Bermudagrass is a serious problem throughout most areas where Bermudagrass is grown as a fine turf for golf courses, athletic fields and lawns. While there are three different organisms that cause Spring Dead Spot, the most virulent one is Ophiosphaerella herpotricha. This organism is responsible for Spring Dead Spot in the more arid areas of the country like Oklahoma, Arkansas and Texas. It has proven to be very difficult and very expensive to control with fungicide applications.
Traditionally, turf managers use low cost water-soluble synthetic fertilizers in their fertility programs on Bermudagrass and then put some serious money into fungicides to try to control the disease. In recent years, some turf managers have been reporting success with using Nature Safe rather than fungicides to suppress Spring Dead Spot. The ones that had the best results used Nature Safe as their regular fertilizer throughout the season and they continued making Nature Safe applications into the fall of the year. Some turf managers in more humid coastal areas, such as Alabama and Mississippi, reported making Nature Safe applications as late as December. The late season applications are important to keep the soil microbe activity at high enough levels to be able to compete with the pathogen. If the more traditional method of fertilizing Bermudagrass is followed, normally all applications of fertilizer are stopped late in the summer. With Nature Safe, it is important to make applications late in the year to keep soil microbe activity at a maximum when the disease becomes active late in the fall. Unlike synthetic fertilizers, Nature Safe will not overly stimulate the Bermudagrass with late season applications. In fact, these late season applications of Nature Safe accelerate the spring green up rate of the Bermudagrass.
The study conducted at Oklahoma State University in Stillwater, Oklahoma looked at using season long applications of Nature Safe 10-2-8 on fairway type Tifway 419 Bermudagrass versus similar turf that was fertilized with synthetic fertilizers and others that received applications of fungicides. The final application of Nature Safe was made on October 3 and the turf was monitored and rated throughout the following spring. The final rating was done on May 22. The data shows that less disease occurred on the Nature Safe plots and that the diseased areas that did occur on the Nature Safe plots recovered much faster during the spring months. Compared to the plots where synthetic fertilizer was used, the Nature Safe plots showed a lessened severity of disease and higher turf quality. The Nature Safe plots were rated as nearly equal to plots that had received several fungicide applications. Comparing photographs of the plots in the spring of 2005 with similar photos taken in the spring in 2006, the Nature Safe plots showed marked improvements over the plots that received synthetic fertilizer and were rated as nearly as good as the plots that were treated with fungicides.
The disease severity ratings were done on a scale of 1 to 6, where 1 equaled no living plants in the diseased areas, 3 equaled 50% living plants in the patches and 6 equaled no evidence of disease. On May 22 the Nature Safe plots were rated at 5.50 versus 3.75 for the synthetically fertilized plots and 5.25 for the plots that received fungicides.
Turfgrass quality ratings were done on a scale of 1 to 6 where 1 equaled large, well defined patches and unsightly turfgrass, 3 equaled moderately acceptable turfgrass and 6 equaled thick healthy turf with no appearance of patches of disease. On May 22, the Nature Safe plots were rated at 5.00 versus 3.50 on the synthetically fertilized plots and 5.00 on the plots receiving fungicides.
The results of this one year trial suggest that making season long applications of Nature Safe to Bermudagrass turf will help to suppress Spring Dead Spot and promote more rapid recovery in the spring without the use of fungicides. In areas of the country where less virulent species of the pathogen exist, the results would be even better. As with most diseases, Nature Safe becomes more effective in suppressing them after it is used for more than one season. We expect to see improvements in disease suppression and overall turf quality in the second and third years of a Nature Safe program without the use of fungicides.