Stemphylium blight: Dark brown blotches on leaves
Pathogen: Stemphylium vesicarium
Symptoms
An attack begins with small, light yellow to brown, watery spots. After a while these develop into elongated blotches that can merge with each other and attack the entire leaf. The blotches are light brown in the middle, becoming darker towardsthe edges. Black fruiting bodies can be seen clearly.
Disease development
Extended periods of leaf wetness from dew formation, rainfall or overhead irrigation during bulb formation and development can result in severe leaf blighting. Bulb size can be greatly reduced due to loss of foliage. Infection is usually limited to leaves and does not extend down to the scales of the bulb.
Disease management
Good control of insects and other diseases is vital. This prevents weak tissue.There are a variety of fungicides that can prevent this disease from causing too much damage. In warm weather do not irrigate in crops with a slight Stemphylium infection.
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