Chemical control of coppicing shoots of brachystegia boehmii brachystegia spiciformis and julbernardia globiflora 1. foliar application of tordon 101 and other chemicals to brachystegia spp
Killilea, D.M.; Heelas, B.V.; Mcneill, L.
Zimbabwe Journal of Agricultural Research 19(2): 171-183
1981
Accession: 004937424
Solutions of Tordon 101, glyphosphate, paraquat or DEF [S,S,S-tributyl phosphorotrithioate] were tested for the control of coppicing trees of B. boehmii and B. spiciformis. In all but 1 experiment, where low volume of spray was applied, the foliage was sprayed to the "point of run-off" using a knapsack-sprayer. Plants were sprayed in Oct., Jan. or March/April. The concentration of Tordon 101 solutions required to kill 80% of coppice plants ranged from 10.8-153.4 g total acid equivalent of the picloram and 2,4-D constituents of Tordon 101 per liter solution. In general, spraying in March or April was more effective than spraying at other times, but the efficacy of sprays varied markedly from day to day. Spraying in Oct., 5-8 wk after leaf emergence, was generally least effective. The addition of (NH4)2SO4 to spray solutions apparently inhibited the action of Tordon 101. Short B. spiciformis plants were apparently more susceptible to Tordon 101 than tall plants. Results for B. boehmii were not affected by plant height. Sprays of glyphosphate, paraquat and DEF caused defoliation at all the concentrations tested but few plants were killed. Tordon 101 applied as an ultra-low-volume foliar spray gave poor control.