TITLE:
Tolerance of Winter Wheat (Triticum aestivum L.) and Under Seeded Red Clover (Trifolium pretense L.) to Fall Applied Post-Emergent Broadleaf Herbicides
AUTHORS:
Kristen E. McNaughton, Lynette R. Brown, Peter H. Sikkema
KEYWORDS:
2, 4-D; Clopyralid; Pyrasulfotole; Saflufenacil; Winter Wheat
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.9,
April
4,
2014
ABSTRACT: The fall application of post-emergent (POST) herbicides on winter wheat
provided effective control of emerged winter annual, biennial, and perennial
broadleaf weeds. In recent years, wheat producers have seen a shift to these
weeds, due in part, to the adoption of reduced-and no-tillage practices and the
use of non-residual herbicides such as glyphosate in the preceding soybean and
corn crops. The tolerance of winter wheat to ten herbicides, applied POST in
the fall, was evaluated between 2008 and 2011 at Exeter and Ridgetown, Ontario.
Winter wheat yield was not reduced by applications of MCPA ester,
dicamba/ MCPA/ mecoprop, clopyralid, bromoxynil/ MCPA,
thifensulfuron /tribenuron +MCPA ester, fluroxypyr +MCPA ester, and
pyrasulfotole/ bromoxynil. In contrast, 2,4-D ester and dichlorprop/2,4-D, caused
visible injury in June and July of the following year and consistently
decreased winter wheat yield by at least 10%. Applications of 100 g a.i. ha-1 saflufenacil also decreased winter wheat yield in two of the four harvest years
examined. None of the herbicide options examined were safe on red clover when
it was under seeded the spring following winter wheat planting. All herbicides
significantly decreased red clover dry biomass one month after wheat harvest.