Glyphosate use with different application technique – late application in winter wheat

Abstract

Glyphosate was used in a field trial in winter wheat shortly before harvest for weed control and desiccation. Application was done with conventional and dropleg application technique at growth stage BBCH 89 of winter wheat. The analyses covered glyphosate and AMPA residues at the time of harvest, 7 and 16 days after application on the outside of the wheat grain, chaff and straw. Depending on the appli­cation technique the results demonstrate varying residues. The highest residues with up to 6 mg/kg were found on the wheat grain with conventional application technique. With dropleg application technique significant lower residues were determined. In straw, glyphosate residues were higher for dropleg application technique in comparison to conventional technique. The level of residues of grain and straw decreased with increasing waiting period. The obtained results suggested that the use of dropleg application technique can reduce residue amounts on grain. The dropleg application technique can only be used for upright cereals.