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Wheat (Triticum aestivum �Knudson�)�� ����������������������������������������������� ������������������������������� S. Halley

�� Tan spot; Pyrenophora tritici-repentis��������������������������������������������������������������� ��������������� Langdon Research Extension Center

�� Septoria blotch; Septoria tritici������������������������������������������� ��������������� ������������������������������� North Dakota State University

�� ������������������������������������������������������������ ��������������� ����������������������������������������������� ��������������� Langdon, ND 58249

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Headline Fungicide for Leaf Disease Control Applied Different Stages of Growth to HRSW, 2003

 

Growers frequently ask about the benefits of fungicide application when herbicides are normally applied for leaf disease control. A study was established to evaluate BASF fungicide Headline (pyraclostrobin) applied at recommended rates, 6 fl oz/A, and half rates, 3 fl oz/A, applied at Feekes growth stages 4.5, 6, and 10. Folicur fungicide at 2 and 4 fl oz/A applied at growth stage 10.51 was included as additional treatments and compared to an untreated. Research is needed so growers will know the consequences of different rates applied at different growth stages.Cultivar �Knudson� HRSW was planted in a field at the Langdon Research Extension Center in spring 2003. An area was planted with a Melroe double-disk grain drill, disks spaced 6-inches apart on 3 May. The area was divided to plots 10 ft. wide by 20 ft. long in a randomized complete block design with four replicates. Recommended production practices for Northeast North Dakota, NDSU Extension, were followed. Wheat grains colonized by F. graminearum were hand broadcast on 19 Jun on individual plots at 3.5 oz per plot to increase chance of infection to Fusarium head blight. Treatments were applied by CO2 backpack sprayer at 9 GPA with hydraulic nozzles XR8001 oriented vertical for Headline treatments and at 18 gpa with XR8001 nozzles mounted on a double swivel angled 30 degrees downward and oriented forward and backward with Folicur treatments at 40 psi for all applications.Fungicide applications were made at Feekes growth stages 4.5, 6, 10, and 10.51 on 9 Jun at 6 a.m., 16 Jun at 6 a.m., 27 Jun at 9 a.m., and 7 Jul at 8 a.m., respectively.Flag leaf necrosis was visually estimated for five samples (1 leaf per sample) per plot. Flag leaf necrosis was the additive effect of tan spot and Septoria blotch on each sample. Each plot was harvested with a Hege plot combine on 19 Aug and the grain sample cleaned and processed for yield and test weight measurement. Data was analyzed with the general linear model procedure in SAS. Least significant differences were used to compare means at the 5% probability levels.

 

Disease levels were extremely low. �Knudson� cultivar has very good tolerance to leaf disease and no differences were measured.

An increase in yield was measured with a 3 fl oz rate application of Headline compared to the 6 fl oz rate applied at Feekes 4.5 growth stage. Other researchers have not found similar results. More study is recommended. A full rate, 4 fl oz, of Folicur increased yield over several rates of Headline at some growth stages. This response would be in part due to efficacy of Folicur for control of Fusarium head blight (FHB) even though FHB levels were very low. No differences in test weight were determined.

 

 

Relative

Feekes growth

Leaf disease

Yield

Test weight

Fungicide and rate

application rate*

stage

(%)

(bu/A)

(lb/bu)

 

 

 

 

 

 

Headline 2.09EC 3 fl oz...

0.5 x

4.5

9.5

61.9

58.1

Headline 2.09EC 6 fl oz...

1.0 x

4.5

6.5

54.0

58.0

Headline 2.09EC 3 fl oz...

0.5 x

6

4.6

57.3

58.0

Headline 2.09EC 6 fl oz...

1.0 x

6

4.1

56.2

58.1

Headline 2.09EC 3 fl oz...

0.5 x

10

4.6

56.6

58.8

Headline 2.09EC 6 fl oz..

1.0 x

10

4.5

58.8

58.6

Folicur 3.6F 2 fl oz��..

0.5 x

10.51

6.4

58.4

59.0

Folicur 3.6F 4 fl oz��..

1.0 x

10.51

4.3

64.2

59.0

Untreated������..

na

na

7.8

55.8

58.1

 

 

 

 

 

 

LSD

 

 

NS

6.1**

NS

% C.V.

 

 

49

7

1

*Relative rate based on full rate of Headline 6 oz/acre and Folicur 4 oz/acre.

**Significant at 0.0557probability level for mean comparisons