Two key actives widely used in the potato sector are up for re-registration later this year. However, indications from the trade suggest that due to environmental and consumer concerns, the likelihood of both diquat and CIPC being approved by the Commission for reregistration is low.

Diquat

Diquat (dibromide) is a non-selective herbicide which forms a key ingredient for many desiccant products such as Reglone, Diquash 200 SL, D-Foliate and Retro.

The herbicide is a vital tool in potato production in Ireland and is often used for preharvest desiccation of the haulm, assisting in manipulating tuber size to meet market specifications, reducing disease transmission on tubers and aiding harvesting.

The active can also be used as a desiccant in oilseed rape production, as well as forming an important component in weed control strategies for a number of broad-acre and speciality crops.

The active is up for re-registration in June 2018 but concerns raised by the European Commission over the substance’s health impact on workers, bystanders and residents, as well as negative impacts on non-target organisms, has fuelled fears that the active may not be re-approved. Furthermore support from other member’s states to re-approve the active is reported to be low.

If diquat is not reapproved in June then there is likely to be a short withdrawal period meaning the herbicide may not be available for autumn desiccation.

CIPC

Chlorpropham (CIPC) is widely used as a sprout suppressing agent when applied to stored potatoes.

The chemical works by interfering with cell division to inhibit sprout development in the crop. Sprout suppression is an important element of managing the quality of stored potatoes.

The chemical is up for re-registration in July 2018. However, it is reported that the European Commission is proposing not to re-approve of the active. Issues centre around environmental and consumer concerns.

As highlighted at this year's National Potato Conference, air circulation plays an important role in ensuring uniform and even distribution of the chemical in potato stores. Uneven airflow may lead to higher dose rates in certain areas of the store which could contribute to the concerns raised by the Commission.

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