Which fertilizer strategy is suggested for lawns affected by necrotic ring spot?

Which fertilizer strategy is suggested for lawns affected by necrotic ring spot?

• A. Increase total annual nitrogen using slow-release forms
• B. Decrease nitrogen altogether
• C. Use only organic compost, no synthetic nitrogen
• D. Do not fertilize until symptoms disappear

Answer: (A)

The main idea here is that necrotic ring spot is managed by keeping the turf strong and healthy, so providing adequate nitrogen through slow-release forms is the most effective approach. A steady supply of nitrogen over time helps grasses grow more vigorously, fill in damaged patches, and develop a denser canopy. That density reduces exposed soil where the pathogen can establish itself and supports better root development, which helps the turf recover from infection. Slow-release nitrogen is preferred because it feeds the grass gradually, avoiding rapid growth spurts that can stress tissue or wash away nutrients, and it minimizes peak conditions that might favor disease progression.

If nitrogen were reduced or withheld, the turf would become weaker and more susceptible to damage from the disease, leaving more bare or thin areas for the pathogen to exploit. Relying solely on organic compost can lead to inconsistent nutrient availability and may not provide enough readily available nitrogen when the lawn needs it most. Waiting to fertilize until symptoms disappear gives the disease time to spread and causes more injury before the turf regains vigor.