. Better fruit. Fruit-culture. Page 8 BETTER FRUIT. Photo Oreeon Experiment Station Figure 2â(A) Two-year-old canker showing opened spore pustules. IB) Pustules enlarged five times. iCl Young Spitzenlniig inoeulaled v. itli the fungus. Note wound of check puncture at top of figure. and of variable sizes, ranging from one inch to eight or ten inches in length. At first these cankers are watery, dry- ing as summer approaches, eventually becoming sunken areas mottled by a series of differently colored concentric rings. The spread of the fungus ceases as soon as the cambium becomes active in the s
. Better fruit. Fruit-culture. Page 8 BETTER FRUIT. Photo Oreeon Experiment Station Figure 2â(A) Two-year-old canker showing opened spore pustules. IB) Pustules enlarged five times. iCl Young Spitzenlniig inoeulaled v. itli the fungus. Note wound of check puncture at top of figure. and of variable sizes, ranging from one inch to eight or ten inches in length. At first these cankers are watery, dry- ing as summer approaches, eventually becoming sunken areas mottled by a series of differently colored concentric rings. The spread of the fungus ceases as soon as the cambium becomes active in the spring. Mature cankers have a definite, limiting crack separating them from healthy tissue. There is usually a definite ridge surrounding the canker caused by the slight formation of cal- lous tissues at the edge under the dis- eased bark. The bark is dry, sunken and dead, being darker in color than the living bark surrounding. Thickly scattered over the surface of the canker are little elevations. These are at first more or less conical in shape, later bursting the outer layer of bark (Figure 1), exposing a creamy-colored mass of fungous tissue. These are the fruiting structures of the fungus in â which spores are produced in great numbers. As time passes there is a gradual shredding of the diseased bark in the cankers. This tissue eventually falls away, leaving a large open wound. These are gradually healed over through the extension of surrounding healthy tissue, the accomplishment of which usually rccjuires several years. In view of the fact that spore dis- semination occurs during the fall a spray applied at this season of the year will be found effective in controlling the disease. Bordeaux mixture used at the rate of six pounds of lime, six pounds of bluestone to fifty gallons of water, immediately following harvest- ing of the fruit will keep the disease well under control, provided the spray- ing is practiced regularly and thor- oughly. Often orchards are permitted to
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