A Serious But Treatable Lawn Disease
Nearly all Bermuda grass varieties are affected by spring dead spot, especially in the cooler parts of the transition zone. Other grass types are affected, but this lawn disease is primarily a problem with Bermuda varieties. As the name suggests, spring dead spot usually appears in the spring as circular patches of bleached dead grass. It becomes visible as the surrounding dormant turf resumes its normal spring growth. These patches range from a few inches to several feet in diameter and tend to show up and expand in the same locations for several years, and then disappear after three to four years. The fungi appear to grow most actively in the fall and spring when temperatures are cool and the soil is fairly moist. Even though damage begins in earnest in the fall, damage is masked by the turf's normal dormancy over winter. This lawn disease is most commonly found on mature and well maintained turf, and is much less serious on lawns receiving little or no fertilization.
Disease Cycle: What Spring Dead Spot Does
During the early stages of this disease, the inside of the patches remain alive, but die off as the infection progresses. The entire plant structure inside these rings dies, including the shoots, rhizomes and roots. Regrowth in these dead areas must occur from the expansion of surrounding healthy plants and is very slow. The rings often fill with weeds or with stunted new turf plants. This appears to be because the lawn disease leaves a toxin in the area of dead grass which makes regrowth difficult.
Treatment Plan Must Include Fall Applications
Treatment for spring dead spot includes carefully controlling the amount of nitrogen fertilizer applied to the turf, since high nitrogen levels increase activity. In addition, fungicides must be applied during the fall months to fend off extreme root and stolon rot over the winter months. Contact type fungicides can be used with some success, but must be applied repeatedly. On the other hand, systemic lawn treatment fungicides that are actually taken into the plants can be applied once in the fall at heavy rates to help control the disease the following spring.
Remember:
- Bermuda varieties with high cold tolerance are less prone to spring dead spot.
- The actual fungi (or causal organism) of spring dead spot is unknown.
- Remember that control for spring must begin in the fall.
- Part of controlling this lawn disease is regulating the amount of nitrogen fertilizer applied.
We make a constant study of lawns and what ails them at Spring Green. Please feel free to contact us at any time to discuss your local lawn service needs.
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