TITLE:
Carryover Effect of Imidazolinone Herbicides for Crops Following Rice
AUTHORS:
L. O. Santos, J. J. O. Pinto, L. B. Piveta, J. A. Noldin, L. Galon, G. Concenço
KEYWORDS:
Clearfield®; Imidazolinones; Soil Persistence; Oryza sativa
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.8,
March
26,
2014
ABSTRACT: We aimed with this study to evaluate the effects
of residual activity in soil of formulated mixtures of the herbicides
imazethapyr + imazapic and imazapyr + imazapic on ryegrass and on rice cultivars, IRGA 424 and BRS Querencia. Two experiments were
conducted under greenhouse in randomized blocks design with four replications in
split-plot and split-split-plot designs, respectively for the first (E1) and
second (E2)
experiments. For
E1, main plots allocated herbicides (imazethapyr + imazapic and
imazapyr + imazapic), and subplots the doses [(0, 0.5, 1.0, 1.5 and 2.0 fold
the label dose of imazethapyr + imazapic (1
L·ha-1)
and imazapyr + imazapic (140 g·ha-1)
plus 0.5% of the adjuvant Dash→)]; for E2, sub-subplots
allocated rice cultivars (BRS 424 and IRGA Querência). Phytotoxicity, plant
height and shoot dry weight (E1 and E2) and plant stand (E2) were evaluated. Results showed that
the annual ryegrass and rice cultivars IRGA 424 and BRS Querencia are sensitive
to imazethapyr + imazapic and imazapyr + imazapic, serving as bioindicators of
its residual activity in soils following Clearfield→ rice. Imazapyr
+ imazapic, applied post-emergence in irrigated rice at doses of 1.0, 1.5 and
2.0× the label dose, present longer residual
activity in soil compared to imazethapyr + imazapic for ryegrass and
non-Clearfield→ rice.