1 What symptoms should golf course superintendents look for when scouting for nematodes?
A: Nematodes usually don’t kill turf directly, but they increase its susceptibility to stress. Symptoms might resemble wilt, nutrient deficiency or a variety of other stresses. These symptoms are usually very irregular across turf, but root-knot nematodes occasionally cause distinct patches. The variety of symptoms makes nematode damage very difficult to diagnose.
2 How are nematode problems diagnosed?
A: If nematodes are a suspected problem, superintendents should submit soil samples to a nematode laboratory for analysis. Tips for proper sampling, as well as where to find a local lab, can be found at GreenCastOnline.com/NematodeKnowledge. The lab will quantify each nematode population (sting, root-knot, lance, etc.). If the population is above the threshold values set for that species, then nematodes are likely contributing to the problem.
3 What factors should superintendents consider when building an agronomic program for nematode control?
A: The best approach to nematode control depends on which nematodes are present, the turf species and climatic conditions. Nematode species have different feeding behaviors and vary in their sensitivity to nematicides, so a nematicide program approach is a lot like building a fungicide program. Divanem® nematicide is an excellent foundation because of its broad-spectrum activity against root-feeding species. Depending on which nematodes are present, other products can be useful in a season-long approach to help manage resistance.
Roots compromised by nematodes are more susceptible to soil-borne diseases. An agronomic program typically includes fungicide applications that help protect turf from diseases that may develop as the result of compromised roots. Heritage® Action™, Velista® or Posterity® fungicides are great options that can help enhance turf quality, and protect against diseases and abiotic stresses. Visit GreenCastOnline.com/Programs to view agronomic programs for your region.
4 When conducting a nematode control trial, why is it important to leave an area untreated?
A: A side-by-side comparison of treated vs. untreated turf is the most definitive way to tell if a nematicide program is helping. Nematode populations naturally fluctuate during the season, so it’s impossible to tell how a nematicide affected the population without comparing treated turf to samples from an untreated area collected at the same time. In some cases, nematicide applications can actually lead to higher nematode populations because the root system is more robust and can support a higher population. I always encourage superintendents to focus more on turf quality and root growth. Having an untreated area for comparison allows you to see these real benefits.
5 What benefits should superintendents expect from the Divanem spot treatment rate?
A: Divanem features a spot treatment rate of 12.2 fl. oz./10,000 ft.2. Superintendents must have the Divanem supplemental label on file when making spot treatments. It is particularly useful for curative situations, where damage has already occurred or nematode populations are extremely high. The spot treatment rate provides greater control of nematodes as well as faster improvements in turf quality. Typically, two to three applications of the spot treatment rate are recommended before transitioning to a preventive management program.
Existing Divanem inventory can be applied at the spot treatment rate by downloading the supplemental label at GreenCastOnline.com/Divanem.
For complete trial info, visit GreenCastOnline.com/Divanem
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