. Some diseases of Puerto Rican forage crops. Forage plants Diseases and pests Puerto Rico. sistant to the disease {9, 28). In Florida, napier plots were killed by eyespot {27). An epidemic of the disease in Hawaii in 1939 practically eliminated napier grass as a forage crop {38). The following are symptoms of this disease on the different parts of the plant: Leaf—The spots (fig. 16, A) ap- pear first as small, red-brown, oval flecks. As they enlarge the center becomes lighter brown and the margins red. Finally, the centers become a dirty straw color and the margins a Bordeaux red. Their measu
. Some diseases of Puerto Rican forage crops. Forage plants Diseases and pests Puerto Rico. sistant to the disease {9, 28). In Florida, napier plots were killed by eyespot {27). An epidemic of the disease in Hawaii in 1939 practically eliminated napier grass as a forage crop {38). The following are symptoms of this disease on the different parts of the plant: Leaf—The spots (fig. 16, A) ap- pear first as small, red-brown, oval flecks. As they enlarge the center becomes lighter brown and the margins red. Finally, the centers become a dirty straw color and the margins a Bordeaux red. Their measurements are to 3 mm. wide and 2 to 5 mm. long. Some strains of napier may develop long streaks in the leaf. Spots on the leaf sheath are larger, lighter in color, and more diffuse in outline. Leaf spots somewhat similar in size and color to the eyespot lesions may be caused b}^ potash deficienc}^ {8). The irregular, or indefinite outline of these lesions differs from the elliptical, sharply defined bor- ders of the infections caused by the eyespot fungus. No fungi were isolated from young lesions sur- rounded by green healthy tissue. Stem.—Stem lesions are more elongate than leaf lesions and are correspondingly narrower. They are smooth at first, regular in outline, and reddish-brown, with or without a lighter colored center. Later they become sunken, irregular in shape, and bluish-purple to black. The border may be grayish-white or retain the original reddish-brown color. Most lesions are found on the first 6 inches above the ground and are more commonly at the nodes. Affected stems are shrunk- en, pithy, and partly or completely hollow; when split longitudinally in the region of the cankers, the interior of the stem is seen to be diseased or dead in part or in whole. Crown.—The crown is seldom affected; occasionally, however, dis- eased tissue can be found and the basal buds are withered and dark-. FiGURE 16.—A, Eyespot on Pennisetum purpureu7n (napier grass) caus
Size: 962px × 2597px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionameri, bookcollectionbiodiversity
