FLAX (Linum
usitatissimum �York�)������������������������� S. Halley
��� Pasmo; Septoria linicola����������������������������������������� Langdon
Research Extension
Center
��� ������������������������������������������������������������������������������� North
Dakota State University
����������������������������������������������������������������������������������� Langdon,
North Dakota 58249
Fungicide efficacy at
two application timings for control of pasmo disease in flax, 2003.�
�� An area was
selected in a foundation seed production field at the Langdon
Research Extension
Center for a trial to evaluate
fungicides and application timings for control of pasmo on cultivar �York�
flax. The field was planted on May 27 with a double disk drill with six inch
spacing between disks. Previous crop was also flax and the trial site was
selected because of a pasmo infection the previous year. The trial design was a
randomized complete block arranged a 5 x 2 factorial. Fungicides tested
included Bravo (chlorothalonil), Folicur (tebuconazole), Headline
(pyraclostrobin), Penncozeb (Mancozeb), and Stratego (trifloxystrobin +
propiconazole). Timings tested were 7 days after first flower growth stage and
a subsequent application to selected plots 21 days after first flower growth
stage. Plots were 7 x 16 ft with the center 4 ft harvested for yield.
Fungicides were applied by pressurized CO2 backpack sprayer at 18
GPA with hydraulic nozzles XR8002 oriented to spray vertical. The first
fungicide application was made on 20 Jul with subsequent applications made on 4
Aug. Disease assessments were recorded 15 Aug by measuring the height above the
ground that leaves were necrotic to represent early Pasmo infection and the
maximum height above the ground that pasmo lesion were visible to quantify late
Pasmo infection. The plant height was 26 in.�
Plots were harvested with a Hege plot combine 8 Sep and the grain sample
cleaned and processed for yield and test weight. Data was analyzed with the
general linear model (GLM) in SAS. Least significant differences were used to
compare means at the 5% probability level.
���� A dry Aug reduced
yield potential on the crop. No differences were measured in yield or test
weight. A fungicide/timing interaction was detected. Headline fungicide had
significantly less necrotic leaves when applied at the early application timing
compared to the two application timing. Stratego had significantly less
necrotic leaves when applied twice. No differences were determined in necrotic
leaves by timings in Bravo, Folicur, or Penncozeb. However an early fungicide timing
of Stratego was not as effective as other select fungicides and timings.
Averaged across all timings Penncozeb was more effective than Folicur in
suppressing late Pasmo infection and the subsequent fungicide application
timing suppressed late Pasmo infection more than early fungicide treatment
alone. Further study is needed to recommend timings with select fungicides. The
limited yield potential in 2003 due to low precipitation amount and flax on
flax crop rotation likely made yield differences not significant.�
�
|
|
|
Necrotic
|
Pasmo
|
Yield
|
Test
|
|
|
Application
|
Leaves
|
Height
|
|
Weight
|
|
Treatment and rate/A
|
Timing*
|
in.
|
in.
|
bu/A
|
lb/bu
|
|
|
|
|
|
|
|
|
Bravo 82.5DF 1.6 lb/A����.
|
7
|
14.3
|
21.0
|
24.6
|
52.9
|
|
|
7 + 21
|
12.3
|
18.5
|
23.0
|
52.0
|
|
Folicur 3.6F 4 fl
oz/A����...
|
7
|
15.0
|
22.8
|
22.4
|
52.4
|
|
|
7 + 21
|
14.3
|
21.0
|
24.9
|
52.4
|
|
Headline 2.09EC 6 fl
oz/A��...
|
7
|
11.3
|
19.8
|
24.7
|
52.4
|
|
|
7 + 21
|
14.7
|
21.0
|
25.8
|
52.8
|
|
Penncozeb 75DF 2 lb/A���...
|
7
|
13.8
|
21.3
|
21.9
|
52.1
|
|
|
7 + 21
|
12.0
|
16.3
|
21.3
|
52.6
|
|
Stratego 11.4%:11.4% 10 fl
oz/A
|
7
|
16.3
|
22.0
|
23.6
|
42.3
|
|
|
7 + 21
|
12.8
|
20.0
|
24.2
|
42.6
|
|
|
|
|
|
|
|
|
Fungicides
averaged across timings
|
|
|
|
|
Bravo
|
|
13.3
|
19.8
|
23.8
|
52.4
|
|
Folicur
|
|
14.6
|
21.9
|
23.7
|
52.4
|
|
Headline
|
|
13.0
|
20.4
|
25.2
|
52.6
|
|
Penncozeb
|
|
12.9
|
18.8
|
21.6
|
52.4
|
|
Stratego
|
|
14.5
|
21.0
|
23.9
|
52.5
|
|
|
|
|
|
|
|
|
Timings
averaged across fungicides
|
|
|
|
|
|
7
|
14.1
|
21.4
|
23.4
|
52.4
|
|
|
7 + 21
|
13.2
|
19.4
|
23.8
|
52.5
|
|
|
|
|
|
|
|
|
Untreated**
|
|
16.0
|
21.5
|
21.3
|
52.3
|
|
Fungicide
|
|
NS
|
2.1***
|
NS
|
NS
|
|
Timing
|
|
NS
|
1.3
|
NS
|
NS
|
|
Fung*Timing
|
|
2.3
|
NS
|
NS
|
NS
|
|
% C.V.
|
|
12
|
10
|
13
|
1
|
|
|
|
|
|
|
|
*Days after first flower
**Not included in statistical
analysis
*** Significant at 0.1
probability level for mean comparisons.
