30 May 1997

Co-formulation allows later application

ENSIGN contains kresoxim-methyl, which also offers good protection against mildew. It is co-formulated with fenpropimorph to provide eradicant activity, which means the new BASF product can be applied later than Fortress.

It has some activity against septoria, and offers some eyespot and rhynchosporium control, too. It also promotes crop greening, particularly in the lower part of the plant. Crop Care trials have given an average 10% yield rise over conventional treatments where crops were under high disease pressure and where there was no moisture stress.

"Kresoxim-methyl seems to enhance nitrogen uptake and alters the balance of the plants diurnal rhythms, so it produces carbohydrate for a longer period," notes Mr Myram. That yield boost is needed to pay for what is an expensive chemical. The full rate of 0.7 litres/ha costs £40/ha (£16/acre). There is little scope to cut back, he warns. "We have not seen the yield benefits at lower rates."

On more resistant wheat and feed barley varieties (the product is not yet cleared for malting barley use) that full rate may be all that is needed at the first application timing in mid-April when the third leaf is emerging.

On septoria-prone varieties like Riband and Brigadier and at the second spray timing at flag leaf on all types, a triazole will be needed to control that and other diseases, especially rusts.

A 0.5 litre/ha rate of epoxiconazole (eg, Opus), the favoured mixing partner, pushes the price to £58.50/ ha (£23.40/acre), although Opus rates could be cut on more resistant types, Mr Myram predicts.

That is substantially higher than for Fortress. "The extra cost represents about 2cwt/acre. But you should get 6cwt/acre more on average," says Mr Myram.

Another new product, Unix (cyprodinil) from Novartis, looks to be a good partner, adds Mr Myram. "It has some mildew effect but uses a different mode of action, and offers new standards of eyespot control." &#42