Wheat (Triticum aestivum ‘Knudson’) S. Halley
Fusarium head blight; Fusarium graminearum
Tan spot; Pyrenophora tritici-repentis
Septoria blotch; Septoria tritici
‘Knudson’ HRSW Response to JAU 6476 Fungicide Rate,
2003
A new fungicide JAU 6476,
prothioconazole, has shown improved efficacy in the control of Fusarium head
blight on durum and hard red spring wheat and reductions in deoxynivalenol levels
compared to most of the currently labeled fungicides on small grains. Research
is needed so growers will know the consequences of different rates under
different environmental conditions and infections from different causal
organisms. Cultivar ‘Knudson’ HRSW was planted for JAU 6476 fungicide rate
evaluation in a field at the
Disease levels were extremely
low with Fusarium head blight incidence and field severity on the untreated at 36
and 2.3%, respectively. Fusarium head blight incidence was reduced by a 1x and
3x fungicide application. A 0.5x fungicide application reduced disease levels
from the untreated. No differences in Fusarium head blight field severity, yield,
and test weight were determined. All fungicide applications reduced
deoxynivalenol compared to the untreated. Levels were also reduced by the 0.5x
rate compared to smaller rates and a 3x rate compared to 1x and lower rates.
Deoxynivalenol levels were significantly correlated with treatment -0.795.
|
FHB |
Leaf |
|
Test |
|
|
|
Incidence |
Field Severity |
Disease |
Yield |
Weight |
DON** |
Treatment* and rate |
(%) |
(%) |
(%) |
(bu/A) |
(lb/bu) |
(ppm) |
Untreated |
36 |
2.3 |
10.3 |
64.5 |
59.3 |
3.9 |
0.125x 0.7 fl oz…….. |
35 |
4.6 |
6.2 |
67.2 |
59.8 |
2.0 |
0.25 x 1.4 fl oz........... |
27 |
2.0 |
7.9 |
67.5 |
59.6 |
2.1 |
0.5 x 2.85 fl oz........... |
24 |
1.8 |
4.2 |
64.9 |
59.8 |
1.4 |
1.0 x 5.7 fl oz………. |
18 |
2.8 |
2.9 |
69.9 |
60.2 |
1.3 |
2.0 x 11.4 fl oz........... |
23 |
1.3 |
3.5 |
66.0 |
60.2 |
0.9 |
3.0 x 22.8 fl oz........... |
12 |
0.6 |
3.8 |
67.2 |
60.1 |
<0.5 |
LSD |
13 |
NS |
4.9*** |
NS |
NS |
0.7 |
C.V. % |
46 |
92 |
75 |
8 |
1 |
36 |
*JAU 6476 (480 SC) applied with
Induce Adjuvant at 0.125% v/v/A.
**Deoxynivalenol
***P=.0381