Posted on May 10, 2013 by Carl Bradley

Stripe rust of wheat observed in Illinois

Stripe rust of wheat was observed in Champaign County, IL on May 10, 2013 (Fig. 1). The incidence of the disease was very low. The observation of this disease in Champaign County indicates that stripe rust likely is present in southern Illinois counties too.

Fig. 1. Beginning symptoms/signs of stripe rust of wheat that were observed in Champaign Co., IL on May 10, 2013 (Photo by Carl Bradley).

 

Wheat producers will need to continue to scout their crop for stripe rust, and apply an effective fungicide if necessary (see this previous post for additional information about stripe rust and fungicides: http://bulletin.ipm.illinois.edu/?p=456). Some varieties may have good levels of resistance to stripe rust, in which a fungicide may not be needed. In a University of Illinois research trial conducted in 2012, stripe rust affected yield of some varieties, but not others (Table 1).

Table 1. Effect of Prosaro fungicide (applied at Feekes 10.5.1 at 6.5 fl oz/A) on stripe rust and yield of six different wheat varieties. Trial was conducted at the University of Illinois Crop Sciences Research & Education Center near Urbana, IL in 2012 and was funded by the U.S. Wheat & Barley Scab Initiative.

Variety

Fungicide

Stripe rust severity (%)

Yield (bu/A)

Pioneer 25R54

No

20

74

Yes

2*

84*

Pioneer 25R47

No

8

82

Yes

1

84

W1104

No

14

77

Yes

2*

90*

Kaskaskia

No

57

69

Yes

7*

79*

BW5530

No

65

67

Yes

7*

72

BW5228

No

28

55

Yes

5*

64*

*Indicates that the fungicide treatment was significantly (alpha = 0.05) different than the untreated check for that variety.

If conditions and risk are favorable for Fusarium head blight, then growers may want to wait to spray an effective triazole fungicide at Feekes 10.5.1 (early flowering), which will help manage both Fusarium head blight and stripe rust (see this previous post about Fusarium head blight: http://bulletin.ipm.illinois.edu/?p=548).

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