Weed control in peanuts in north Queensland

Abstract

Experiments conducted over two seasons with Virginia Bunch peanuts on krasnozem soils in north Queensland showed that cultivation controlled weeds sufficiently to prevent significant reduction of crop value. In one of these experiments two cultivations made 2 and 5 weeks after sowing increased the percentage of edible kernel by a mean of 4.8%. A range of herbicides tested in conjunction with cultivation did not significantly increase crop yields or weed control over that obtained by cultivation. Most of the herbicide treatments had no adverse effects on crop yield although some foliar damage occurred on plants treated with vernolate, MCPB, 2,4-DB and dinoseb. Vernolate, incorporated before planting at 4.78 kg active ingredient ha-1 caused a reduction in yield of nut-in-shell and in crop value when compared with the hand weeded, cultivated control. In both experiments, uncontrolled weeds markedly reduced crop yields (by a mean of 69%) and their monetary value (by a mean of 68%). In a third experiment a single application of 2,4-DB plus dinbseb (0.5 kg acid equivalent ha-1 each) made 3 weeks after sowing, with or without multiple applications of 2,4-DB (0.5 kg acid equivalent ha-1) made at 6,9 and 12 weeks, did not significantly reduce crop yields or values, and increased the control of Hyptis suaveolens and other broad-leaved weeds when compared with a standard trifluralin-plus cultivation treatment.