Comparative effects of entomopathogenic fungi and nematodes and bacterial supernatants against rice white tip nematode

The rice white tip nematode, Aphelenchoides besseyi, is the primarily important seed-borne pest of rice and was first recorded in Turkey in 1995. These biological agents, such as an entomopathogenic fungus (EPF), entomopathogenic nematodes (EPN), and bacterial supernatants, have been used against other plant parasitic nematodes but as far as not against A. besseyi. Accordingly, the EPF species, Purpureocillium lilacinum, and the four EPN species, Heterorhabditis bacteriophora, Steinernema carpocapsae, S. glaseri, and S. feltiae, and the supernatant of the two bacterial symbionts, Photorhabdus luminescens and Xenorhabdus bovienii, were used against A. besseyi. In addition, infected Galleria mellonella cadavers with S. feltiae were evaluated as a biological agent to the white tip nematode. The percentage of observed white tip symptoms, decrease in kernel numbers in the panicles, and decrease in panicle weight were evaluated. Evaluation of these parameters showed that X. bovienii supernatant, S. feltiae infective juveniles, and P. lilacinum at 10 conidia ml consistently suppressed the A. besseyi population.