APPLICATION OF HERBICIDE GOAL SUPREME^® WITH BOOM SPRAYER UNDER THE CANOPY OF THE OLIVE TREE

The olive orchard and olive oil form a part of Spanish culture and heritage, and thus it is urgent to develop sustainable cultivation systems, for which herbicides are necessary. In soil-management systems, to limit weed growth under the canopy, cover crops are used, with plants in the central lane of the olive orchard. Pre-emergent herbicides are applied under the canopy in autumn before harvest in order to keep this zone weed free for the harvest. To foment the proper use of herbicides, there are rules and regulations that establish the correct application practices. The aim of the present work was to detect mechanisms of direct contamination of the fruits in the lower parts of the olive tree by the herbicide oxifluorfen (Goal Supreme^®) at different application rates when applied by boom sprayers, with and without off-centre nozzles.
The oils from the fruits collected exclusively from the lower parts of the tree enabled us to identify a number of risk factors. The use of spray booms with anti-drift nozzles do not completely limit the possibility of contaminating the fruits and sub¬sequently the olive oil, even using half the herbicide application rate recommended. The combination of the boom sprayer with off-centre nozzles at the maximum appli¬cation rate registered the highest number of cases of contamination.
According to the assay results, we highlight that the low limbs of the trees play an important part in the pollution detected, since they bear the fruit that the off-centre and anti-drift spray nozzles reach with the herbicide, as these fruits are situated below the 50 cm of the bar height. For herbicide use under the canopy area, to be com¬patible, more work is needed under field conditions until a safe management model is developed. Goal Supreme^® is a trademark registered by Dow Agrosciences S.A.