Tolerância de plantas de Khaya ivorensis e Toona ciliata a herbicidas

Abstract

Dois experimentos foram conduzidos com o objetivo de avaliar a tolerância de plantas mogno-africano (Khaya ivorensis) e cedro-australiano (Toona ciliata var. australis) a herbicidas. O delineamento experimental foi inteiramente casualizado, com quatro repetições. Tratamentos: i) testemunha sem aplicação, ii) imazapyr (25 g i.a. ha-1 ), iii) oxyfluorfen (360 g i.a. ha-1 ), iv) oxyfluorfen (720 g i.a. ha-1 ), v) isoxaflutole (75 g i.a. ha-1 ), vi) isoxaflutole (112,5 g i.a. ha -1 ), vii) chlorimuron-ethyl (7,5 g i.a. ha-1 ) + 0,05% v/v de óleo mineral, viii) chlorimuron-ethyl (12,5 g i.a. ha-1 ) + 0,05% v/v de óleo mineral, ix) imazethapyr (100 g i.a. ha-1 ) e x) nicosulfuron (40 g i.a. ha-1 ). Para o mogno africano, os herbicidas imazapyr (25 g i.a. ha-1 ), oxyfluorfen (360 g i.a. ha-1 ) e chlorimuron-ethyl (7,5 e 12,5 g i.a. ha-1 ) proporcionaram sintomas leves de fitotoxicidade. O oxyfluorfen (720 g i.a. ha-1 ), o imazethapyr e o nicosulfuron foram moderadamente fitotóxicos e o isoxaflutole (75 e 112,5 g i.a. ha-1 ) foi o herbicida mais fitotóxico. Para o cedro australiano, o herbicida imazapyr (25 g i.a. ha-1 ) proporcionou os menores níveis de injúria. O oxyfluorfen, o isoxaflutole, o chlorimuron-ethyl, o imazethapyr e o nicosulfuron proporcionaram altos níveis de fitotoxicidade.

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.