Chemical control of coppicing shoots of brachystegia boehmii brachystegia spiciformis and julbernardia globiflora 5. foliar application of tordon 101 and tordon 225 to re growth of mattocked plants
Millilea, D.M.; Mcneill, L.
Zimbabwe Journal of Agricultural Research 20(2): 153-164
In a series of trials, B. boehmii, B. spiciformis and J. globiflora were mattocked and arboricides applied to the subsequent regrowth. Tordon 101 (a 1:4 mixture of picloram and 2,4-D) and Tordon 225 (a 1:1 mixture of picloram and 2,4,5-T) were tested at 5 concentrations. Plants were sprayed at different times of the year and a herbicide glove was used to apply the minimum amount of arboricide solution required to wet the leaves and stems of plants. For the same concentrations of picloram, Tordon 101 and Tordon 225 were equally effective. Concentrations of picloram required to kill 80%, of plants (when sprayed on the foliage to the 'point of run-off' using a knapsack-sprayer) were 8, 12 and 32 g acid equivalent/l spray solution for B. boehmii, B. spiciformis and J. globiflora, respectively. The use of a herbicide glove, compared with a knapsack-sprayer, reduced the volume of arboricide solution applied to each plant by 1/3. However, there was little difference between methods in the total amount of picloram per plant required for an 80% kill rate. Optimum results were obtained with treatment of regrowth 13-26 wk after mattocking. Spraying young regrowth, when the leaves had just unfolded, or regrowth 30-38 wk old, when leaves were becoming senescent, tended to be less effective.