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

Abstract 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 108 conidia ml−1 consistently suppressed the A. besseyi population

Effect of Purpureocillium lilacinum on Root Lesion Nematode, Pratylenchus thornei

Wheat (Triticum spp.) is highly susceptible to the root lesion nematode, Pratylenchus thornei, which causes excessive amounts of crop losses each year. In this research, we investigated the cumulative effect of the biocontrol agent Purpureocillium lilacinum (syn: Paecilomyces lilacinus) against P. thornei. Three doses of P. lilacinum (106 , 107 and 108 conidia cultures mL-1) with one dose of 400 P. thornei individuals (adults and juveniles) mL-1 were applied in 100 cm3 soil under greenhouse conditions. The number of nematodes in the soil and root in addition to total nematode in soil+root were determined. Moreover, different plant parameters such as the plant height, plant fresh and dry weight, root fresh and dry weight were evaluated. Applications with the higher dose of bio-agents (100 cm3 P. thornei infested soil with 108 conidia culture of P. lilacinum mL-1) exhibited maximal enhancement in dry and fresh weight of shoot and reduced P. thornei population. As a consequence, P. lilacinum individually was highly effective in enhancing different plant parameters and suppressing P. thornei reproduction. Overall, present findings suggest that the exploitation of the biocontrol agent P. lilacinum could be helpful for effective management of the root lesion nematode P. thornei