0 x0 he y21 ff5 fs7 fc0 sc0 ls4 ws1">moisture.
All data were subjected to analysis of variance using
the PROC MIXED procedure of SAS (software Ver. 9.1,
SAS Institute, Inc., Cary, NC). The assumptions of the
variance analyses (random, homogeneous, normal dis-
tribution of error) were confirmed using residual plots
and the Shapiro-Wilk normality test. To meet the as-
sumptions of variance analyses, the July injury rating
was log transformed. Data were converted back to origi-
nal scale for presentation of results. Injury 1 and 2 WAT
as well as May injury, height and yield data met the as-
sumptions of normality, therefore no transformations
were necessary. Crop injury was not observed at any of
the Ridgetown sites therefore was excluded from analy-
sis and are not shown. Data were combined and analyzed
over environments when possible (i.e. environment by
timing by dose interactions were not significant).
Means were separated using Fisher’s protected LSD.
Type I error was set at 0.05 for all statistical compari-
sons.
3. RESULTS AND DISCUSSION
There was no effect of saflufenacil dose at the PP and
PRE application timings on winter wheat injury 1 WAT
and in May of the following spring (Table 2 ). These re-
sults are consistent with a recent study conducted by
Knezevic et al. [8] that also showed no injury on winter
wheat when saflufenacil (at doses up to 400 g a.i. ha1)
was applied PRE. There was however, a dose effect
when saflufenacil was applied POST with and without
the adjuvant Merge. At 1 WAT, the POST application of
saflufenacil applied at 100 and 200 g a.i. ha1 caused 7%
and 10% injury. This injury was transient with 5% injury
observed at the 200 g a.i. ha1 in the following May.
There was greater injury when saflufenacil was ap-
plied POST + Merge. At 1 WAT, injury from saflufenacil
(25 to 200 g a.i. ha1) applied POST with Merge was
12% - 18% higher than the POST application without an
adjuvant (Table 2). Similarly, winter wheat injury the
following May from saflufenacil (25 to 200 g a.i. ha1)
applied POST with Merge was 2% - 9% higher than the
POST application without an adjuvant. Saflufenacil ap-
plied POST with Merge consistently had the greatest
injury at all the doses evaluated.
Other research has also shown that POST applications
of saflufenacil can cause significant injury in cereals.
Frihauf et al. [2] showed that a POST application of
saflufenacil + non-ionic surfactant at 25 to 50 g a.i. ha1
caused 27% - 38% injury in winter wheat at 1 WAT. In
another experiment, Frihauf et al. [6] showed that in-
creasing saflufenacil doses caused winter wheat injury to
be as high as 30% at 3 - 6 days after treatment. Similarly,
Sikkema et al. [4] showed injury from a POST applica-
tion of saflufenacil at 50 g a.i. ha1 on spring cereals to
be as high as 67% at 3 days after treatment.
When data were combined for all application timings
(Table 3), saflufenacil applied at 25 to 200 g a.i. ha1,
caused 4% to 11% injury in winter wheat 2 WAT with the
POST + Merge application ausing the greatest injury c
Copyright © 2012 SciRes. OPEN ACCESS
L. R. Brown et al. / Agricultural Sciences 3 (2012) 755-758 757
Table 2. Winter wheat injury as a function of saflufenacil application timing and dose. Means followed by the same letter within a
column (a-e) or row (X-Z) for each section are not significantly different according to Fisher’s Protected LSD at P < 0.05a.
