Potato growers are facing outbreaks of more aggressive potato blight, pest management provider Dow AgroSciences has warned.

Andy Leader, principal biologist for Dow AgroSciences said industry growers and advisors needed to focus on controlling blight, as well as managing the risk of fungicide resistance.

Since blight has a very short infection cycle it can yield a prolific number of generations in any one season, which leads to the need for frequent fungicide use and increases the likelihood of resistance.

Leader recommends that growers use products with multi-site activity such as mancozeb since they are at low risk to resistance.

No resistance to mancozeb has been detected even after thirty-plus years of use, which explains why it is still incorporated into nearly two-thirds of all blight fungicides used in the UK, including some of the most recently launched products, he said.

Other products, with a unique mode of action, such as zoxium, or a combined formula, such as Electis, which contains zoxium and mancozeb ,also present a low risk of resistance, Leader claimed.

Dow Agrosciences generally advises growers to alternate fungicide groups within a programme, using multi-site products more frequently and integrating products with more than one active ingredient throughout the programme.

“Best used from stable canopy onwards right through to early canopy senescence, Electis acts as the backbone to any blight programme,” Leader said.

“Its use is a sound approach to ensure that foliar and tuber blight are well controlled, that marketable yields are enhanced and the risk of resistance is minimised.”