DISEASES
Click on image to view larger. Bacterial Blight
(Xanthomonas campestris)
Most susceptible plants: begonia, geranium, zinnia.This disease can be devastating, causing loss of an entire crop. The pathogen is systemic so watch for symptoms and take immediate action upon detection.
Symptoms:
Leaf spots begin as water-soaked blotches on leaves, frequently with large areas of chlorosis and browning at the leaf margins. An inverted "V" pattern commonly develops soon after initial symptoms occur; the "V"-shaped lesion usually turns a copper color as the infection proceeds. Leaf collapse is common as is the development of a soft, watery deterioration of the plant stem. Plant wilt and decline follows.Control:
The most important management strategy for this disease is to avoid introducing the pathogen into the greenhouse. Use disease-free, culture-indexed cuttings. Know the typical symptom to look for. There is no effective chemical control. Aggressive roguing of infected or symptomatic plants is important. Keep foliage dry; avoid overhead wetting/irrigation.
