Development of Steinernema feltiae (Rhabditida: Steinernematidae) in diseased insect hosts

The interaction between the entomopathogenic nematode, Steinernema feltiae, and a nuclear polyhedrosis virus (NPV) or Bacillus thuringiensis var. kurstaki in a common host was investigated. S. feltiae reproduced successfully in 68.3% of moribund hosts infected with NPV. S. feltiae infectives retained sufficient NPV to infect neonate larvae of Spodoptera exigua. Nematodes from NPV-infected hosts when fed whole or macerated to neonate S. exigua larvae caused 44 and 58% NPV infections, respectively. On the other hand, S. feltiae did not produce progeny in B. thuringiensis-infected hosts, except in a few cases. Those hosts which had a dual infection had B. thuringiensis infection in the anterior part and S. feltiae infection in the posterior part of the body. In general, B. thuringiensis-killed insects were not satisfactory hosts for S. feltiae.