. Better fruit. Fruit-culture. Page 4 BETTER FRUIT March, ip20. On tender twig growth scab first ap- pears in the characteristic sooty spots, but persists over winter and eventually causes the bark to become ruptured, so that after a year or two the younger branches seem to be covered with small irregularly circular shaped and blister- like cankers. As the brancli grows older these roughened areas slough off' and healthy bark is formed over the in- jury. Twig infection is not as prevalent as llie other types, but is likely to be foun<l in neglected orchards. It is im- portant chiefly as a s
. Better fruit. Fruit-culture. Page 4 BETTER FRUIT March, ip20. On tender twig growth scab first ap- pears in the characteristic sooty spots, but persists over winter and eventually causes the bark to become ruptured, so that after a year or two the younger branches seem to be covered with small irregularly circular shaped and blister- like cankers. As the brancli grows older these roughened areas slough off' and healthy bark is formed over the in- jury. Twig infection is not as prevalent as llie other types, but is likely to be foun<l in neglected orchards. It is im- portant chiefly as a source of infection for fruit and foliage. The Fungus Causing the Disease— The fungus causing the disease is close- ly related to the well known apple scab fungus, but it is a different species. It persists over winter not only on the FiciRF. 2 l.:rlc iiifictioii of scab on a Bartlett pear and injury caused by the syneta leaf beetle. Ttie elongated spots were produced by the beetle. pearance, black or olive green in color. In size the spots range from mere specks to areas that may cover the en- tire side of a young pear, while two or more spots may coalesce and increase the extent of the affected area. When very young pears are affected they may drop before they become one-half inch in diameter. The fungus causing the disease grows just beneath the cuticle, which becomes ruptured, exposing the epidermis, which is rendered corky on exposure, thus forming a roughened spot. Its effect is strictly local at first and causes no discoloration or harden- ing of the flesh beneath; but as the pear grows the scab injury restricts the ex- pansion of the fruit and causes it to be- come distorted in shape, a most objec- tionable feature. If the normal growth of the fruit is greatly distorted, cracks may be formed which extend halfway around the pear and almost to the core. The infection of buds and blossoms on unsprayed trees is frequently severe and often results in a great reduction of th
Size: 1487px × 1681px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcollect, bookcollectionbiodiversity, booksubjectfruitculture
