Use entomopathogenic nematodes to control western corn rootworm

Efficacies of two biological control agents including entomopathogenic fungus (Metarhizium anisopliae) and insect-parasitic nematode (Heterorhabditis bacteriophora) against western corn rootworm, Diabrotica virgifera virgifera was compared with two insecticides including Tefluthrin (synthetic pyrethroid compound) and clothianidin (neonicotinoid compound).  According to Pilz et al (2009), insect-parasitic nematode,  H. bacteriophora was as effective as both insecticides in reducing population of the western corn rootworm. Reference:

Pilz, C., Keller, S., Kuhlmann, U. and Toepfer, S. 2009.  Comparative efficacy assessment of fungi, nematodes and insecticides to control western corn rootworm larvae in maize.  Biocontrol. 54: 671-684.

Plants can call for help for their protection against insect pests

It has been demonstrated that the plants when attacked by herbivorous insects can emit volatile compounds that can attract natural enemies of the insects.  For example, the roots of maize plants when attacked by western corn root-worms (a noxiuos insect pest of corn) can synthesize and emit a volatile compound called (E)-beta-caryophyllene that attracts insect-parasitic nematodes that infect and kill many soil dwelling insect pests (Rasmann et al., 2005; Degenhardt et al., 2009). Read following scientific papers for more information on insect induced plant volatiles that attract natural enemies of insect pests.

Degenhardt, J., Hiltpold, I., Kollner, T.G., Frey, M., Gierl, A., Gershenzon, J., Hibbard, B.E., Ellersieck, M.R. and Turlings, T.C.J. 2009. Restoring a maize root signal that attracts insect-killing nematodes to control a major pest. Proceedings of the National Academy of Sciences of the United States of America. 106: 13213-13218.

Rasmann, S., Kollner, T.G., Degenhardt, J., Hiltpold, I., Toepfer, S., Kuhlmann, U., Gershenzon, J., Turlings T.C.J. 2005. Recruitment of entomopathogenic nematodes by insect-damaged maize roots. Nature 434: 732–737.