. Diseases of glasshouse plants. Greenhouse plants; Plant diseases. DISEASES DUE TO FUNGI 93 ing an ochreous-brown colour. The spots are definite in outline, irregular in shape, and may be distinguished readily from other leaf spot diseases. Frequently the entire leaf withers within the space of forty-eight hours after infection. An examination with a pocket lens of the upper Burface of a " spot" shows the presence of brown erect fungal filaments, bearing conidia at their tips. These conidia are comparatively large, cylindrical in shape, but narrowed towards one end, and each possess
. Diseases of glasshouse plants. Greenhouse plants; Plant diseases. DISEASES DUE TO FUNGI 93 ing an ochreous-brown colour. The spots are definite in outline, irregular in shape, and may be distinguished readily from other leaf spot diseases. Frequently the entire leaf withers within the space of forty-eight hours after infection. An examination with a pocket lens of the upper Burface of a " spot" shows the presence of brown erect fungal filaments, bearing conidia at their tips. These conidia are comparatively large, cylindrical in shape, but narrowed towards one end, and each possesses seven to nine cross walls (Fig. 22). Infection spreads rapidly, the conidia being easily blown about the house, as well as being transported by the workers, insects, and by the process of overhead damping. The disease can only attain epidemic proportions under conditions of high temperature and humidity, but rapidly growing, sappy plants are more susceptible to attack than slow growing plants with harder tissues. It has been observed that the tops of badly diseased plants ^'^â - ^vore. ot Cercospora r>.eloâU. grow away clean if by any chance they pass through the ventilators into the open ak. Similarly, cucumbers grown imder frames or in the open air are not attacked by this disease. The control of the disease depends very largely upon the humidity of the glasshouse atmosphere, and efficient ventilation readily checks it by drying out the moistiu-e from the house. All diseased leaves should be at once removed and burnt, for if these fall upon the damp earth they become covered with a fungal growth bearing. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bewley, W. F. (William Fleming). London, E. Benn
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectplantdi, bookyear1923
