Improve turf quality by preventing nematodes

By Lane Tredway, Ph.D., technical services manager for Syngenta

Spring is an important time to protect turfgrass roots from nematode feeding. If nematodes are left uncontrolled, they can severely hamper new root growth, slow spring green-up and send turf into the summer in a weakened state.

Additionally, late summer control of Anguina pacifica is critical for the health of Poa annua putting greens to hold up to winter play.

Developing a nematode prevention program

With activity against all major root-feeding nematodes and Anguina pacifica, Divanem® nematicide is an important foundation for any nematode prevention program.
    Divanem is also available in a convenient Multipak with Heritage® Action™ fungicide, which is designed to help prevent troublesome nematodes and boost turf’s natural defenses.
    • Spring applications of Divanem protect new root growth from nematode feeding, enhancing overall turf quality and stress tolerance
    • Make four applications on a 21- to 28-day interval when conditions are conducive to turfgrass root growth.
      • In many cases, the broadcast rate of Divanem (12 fl. oz./A) is recommended for preventive applications
    • If sting, lance or spiral nematodes are above damage thresholds, apply the spot treatment rate of Divanem (12 fl. oz./10,000 ft.2)
    • Anguina responds best to Divanem at 14-day intervals when symptoms first start to appear.
    • Because turf roots damaged by nematodes are more susceptible to disease, Syngenta recommends the addition of a fungicide with a nematicide treatment to protect against diseases and abiotic stress
    • These applications are often tank mixed and watered in with fungicides such as Velista, Briskway® and Posterity® XT fungicides to help prevent fairy ring, summer patch and other root diseases
    • All Divanem applications should be tank mixed with a soil surfactant and watered in immediately for best results
    Scouting for nematodes
    • As turfgrass root growth begins to ramp up in the spring, you should scout for nematode pressure and send soil samples to a nematode laboratory 
    • All turf is susceptible to nematode damage, regardless of region or soil type
    • A lab can provide an initial population count, which can be used to decide whether nematicide applications may be beneficial
    For more information on how to collect a nematode sample and for a list of nematode labs in your area, visit the Nematode Knowledge webpage.

    See the difference

    While nematode assays are useful for making management decisions, they are generally not good tools to measure nematicide performance. Nematode populations fluctuate over time, increasing and decreasing with root growth and soil conditions. Furthermore, nematicide applications can lead to increased nematode populations in the long run, as more roots can support higher nematode populations. 

    The best way to evaluate nematicide performance is by:
    • Assessing turf quality, root growth and stress tolerance 
    • If possible, leave an untreated area for comparison so you can see the impact of your nematicide program side by side
    Treatments applied four times on a 28-day interval (June 26, July 27, August 21 and September 30, 2016). Photo taken September 27, 2016. Trial by Neil Young, Turfgrass Environmental Research.

    Spot Treatments

    If nematode populations are very high or damage is already evident, Divanem can be applied to golf course turf at a spot treatment rate of 12.2 fl. oz./10,000 ft.2 for improved control and enhanced turf quality.

    Spot treatment applications of Divanem have been shown to:
    • Stimulate more rapid turf recovery
    • Reduce sting, lance, root-knot and spiral nematode populations
    • Reduce damage to Poa annua putting greens from Anguina pacifica
    Treatments applied four times on a 28-day interval (June 26, July 27, August 21 and September 30, 2016). Photo taken September 27, 2016. Trial by Neil Young, Turfgrass Environmental Research.
    • Spot treatments are limited to 10,000 ft.2/A and four applications per year
    • They should be tank mixed with a soil surfactant and watered in immediately, just like with broadcast applications
    • Begin with two applications on a 21- to 28-day interval and make additional applications as needed based on turf recovery, root growth and nematode populations
    For more information about effective nematode control and the spot treatment rate for Divanem, visit or the Nematode Knowledge webpage.

    All photos are either the property of Syngenta or used with permission.

    © 2024 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties and/or may have state-specific use requirements. Please check with your local extension service to ensure registration and proper use. Divanem is a Restricted Use Pesticide. Syngenta supports a FIFRA Section 2(ee) recommendation for Velista fungicide to control large patch, summer patch, brown ring patch, spring dead spot, fairy ring, leaf and sheath spot and rapid blight on all turf types. Please see the Section 2(ee) recommendation to confirm that the recommendation is applicable in your state. The Section 2(ee) recommendation for Velista should be in the possession of the user at the time of application. Action™, Appear®, Briskway®, Daconil®, Divanem®, GreenCast®, Heritage®, Posterity®, Velista® and the Syngenta logo are trademarks of a Syngenta Group Company. Secure® is a registered trademark of Ishihara Sangyo Kaisha, LTD. All other trademarks are property of their respective third-party owners.

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