5 April 2002

Fungicide is approved for use on vegetables

CARROT, leek and onion growers can now use strobilurin fungicide Amistar (azoxystrobin) to control a wide range of diseases.

Yield and quality benefits will boost the proportion of marketable crop growers can expect to sell, says Syngenta vegetable manager Bruce McKenzie.

Label approval now covers downy mildew in bulb onions, alternaria and powdery mildew in carrots and rust and purple blotch in leeks. But a wide range of other diseases will also be controlled, says Mr McKenzie. The limited number of diseases was pursued for label approval to secure a fast track registration, he explains.

Field observations show Amistar also offers control of botrytis in onions and white tip in leeks, a problem growers have found increasingly difficult to control, says Mr McKenzie. Extension of use rules also mean the carrot approval can be applied to parsnips.

In carrot trials at Stockbridge Technology Centre in Yorkshire Amistar boosted alternaria control, stretching green leaf retention, adding 15% to yield and lifting weight per 100 marketable roots from 17g with conventional fungicides to nearly 20kg. That would have increased grower return by £1100/ha, says Syngenta.

The label additions introduce a new mode of action for veg disease control, but anti-resistance measures will need adopting to prevent resistance developing to the strob fungicide group, says technical manager Michael Tait. That means using a limited number of applications per crop, maintaining correct doses, using sequences and mixing appropriate partners where required, &#42