Non-chemical weed control on traffic islands: a comparison of the efficacy of five weed control techniques

Summary The e! cacy of five non-chemical weed control methods for reducing weed cover on tra! c islands was investi- gated in the growing season of 2004. Three trial sites were divided into six treatment areas which were treated with either flame, steam, hot air, hot water, brushes or left untreated. The treatments were carried out at regular intervals throughout the growing season. The percentage weed cover was measured every second week using a 75 · 75 cm quadratic frame with 100 squares. In the control areas, a rapid increase in weed cover was observed, whereas all treatments reduced weed cover. Hot water was the most e" ective method, although not significantly better than hot air or steam. Hot air treatment was more e" ective than brushing, whereas hot water was more e" ective than both flaming and brush- ing. The doses that were used were relatively high (150- 355 kg ha )1 ), partly because of the irregular shape of the traffic islands and the treatment intervals were quite short in comparison with those in similar studies. However, the treatments could keep down the weeds only to a certain extent. The present knowledge of the efficacy of various weed control methods, as well as an increase in our knowledge of adequate treatment inter- vals, supports an optimisation of hard-surface weed control. Data and experience gained from these trials were used to develop further calibrated application