Even in a high pressure year like last year with more aggressive blight and exceptionally high blight pressure, the multi-site blight fungicide Dithane NT continued to deliver excellent protection to potato growers who did not necessarily want to resort to expensive or complicated programmes, according to Interfarm UK Ltd.
According to Dr. David Stormonth, Technical Manager, Dithane is the most cost-effective protectant fungicide, still widely used throughout the UK's crop, even after decades of use. "Mancozeb is particularly important as a major multi-site fungicide and is the key element for resistance management in late blight programmes, either as a straight or in co-formulation. There is no known resistance to mancozeb, which is why it is also co-formulated into many blight fungicides to help protect them from resistance problems."
Although Dithane was introduced to the UK market many years ago, it has been continuously updated and improved. Advances in production technology and formulation have improved its crop coverage, increased rainfastness, reduced dust, improved packaging and reduced operator risk: all giving better handling, shelf life properties and product effectiveness," says David.
"Dithane NT (which stands for "Neotec") is now a modern WDG formulation has been re-engineered to make it even more effective. The NT granules are 250 microns in size and are easily dispersed in the spray solution. These granules break down in the solution to smaller, evenly-sized particles of between 1.3-1.5 microns diameter, much smaller than generic mancozeb WDG's which have particles up to 3 microns in size."
"This means that Dithane NT delivers 510,000 particles per square mm, nearly twice the number of particles that generic competitors can deliver (around 207,000 particles/sq mm). The smaller mancozeb particles get caught onto the leaf more easily, give a greater surface to volume ratio and result in double the leaf coverage. Consequently growers using Dithane get superior disease protection," explains Dr. Stormonth.
"Special wetting agents and the smaller DG particle size make Dithane NT very rainfast and weather proof, essential when the weather is showery and also when the majority of the UK crop is now irrigated," says David.
"User safety has always been high on the list of priorities and the new lower hexamethyl tetramine (HMT) formulation of Dithane reduces inhalation risks and gives the product a lower toxicity rating on the label. The product pours freely from the bag with minimal dust. Better vacuum packaging has significantly improved product integrity and shelf life," points out Dr. Stormonth.
Registration is being constantly updated and refined, with an increasing number of crops on which Dithane can be used for disease protection. "As a result of significant effort and investment in Dithane, mancozeb has been added to the EU's Annex 1. Also its MRL for mancozeb in potatoes has also been raised, an unusual event, minimising any risk of growers producing unmarketable crops. In the UK Dithane has a wide range of crops on its label including potatoes, cereals and oilseed rape and it also has many SOLA's including onions, shallots, garlic, daffodils, pharmaceutical poppies, asparagus, beetroot, celery, celeriac, chicory, courgettes, marrow and pumpkins," says David.
"Not all mancozebs are the same and Dithane NT is the most modern and up-to-date formulation of mancozeb available. The programme of continuous improvement over the years means that potato growers benefit from its proven record of reliability and cost-effectiveness even in bad blight seasons and they should be incorporating it into their blight control programmes this season," concludes David.
For further comment and information, please contact Dr. David Stormonth, Technical Manager, Interfarm UK Ltd. on 01354 741414 or 07818 036506 (mobile) or via e-mail david.stormonth@interfarm.co.uk
