A sugar-beet fungicide widely used on the Continent will be available for the first time this season in the UK.
Syngenta’s Spyrale, which contains difenoconazole plus fenpropidin, gives growers a new mode of action against rust, powdery mildew and ramularia, as well as the persistence to maintain leaf growth into the autumn, according the firm’s Alison Pawson.
In trials the product, which has been available in France for 10 years, has given 80% better rust control than flusilazole/carbendazim (Punch C) up to 72 days after application, plus 40% better control of powdery mildew and 70% better ramularia control up to 64 days after application, Syngenta claims.
“A lot of the new rhizomania resistant varieties have low inherent resistance to other diseases like powdery mildew and rust, so there is potential for problems to come in stronger and earlier.
“Growers of these varieties will have to give more consideration to what they will apply,” Mrs Pawson says.
Sprays should be timed to meet the onset of disease, generally some time in July.
“This should see you through to October or November lifting. But if you’re harvesting later – say December or January – it may be worth making one application in July and a second in August/ September, depending on disease levels.
Also, if you’re growing exceptionally weak [disease resistance] varieties you may need to go in twice.”
An added benefit of the product is its effect on extending crop greening, Mrs Pawson continues.
In British Sugar trials in 2004 and 2005, Spyrale gave similar levels of greening to cyproconazole, Punch C and Opera (pyraclostrobin + epoxiconazole) 56 days after application, she says.
The recommended maximum dose rate for Spyrale is 1 litre/ha and up to two treatments per crop are allowed (compared with one for Punch C).
The product is likely to be priced at a premium to Punch C.