Charles Overstreet, Ferrin, Donald M., Koske, Thomas J. | 7/25/2006 1:37:01 AM
Big changes are soon to take place in the battle to keep golf greens healthy and protected from plant-parasitic nematodes. As in most of the other Southern states, nematodes have been a perpetual problem in Louisiana and caused us many problems in trying to maintain good greens.
Sting nematode appears to be our primary culprit in golf greens. This is the nematode that can cause large dead areas in greens as well as really thin, unthrifty grass that fails to respond to any fertilizer, watering or cultural management regime. However, we had had our share of problems from other nematode species that include southern root-knot, lance, stubby-root, awl and ring. Likewise, any of these nematodes or combinations of them can cause turfgrass to be weak and unhealthy.
Our chief nematicide for many years has been Nemacur. However, cancelation of this nematicide is underway, and Bayer will continue to sell and distribute Nemacur until May 31, 2007. Distributors can continue to sell this chemical until the same time in 2008. The loss of this nematicide is going to really have a strong impact on our ability to manage these pests in greens.
Curfew is a relatively new fumigant material that may really help us out. This product was first labeled for use in Florida in 2003 but has recently obtained Section 24(c) Special Local Needs registration for a number of Southern states including Mississippi, Georgia, North and South Carolina, Alabama and Texas. Louisiana was granted a Special Local Needs use of Curfew on May 16, 2006.
Because it is a fumigant material and can cause some damage to turfgrass if not applied properly, special application equipment is required. There is currently only one company that is certified to apply this nematicide to golf greens. This is International Turf Applicators, Inc. located in Lakeland, Florida.
Over the next two years, we will be forced to transition from Nemacur to Curfew for nematode control. Curfew works great against sting nematode but will likely be a fairly costly treatment because of custom application. Our only other options are to maintain good growing conditions for turfgrass, including keeping pH and nutrient levels optimum for good growth, raising the cutting height to get better root growth and good water management. Unfortunately, we may have a hard time of compensating for the damage caused by nematodes in many situations.
One of the problems that we observed with Nemacur at some golf courses in Louisiana was enhanced biodegradation. This is nothing more than the microorganisms in the soil breaking down the product rapidly, thus reducing its effectiveness as a nematicide. Using high rates and multiple applications probably contributed greatly to this problem. Since Curfew is a fumigant nematicide, this problem is not nearly as likely to happen with it. Fumigants move fairly quickly through the soil profile, killing the nematodes and then escaping into the atmosphere.
Although the loss of Nemacur will certainly impact our golf industry and our ability to manage nematodes on our own greens, the advent of Curfew keeps us from being completely without an alternative. There is still considerable effort underway to try to find chemical or biological management options against nematodes. Meanwhile, our choice of an effective nematicide may be fairly thin for the next few years.
Keep a close watch on your greens for nematode damage and prepare to take steps to help reduce the damage potential from this important pest. Late summer (August and September) are good months to have greens checked, since you still have time to reduce nematode populations and improve the health of the turfgrass before the onset of winter. April and May are also good times in the spring to check for nematodes. Turfgrass is coming back out of winter and starting to grow fast at this time. There is now a $10 per sample charge for each nematode sample. Checks should be made out to: LSU Agricultural Center-Nematode Advisory Service and included with the samples and forms.