Which of the following is an abiotic injury source to turf grass?

• A. Bug spray
• B. Fertilizer burn
• C. Necrotic ring spot
• D. Summer patch

Answer: (B)

Non-living factors causing stress to turfgrass are abiotic injuries. Fertilizer burn fits this category because it results from chemical salts in the fertilizer harming the tissue rather than a living organism. When fertilizer is applied at too high a rate or irrigation doesn’t flush away the excess salts, the roots have trouble taking up water and the plant tissue becomes dehydrated, leading to scorched, brown edges and overall turf thinning. The other options involve living agents or processes: necrotic ring spot and summer patch are fungal diseases, which are biotic injuries. While a pesticide product like bug spray can cause chemical injury if misused, the classic abiotic injury demonstrated here is fertilizer burn, caused by non-living chemical stress rather than a pathogen.