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Entomopathogenic nematodes and Colorado potato beetle

• Colorado potato beetles (Leptinotarsa decemlineata) are a most damaging pest of potatoes but they can also cause a significant damage to tomatoes and eggplants.
• Generally, both adults and larvae feed voraciously on leaves causing hundreds of millions dollars in yield loss each year in the United States.
• Many chemical insecticides have been recommended to control these beetles but unfortunately beetles have an ability to develop resistance to insecticides.
• Entomopathogenic nematodes as biological control agents could provide an alternative to chemical pesticides in management of Colorado potato beetles.
• As entomopathogenic nematodes naturally found soil, they are very effective against soil dwelling stages of host insect pests.  For example, mature larvae of Colorado potato beetle that moves in the soil for pupation can be a very good target for entomopathogenic nematodes.
• Commercially available entomopathogenic nematode species including Steinernema carpocapsae, Steinernema feltiae, Heterorhabditis megidis, Heterorhabditis marelata and Heterorhabditis bacteriophora have showed a very high efficacy against adult, larval and prepupal stages of Colorado potato beetles when tested in soil under laboratory conditions.

Publications:

1. Ebrahimi, L., Niknam, G. and Lewis, E. E. 2011.   Lethal and sublethal effects of Iranian isolates of Steinernema feltiae and Heterorhabditis bacteriophora on the Colorado potato beetle, Leptinotarsa decemlineata.  Biocontrol 56: 781-788.
2. Ebrahimi, L.,Niknam, G.and Dunphy, G.B. 2011. Hemocyte responses of the Colorado potato beetle, Leptinotarsa decemlineata, and the greater wax moth, Galleria mellonella, to the entomopathogenic nematodes, Steinernema feltiae andHeterorhabditis bacteriophora . Journal of Insect Science 11, Article Number: 75.
3. Armer, C.A., Berry, R.E., Reed, G.L. and Jepsen, S.J. 2004.  Colorado potato beetle control by application of the entomopathogenic nematode Heterorhabditis marelata and potato plant alkaloid manipulation. Entomologia Experimentalis et Applicata. 111: 47-58.
4. Berry, R.E., Liu, J. and Reed, G. 1997.  Comparison of endemic and exotic entomopathogenic nematode species for control of Colorado potato beetle (Coleoptera : Chrysomelidae). Journal of Economic Entomology. 90: 1528-1533.
5. Cantelo, W.W. and Nickle, W.R. 1992. Susceptibility of prepupae of the Colorado potato beetle (coleoptera, chrysomelidae) to entomopathogenic nematodes (Rhabditida, Steinernematidae, Heterorhabditidae). Journal of Entomological Science. 27: 37-43.
6. Nickle, W.R., Connick, W.J. and Cantelo, W.W. 1994. Effects of pesta-pelletized Steinernema-carpocapsae (all) on western corn rootworms and colorado potato beetles. Journal of Nematology. 26: 249-250.
7. Trdan, S., Vidrih, M., Andjus, L. and Laznik, Z. 2009. Activity of four entomopathogenic nematode species against different developmental stages of Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera, Chrysomelidae. Helminthologia. 46: 14-20.

Colorado potato beetle, Leptinotarsa decemlineata: This is an economically important pest of potatoes with more than 40 species have been reported from North America.  The larvae of this beetle are voracious feeder of potato leaves costing hundreds of millions of dollars for pesticide control and yield loss each year in the United States. Entomopathogenic nematodes as biological control agents could provide an alternative to chemical pesticides in management of this noxious pest.

In a laboratory bioassay, four species of entomopathogenic nematodes including Steinernema carpocapsae, S. feltiae, Heterorhabditis bacteriophora, and H. megidis showed highest virulence against both larval and adult stages of the Colorado potato beetle, Leptinotarsa decemlineata at temperatures higher than 15oC when tested at the rate of 200 -2000 infective juveniles per individual of Colorado potato beetle (Trdan et al., 2009).

In another laboratory study, entomopathogenic nematode, H. marelata can cause 100% mortality of Colorado potato beetle larvae (Berry et al., 1997) but in the field, this nematode when applied twice in potato growing season can reduce only 50% population of adult Colorado potato beetles (Armer et al., 2004).

The efficacy of pesta-pelletized Steinernema carpocapsae All strain was tested against prepupal stages of Colorado potato beetle in a greenhouse (Nickle et al., 1994).  Infective juveniles of S. carpocapsae were able to survive the pesta-pellet process and able to reduce over 90% emergence of adults of Colorado potato beetle.

It has been also reported that prepupal stages of Colorado potato beetle were very susceptible to different species/strains of entomopathogenic nematodes including S. carpocapsae All strain; S. carpocapsae Mexican strain; S. feltiae strain #27; S. feltiae strain #980 and Heterorhabditis bacteriophora.  All these nematode species caused 100% mortality of beetle prepupae when applied in the soil at the concentration of 165 infective juveniles/cm2 (Cantelo and Nickle, 1992).

For more information, read following literature on interaction between entomopathogenic nematodes and Colorado potato beetle.

Armer, C.A., Berry, R.E., Reed, G.L. and Jepsen, S.J. 2004.  Colorado potato beetle control by application of the entomopathogenic nematode Heterorhabditis marelata and potato plant alkaloid manipulation. Entomologia Experimentalis et Applicata. 111: 47-58.

Berry, R.E., Liu, J. and Reed, G. 1997.  Comparison of endemic and exotic entomopathogenic nematode species for control of Colorado potato beetle (Coleoptera : Chrysomelidae). Journal of Economic Entomology. 90: 1528-1533.

Cantelo, W.W. and Nickle, W.R. 1992. Susceptibility of prepupae of the Colorado potato beetle (coleoptera, chrysomelidae) to entomopathogenic nematodes (Rhabditida, Steinernematidae, Heterorhabditidae). Journal of Entomological Science. 27: 37-43.

Nickle, W.R., Connick, W.J. and Cantelo, W.W. 1994. Effects of pesta-pelletized steinernema-carpocapsae (all) on western corn rootworms and colorado potato beetles. Journal of Nematology. 26: 249-250.

Trdan, S., Vidrih, M., Andjus, L. and Laznik, Z. 2009. Activity of four entomopathogenic nematode species against different developmental stages of Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera, Chrysomelidae. Helminthologia. 46: 14-20.