Five Tips For Using Beneficial Nematodes

By Cozette Hadley, Becker Underwood, Inc.

Now, more than ever, nematodes are gaining acceptance and use as an important tool in controlling insect pests.  “But,” you say, “I always thought nematodes were bad and damaged crops.”  The truth is, those are the “bad guys” and we’re talking about the “good guys.”

Certain plant parasitic nematodes are associated with crop damage. These “bad guys” include cyst, sting, lance, and root knot nematodes. But the “good guys” … Entomopathogenic nematodes … have proven highly effective in controlling insect pests and reducing the damage they can cause. Entomopathogenic nematodes belong to the Steinernema and Heterorabditis nematode families.

At least seven different strains of beneficial nematodes are currently marketed in North America for controlling insect pests in both field and greenhouse settings. As you consider the use of beneficial nematodes in your operation, keep these five tips in mind.

1. Take the tool box approach.   Think of beneficial nematodes as another tool in your integrated pest management tool box.  When used along with beneficial insects, crop scouting, and other cultural practices, beneficial nematodes provide another valuable tool for controlling crop pests.  They also are a great asset in resistance management strategies for traditional insecticides. By including nematode use in your insecticide rotation with traditional chemistries, the likelihood of a pest developing resistance can be reduced.
2. Buy quality and know what you are getting.  Not all nematodes are created equally.  Because nematodes are a living organism, they require special handling to ensure they will be effective when applied.  Be sure the nematodes you purchased have been shipped and stored in a way that does this.  Most nematode suppliers ship directly to the grower using next day or second day air freight along with ice packs to keep the nematodes cool.
   
   There are several quality manufacturers and marketers of nematodes in North America; many of whom are members of ANBP. For a list of these suppliers, visit the ANBP Web site at www.anbp.org.   Another good reference on nematode quality is the recently published study, Quality Assessment of Two Commercially Available Species of Entomopathogenic Nematodes: Steinernema feltiae and Heterorhabditis indica, by Erick Caamano, Ray Cloyd, Leellen Solter, and Declan Fallon, HortTechnology 18:84-89.
3. Read and follow label directions.  The formulation of nematodes varies from manufacturer to manufacturer.  As a result, the mixing and handling instructions may differ depending on the manufacturer.  Be sure to read the directions for use provided with the nematodes.   Pay special attention to the storage guidelines and expiration date information.  Most nematodes need to be stored in refrigeration and cannot freeze.  Removal of screens from spray nozzles may also be recommended.
4. Know the pest’s life cycle.  While few of us are entomologists, having a good understanding of the life cycle of the pest being controlled is still needed.  Nematodes are primarily effective on the insect’s larva stage, and not on adults.   The nematode will enter the larvae and release a lethal bacterium.   Thus, being able to recognize and anticipate the life cycle of the pest will help you in timing the nematode application to maximize its effectiveness. 
5. Resource the industry contacts. Because nematodes are very specific and selective in the pests they control, having the assistance and input of others knowledgeable in the use of nematodes will be helpful.  Reach out to your industry contacts for further help and assistance.  Some university researchers and extension professionals specialize in the study and use of nematodes.  Other growers and producers may be able to provide information about their experiences in using nematodes. 
   Your distributor sales representatives and the nematode manufacturer are also important resources to provide assistance and recommend the right nematode and rate to use in controlling the target pest.