New label recommendations for fungicide Dithane NT

The fungicide Dithane NT has new label recommendations for the control of downy mildew (Peronospora destructor) and rust (Puccinia allii) in outdoor bulb onions and shallots and for the control of Alternaria leaf blight (Alternaria dauci) in outdoor crops of carrots and parsnips, a welcome addition to the dwindling options that growers have to control these diseases and maintain quality.

"Allium and root vegetable crop growers need a range of fungicides to use within their programme in order to protect against damaging diseases as well as managing resistance. The new label recommendations for multi-site Dithane NT will be welcomed, especially when resistance management is so critical. Mancozeb, the proven active ingredient in Dithane NT, is an extremely important tool in the fight against disease resistance as it works at over 6 different metabolic sites in the pathogen and there is no known resistance," says Dr David Stormonth, Technical Manager for Interfarm.

David points out that downy mildew and rust are serious foliar diseases that need routine treatment. "With this season’s warm conditions and the influence of microclimate within the crop, onions and shallots will be at risk once again. The recommended label rate of 2.5 kg per ha of Dithane NT for bulb onions and shallots delivers 1875 gms a.i per ha and this robust dose rate of mancozeb delivers effective protection. It can be applied from the 2 leaf stage onwards before disease has been established in the crop. Up to 4 sprays of Dithane NT can be applied at 7 day intervals to protect new growth. It has a 28 day Harvest Interval."

Dithane NT should be applied in a protectant programme, starting before the appearance of disease symptoms or when local monitoring and forecasting indicates a high risk of infection.

In carrots and parsnips Dithane NT is recommended at a dose rate of 2 kg per ha with a maximum of 4 sprays per crop. It should be applied from the 2 leaf stage onwards at a 14 day spray interval with a 30 day harvest interval.