Injury at various application timings %
Saflufenacil dose (g a.i. ha1)
PP PRE POST POST + Merge
SE
1 WAT injuryb
0 0 a Z 0 a Z 0 a Z 0 a Z 0
25 0 a Z 0 a Z 4 a Z 16 b Y 1
50 0 a Z 0 a Z 5 ab Z 19 c Y 2
100 2 a Z 1 a Z 7 bc Z 24 d Y 2
200 1 a Z 2 a Z 10 c Z 28 e Y 2
SE 0 0 1 1
May injuryc
0 0 a Z 0 a Z 0 a Z 0 a Z 0
25 0 a Z 2 a Z 1 a Z 3 b Z 1
50 1 a Z 1 a Z 1 a Z 9 c Y 1
100 0 a Z 1 a Z 2 ab Z 7 c Y 1
200 1 a Z 2 a YZ 5 b Y 14 d X 1
SE 0 1 1 1
aAbbreviations: Merge added at 1% v/v; WAT: Weeks after treatment; PP: Pre-plant; PRE: Pre-emergence; POST: Post-emergence; bData averaged for Exeter in
2008 & 2009; cExeter 2008.
Table 3. Winter wheat injury, height and yield as a function of saflufenacil dose and application timing. Means followed by the same
letter within a column are not significantly different according to Fisher’s Protected LSD at P < 0.05a.
Injury%
2 WATb Mayc Julyb Heightd cm Yieldd MT ha1
Saflufenacil dose (g a.i. ha1)
0 0 a 0 a 0 a 79.9 a 6.87 a
25 4 b 11 b 1 a 79.6 a 6.68 a
50 5 b 11 b 1 a 80.0 a 6.73 a
100 8 c 18 c 1 a 79.5 a 6.60 a
200 11 d 20 c 1 a 79.8 a 6.55 a
SE 1 2 0 0.2 0.05
Application timing
Untreated 0 a 0 a 0 a 79.9 a 6.87 a
PP 1 a 1 a 0 a 80.2 a 6.87 a
PRE 1 a 2 a 0 a 80.2 a 6.85 a
POST 6 a 16 b 1 a 79.6 a 6.68 a
POST + Merge 20 b 41 c 1 a 79.1 a 6.35 a
SE 1 2 0 0.2 0.05
aAbbreviations: Merge added at 1% v/v; WAT, week after treatment; PP, pre-plant; PRE, pre-emergence; POST, post-emergence; bData averaged for Exeter in
008 & 2009; cExeter 2009; dData averaged for Exeter and Ridgetown in 2007-2009. 2
Copyright © 2012 SciRes. OPEN ACCESS
L. R. Brown et al. / Agricultural Sciences 3 (2012) 755-758
758
(20%). Saflufenacil caused 11% (25 and 50 g a.i. ha1),
18% (100 g a.i. ha1) and 20% (200 g a.i. ha1) injury in
May of the following spring in winter wheat with the
greatest injury occurring with the POST (16%) and
POST + Merge (41%) applications (Table 3). As the
season progressed into July, there was little to no injury
from saflufenacil application the previous autumn.
There was no effect of saflufenacil on winter wheat
height or yield (Table 3). Even though saflufenacil ap-
plied POST and POST + Merge caused up to 16% and
41% injury respectively, this injury was transient with no
effect on winter wheat height or yield. These results dif-
fer from studies conducted by Knezevic et al. [8] who
reported a significant yield reduction (up to 66%) with
autumn POST applications of saflufenacil and up to 67%
with spring POST applications in winter wheat.
4. CONCLUSION
This study concludes that there is an acceptable mar-
gin of crop safety in winter wheat to PP and PRE appli-
cations of saflufenacil. The POST applications caused
injury that would be unacceptable to growers even
though in this study it did not result in a yield loss. There
was greater injury when saflufenacil was applied POST +
Merge. Injury was the greatest at higher doses. Since this
research has shown that saflufenacil can be applied
safely to winter wheat either PP or PRE future research
should focus on the control of winter annual, biennial
and perennial broadleaf weeds. The autumn application
of saflufenacil may eliminate the need for spring applied
herbicides for broadleaf weed control.
5. ACKNOWLEDGEMENTS
The authors would like to acknowledge Todd Cowan for his exper-
tise and technical assistance in these studies. Funding for this project
was provided in part by the Grain Farmers of Ontario (GFO) and
BASF.
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Copyright © 2012 SciRes. OPEN ACCESS