Gowan Crop Protection Limited can now offer UK growers a completely new blight fungicide for the UK market, Presidium (dimethomorph and zoxamide).
Technical Manager Robert Plaice reports that using a fungicide with contact, anti-sporulant and translaminar activity is key to success with more virulent blight. “The UK blight population is dominated by two particularly aggressive strains – 6_A1 and 13_A2. These strains are characterised by the ability to thrive at lower temperatures, by producing more spores from larger lesions and by cycling extremely quickly. At most stages in the blight life cycle, fungicides need to be able to control spores to stop infection. In Presidium we have two actives that tackle spores well.”
Zoxamide in Presidium acts on cell division of the fungus, preventing formation of the next nucleus, stopping germ tube elongation of spores and preventing infection. This contact action occurs as the germ tube grows along the leaf surface or down through the waxy leaf cuticle into the leaf. There is also anti-sporulant activity which delivers zoxamide’s activity on zoospores, the agent for tuber blight, where it inhibits spore development in the sporangia and subsequent spore release. By reducing zoospore loading in the crop early on, zoxamide will enhance the activity of other fungicides that act on motile zoospores,” explains Rob.
“Dimethomorph in Presidium also has fantastic anti-sporulant activity. It is also locally systemic, moving within the stem to control blight. This systemic activity helps to protect new growth in the leaves and will protect both upper and lower surfaces of leaves.”
Rob goes on to say that Presidium contains two actives with completely different modes of action within the pathogen, helping to minimise resistance build up. “It is also a product for use at many stages but particularly at early mid season and full canopy onwards. It is formulated as a SC formulation with a maximum dose rate of 1l/ha, delivering 180 gms a.i of both actives/ha, and can be mixed with other active ingredients in order to tailor the requirement for disease control at the time of application. Presidium can be used a maximum of 5 times per season, applied as a single or block application with a maximum of three
consecutive applications in alternation with other fungicides. Presidium has a Harvest Interval of 7 days.”