PERTANIKA JOURNAL OF TROPICAL AGRICULTURAL SCIENCE

Low concentrations of paclobutrazol and daminozide at 0, 5, 10 and 15 mgl1 were foliar sprayed on 12 week old A. mangium seedlings at three different frequencies of application i.e. 1 (week 0), 2 (week 0 & 4) and 3 (week 0, 4 & 6). Either chemical was effective in controlling growth but paclobutrazol was more potent than daminozide. A low concentration of 5 mgt1 paclobutrazol at 1 application was sufficient to cause a significant reduction in height growth compared to daminozide which required a minimum concentration of 10 mgl1 with 2 applications. In general, the main effects of the chemicals increased with increasing concentration and frequency of spray.