Diseases of flowers and other Diseases of flowers and other ornamentals diseasesofflower118smit Year: 1940 Diseases of Flowers and Other Ornamentals 55 Cronartiwm ribicola, attacks only species of the white-pine type, includ- ing eastern white pine (Pinus strobus), sugar pine (P. Lambertiana), and western white pine (P. monticola). Blister rust, like many other rusts, has another, so-called 'alternate' form on an entirely different type of host plant, this being certain spe- Fig. 22.—Gall rust on digger pine. cies of Bibes (see 'Currant and Gooseberry, Native,' p. 19). The disease cannot
Diseases of flowers and other Diseases of flowers and other ornamentals diseasesofflower118smit Year: 1940 Diseases of Flowers and Other Ornamentals 55 Cronartiwm ribicola, attacks only species of the white-pine type, includ- ing eastern white pine (Pinus strobus), sugar pine (P. Lambertiana), and western white pine (P. monticola). Blister rust, like many other rusts, has another, so-called 'alternate' form on an entirely different type of host plant, this being certain spe- Fig. 22.—Gall rust on digger pine. cies of Bibes (see 'Currant and Gooseberry, Native,' p. 19). The disease cannot pass directly from pine to pine but must first infect Bibes from pines and there produce spores to infect other pine trees. The fungus may spread from pine to Bibes over distances as great as 150 miles, but from Bibes to pine the maximum infection range is only about 300 yards under normal conditions. In new localities, therefore, blister rust is usually found first on currant or gooseberry bushes. After pines are first in- fected, a period of two to three years elapses before a new crop of spores is produced. Federal and state authorities are carrying on an extensive campaign to limit the spread of this disease and prevent serious damage to valuable stands of sugar-pine and western-white-pine timber. This is done mainly by eradicating susceptible species of Bibes, since the fungus cannot go from pine to pine. Any suspicious symptoms on either host should be
Size: 1116px × 1792px
Photo credit: © Bookend / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: archive, book, drawing, historical, history, illustration, image, page, picture, print, reference, vintage
