Bush control : The control of brachystegia boehmii and colophospermum mopane in Rhodesia using a picloram/2,4‐d mixture

Abstract

Mature Brachystegia boehmii and Colophospermum mopane trees were treated with Tordon 101 (a 1 : 4 mixture of picloram and 2,4‐D) at five rates and at three different times of the year. The arboricide was applied with a syringe to freshly cut stem tissues, either to cuts in the bark, or to the lower lip of ringbarked trees or (in various ways) to cut stumps. Some treatments were repeated at several sites.

Responses to arboricide were not markedly influenced by the method of application. Overall, prising the bark from the wood of cut stumps and placing arboricide in the gap so formed, resulted in the highest percentage kills. Applications were most effective in the growing season (November to March).

Medium sized trees were more readily killed than smaller or larger ones. Response to arboricide varied between sites.

Uittreksel

Volwasse Brachystegia boehmii en Colophospermum mopani borne is behandel met Tordon 101 ('n 1 : 4‐mengsel van picloram en 2,4‐D); die chemikalieë is toegedien teen vyf verskillende hoeveelhede op drie verskillende tye ge‐durende die jaar. In die verskeie proefnemings is die boomgifmiddel dear middel van ‘n spuit toegedien op pasgemaak‐te snitte in die bas, die onderste rand van die ring van geringeleerde bome, of toediening op verskillende wyse op die oppervlaktes van afgesnyde stompe. Sommige van die behandelings is herhaal op verskillende terreine.

Daar was geen waarneembare verskille op die manier van toediening van die boomgif nie. In die algemeen is die hoogste persentasie suksesse behaal deur die bas vanaf afgekapte stompe weggetrek en die gif in die opening te plaas wat so ontstaan het.

Die beste tyd behandeling was gedurende die hoof‐groeiseisoen (November tot Maart).

Die gemiddelde grootte bome is makliker gedood as die kleiner of groter bome. By die verskillende terreine was daar ‘n verskil in die reaksie tot die boomgifmiddel.

Notes

New address: Department of Agriculture, University of Rhodesia, P.O. Box MP 167, Mount Pleasant, Salisbury.