Reduction in mancozeb raises alternaria risk in potatoes

A reduction in the amount of mancozeb in potato late blight fungicide programmes could see an increase in alternaria (early blight) in the crop, says Reuben Morris of Cropwise.

The disease is becoming more prevalent partly due to higher temperatures, so growers need to adapt blight programmes, especially during the mid-season phase.

Key fungicides, such as Ranman (cyazofamid) and Revus (mandipropamid) offer little alternaria control, he says, while mancozeb, which does offer some suppression, is now very expensive and in short supply. Historically, growers have alternated Electis (mancozeb + zoxamide) with Ranman, but an alternative could be tanos (cymoxanil + famoxate), he suggests.

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