikely to be impaired. The possible significance of the three correlated responses to selection are discussed. © 1990.