Entomopathogenic nematodes

Entomopathogenic or beneficial nematodes have been used quite successfully for insect management. In Pacific Northwest nursery production they are used primary for suppression of root weevil, thrips, and fungus gnat larvae.

For root weevil suppression, insect parasitic nematodes are used for the soil-dwelling stage of the weevils. Drenches weevils species such as black vine weevil, strawberry root weevil, and rough strawberry root weevil are timed for the late spring-early summer prior to emegence of adult weevils or applied in the late summer-early fall to manage the young weevils the emerge from summer-laid eggs. These drenches should be applied when soil temperatures are sufficiently warm (at least 55-60 degrees F) for survival and activity of the nematodes.

Nematodes may be applied in various ways including with a bucket or watering can, or through overhead and drip irrigation lines (remove screens). Nematodes generally work best in container substrates but field releases may help to suppress nematodes. Pulling back mulch or plant debris can increase the efficacy of the drenches when applied in the field. WSU entomologist Lynell Tanigoshi (now retired) saw the infection rate for larval and pupal stages of root weevils, 12 days after receiving insect parasitic nematode drenches, increase from 13.2% to 58.4% when debris was removed compared to no removal prior to the applications in strawberries.

Want more information on entomopathogenic nematodes? There are several useful sites with information about using nematodes for insect management.

An updated resource Pacific Northwest Extension Publication, PNW 544, Using Entomopathogenic Nematodes for Crop Insect Pest Control is nice place to start learning about use of nematodes for pest control. The authors are Carol Miles, Caitlin Blethen, Randy Gaugler, David Shapiro-Ilan, Todd Murray. Revised May 2012. <21 September 2017>

W.S. Cranshaw and R. Zimmerman. 2013. Insect Parasitic Nematodes. Colorado State University Extension. 5/94. Revised 6/23. <21 September 2017>

Dreves, A. and J. Lee. 2015. Entomopathogenic Nematodes. PNW Insect Management Handbook. March 2015. <21 September 2017>

Barbercheck. M. 2015. Insect Parasitic Nematodes for the Management of Soil-Dwelling Insects. Penn State College of Agricultural Sciences. March 2015. <21 September 2017>

We held a very hands-on workshop in Oregon that has practical information particulary concerning application techniques
Proceedings of the Beneficial Nematode Workshop, Sept. 7, 2000. NWREC, Aurora, OR <21 September 2017>

Wainwright, S. 2017. Where to buy "THE GOOD BUGS": Supplier beneficial insects, mites and nematodes for commercial growers. Buglady Consulting. <21 September 2017>

Just for fun, check out the following creative website about nematodes
Imaginemas <21 September 2017>


Original version: <26 July 2012)

Last update <9 September 2017>

Author: R.L. Rosetta, Extension Nursery Integrated Pest Management, Department of Horticulture, Oregon State University/NWREC.

Steinernema infected weevil: photo by Ralph Berry