A fungicide tank-mix has been granted a temporary emergency-use registration against downy mildew in greenhouse cucumbers.
The registration applies strictly to the tank-mix of Syngenta’s Revus and Bayer’s Previcur N fungicides for use on greenhouse cucumbers in Ontario, Quebec and Nova Scotia, until Dec. 31 this year.
Downy mildew, caused by a fungus-like water mould, attacks only cucumbers and related species such as gourds, squash, pumpkins and melons. It mainly affects plant foliage and can cause severe yield losses in a short period of time, according to Syngenta.
Growers must apply Revus as a foliar application in a tank-mix with Previcur N when plants begin to vine or when the disease threatens, Syngenta said.
The initial symptoms of downy mildew typically consist of angular, yellow spots on the upper leaf surfaces, Syngenta said in a release Monday. The disease can then travel to other parts of the cucumber leaf and, if left untreated, will lead to leaf kill.
Revus is a Group 40 mandipropamid product which, among other uses in vegetable crops, is already approved to suppress downy mildew in field cucumber.
Previcur N, marketed through Bayer’s Environmental Sciences division, is a Group U propamocarb hydrochloride registered for control of pythium root diseases in cucumbers and other hothouse crops.