Interactions of Foliarly Applied Herbicides on Three Weed Species in Peanut (Arachis hypogaea)

Abstract

In the greenhouse, naptalam at 1.1 to 4.5 kg ai ha−1antagonized activity of paraquat at 0.04 to 0.14 kg ai ha−1in 14 of 16 rate combinations when applied to sicklepod. Sicklepod shoot fresh weight reduction was less compared to that obtained with paraquat alone when paraquat at 0.04 kg ha−1was mixed with bentazon at 0.42 to 0.84 kg ai ha−1or monocarbamide dihydrogensulfate at 14 to 58 kg ai ha−1. Paraquat activity on Florida beggarweed was antagonized by mixtures of paraquat at 0.04 or 0.07 kg ha−1with bentazon at 0.63 or 0.84 kg ha−1or paraquat at 0.04 to 0.14 kg ha−1with naptalam at 3.4 or 4.5 kg ha−1. Mixtures of lactofen at 0.06 to 0.22 kg ai ha−1with monocarbamide dihydrogensulfate at 14 kg ha−1or lactofen at 0.06 or 0.16 kg ha−1with alachlor at 1.4 to 2.8 kg ai ha−1synergistically increased tall morningglory shoot fresh weight reduction. In the field, excellent sicklepod shoot fresh weight reduction by paraquat applied alone masked most antagonistic effects of paraquat mixtures. Addition of alachlor to monocarbamide dihydrogensulfate at 29 kg ha−1improved activity on sicklepod compared to monocarbamide dihydrogensulfate applied alone.