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Catalogue: GRDC Media
Department of Agriculture, Fisheries and Forestry (DAFF) principal pathologist Greg Platz said there was a lack of evidence to suggest that the black spotting was caused by spot form net blotch and fungicide applications would be a costly and ineffective means of control... "It is logical to conclude that the black spotting we are currently seeing on some barley crops in the northern region may be spot form net blotch as the symptoms are very similar to the early stages of the disease," Mr Platz said... "Spot form net blotch has seldom been isolated from samples tested and we believe the cause is physiological leaf spotting (PLS), or oxidative stress, largely as a result of current environmental conditions...
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Catalogue: GRDC Media
Department of Agriculture, Fisheries and Forestry (DAFF) principal pathologist Greg Platz said there was a lack of evidence to suggest that the black spotting was caused by spot form net blotch and fungicide applications would be a costly and ineffective means of control... "It is logical to conclude that the black spotting we are currently seeing on some barley crops in the northern region may be spot form net blotch as the symptoms are very similar to the early stages of the disease," Mr Platz said... "Spot form net blotch has seldom been isolated from samples tested and we believe the cause is physiological leaf spotting (PLS), or oxidative stress, largely as a result of current environmental conditions...
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Catalogue: Grains Notes DEPI VIC
The Agriculture Note provides information on the importance, symptoms, and biology of pepper spot, common leaf spot, Stemphylium leaf spot, Stagonospora leaf spot, downy mildew and rust in lucerne... Pepper spot, caused by the fungus Leptosphaerulina trifolii , is one of the most common diseases on lucerne, but usually does not cause serious herbage losses... Host Range: Uromyces striatus occurs on lucerne, medics and sweet clover...
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Catalogue: Grains Notes DEPI VIC
The Agriculture Note provides information on the importance, symptoms, and biology of pepper spot, common leaf spot, Stemphylium leaf spot, Stagonospora leaf spot, downy mildew and rust in lucerne... Pepper spot, caused by the fungus Leptosphaerulina trifolii , is one of the most common diseases on lucerne, but usually does not cause serious herbage losses... Host Range: Uromyces striatus occurs on lucerne, medics and sweet clover...
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Catalogue: Broadacre Field Crops DAFF QLD
Early leaf spot: brown spots on upper (left) and lower (right) leaf surfaces some showing a yellow halo around the spot... Leaves fall off and stems and pegs are weakened if the epidemic starts early, is uncontrolled and weather conditions favour disease spread... Leaves must be wet from rain, dew or irrigation for long periods to trigger infections...
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Catalogue: Broadacre Field Crops DAFF QLD
Early leaf spot: brown spots on upper (left) and lower (right) leaf surfaces some showing a yellow halo around the spot... Leaves fall off and stems and pegs are weakened if the epidemic starts early, is uncontrolled and weather conditions favour disease spread... Leaves must be wet from rain, dew or irrigation for long periods to trigger infections...
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Catalogue: Broadacre Field Crops DAFF QLD
Early leaf spot: brown spots on upper (left) and lower (right) leaf surfaces some showing a yellow halo around the spot... Leaves fall off and stems and pegs are weakened if the epidemic starts early, is uncontrolled and weather conditions favour disease spread... Leaves must be wet from rain, dew or irrigation for long periods to trigger infections...
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Catalogue: GRDC Updates
Sowing a susceptible wheat variety on stubble of a previously infected susceptible variety (e.g. Gregory-on-Gregory) represents a much higher risk for developing high levels of yellow spot... The incidence and severity of yellow spot increases as moisture periods lengthen such that it takes repeated rain events to drive the disease from the lower to the upper canopy later in the season... Yellow spot is generally considered a significant disease in very wet seasons (e.g. 1998 and 2010) where yield losses of up to 30% have been recorded in susceptible wheat varieties...
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Catalogue: GRDC Updates
Sowing a susceptible wheat variety on stubble of a previously infected susceptible variety (e.g. Gregory-on-Gregory) represents a much higher risk for developing high levels of yellow spot... The incidence and severity of yellow spot increases as moisture periods lengthen such that it takes repeated rain events to drive the disease from the lower to the upper canopy later in the season... Yellow spot is generally considered a significant disease in very wet seasons (e.g. 1998 and 2010) where yield losses of up to 30% have been recorded in susceptible wheat varieties...
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Catalogue: Ground Cover
Yellow spot is caused by a fungus ( Pyrenophora tritici-repentis ), which survives between crops on wheat stubbles... Dr Simpfendorfer is concerned that many growers and advisers believe they can control yellow spot with fungicides, as they do for stripe rust, even though the research clearly shows this is not the case... Once the fungicide wears off in a leaf, after about three weeks, it can get rapidly reinfected off the stubble if there are moist conditions."..
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