Tolerance of Khaya ivorensis and Toona ciliata to herbicides

Abstract

Abstract

We conducted two experiments to evaluate the plant tolerance of African mahogany (Khaya ivorensis) and Australian cedar (Toona ciliata var. australis) to herbicides. The experimental arrangement was a completely randomized design, with four replications. The treatments were as follows: i) untreated control, ii) imazapyr (25 g ai ha^-1), iii) oxyfluorfen (360 g ai ha^-1), iv) oxyfluorfen (720 g ai ha^-1), v) isoxaflutole (75g ai ha^-1), vi) isoxaflutole (112.5 g ai ha^-1), vii) chlorimuron-ethyl (7.5 g ai ha^-1) + 0.05% v / v mineral oil, viii) chlorimuron-ethyl (12.5 g ai ha^-1) + 0.05% v / v mineral oil, ix) imazethapyr (100 g ai ha^-1), and x) nicosulfuron (40 g ai ha^-1). For the African mahogany, imazapyr (25 g ai ha^-1), oxyfluorfen (360 g ai ha^-1) and chlorimuron-ethyl (7.5 and 12.5 g ai ha^-1), showed mild symptoms of phytotoxicity. The oxyfluorfen (720 g ai ha^-1), imazethapyr and nicosulfuron were moderately phytotoxics, and isoxaflutole (75 and 112.5 g ai ha^-1) was the most phytotoxic herbicide. For Australian cedar, imazapyr (25 g ai ha^-1) caused low levels of injury. Oxyfluorfen, isoxaflutole, chlorimuron-ethyl, imazethapyr and nicosulfuron were the most phytotoxic herbicides.

Keywords: African mahogany; Australian cedar; weeds; selectivity.