10 April 1999

Chemical Update

A ROBUST challenge to potato blight – claimed by some experts to be increasing in its vigour – will be mounted next year with the launch of a new fungicide mixture.

Codenamed KP481, the new product from DuPont includes a high level of the familiar fungicide cymoxanil in combination with DuPonts new compound famoxate which uses a similar mode of action to strobilurins in the way in which it attacks fungi.

Cymoxanil, already in use in Curzate M, has curative as well as protectant capability and is translaminar in activity rather than systemic. The higher rate proposed by DuPont will increase its mobility in potato plants. Famoxate is particularly effective at killing the mobile zoospores which can move from one plant leaf to another, or drop on to the soil surface and cause early tuber blight.

According to DuPonts Neil Beadle, KP481 is highly rainfast and its ability to move quickly through the crop will help make it particularly suitable for use in irrigated crops. Its timing flexibility will range from 7-14 day intervals. The company believes it could replace systemic products during the mid-stages of rapid growth.

Famoxate is also going through the registration system for use on cereals. It is already available in France and in Ireland as Charisma and should get UK approval for use in 2000. It is similar in activity to the strobilurins but DuPonts first real strobilurin fungicide is still around seven years away from the market.

AGREVOS new triazole wheat fungicide (fluquinconazole) comes with an added extra to boost performance against mildew, septoria and yellow rust.

The extra ingredient is not an adjuvant or fungicide; the patented chemical is called Maximiser. It acts as a chemical bridge carrying some fungicide from the leaf surface into the plant, leaving it in a reservoir just below the outer skin.

This explains outstanding long-lasting protection and curative action against septoria and mildew, says manufacturer AgrEvo. The molecule is also exceptionally crop safe.

With up to 10 weeks protection against septoria, fluquinconazole gives extra flexibility on spray timing. It would help bridge a wide gap between an early T1 and T2, or between a T1 and a later flag/ear spray. And mildew control (protective and curative) equal to the best morpholines is claimed. Brown rust is not controlled.

For those looking to add a cheaper partner to expensive strobilurin chemistry, the Maximiser element also works its magic with these products, says AgrEvo. Added to a strob mix, the fluquinconazole Maximiser products enable the use of cut rates without any loss of activity – both in terms of disease control and the strob yield boosting effect.

The Maximiser ingredient is only available as part of the fluquinconazole products. Two are available now:

&#8226 Flamenco, which is straight fluquinconazole at 100g/litre. Full dose is 1.8 litres/ha.

&#8226 Foil, a fluquinconazole/prochloraz mix (54g/litre and 174g/litre respectively); the prochloraz element brings extra eyespot and curative septoria control. Full dose is 1.25 litre/ha.

A co-formulation with Amistar is under discussion. With the kresoxim-methyl/fenpropimorph strobilurin Ensign, adding fluquinconazole could be valuable as a mildew resistance strategy, as well as allowing rate reductions.

In line with AgrEvos marketing strategy, distributors will offer either Foil or Flamenco, but not both. The company is coy about revealing price details, but growers might expect a price tag similar to the best of the current triazoles (ie Opus).

Fluquinconazole is also the active ingredient in a new take-all seed treatment being developed by AgrEvo. Subject to approval, this product may be available in time for autumn drilling.

THE Government is issuing more stringent guidelines in case pregnant women come into contact with tridemorph. New research has shown that the active ingredient in this cereal fungicide can harm unborn children. Additional protective equipment, engineering controls and restrictions on dose are now advised.