Good micro climate for disease

1 March 2002

Good micro climate for disease

THE micro-climate within thick, early drilled crops has been ideal for eyespot development, says Dick Neale, Hutchinsons technical manager.

"Unusually, the early drilled first wheats are at much greater risk than second wheats drilled at more traditional times. They have a mass of tillers and it has been exceptionally warm down at the base of the plant."

Second wheats are still at risk, particularly if they were sown early, adds Mr Neale. "The spores wouldnt have died before drilling took place. And even if you ploughed, its possible to bring inoculum back up again."

Growers must assess their own crops for eyespot, he advises. "Get right down and look at the part of the stem which is one inch above ground level. Youre looking for a light coloured smudge.

"Soils are still very wet, so conditions in the crop will be perfect for a while. Eyespot is unlikely to dry up just yet."

"Be sure to check all tillers, so that you can decide what level of infection exists. Then you might want the advice of an agronomist to determine whether it is worth treating."

Too late

Mr Neale believes GS32 is too late to get on top of the disease. "Start at GS30 if you are using a product such as Sportak (prochloraz). Unix works better at GS31, when the plant has started to lose tillers naturally, and the chemical is applied to tillers that matter."

Mr Neale stresses the importance of knowing infection severity. "You can have infection on every tiller, but the lesions arent penetrating. You need to find out whether they are penetrating the outer stem."

Inspecting crops now offers an opportunity to include an eyespot product in with the early pgr at GS30 if necessary. "Opt for Landmark (kresoxim-methyl) or Foil (prochloraz + fluquinconazole) at this stage," he advises.

If the crop still has eyespot at GS31/32, then Unix can be added to the second pgr. "Dont forget that if the weather dries up, eyespot will too. But while theres humidity in the crop, the disease will thrive." &#42

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