Control of pachystigma pygmaeum with herbicide

Abstract

Animal deaths caused by Pachystigma pygmaeum have reached considerable proportions (reportedly over 70% on some farms) in the Western Transvaal portion of the Bankenveld in some years. In order to investigate methods of eradicating this plant an experiment was laid down on “klipveld” (stony veld) to investigate the effect of Tordon and Fenotrol (active substance Fenac) on the plant. A 7 × 3 factorial design with two replications was used. Herbicides were applied at three different times of the year and their influence on P. pygmaeum and on the sward was investigated for three years following the application of the herbicides. The concentrations of the active ingredients in the Tordon treatments were respectively 0,530 kg, 1,060 kg and 2,012 kg per ha. The Fenac concentrations used were 2,638 kg, 15,877 kg and 29,070 kg per ha. Treatments wore applied during January, March and April. The best long term results were obtained with 29,070 kg Fenac/ha applied during April. This treatment gave, on the average, 98,15 per cent control with no significant decrease in basal cover and herbage production. The other spray treatments tended to increase the basal cover and herbage production of the sward.

Uittreksel

Vrektes onder vee veroorsaak deur Pachystigma pygmaeum, het aansienlike afmetings (gerapporteer lot meer as 70% op somige plase) in die Wes‐Transvaal gedeelte van die Bankenveld aangeneem. ‘n Eksperiment is op ,,klipveld” uitgelè om die invloed van Tordon en Fenotrol (Fenac die aktiewe bestanddeel) op die plant te ondersoek. ‘n 7 × 3 Faktoriale ontwerp met twee herhalings is gebruik. Onkruiddoders is tydens drie verskillende lye gedurende die aanvangsjaur toegedien en die invloed daarvan op P. pygmaeum en die grasstand is vir drie jaar bestudeer. Die konsenlrasies van die aktiewe bestanddeel in die Tordon behande‐lings was onderskeidelik 0,530 kg, 1,060 kg en 2,012 kg per ha. Die volgende Fenac konsentrasies is gebruik: 2,638 kg, 15,877 kg en 29,070 kg, onderskeidelik, per ha. Behandelings was gedurende Januarie, Maart en April toegepas. Die beste langtermyn resultaat is met 29,070 kg Fenac/ha, wat gedurende A pril loegedoen was, behaal. Hierdie behandeling het ‘n gemiddelde beheer van 98,15% gelewer. Geen betekenisvolle vermindering in basale bedekking en plantmateriaal produksie is waargeneem nie. Die ander spuitbehandelings het geneig om die basale bedekking en plantmateriaal produksie van die stand te verhoog.