Take-all of Wheat
Gaeumannomyces graminis var. tritici
Take-all refers to the taking of all the grain from the head.
Hay-die refers to the white heads with no grain at maturity as if the plant had been cut for hay.
Description:Blackening of infected roots especially the sub crown internode that joins the grain to the crown of the plant. In severe cases the base of the plant and lower stem may also be discoloured or brown to black. Mature crops may have unfilled heads or white heads.
Species Affected:Wheat, Barley, Barley Grass, Rat-tailed Fescue, Squirrel-tailed Fescue, Sand Fescue, Annual Ryegrass, Brome Grass, Wild Oats and occasionally Oats.
Biology:Carried on infected roots of the previous crop.
The incidence of Take-all increases by 5-10% for each 100 kg of grass in the previous season.
Rat-tailed Fescue, Squirrel -tailed Fescue (Silver Grasses) and Barley Grasses are better hosts of Take-all than Annual Ryegrass, which is better than Brome Grass.
Ammonium sulphate reduces disease levels slightly. Ammonium sulphate is better than Agras 1 or 2, which is better than DAP for reducing disease effect.
Life Cycle:Origin and History:
Poorly defined patches in crop.
Most severe in light textured, low fertility soils with a pH>5
Significance:Take-all causes major yield losses in Wheat, a minor loss in Barley and this form causes little loss in Oats.
Management and Control:Adjust rotations to avoid Wheat following grassy pastures, Barley, Cereal Rye or Wheat. Any broadleaf crop or pasture provides an effective disease break. Oats may be used as a break crop if the strain infecting oats is not present.
Control grasses in the previous crop or pasture.
Do a PreDicta-B soil test which is available from the SARDI Root Disease Testing Service.
Control volunteer grasses and cereals after the break of the season.
Use adequate fertilizer to reduce effects of the disease.
Treat seed with a fluquinconazole (Jockey®) fungicide to reduce Take-all risk.
Triadimefon and flutriafol (Impact®) applied on fertiliser have only provided suppression of Take-all in WA.
Avoid planting Wheat after liming.
Use sulphate forms of nitrogen if possible.
Spear and Dagger have some tolerance of Take-all.
See Disease Susceptibility of Wheat Varieties
Test for inoculum levels in soil.
Delay planting on high risk paddocks
Related and Similar Species:Take-all of Oats (Gaeumannomyces graminis var. avenae)
Collated by HerbiGuide. Phone 08 98444064 or www.HerbiGuide.com.au for more information.