Field bindweed ( Convolvulus arvensis L.) and redroot pigweed ( Amaranthus retroflexus L.) control in potato by pre- or post-emergence applied flumioxazin and sulfosulfuron

Field bindweed ( Convolvulus arvensis L.) is one of the most serious weeds in potato ( Solanum tuberosum L.), but selective herbicides controlling this weed have not been reported. A field experiment was conducted in 2010 and repeated in 2011 in Greece to study the efficacy of herbicides flumioxazin and sulfosulfuron, applied pre- or post-emergence, on field bindweed and redroot pigweed ( Amaranthus retroflexus L.), as well as their phytotoxicity on potato. Gas chromatography-mass spectrography (GC-MS) and high-performance liquid chromatography (HPLC) analyses were conducted for possible herbicide residues in potato tubers. Also, the efficacy of these herbicides on field bindweed generated from root fragments was investigated in greenhouse pot experiments. In pots, both herbicides provided 78% to 100% control of field bindweed generated from root fragments. In field, both herbicides when applied pre-emergence at 72 to 144 g ai ha-1 provided 65% to 100% field bindweed control. However, the corresponding post-emergence applications did not provide satisfactory weed control. All treatments provided excellent control of redroot pigweed. Potato growth was not significantly affected by herbicide application in 2010. However, in 2011, post-emergence applications of flumioxazin caused significant crop injury and yield reduction. The results of this study indicate that satisfactory control of field bindweed and redroot pigweed, as well as high potato yield can be obtained by the pre-emergence application of flumioxazin or sulfosulfuron at 72 to 144 g ai ha-1, without herbicide residues on potato tubers