Here is the response from Gerofe Kelley owner of Greenway and Stevenson Ranch
Nematodes are organisms that can cause damage to many plant types. In fact they cause billions of dollars of loss to the agricultural crops world-wide each year. In turf grass there are about a dozen parasitic nematodes that have been identified that cause major damage to turf grass species. Specific nematodes cause damage to different turf grasses, such as the Sting nematode that causes damage to Bermuda grass greens, the spiral nematode that attacks Paspalum, the ring nematode that attacks bent grass (High populations of ring nematodes have been recently tied to the decline and death of bent grass greens, Auburn University) and as you likely already know the anguina nematode that attacks poa annua turf in costal California. Other parasitic nematodes attack these turf grasses as well but these specific nematodes are more damaging to the individual grass types.
What has been widely accepted as the achilles heel of sand based greens is the nematode infestation susceptibility. The low organic content of the sand based USGA Greens profile mix provides little antagonistic buffering to the damaging nematodes. Sure, there exists some organic content at the thatch layer that increases over time. But this layer does not provide any antagonistic biology as it is still too immature to harbor the more desirable biology. Therefore, the root zone has become a susceptible environment for nematodes. Interestingly, we are experiencing the damage on our USGA greens, however our extended bent grass collars that were built on native sand have no damage.
Typically more native and pushup type greens have much more organic and biological protection to control the damaging nematode species and usually have less nematode pressure except when sand topdressing has been used for long periods of time, there can be an increase in nematode populations.
Nematodes inject toxic enzymes, probably to aid in digesting the cell contents and this causes a rapid deterioration of the cell and neighboring cell tissue. It has been well documented that a nematode can literally kill cells within minutes to several hours once feeding commences. Not surprisingly, the more of them there are, the more likely and more rapid the serious tissue damage will be.
As the root is attacked, it loses its metabolic function of absorption of soil, water and nutrients into the plant. Any stress and the plant rapidly declines and there is often no turning back, because the root system is usually so depleted, that the plant cannot provide moisture and metabolites for the rest of the leaf tissue.
Extensive studies of nematodes from universities show that when populations greatly increase there is the potential for turf damage. With the removal of Nemacur the most effective nematicide in the last 35 years and the removal of other organophosphates, nematodes are on the rise. An article in a recent USGA Green Section Record (9/7/12 issue) written by Dr. Jeff Nus a USGA research expert he points out that we are seeing an increase in damage to putting greens throughout the country. Many areas throughout California have been identified with nematode infestations and identification of various parasitic nematodes has caused several golf courses to replace greens. As weather conditions also change we will likely see more nematode activity throughout the country, nematodes are tough pests to deal with on established turf. Regardless of the situation good management practices will minimize damage caused by nematodes, but effective nematicide treatments are the only effective control once all other management procedures have failed to suppress turf damage.
Without a reliable product for control, we are raising the cutting height and applying more fertilizer and water to grow more tissue which means that we will have slower and softer greens here at Stevinson Ranch GC. This is not what we desire. We have developed a reputation for having extraordinary bent grass greens that play fast and firm. In order to return to these conditions we are developing a large nursery green and intend on replacing our 18 year old bent grass greens with a newer and more aggressive bent grass variety, Tyee 3. We also plan on fumigating and modifying our root zone to make it less susceptible to nematodes in the future so we can maintain the level of quality in our putting surfaces our players have come to expect.
Michael, I hope that this helps explain the issues that we are experiencing with our greens. The greens are not what we desire, however they are playable and the rest of the course is perfect