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Symptoms and Signs

Field symptoms

On small grains, take-all first becomes apparent near the time when the seed head emerges. The leaves are yellow and plants may be stunted. The disease usually occurs in circular patches (Figure 2) although it also can be fairly uniform throughout a field (Figure 3, right three-quarters). Perhaps the most diagnostic field symptom is prematurely-ripe tillers ("whiteheads") (Figure 4).


Figure 2	Figure 3	Figure 4

On closely mowed bentgrass turf, take-all results in the formation of roughly circular dead patches ranging from a few centimeters (inches) to more than a meter (3 feet) in diameter (Figure 5). Patch margins often are bronze to yellow-orange. Patches may reappear in the same location in successive years.


Figure 5	Figure 6	Figure 7

Root Symptoms

Take-all is identified by the dark brown to black rotten roots or stolons. Initially, roots have small black lesions that expand and later coalesce (Figure 6). Heavily rotted roots are very brittle and much of the root system remains in the soil when plants are pulled up(Figure 7). When the leaf sheaths are pulled away from the stem, a shiny black discoloration of the basal stem is highly diagnostic for take-all (Figure 7). Under a microscope, dark brown "runner hyphae" (or ectotrophic growth, Figures 8 and 9) and mycelial mats (Figure 10) on roots or stolon surfaces are easily seen and are also helpful in diagnosing this root disease.


Figure 8	Figure 9	Figure 10

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