Response of three potato ( Solanum tuberosum) cultivars to pyraflufen-ethyl used as a desiccant in Canada

Abstract

At present, in Canada, there are only three desiccants available for use in potato production to remove haulms prior to harvest. The new herbicide pyraflufen-ethyl was evaluated as a haulm desiccant and for its effect on daughter tuber sprouting the following spring. Field trials were carried out in four seasons. Stem desiccation was not improved by increasing doses of pyraflufen-ethyl above 10 g ai ha −1 except on the variety, Russet Burbank, at 60 g ai ha −1. Pyraflufen-ethyl gave slower desiccation at 7 and 14 days after treatment than diquat but desiccation was comparable 21 days after treatment. Splitting the total dose into two applications, 5 days apart, reduced early desiccation but had no effect on final desiccation level. Pre-treatment with pyraflufen-ethyl improved level of desiccation at 7 and 14 days after treatment compared to the single application and to diquat; however, final desiccation level was not affected. The cultivar, Yukon Gold, was most easily desiccated with Russet Burbank and Shepody being comparable but slower. Tuber stem end discolouration and marketable yield were not affected by pyraflufen-ethyl in any year on the cultivars tested. Pyraflufen-ethyl had no effect on number of eyes that sprouted or sprout weight on daughter tubers when compared with untreated controls.