Fungous diseases of plants . comes subgelatinous, and in ten days there is a clearliquid above. This is at first acid, becoming slightly milk is unchanged. On slanting agar tubes growth in twenty-fouK hours is moderate,opalescent, spreading slowly, producing turpidity in the water ofcondensation ; growth not viscid. On gelatin stab cultures growth is similarly slow, and beadedor granular along the needle path ; surface growth with irregularor erose margin, center thin and granulose; liquefaction slow,crateriform and stratiform. Control. The control of pear blight was for a long
Fungous diseases of plants . comes subgelatinous, and in ten days there is a clearliquid above. This is at first acid, becoming slightly milk is unchanged. On slanting agar tubes growth in twenty-fouK hours is moderate,opalescent, spreading slowly, producing turpidity in the water ofcondensation ; growth not viscid. On gelatin stab cultures growth is similarly slow, and beadedor granular along the needle path ; surface growth with irregularor erose margin, center thin and granulose; liquefaction slow,crateriform and stratiform. Control. The control of pear blight was for a long time con-sidered impossible, but careful study under various conditions 128 FUNGOUS DISEASES OF PLANTS (particularly the work of Waite) has shown that this diseasemay be controlled or even practically eradicated in large essential step consists in pruning out the blight in situationswhere it may winter over. If all of the blight could be thoroughlypruned out of the orchard during the fall and winter, there would. Fu;. 35. Blight Canker on Trunk of Apple, from Infected Prun-ing Knife. (Photograph by H. 11. Whetzel) probably be no opportunity for infection the following season, ex-cept from distant orchards. In practice the pruning out of theblight during winter is not an easy process, and it requiresthe greatest care and keenest eyesight. It would be necessaryto go over the orchard several times, the final observation beingmade only a short time before the opening of the blossoms. SCHIZOMYCETES. BACTERIA 129 Pruning during the growing season is also practiced, but it is lessreliable. Such pruning has not proven a great success on accountof the fact that infection may be constantly taking place. More-over, when the blight is rapidly extending in a limb or trunk, itis difficult to determine the extent of the region affected. In deal-ing with this organism, in general, all possible bacteriological pre-cautions must be taken. Carelessness in the pruning of nurserystock
Size: 1536px × 1627px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisherbostonnewyorketcgi
