Publicação on-line; 22 ref.; 1 table; 4 illus.; Summary (En)

ABSTRACT
Background: The application of Acetyl CoA carboxylase (ACCase)
inhibitors prior to sowing of grass crops may result in crop damage due
to residual effect of these herbicides in soil. The hypotheses was that
different corn hybrids and ACCase herbicides can result in different plantback
intervals after burndown treatments.
Objective: This work was planned to determine safe plant-back periods
for three corn hybrids where ACCase herbicides clethodim and
haloxyfop-methyl are applied.
Methods: Herbicides were sprayed at 21, 14, 7, 2 and 0 days before
sowing (DBS) at 192 g a.i. ha-1 (clethodim) and 120 g a.i. ha-1 (haloxyfopmethyl).
Individual experiments were carried out with three hybrids:
KWS9110 and 2B587 with glyphosate and glufosinate tolerance and
Enlist with aryloxyphenoxypropionate tolerance.
Results: Haloxyfop-methyl resulted in higher damage potential
compared to clethodim for the hybrids KWS9110 and 2B587. For
these hybrids, significant crop stand and grain yield reductions were
observed mainly when haloxyfop was applied closer to sowing date
(7, 2 and 0 DBS).
Conclusions: Based on the effects on corn grain yield, a safe plant-back
period for haloxyfop was estimated to be 8 and 11 days for the hybrids
KWS9110 and 2B587, respectively. For the Enlist corn hybrid, there were
no yield decreases, even when haloxyfop was applied at 0 DBS.
Clethodim did not affect corn yield of any hybrid in any application time

Keywords:
residual
clethodim
haloxyfop-methyl
selectivity
ACCase-inhibitors