Formulation and application of entomopathogenic nematode-infected cadavers for control of Hoplia philanthus in turfgrass

BACKGROUND: Commercially produced entomopathogenic nematodes (EPNs) are usually applied in an aqueous suspension. However, recent studies demonstrate that they can be successfully applied as infected cadavers. EPN-infected insect cadavers were formulated in various carrier/coating materials, but only infective juveniles (Us) from kaolin-formulated and non-formulated cadavers were tested for survival, emergence and virulence. The efficacy of Us from kaolin-formulated and non-formulated cadavers applied against Hoplia philanthus Fuessly in greenhouse and field was also assessed. RESULTS: The kaolin-based formulation (kaolin-starch combination) proved to be the most stable. Emergence of Heterorhabditis bacteriophora Poinar CLO51 from cadavers formulated in kaolin was significantly higher than from non-formulated cadavers. In greenhouse conditions, efficacy of freshly formulated (8 days post-infection) cadavers of H. bacteriophora provided significantly higher H. philanthus control (62%) than three-month-old cadavers (31%) or aqueous applications of the same EPN (39% and 43%). Similarly, under field conditions, significantly higher H. philanthus control was achieved with freshly formulated cadavers (39%) than with three-month-old cadavers (21%) or with aqueous applications (24% and 28%) of H. bacteriophora 2 weeks after application. Additionally, after 1 year, cadaver applications provided >90% H. philanthus control, while aqueous applications of H. bacteriophora gave only 55% control. CONCLUSIONS: This study demonstrated that kaolin-starch coating provided superior protection and preservation of EPN-infected cadavers. Use of formulated cadavers may solve several current problems preventing the wider utilisation of EPNs in pest management. (C) 2009 Society of Chemical Industry