. Bulletin. Natural history; Natural history. Diseases of Fruit Trees, 1922-1928 491 disease increased in severity in 1923 to the point of attaining an index of 49 per cent. Though this high percentage of fruit disease fell off to the not very moderate amount of per cent, in 1924, the attack again attained such serious proportions in 1926 that the intensity index stood at 80 per cent. This was reduced in 1927 to 25 per cent.; but the seriousness of plum brown-rot as an annual menace to the plum crop is well expressed by its average annual fruit intensity index of per cent. Leaf spo
. Bulletin. Natural history; Natural history. Diseases of Fruit Trees, 1922-1928 491 disease increased in severity in 1923 to the point of attaining an index of 49 per cent. Though this high percentage of fruit disease fell off to the not very moderate amount of per cent, in 1924, the attack again attained such serious proportions in 1926 that the intensity index stood at 80 per cent. This was reduced in 1927 to 25 per cent.; but the seriousness of plum brown-rot as an annual menace to the plum crop is well expressed by its average annual fruit intensity index of per cent. Leaf spotting of plums appears in our records only for the years 1922, 1923, and 1924. In the first of these years its prevalence among the plum trees examined was per cent.; in 1923 it was 100 per cent.; and in 1924 it fell slightly to per cent. Its average annual prevalence, as indicated by these three indexes, is per cent. Cherry P/um. 3rouvn-rof \ Srotvn-rof \ Lzaf-spof 9736 \ /O 20 30 40 £0 60 70 SO /r7 90 /OO C/rerry P/(//?7 \\6roy<fn-rof I Leafspof. 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 Illinois. Natural History Survey Division. Urbana, State of Illinois, Dept. of Registration and Education, Natural History Survey Division
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Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
