The application of various chemicals to cuts made in the stem bases of Brachystegia spiciformis Benth., Julbernardia globiflora (Benth.) Troupin and Terminalia sericea Burch. ex DC.

Abstract

Picloram‐potassium and various mixtures of picloram with 2,4‐D amine, 2,4,5‐T ester or amine, or 2,4,5‐T ester alone were injected into incisions made in the cambium of standing Brachystegia spiciformis and Julbernardia globiflora trees. Each arboricide was tested at a range of application rates, at different times of the year and at three different sites for each species. Picloram‐potassium and 2,4,5‐T ester were also tested on Terminalia sericea trees. Glyphosate, MCPA, mixtures of mecoprop and 2,4,5‐T amine and different mixtures of 2,4‐D ester with 2,4,5‐T ester, cacodylic acid and Tandex were tested on B. spiciformis and J. globiflora trees at one site and only in January. Aboricides containing picloram, with or without the addition of 2,4‐D or 2,4,5‐T, were the most effective chemicals for the control of trees. Higher application rates were required to kill B. spiciformis and J. globiflora between May and October when they were not actively growing. T. sericea trees were susceptible to arboricide treatment throughout the year. The response of individual trees to treatment with arboricides appears to be related to size.