Glyphosate is the main herbicide used in coffee (
Coffea arabica
L.) plantations in Brazil. Problems with herbicide drift
commonly occur in orchard fields due to non-adequate spraying conditions. A series of experiments was carried out aiming
to evaluate physiological dose-response of
C. arabica plants submitted to exposure to simulated glyphosate drift in two
distinct plant growth stages. Glyphosate was applied at 0, 180, 360, and 720 g acid equivalent (AE) ha
-1 directly on
coffee plants with 10 and 45 d after transplanting (DAT). Glyphosate doses in a range of 180-360 g AE ha
-1 increased
photosynthesis, transpiration and stomatal conductance in 10 DAT-plants up to 14 d after application (DAA) while, in 45
DAT-plants, an increase was observed only up to 2 DAA, but this pattern was not persistent afterwards so that no difference
in gas exchange was observed at 60 DAA in both plants. Macronutrient content was not affected by glyphosate application
in both plants. Plant DM accumulation was not affected by glyphosate application at 10 DAT-plants, but an increase in
plant growth was observed when glyphosate was applied in a range of 360-720 g AE ha
-1 in 45 DAT-plants.
Coffea arabica
cv. Catuaí Vermelho IAC-144 responded differentially to glyphosate drift depending on plant growth stage, regarding on
photosynthesis, transpiration, stomatal conductance, and plant growth, in spite of macronutrient nutrition was not affected.
