6/7/2021 - By Dr. Raymond Snyder

Managing turf experiencing nematode stress requires a holistic approach. The turf likely will require greater inputs of water and foliar applied nutrients due to the compromised root system. A proactive, integrated nematode control program is often essential, due to the potential presence of multiple nematode species which all have their own biological behaviors.

To identify an effective nematode management strategy, Harrell’s funded a two-year study with Dr. Crow, University of Florida professor of nematology. The overall objective of this study was to evaluate the effect of multiple nematode control agents alone and in combination with proven soil amendment sources on nematode populations and turfgrass health. The study was conducted in Citra, FL using Jones Dwarf bermudagrass.

The treatment list is below:

Dr. Crow summarized his findings below:

Discussion: Nematicide applications impacted each of the three target nematode species differently. Sting nematodes were virtually eliminated from the two treatments receiving nematicides during the second year of the trial. However, lance nematode numbers increased in the treatments receiving nematicides throughout the trial, and at some observation dates from the Harrell’s Root Health Program alone. Treatment effects on root-knot nematodes were inconclusive.

Treatments receiving nematicides had greater percent green cover, turf quality, and NDVI at most observation dates and cumulatively. The Harrell’s root health program did not have a significant effect on cumulative turf percent green cover and quality, although it had a slight statistical effect on a couple individual dates.

Treatments receiving nematicides improved turf root length at most observation dates, and cumulatively. The treatment receiving both the Harrell’s root health program and nematicides had greater cumulative root length than the nematicides alone.

The results of this experiment do not indicate that the Harrell’s root health program has direct effect on plant-parasitic nematodes, or is sufficient alone to overcome the negative impacts from plant-parasitic nematodes. However, the results do indicate that when sting and root-knot nematodes are present, the Harrell’s root health program can enhance turf root growth if an effective nematicides program is followed.

Currently, Harrell’s has funded ongoing work with Dr. Crow to build upon this successful study. These studies, both ongoing in central Florida, are designed to evaluate the potential benefits of including Curfew soil fumigant as component in this integrated nematode management program.