Chemical control of coppicing shoots of brachystegia boehmii brachystegia spiciformis and julbernardia globiflora 4. basal stem painting with tordon 155
Killilea, D.M.; Mcneill, L.
Zimbabwe Journal of Agricultural Research 20(1): 59-70
1982
Accession: 004937427
In a series of experiments on the control of coppicing shoots of B. boehmii, B. spiciformis and J. globiflora various concentrations of Tordon 155 in diesel oil were painted on the basal 40, 20 or 10 cm of stems. Treatments were repeated at 3 sites and at different times of the year. The effects of burning shoots before chemical application and mattocking plants after treatment were investigated. Dosage rates required to kill 80% of B. boehmii, B. spiciformis and J. globiflora plants ranged, respectively, from 0.5-13.8, 6.2-46.5 and 0.2-4.2 g total acid equivalent (total of both the picloram and 2,4,5-T ingredients) of Tordon 155 per plant. Progressively more concentrated mixtures of Tordon 155 were required for an 80% kill as less stem was painted, but the amount of Tordon 155 required per plant remained approximately the same. The chemical was generally more effective when applied in Jan. or March/April rather than in June/July or Sept./Oct., but results varied markedly between sites, and between applications on different days at the same time of year and the same site. Mattocking regrowth of B. boehmii plants at intervals after application of Tordon 155 had a negligible effect on the rate of kill. The effect of a similar treatment on B. spiciformis could not be assessed because of a secondary infection of treated plants with the fungus Armillaria mellea.