Two trials were carried out to evaluate the effect of flame weeding on Eichhornia crassipes, Brachiaria subquadripara, Pistia stratiotes and Salvinia auriculata. In the first trial, different doses of flame were applied, according to the amount of gas consumed during application. In the second trial, two flame applications (14 day interval between each application), triple flame application (7 day interval between each application) and single flame application were used. Untreated plants were used in both trials as check. Injury was assessed at 1, 3, 7, 10, 13, 17, 21 and 30 days after applications. Dry biomass of survival plants was also obtained at the final experimental period. The first trial results showed a significant reduction in the biomass of E. crassipes, B. subquadripara and P.stratiotes, treated with the highest flame. All the sequential applications provided significant dry biomass reduction (over 90%) in E. crassipes and B. subquadripara. The sequential and single applications provided dry biomass reductions up to 37% in S. auriculata. The results show that it is viable to use flame weeding as an alternative in the management of aquatic environments.
physical control; flame; aquatic weed; sequential application
