How are Biocontrol Nematodes applied to the field?

• Biocontrol nematodes are applied to the field using either a slightly modified pesticide sprayer or through a center pivot irrigation system.  Both methods are simple and highly effective.

• Pesticide Sprayer:  The only modification needed is to remove all the filters and screens which trap biocontrol nematodes. Nozzles then need to be changed to a fertilizer stream nozzle similar to a TeeJet 0015.  Some applicators simply drill nozzle blanks with an appropriatly sized drill bit (~1/8”) to achieve the required 50 gallons per acre.  Please refer to the application guide here for more information.

• Center Pivot Irrigation:  Biocontrol nematodes are directly injected into irrigation water during normal irrigation.  Typically, farmers run their irrigation system at 100% during application and the nematodes are applied in 0.20-0.25” of water.  Application can be made any time of the day.  Please refer to the pivot application guide here for more information.

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Which method works best if both are available?

If a farmer has a choice between a irrigation application or a sprayer application, the irrigation application gives a better initial coverage and the biocontrol nematodes provide a higher level of activity against rootworm in the year of application.  However, both application methods will provide full biocontrol nematode activity in the second growing season.

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When is the best time to apply Biocontrol Nematodes?

Persistent Biocontrol Nematodes can be applied anytime the soil temperatures are above 50⁰F.  After persistent biocontrol nematodes become established in the soil profile, they will be active against any susceptible soil insect.  Using rootworm as an example, an early May application would have a direct impact on rootworm. Rootworm egg hatch is usually around June 1st.  However, the larger the time span between biocontrol nematode application and the presence of the target soil insect in the field, the greater the first year impact.  Recent field studies have shown that when biocontrol nematodes were applied the previous September, year 1 activity was higher than a May application (just before rootworm hatch).  Farmers with experience using biocontrol nematodes prefer to use a fall application with expected control the following spring. This helps alleviate the limited availability of spray equipment during May.

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When is the best time of the day to apply Biocontrol Nematodes?

If Biocontrol Nematodes are applied through a pesticide sprayer, application needs to be delayed until late in the day to protect the biocontrol nematodes from UV exposure and allow them time to enter the soil.  If biocontrol nematodes are applied through an irrigation system, application can occur any time of the day.