The Ohio State University

Home International SportsNotes In the summer, grass goes brown for many reasons: disease, pest attack, heat stress, dormancy, animal and human damage or any number of physiological stresses. Take this quiz and test your diagnostic skills! Pictures & clues are numbered below. All of these problems occur in summer (late June/July/August). Answers will be posted next week. Good luck!
1. Clue: The original goal was to save time weed whacking/strimming around goal posts and other obstacles. ANSWER: An application of Roundup (glyphosate) was made around the goal posts. The sprayer was broken and stayed on but the applicator carried on as she didn't realise what the extent of the damage would be. oops!
2. Clue: Highly maintained Kentucky bluegrass turf, recently mowed and aerated. ANSWER: Aggressive practices like core aeration can cause severe stress in the summer, especially on cool-season grasses.
3. Clue: Easier to prevent than rectify. ANSWER: Objects sat on turf will quickly kill the grass underneath, either through lack of sunlight, scorching, or disease
4. Clue: Kentucky bluegrass turf is dead and pulls away easily from the soil, perennial ryegrass is not affected. ANSWER: Bluegrass billbugs have eaten the crowns of the bluegrass plants
5. Clue: Bermudagrass, tall fescue and perennial ryegrass most susceptible in hot, humid conditions. The problem is aggravated by N fertilizer and light/frequent irrigation. ANSWER: Brown patch (Rhizoctonia) disease
6. Clue: A problem on warm and cool season grasses. Often associated with low N soils and stressed turf. ANSWER: Dollar spot (Sclerotinia homeocarpa) disease
7. Clue: Next 3 pictures. Very common and usually misdiagnosed. Looks like drought stress/disease/fertilizer burn but is in fact none of these things. Watering & coring will not help. Upon closer inspection, turf has formed a straw-colored, musty smelling mat. Recovery in the fall is surprising and rapid. ANSWER: Rough bluegrass (Poa trivialis) going dormant in the heat. It recovers with cooler temperatures in the fall.


8. Clue: Trying to establish new seedlings in summer can be a challenge. ANSWER: Damping off disease/Pythium caused by a number of fungi, including Rhizoctonia. Summer seedings are especially vulnerable.
9. Clue: A common sight on low-budget fields in summer. ANSWER: Drought stress. Cool-season turf wil typically go dormant.
10. Clue: Accidents will happen. Time to get the hose out. ANSWER: Fertilizer burn
11. Bonus question, so no clue. ANSWER: The applicator sprayed glyphosate, then carried it off on their shoes onto adjacent turf

Posted by Pam Sherratt & Dr. John Street