Brown patch is more severe on which turf condition?

Brown patch is more severe on which turf condition?

• A. Turf grasses under high nitrogen fertilization
• B. Drought stressed turf grasses
• C. Shade tolerant grasses
• D. Newly seeded turf areas

Answer: (A)

Brown patch grows most aggressively when turf is fed with high nitrogen. Nitrogen makes the grass put out rapid, lush growth, creating a dense, expansive canopy. That dense canopy traps moisture and keeps leaf surfaces wet longer after dew or irrigation, which is exactly the environment the brown patch fungus (Rhizoctonia solani) needs to infect and spread. The rapid, succulent tissue also makes it easier for the pathogen to invade and move through the leaf tissue, so patches develop and expand more quickly. Drought-stressed turf has less leaf wetness and moisture available for the fungus, so brown patch is typically less severe there. Newly seeded areas have sparse, immature growth and less canopy density, which doesn’t provide the same conducive microclimate for the disease, so outbreaks aren’t as severe. Shade can alter humidity and leaf moisture, but without the high nitrogen-driven canopy and moisture retention, it isn’t as strong a predictor of severe brown patch as high nitrogen fertilization.

Brown patch grows most aggressively when turf is fed with high nitrogen. Nitrogen makes the grass put out rapid, lush growth, creating a dense, expansive canopy. That dense canopy traps moisture and keeps leaf surfaces wet longer after dew or irrigation, which is exactly the environment the brown patch fungus (Rhizoctonia solani) needs to infect and spread. The rapid, succulent tissue also makes it easier for the pathogen to invade and move through the leaf tissue, so patches develop and expand more quickly.

Drought-stressed turf has less leaf wetness and moisture available for the fungus, so brown patch is typically less severe there. Newly seeded areas have sparse, immature growth and less canopy density, which doesn’t provide the same conducive microclimate for the disease, so outbreaks aren’t as severe. Shade can alter humidity and leaf moisture, but without the high nitrogen-driven canopy and moisture retention, it isn’t as strong a predictor of severe brown patch as high nitrogen fertilization.