Summer weed control is based around 2,4-D glyphosate mixes which are low cost and control a broad spectrum of weeds. New regulations for application of 2,4-D have been introduced to eliminate the risks of off target damage however indications are that some growers are not complying. The industry is concerned that a small number of growers doing the wrong thing will cause drift that damages sensitive crops and result in deregistration of 2,4-D products. The alternatives to 2,4-D are not as broad spectrum and often more expensive. Growers are also concerned that the regulations on application of 2,4-D limit the spray application window and make it more difficult to control weeds in a timely manner, resulting in higher rates being needed to control larger weeds and control being less effective. All of these factors will increase costs.
Important summer weeds which need to be controlled include Caltrop, melons, Fleabane, Roly Poly (Buckbush), Marshmallow, Sow thistle, Capeweed, Heliotrope, Wireweed, Convolvulus, Lincoln Weed, Skeleton Weed, Silverleaf Nightshade, Quena, Feathertop Rhodes Grass, Summer Grass, Black Grass, Lovegrass, Stemless thistle, Medic, Statice, Portulaca, Button Grass and Pigweed.
Commonly used herbicides used to control summer – 2,4-D, glyphosate, triclopyr (Garlon), dicamba, paraquat and metsulfuron-methyl (Ally).
