Biocontrol potential of entomopathogenic nematodes heterorhabditis and steinernema against pupae and adults of white grubHolotrichia serrata F.

The effectiveness of four entomopathogenic nematodes (EPN)viz., Heterorhabditis indica (isolate LN2),H. bacteriophora, Steinernema glaseri andS. riobrave against pupae and adult beetles ofHolotrichia serrata F., a serious pest of sugarcane was evaluated in the laboratory. All the EPN tested caused mortality of the pupae. The lowest LD50 value was recorded forS. glaseri (113.3 IJs/pupa) followed byH. indica (127.0 IJs/pupa). The lowest LT50 value was recorded forS. glaseri (24.9 h) followed byH. indica (27.3 h) at 1000 Us/pupa. In another experiment,H. indica andS. glaseri were pathogenic to adult beetles ofH. serrata. The mortality of adult beetles noticed after 24 h of inoculation and 100 per cent mortality was recorded when the nematodes were dispensed either through soil application or by injection of IJs into haemocoel of white grub.Steinernema glaseri introduced by injection method caused 100 per cent mortality of beetles in 3 days followed byH. indica in four days.