GROWTH OF SUCKERS IN OLIVE (OLEA-EUROPEA L) TREES AND THEIR CONTROL WITH GLYPHOSATE PLUS MCPA

Field studies were conducted in Andalusia (Southern Spain) in 1984-198 8 in olive orchards to observe the growth of suckers, their control wi th glyphosate plus MCPA and influences on olive yield. Emergence of th e suckers starts with the vegetative activity of the tree, ends with f ull flowering, and does not occur in later stages of development. The number, height and biomass of suckers varies considerably with site, y ear, tree age and cultivar. These indexes were 32, 103 cm and 846 g of dry matter per olive tree averaged over location, respectively. Contr ol of olive suckers with glyphosate + MCPA requires less herbicide in the early growth stages than later. Control of 90% of 10-20 cm and 40- 60 cm suckers was achieved with glyphosate + MCPA at dose equal to or higher than 0.7 + 0.7 and 1 + 1 kg ha-1, respectively. Generally, doub le applications of glyphosate + MCPA at 1 + 1 kg ha-1 effectively cont rolled the suckers and enhanced olive growth. Vegetative growth of the newly formed shoots and olive yield was 11.5% and 8.5% higher, respec tively, in trees treated with the herbicides than when suckers were re moved using knives on one occasion in September.