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AVRDC International
Cooperators'
Fact Sheet |
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Cucurbit Diseases Angular Leaf Spot Pseudomonas syringae pv. lachrymans Found worldwide |
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Damage Symptoms The disease can occur on most cucurbits but it is most common on cucumber. Characteristic symptoms on leaves are angular shaped, watersoaked lesions delimited by veins. With them the lesions turn brown and the centers fall out causing the leaves to be tattered. On fruits and stems, watersoaked spots exude a millky bacterial exudate that dries to form a white crust. Lesions on young fruit may cause a depression and result in a curved fruit. |
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Conditions for Development The pathogen survives from one
season to the next in infected crop debris and seed. Disease
development is favored by excessive rainfall and humid conditions
that lead to extended periods of leaf wetness. The pathogen is
readily spread by water splash and wind-blown rain. Rotate crops, use pathogen-free seed, and use resistant cultivars. Fixed copper sprays beginning at first evidence of disease may minimize disease loss. |
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Last updated: 2001. Information from: Vegetable Diseases: A Practical Guide. Lowell L. Black, AVRDC. |
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