Weed infestation and shoot borer incidence in sugarcane intercropped with aggregatum onion (Allium cepa var.aggregatum) under Garden Land conditions

Abstract

Field observations on weed infestation and early shoot borer incidence in sugarcane + aggregatum onion intercropping systems under different row arrangements, were recorded during the intercropping period under garden land conditions. The intercropping of onion was not very effective in reducing the weed biomass eventhough there was marginal reduction in weed dry weight under the intercropping situations compared to the sole crop of sugarcane. Significantly lower dry weight of weeds was observed under. normal row spaced (90 cm) than the wide row (120 and 150 cm) spaced cane. Onion as intercrop in sugarcane could not compete with fast and aggressive weeds likeTrianthema portulacastrum, Amaranthus viridis, Parthenium hysterophorus andCynodon dactylon in the experiment. The percentage of shoot borer incidence was also not significantly affected due to intercropping of onion in the system because of the lower shoot borer incidence (7.6-11.2%) observed in the experiment plots than the general economic threshold value of around 15-20% damage.