Nematode damage can cause severe problems on highly-maintained turfgrass. I have recently received a number of inquiries about nematode control, and I wanted to share some information on this topic for those who may be interested.
Nematodes are very small worms; there are many different species of nematodes, some of which are harmless or even beneficial, and others that damage turfgrass plants which are termed plant pathogenic or plant parasitic nematodes. In short, the problem associated with high populations of plant pathogenic nematodes is a stunted root system. When the root system is restricted, the turfgrass will be particularly susceptible to drought, nutrient deficiencies, and other stresses.
For a summary of the problems nematodes may cause, what control measures are available, and how to minimize nematode damage, I recommend this article from Australian Turfgrass Management, Managing Nematode Pests on Turfgrass by Dr. Graham Stirling.
I would summarize the turfgrass nematode problem by noting three crucial points:
- There are very few chemicals that can be used to control nematodes, these products tend to be extremely toxic, and their use should be minimized
- By the time you can see turfgrass damage from nematodes, it is too late; the damage is done, it will take careful management to allow the grass to recover, and pesticide applications at this point may allow the turf to recover faster, but there is already significant damge.
- This is the crucial point - MINIMIZE turfgrass stresses so that nematode damage does not cause unplayable turfgrass conditions. Create a rootzone environment that is amenable to turfgrass root growth, avoid drought stress, eliminate any nutrient deficiencies, don't cause undue stress on the turf by cutting with dull blades or smothering the leaves in topdressing sand. If we can reduce the stress that the turf is under, nematode damage will be minimized. As Dr. Stirling wrote in his article:
Nematodes can cause severe damage to turfgrass stands, but the damage is not a given; by implementing a turfgrass management program that minimizes stress on the turfgrass, turfgrass problems associated with nematodes can be avoided.