Post-emergent control of balsam pear

Balsam pear (Momordica charianta) is an invasive climbing vine found in sugarcane fields from Daintree to Mackay. It is particularly effective at smothering the cane, competing for sunlight and lodging the crop. Growers have been using different combinations of synthetic auxin mixtures to try and control it with variable success. Three pot trials were established to identify which synthetic auxins and mixtures are the most effective as a post-emergent control. Replicated comparisons of up to 25 mixtures showed that: ? A mixture of fluroxypyr at 260 g a.i /ha and dicamba was an effective control method that achieved 83% plant mortality. This mixture, not currently subject to buffer zone restrictions, can be boom applied from the ground or by air. ? The addition of picloram to the previous mixture seemed to enhance the control of balsam pear, but mixtures with picloram require 2,4-D as an obligatory mixing partner, and sicklepod presence in the sprayed cane block is necessary as picloram is only registered in cane for the specific control of sicklepod. ? A mixture of fluroxypyr at 260 g a.i /ha and Dropzone also resulted in 83% mortality of balsam pear and full control of red and pink convolvulus vines. This mixture can be boom applied from the ground or by air, but it is subject to mandatory downwind buffer zones. Effective auxin mixtures for the control of balsam pear were identified and specific label requirements associated with each mixture are highlighted.