Q&A Lane Tredway, Ph.D., technical services manager for Syngenta

1. What are the key nematode species in the U.S. and the best time of year to control each?

Nematode species vary in the time of year when they feed and actively cause damage. Sting, lance and Anguina nematodes are most active in the spring and fall when soil temperatures are moderate. Root-knot nematodes are active year-round when turf roots are growing. For best results, apply Divanem® nematicide when the target species is actively feeding.

2. How important is resistance management when controlling nematodes?

Nematicide resistance is a new issue that currently appears to be limited to specific nematodes (e.g., sting and root-knot), chemistries (SDHIs such as fluopyram) and locations (e.g., Florida). To help prevent widespread resistance, these management strategies are crucial:

• Rotate and/or tank mix different modes of action
• Apply only enough product to keep nematode populations below damage thresholds

3. What makes Divanem a unique solution for nematode control, and how can superintendents get the most out of each application?

Divanem offers broad-spectrum control of nematode species like sting, root-knot, lance, spiral and Anguina. Its formulation targets nematodes where they are most active to enhance turf quality, improve drought tolerance and enable turf to recover quickly from stress.

Divanem recommendations:

Spot treatments are recommended for areas with nematode damage or damaging levels of Anguina, sting or lance nematodes

• Spot treatment: 12.2 fl. oz./10,000 ft.² (max.: 10,000 ft.²/A of treatable turf)
• Broadcast to control root-knot nematodes and bermudagrass mites:
  • 3.125-6.25 fl. oz./A applied on a 14-21 day interval
• Rates >6.25 fl. oz./A: reapply on a 21-28 day interval
• Annual limit: 50 fl. oz./A at any rate

For best results:

• Apply to wet turf in early morning
• Tank mix with soil surfactant and water in immediately to move into the thatch and root zone
• When possible, apply after aerification for maximum movement into the root zone
• Tank mix with a fungicide like Heritage® Action™ to speed recovery from aerification and improve overall turf quality
  • Divanem and Heritage Action can be purchased together as part of a convenient Multipak for 10% savings

4. Why is it important to tank mix Divanem with a fungicide when nematode counts are high?

Nematode feeding causes wounds on turfgrass roots, making them more prone to fungal infections. Where nematode populations are high, we often see more problems with root diseases like Pythium root rot, summer patch, mini ring and take-all root rot. In field trials, we see improved root growth and turf quality when Divanem is tank mixed with a broad-spectrum fungicide like Heritage Action, Briskway® or Velista® fungicides.

5. We heard about TYMIRIUM technology at the 2025 GCSAA Conference and Trade Show. What can you tell us about it?

Upon registration, this new nematicide/fungicide featuring novel TYMIRIUM® technology will be the only product labeled to control both nematodes and fungal diseases with a single active ingredient. It targets key turf-feeding nematodes such as sting, lance, root-knot and Anguina and fungal diseases including spring dead spot, mini-ring, take-all root rot and fairy ring.

Application timing varies by turf species, nematodes and/or diseases. Fall applications control sting/lance nematodes, spring dead spot and take-all root rot. Spring-to-summer applications control root-knot nematodes and help prevent fairy ring in a program approach. Upon registration approval, TYMIRIUM technology will be marketed as Trefinti® nematicide/fungicide.