Effect of entomopathogenic fungi and entomogenous nematodes, and low risk insecticides against wheat stem sawfly (Cephus cinctus)

Entomopathogenic nematodes, fungi, and low risk insecticides were evaluated for the management of the wheat stem sawfly, Cephus cinctus Norton, in winter wheat at two locations (Devon and Western Triangle Ag Research center) in the Golden Triangle area of Montana (USA) in 2013. Two fungi (Beauveria bassiana and Metarhizium brunneum), four nematodes species (Steinernema carpocapsae, Steinernema kraussei, Steinernema feltiae, and Heterorthabditis bacteriophora), an insect growth regulator (diflubenzuron/dimilin), and a botanical-based chemical (azadirachtin/Aza-direct) were used. When applied as a foliar spray, these control agents significantly reduced damage caused by C. cinctus larvae, compared to the untreated control. No yield differences were observed among entomopathogenic fungi, nematodes, and low risk insecticides. The effectiveness of azadirachtin, diflubenzuron, the entomopathogenic fungi, and the nematodes persisted through the 28^th day post application, by which time the wheat had been harvested. Stubble collected after harvest showed significantly fewer sawfly larvae in the plots treated with entomopathogenic fungi, nematodes, diflubenzuron, and azadirachtin compared to the untreated and water spray plots because of the residual effect of the treatments. This clearly indicate that these bio-rational pesticides have potential to be used as alternatives to conventional pesticides for controlling the wheat stem sawfly larvae.