Arable News

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Mancozeb still a key component of early blight protection

Mancozeb was first registered in 1962 as a fungicide and after over 50 years it still has an important role to play

Mancozeb still a key component of early blight protection Mancozeb was first registered in 1962 as a fungicide and after over 50 years it still has an important role to play, reports UPL (United Phosphorus Ltd) technical support manager, Pam Chambers (left). The mode of action of mancozeb is classified as a multi-site inhibitor and during its long history there have been no cases of resistance recorded. Within the UK mancozeb should form a key component of potato fungicide programmes as it offers protection against both early blight (phytophthora infestans) and late blight (alternaria solani and alternaria alternata) and it helps with the resistance management of other actives. Recent work by Dutch researchers at Applied Plant Research (PPO Lelystad) found that mancozeb continues to give protection against all strains of late blight, including the strains that have become insensitive to other actives. Some industry experts believe the increase in early blight on potatoes in the UK is due to the use of fungicide products which have no activity against this disease; cyazofamid, fluopicolide, mandipropamide and propamocarb do not have any measurable effect against alternaria spp. The inclusion of mancozeb at the maximum individual dose allowed along with other actives will help protect against early blight. Where repeated doses of mancozeb are applied to potatoes, part of the manganese requirement of a crop can also be met (1.7kg/ha rate of Penncozeb 80 WP will supply approximately 272g/ha of manganese). Table 1 (below) provides information on some mancozeb-containing products available for use in the UK. In tank mix with a suitable partner or as part of a formulated product, mancozeb is a useful edition to a potato fungicide programme. In winter wheat, approved mancozeb-containing products can be used in tank mix with other fungicides with different modes of action as part of an anti-resistance strategy. Used in partnership with triazole, strobilurin or SDHI products, mancozeb can offer an alternative to the protectant multi-site fungicide actives chlorothalonil or folpet as part of a septoria tritici control programme. There have been no cases of resistance recorded in septoria tritici to mancozeb and it is considered a low risk active because of its multi-site activity. Due to its protectant mode of action mancozeb needs to be applied prior to disease infection taking place. The EU Mancozeb Task Force is committed to the regulatory support of mancozeb in the UK. Extensive research work is being carried out to demonstrate the safety and efficacy of this active for its use in potatoes, winter wheat and other crops.


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