Chemical weed control in young peach trees

Abstract

The effects of five residual herbicides and two mixtures of herbicides on tree and weed growth were studied in two trials over two consecutive seasons in a young peach orchard at Bathurst, New South Wales. In the first trial, dichlobenil at 4.5 and 9.0 kg ha-1 increased tree growth and suppressed weeds, but the residual effects of the low rate were short; simazine (2.2 kg ha-1), trifluralin (2.2 kg ha-1) and simazine (1 1 kg ha-1) plus trifluralin (1.1 kg ha-1) also reduced weed incidence but did not improve tree growth. In the second trial, terbacil (2.2 kg ha-1) and mixtures of diuron (1.1 kg ha-1) and terbacil at 1.1 or 2.2 kg ha-1 effectively controlled weeds, giving faster tree growth. Terbacil (1.1 kg ha-1) and diuron (1.1 kg ha-1) suppressed broadleaf but not grass weeds. Terbacil (1.1 kg ha-1) improved tree growth only in the second season; diuron (1.1 kg ha-1) did not affect tree growth. None of the peach trees displayed toxic symptoms. The main weeds present in the trial site were: Amaranthus powellii, Chenopodium album, Polygonum aviculare, Lepidium hyssopifolum, Lactuca serriola, Rumex acetosella, Sonchus oleraceus, Plantago lanceolata, Cynodon dactylon, Bromus sp, and Eragrostis sp.