Impact

Take-all is a soilborne fungus, Gaeumannomyces graminis, typically affecting barley and wheat. Influence on barley is minimal. The greatest impact can be realized after the second year of continuous wheat. Grain yield reductions can reach 60 percent. Yields are reduced, because of inhibited grain filling. Infections that occur late in the season remain confined to the roots and usually cause little damage. Take-all occurs throughout the San Luis Valley and typically develops after the second year of continuous grains.

Take-all discoloration of basal nodes (right).

Description and Symptoms

Take-all infects the crown and roots of the plant.

Severely infected plants are stunted, produce fewer tillers, ripen prematurely, and produce bleached-white heads, shriveled kernels or no seed.

Symptoms become obvious at heading especially the white heads and stunting.

Severely infected plants are easy to pull out of the soil.

Uproot severely infected plants to reveal crown rot, severely pruned roots, and a shiny, steel-black stem surface under the lower sheaths.

Black masses of mycelium are easily scraped off the base of the culms, a key characteristic.

Black masses of mycelium are easily scraped off the base of the culms, a key characteristic.

Black masses of mycelium are easily scraped off the base of the culms, a key characteristic.

Early signs of infection are a darkness inside the roots.

Integrated Management

Rotate with non-host crops such as oats, alfalfa, or other broadleaf plants. A one-year break in small grains cultivation is sufficient to reduce soilborne inoculum levels but will not eliminate the take-all fungus.

Maintain sufficient nitrogen and phosphorus fertility to encourage root and crown development. Limit soil compaction to discourage irrigation runoff and disease development.

Select fertilizer materials for limiting take-all development. Nitrate-based fertilizers support take-all more than ammonium or urea fertilizers. Chloride-containing fertilizers, like potassium chloride, can limit take-all in Some regions.

Maintain adequate copper levels to reduce take-all. When soil levels test low, soil apply 5 to 10 pounds of copper per acre to the soil or foliar apply 0.25 pounds per acre.

Avoid excessive irrigation, especially during the early part of the season. Accurate irrigation management can greatly reduce take-all infection even if all other conditions support take-all development.

Limit infection of the next crop by burying crop residues through tillage. However, soil erosion potential may increase.