Effect of Pre- and Post-Emergent Herbicides on Weed Control in Sweet Orange Orchards

To overcome weed problem in sweet orange orchards, a herbicidal trial was started with eight treatments; viz. diuron, simazine, atrazine, weedone, dalapon followed by gramoxone at 15 days interval, dalapon followed by gramoxone at 15 days interval each, haad weeding and control. The herbicides were sprayed round the year at an interval of 90 days, i.e. during July, October, January and April. All the herbicides brought about significant reductions in weed population over control. Diuron was the most effective among all the herbicides used which killed 67.6 per cent monocot and 81.8 per cent dicot weeds over control. The average yield (fruits/tree) was significantly affected during 1983 only, whereas there was no effect on fruit quality except on TSS. No phyto-toxic effect was observed on the sweet orange trees with any of the herbicides used.