Diseases of flowers and other Diseases of flowers and other ornamentals diseasesofflower118smit Year: 1940 72 California Agricultural Extension Service [Cir. 118 Mosaic.—The sweet pea is subject to several mosaic diseases. In the one most commonly found in California, called 'pea virus,' the leaves are mottled with green and yellow or transparent streaks and spots and become much crinkled and deformed. The flower stalks are shortened, the blossoms deformed, and the color breaks—that is, the normal colors are marked with clear, colorless streaks (fig. 32). ¥ Fig. 33.—Spotted wilt of sweet
Diseases of flowers and other Diseases of flowers and other ornamentals diseasesofflower118smit Year: 1940 72 California Agricultural Extension Service [Cir. 118 Mosaic.—The sweet pea is subject to several mosaic diseases. In the one most commonly found in California, called 'pea virus,' the leaves are mottled with green and yellow or transparent streaks and spots and become much crinkled and deformed. The flower stalks are shortened, the blossoms deformed, and the color breaks—that is, the normal colors are marked with clear, colorless streaks (fig. 32). ¥ Fig. 33.—Spotted wilt of sweet pea causing so-called streak disease. The disease, caused by a virus, is spread by the pea aphid, Illinoia pisi. The spread of mosaic may be delayed by dusting with nicotine to keep down the aphids. Powdery Mildew.—The leaves and buds become covered with a white, powdery fungus, Erysiphe polygoni, which causes stunting of the growth and worthless flowers. To control, dust frequently with dry, powdered sulfur, beginning before mildew develops. This may be combined with nicotine dust for aphids.
Size: 1330px × 1504px
Photo credit: © Bookend / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: archive, book, drawing, historical, history, illustration, image, page, picture, print, reference, vintage
