NDSU Crop and Pest Report
Plant Pathology


ISSUE 16  August 21, 2003

PLANT DIAGNOSTIC LAB UPDATE

As part of a national effort to increase homeland security, the Plant Diagnostic Lab is a member of the Great Plains Diagnostic Network (GPDN), which is a component of the National Plant Diagnostic Network (NPDN). For those of you in Minnesota, your state is a member of the North Central Plant Diagnostic Network (NCPDN). These regional networks were established last year, but their work is now becoming tangible. The objectives of the NPDN, through the work of the regional networks include implementation of common databases to more quickly identify and monitor plant pest problems, as well as training for the following purposes:

  1. to increase awareness of the networks
  2. to give 1st detectors (in most cases, you)resources to:

The GPDN will begin implementing the database in October. For some of you, this will impact the way you will submit samples, especially digital samples. We will also be rolling out some training modules this fall and winter, beginning with a basic diagnostic module and a wheat pest module. If you would like more information on theses networks, check out the following web sites:

http://www.ndn.org          http://www.gpdn.org          http://www.ncpdn.org

One of the most useful components of this system is an image library. These images can be used for both diagnostic and educational purposes, and they are peer reviewed upon submission so that you can be assured of both a quality image as well as accuracy of identification. The photographer’s credit will be embedded in the image. This library is not limited to plant disease, but includes insect and weed images as well. You may link to any of these network sites, to the image library, or monitor new hot topics in plant biosecurity by checking the Plant Diagnostic Lab web site:

http://www.ag.ndsu.nodak.edu/diaglab

In an early pest report issue, I told you we were working toward a joint operation of the Plant Diagnostic Lab and Soil and Water Testing Labs. This project will not be moving forward in the near future due to budgetary and personnel constraints in the soils department. Each of these labs, however, will continue to operate independently.

Cheryl Biller
NDSU Plant Diagnostic Lab

 

WINTER WHEAT FUNGICIDE RESULTS

A fungicide trial was established on ‘Falcon’ winter wheat at the Randy Mair farm near Lisbon, ND in 2003. This project was done in cooperation with Ducks Unlimited and had financial support from Syngenta, Bayer, and BASF. The intent was to evaluate the leaf and head disease control provided by either a single application of fungicide applied at heading vs the possible additional control achieved by applying a reduced rate of early season fungicide followed by a heading application at the full or recommended label rate.

The primary diseases on ‘Falcon’ at this site were the fungal leaf spots of tan spot and Septoria. Leaf rust was not present on this variety and Fusarium head blight development was quite low. The fungicide effects, therefore, were primarily in controlling the fungal leaf spots.

Leaf disease control varied from 68.3 to 92%. Yield increases varied from 8.2 to 15.2 bu. The two applications generally provided greater disease control and higher yield than one application at heading. With the Tilt applications, the early application was with 1 fl oz instead of half the full label rate of 2 fl oz, and the heading application was with 3 fl oz instead of the full 4 fl oz label rate, which may explain why two applications of Tilt did not do better than one. For the other fungicides, the early application was the half label rate and the heading application was the full recommended rate.

Winter wheat fungicide results, Lisbon, ND 2003

Treatment

Rate/ac
fl oz

Applic.Stage
Feekes

% leaf spot July 10

Yield
bu/a

Twt
lbs/bu

Untrt

   

75 a

65.5 a

61 a

Tilt
Tilt

1
3

2
10.5

20 b

73.7 b

61.1 a

Tilt

4

10.5

20 b

76.2b

61.1 a

Stratego
Folicur

5
4

2
10.5

14 bc

77.9 b

61.4 a

Folicur

4

10.5

21 b

76.3 b

61 a

Headline
Headline

3
6

2
10.5

6 c

80.7 b

61.4 a

Headline

6

10.5

20 b

74.5 b

61.5 a

Numbers followed by different letters are significantly different at 95% confidence level

In communications with producers and crop consultants, the above yield results with winter wheat are very similar to observations with spring wheats in eastern ND this year. Even with very high yields in untreated plots, fungicide treatments are resulting in 17- 20% yield increases plus quality improvements over the untreated wheat.

 

NDSU IPM SURVEY COMPLETED

The NDSU IPM survey was essentially finished the week of Aug. 11-15, but a few observations will be added for the week of Aug. 18-22. A complete summary of the survey results will be compiled this fall. Currently, information on disease and insect observations on wheat, barley, soybean, canola, and sunflower can be found at the following web site:

http://www.ag.ndsu.nodak.edu/aginfo/ndipm/

Maps of disease and insect occurrence observed each week can be viewed, as well as crop growth stages across the state each week, and a summary map for each pest for the season. Some maps may need to be updated at a later date. The survey provides us information on distribution of pests, incidence within a field, and severity of occurrence.

For wheat and barley, the Fusarium head blight disease overall was not severe, with the most common detections averaging <1%-5% field severity range.

           

Wheat leaf rust was common in the eastern half of the state, while the fungal leaf spots of tan spot and Septoria were common throughout.

                       

Marcia McMullen
Extension Plant Pathologist
mmcmulle@ndsuext.nodak.edu


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