Ascochyta blight in Chickpea, Symptoms and Identification · Ascochyta blight in Chickpea, Symptoms...
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www.pulseaus.com.au PA 2008 #23 Ascochyta blight in Chickpea, Symptoms and Identification. Gordon Cumming Pulse Australia Northern ph: 0408 923474 Ascochyta blight, caused by the fungus Phoma rabiei (formerly Ascochyta rabiei) is a serious disease of chickpeas. In the chickpea growing regions where Ascochyta blight is present, the disease is managed through crop rotation, hygiene, seed treatment, prophylactic fungicide application and planting varieties with improved resistance. Description: Initial symptoms are commonly the wilting of individual or small groups of seedlings. Patches of wilted, pruned, and dying plants develop within the crop; these patches appear as premature haying off. Circular spots with tan to grey centres with dark brown to black margins develop on leaves, stems and pods.
Transcript of Ascochyta blight in Chickpea, Symptoms and Identification · Ascochyta blight in Chickpea, Symptoms...
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PA 2008 #23
Ascochyta blight in Chickpea,Symptoms and Identification.
Gordon Cumming Pulse Australia Northern ph: 0408 923474
Ascochyta blight, caused by the fungus Phoma rabiei (formerly Ascochyta rabiei) is a serious disease ofchickpeas. In the chickpea growing regions where Ascochyta blight is present, the disease is managedthrough crop rotation, hygiene, seed treatment, prophylactic fungicide application and planting varietieswith improved resistance.
Description:
Initial symptoms arecommonly the wilting ofindividual or small groups ofseedlings.
Patches of wilted, pruned,and dying plants developwithin the crop; thesepatches appear as prematurehaying off.
Circular spots with tan togrey centres with darkbrown to black marginsdevelop on leaves, stemsand pods.
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Leaf Lesions: Lesions usually begin as a pale green-yellow discolouration on leaves and stems and progress into
small round lesions with dark-brown margins and pale grey to tan sunken centres. Toward the centre of the lesion, fruiting bodies called pycnidia develop (appearing as black
specks), often in concentric rings. These pycnidia produce spores, which spread on wind-borne stubble and/or water (rain-splash) to
infect other plants.
Note the concentriccircles of brown-black dots in thecentre of thelesions.
These are thepycnidia or fruitingbodies which areunique toascochyta blight.
Ascochyta, leaf ghostingmay appear 4-7 days afterinfection following rainfallor heavy dew.
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Stem Lesions: Lesions on stems at first tend to be oval shaped, with brown centres and a darker margin. Lesions often girdle the stems of the plant, causing them to weaken and subsequently break off.
Pod Lesions:
Pod lesions are similar in appearance to leaf lesion.They lead to infection of the seed.
DO NOT keep planting seed from any crop that has beenidentified as having ascochyta blight.
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Visual effects that are NOT Ascochyta blight. Frost is the most common cause of leaf necrosis (whitening, death) which might be confused with
Ascochyta blight. Herbicide injury (eg: simazine, Balance®) may also cause similar effects. However, there are clearly no pycnidia (fruiting bodies) present. Other causes of branch death can include frost, and physical damage from wind, mice, other
animals as well as the passage of machinery.
Note the lack of anypycnidia
(fruiting bodies).
