- Special Sections
- Public Notices
Nitrogen fertility has a significant impact on large patch development. High nitrogen levels promote the growth of soft, succulent leaves that are susceptible to attack by the large patch fungus. To help prevent disease outbreaks, apply a low rate of nitrogen fertilizer at 4 to 8-week intervals or use a slow-release nitrogen source to maintain an even growth rate. To reduce disease outbreaks during the winter and early spring, avoid fall applications of nitrogen fertilizer. Finally, maintain phosphorus and potash fertility levels according to soil test recommendations. In addition:
1) Avoid over-fertilization of turfgrass growing in shaded areas.
2) Use slow-release nitrogen fertilizers. Fertilize to maintain adequate but not lush growth during the growing season. Properly fertilized turf will recover quicker from disease injury than will under-fertilized turf.
3) Remove and dispose of clippings from the affected areas or when conditions are conducive to disease development. Mulching mowers that chop clippings 1/4-inch or less do not contribute to large patch development.
4) Prune woody landscape plantings and trees to allow better air movement and light penetration to reach the turfgrass canopy.
5) Water infrequently, but deeply, in the morning, and avoid late evening and night watering. Moisture also plays an important role in disease development. Good drainage is needed to remove excess water.
6) Use a preventative fungicide program on high-rate turfs with a history of large patch. On other turfs, apply a registered fungicide at first evidence of the disease. Integrate fungicide treatments with other management practices to maximize their effectiveness. On most lawns, a fungicide spray program should begin prior to symptoms appearing and continue until the turf starts to recover or until weather conditions no longer favor the spread of the disease. Make fungicide applications only when weather conditions are favorable.
The most recent data that we have worked on this year indicated that Heritage TL applied one or two times preventively at 2 oz./1,000 square feet offered the best control. These treatments were not significantly different. Our treatments were initiated in late August and repeated four weeks later.
Send your gardening questions or comments to: Brunswick County Master Gardener Column, P.O. Box 109, Bolivia, NC 28422, or call 253-2610. Enclose a self-addressed stamped envelope if requesting information or a reply. Answers may be printed in this column.