. California plant diseases. Plant diseases. Bulletin 218] CALIFORNIA PLANT DISEASES. 1179 ground. This trouble is not a common one, but seems to occur in some districts more than others. Whether such knots are due to the real crown gall organism (Bacterium tumefaciens) has never been de- termined, but their appearance leads one to suspect that they originate from infection of scars or wounds on the trunk by this parasite. Known only upon the English walnut. As soon as the trouble appears cut out the diseased tissue, disinfect with strong bluestone solution and paint over the Fig. 101.
. California plant diseases. Plant diseases. Bulletin 218] CALIFORNIA PLANT DISEASES. 1179 ground. This trouble is not a common one, but seems to occur in some districts more than others. Whether such knots are due to the real crown gall organism (Bacterium tumefaciens) has never been de- termined, but their appearance leads one to suspect that they originate from infection of scars or wounds on the trunk by this parasite. Known only upon the English walnut. As soon as the trouble appears cut out the diseased tissue, disinfect with strong bluestone solution and paint over the Fig. 101.—Black knot on walnut trunk (Bacillus tumefaciens). Crop Failure. It is a very noticeable fact in connection with the California walnut industry that the total product of the groves of the State is not mate- rially increasing, although the acreage has multiplied many times during recent years. This is due to a very general condition of poor produc- tion in the large walnut-growing sections of the southern portion of the State. The older groves, although by no means at an age when they should be deteriorating, show very little tendency to increase their yield, and in many cases are gradually going back. The quality and size of the nuts, as well as the quantity, is also a source of complaint. Many of the nuts which mature are empty or poorly filled with shriveled, light weight meat, giving the nut when cracked an unattractive appear- Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Smith, Ralph E. (Ralph Eliot), 1874-1953; Smith, Elizabeth H. (Elizabeth Hight), 1877-1933. Berkeley, Cal. : Agricultural Experiment Station
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectplantdi, bookyear1911
