I had never heard of them until yesterday when I read our greens superintendent's report that mentioned we had them. We've had a very wet summer here in the Northeast. Here's what he had to say (and by the way - he's an absolutely marvelous greenskeeper, formerly the head assistant at Oakmont and he helps prepare USGA sites, so I put great stock in what he says):
Following rapid turf decline on the putting green, #4-#6 and #18, we performed extensive evaluation and testing and have been
diagnosed with turf parasitic nematodes. Nematodes are microscopic worms that, when present in very high populations, feed
on and destroy turfgrass roots. Small populations of nematodes are common in all soils, but very high populations that cause
turf damage are somewhat rare. The symptoms expressed by the nematodes are very hard to diagnose, and laboratory analysis is
imperative to confirm diagnosis. Our current nematode populations are approximately 7x the damage threshold which went undetected until the week of August 15, 2011 when test results were received. They were detected at this point as symptoms of damage were evident on the turf. Based on the volume of nematodes, our populations represent an accumulation over several years that have gone unnoticed until this point.
As a result, we will have to significantly alter our current management practices on these putting greens. We will be raising
mowing heights, mowing less often, rolling less often, syringing more often, and foliar fertilizing on a very regular basis. You
may see a noticeable decrease in green speed due to the aforementioned agronomic adjustments. We are yet to experience any
damage on tees and fairways and probably will not at this point due to a higher height of cut which reduces stress on turf plant.
The best way to manage nematodes is by relieving all stresses from the turf. Since the rootzone of the effected turfgrass is
totally absent, all water and nutrition needed for plant survival must be manually applied to the plant. The turf is unable to
extract any material from the soil. In addition to experiencing damage from the nematodes, the plant is now extremely
vulnerable to other fungi and insects.
Managing nematode populations is very difficult. We must fortify turf health to help withstand the feeding of the nematodes.
However, since nematodes are a parasite, they are active when they have a viable, healthy host species (i.e. healthy turfgrass
roots). Damage is most evident during the summer as environmental stresses further weaken turf health and vigor. Nematode
populations vary widely from green to green and are influenced by countless factors. Nematodes are virtually impossible to
predict and pose a significant turfgrass issue.
We would like to thank everyone for their patience and support as we work to correct this situation. We are currently making
every possible adjustment in our management program to minimize the severity and volume of the nematode damage. We will
keep everyone notified regarding future nematode developments. We greatly appreciate everyone’s support and understanding
regarding this issue. Rest assured that the entire Grounds Department is working tirelessly to overcome this problem.