Slicer cucumbers

Cucumbers are affected by powdery mildew

A fungicide that tackles powdery mildew in courgettes, cucumbers and melons has been granted an Extension of Authorisation for Minor Use (EAMU).

Certis-owned Karma, which contains the active ingredient potassium hydrogen carbonate, can now be used by growers on protected and indoor crops, with a maximum individual dose of 3kg/ha. Growers can make a maximum of eight applications per crop per year, providing the maximum total dose of 24kg per ha and per crop isn’t exceeded.

Derek Hargreaves, technical officer at the Cucumber Growers Association, said: “Cucumbers, courgettes and melons are particularly susceptible to mildew. Being short term crops, it is well-known that powdery mildew will continuously build throughout the season.'

With up to three crops of cucumbers grown from January to October, Hargreaves said it is often a question of when, not if, crops will be affected by powdery mildew.

“The fact the Karma has been granted an EAMU for this purpose will provide growers with added security to continue to use a fungicide containing the active ingredient potassium hydrogen carbonate, which has the significant advantage of leaving no chemical residue on crops,” he added.

This extension of the authorised use means Karma can be used in small doses at the discretion and choosing of the grower. As no efficacy or phytotoxicity data have been assessed, any commercial risk through using the extension is held by the grower.