By Joseph M. Vargas Jr.
A new problem that has manifested over the last few years is nematodes. Why they are suddenly becoming a problem is mysterious. Nematodes are being found at counts around 6000 per 100 cc (6.1 cu in.) of soil. If present, they feed on the roots of the turfgrass plants because they are obligate parasites. This means they can only obtain their food from a living host and, in this case, a living turfgrass root. Once the turfgrass plant dies, the nematode also dies since it no longer has a living food source. The most common nematodes associated with this new problem include the stunt (Tylenchorhynchus), the ring (Criconemoides), and the spiral (Helicotylenchus), which have become affectionately known as the “triple-headed turfgrass monster.”
The next time there is a problem with the turf, and every fungicide has been tested but the problem has not gone away, you might want to check for nematodes. They are obligate parasites and, therefore, you should take the sample from a declining area or near a dead area, but never from the dead area. It may well be there are no longer any really effective nematicides, but at least you will save money when you stop making ineffective fungicide applications for a nematode problem. Until new nematicides come along, the best you can do is increase irrigation frequency and foliar feed the turf with its severely damaged root systems.
Read the full article: Controlling Turfgrass Diseases