Growth of suckers in olive(Olea europeaL.) trees and their control with glyphosate plus MCPA

Field studies were conducted in Andalusia (Southern Spain) in 1984-1988 in olive orchards to observe the growth of suckers, their control with glyphosate plus MCPA and influences on olive yield. Emergence of the suckers starts with the vegetative activity of the tree, ends with full flowering, and does not occur in later stages of development. The number, height and biomass of suckers varies considerably with site, year, tree age and cultivar. These indexes were 32,103 cm and 846 g of dry matter per olive tree averaged over location, respectively. Control 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, double applications of glyphosate + MCPA at 1 + 1 kg ha-1 effectively controlled the suckers and enhanced olive growth. Vegetative growth of the newly formed shoots and olive yield was 11.5% and 8.5% higher, respectively, in trees treated with the herbicides than when suckers were removed using knives on one occasion in September.