ISSUE 7   June 15, 2006

WHEAT LEAF RUST FOUND IN OTHER COUNTIES

After last week’s Crop and Pest Report was published, a few additional observations of wheat leaf rust were reported. An independent crop consultant found very low levels of leaf rust in Alsen and Briggs spring wheats in Bottineau county, Kent McKay found very low levels in Jagalene winter wheat at the Minot Station, Terry Gregoire, Area Extension Specialist, found trace levels of leaf rust on winter wheat in Ramsey county and Cavalier county, and NDSU IPM field scout Tom Gross found a few pustules on a winter wheat in Griggs county and NDSU IPM field scout Matt Leiphon found a couple fields in Cavalier and Towner county with trace levels.

 

NDSU DISEASE FORECASTING SITE

On June 12, the NDSU forecasting site actually had a few areas indicated to be of moderate risk for Fusarium head blight on very susceptible varieties. Moderately susceptible to moderately resistant varieties were not at risk. The moderate risk areas for very susceptible varieties were predominately in the northcentral region (see map). The most likely candidate for a fungicide spray in that area at this time would be a very susceptible winter wheat, such as Jagalene.

scab map

Dr. Shaukat Ali, NDSU plant pathologist, distributed spore trapping devices to research extension centers this past week , and data on Fusarium head scab fungal spore detection should be coming in soon.

 

NDSU IPM SURVEY RESULTS, June 5-9

NDSU IPM’s summer field scouts surveyed 218 wheat fields and 24 barley fields the second week of June. Diseases were almost absent in the barley fields scouted, but a few in the northeast district and in Griggs county had trace levels of spot blotch. In wheat, the tan spot symptoms were still the most common observation, found in 83% of all fields surveyed. The average leaf area infected was 3.8%, but higher severities were seen in some southwest and northwest counties.

The field scouts observed BYDV symptoms in six fields but only four fields showed detectable, but low numbers of grain aphids.

Marcia McMullen
Extension Plant Pathologist
marcia.mcmullen@ndsu.edu

 

ASCOCHYTA BLIGHT OF DRY PEA

Ascochyta blight, which is a fungal disease that can be caused by a "complex" of three different pathogens was observed in a dry pea field near Carrington recently. Symptoms of Ascochyta blight appear as either tan to brown or purple in color, depending on the pathogen. Pycnidia, which are small black fruiting bodies of the fungus, may be found spread throughout the center of the lesions (See figure). Wet conditions promote the disease. All dry pea varieties are susceptible to Ascochyta blight, but some may be more susceptible than others. Headline, Amistar, and Quadris fungicides are registered for control of the disease. Before applying a fungicide, it might be best to evaluate the amount of disease present and the potential yield of the crop. Saskatchewan guidelines indicate that applications may be needed when 50% of the leaf area in the bottom 1/3 of the plant is covered with lesions. Fungicide trials conducted by NDSU Research Extension Center personnel at Langdon and Minot showed some yield benefits of applying a fungicide to dry pea plants under Ascochyta blight pressure last year, but the return on the fungicide investment may not have always been achieved (See tables).

Location

Fungicide

Yield (bu/A)

Leeds

None

37

Quadris

44

Headline

43

LSD 0.05

5

Mohall None

40

Quadris

43

Headline

46

LSD 0.05

ND


Location

Fungicide

Timing

Yield (bu/A)

Langdon

None

 

58

 

Headline

1st bloom

63

 

Headline

1 wk after 1st bloom

71

 

Headline

2 wk after 1st bloom

67

   

LSD 0.05

7


Ascochyta blight lesions on dry pea

Carl Bradley
Extension Plant Pathologist
carl.bradley@ndsu.edu


NDSU Crop and Pest Report Home buttonTop of Page buttonTable of Contents buttonPrevious buttonNext button