Angular Leaf Spot

Cucurbit Diseases


Angular Leaf Spot
Pseudomonas syringae pv. lachrymans


Found worldwide

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.

Symptoms on cucumber fruits

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.


Control

Rotate crops, use pathogen-free seed, and use resistant cultivars. Fixed copper sprays beginning at first evidence of disease may minimize disease loss.