File:The publications of the Pennsylvania chestnut tree blight commission, 1911-1913 (1915) (14579359358).jpg

Identifier: publicationsofpe00penn (find matches)
Title: The publications of the Pennsylvania chestnut tree blight commission, 1911-1913
Year: 1915 (1910s)
Authors: Pennsylvania. Chestnut tree blight commission
Subjects: Chestnut blight Chestnut blight
Publisher: Harrisburg : W. S. Ray, state printer
Contributing Library: Penn State University
Digitizing Sponsor: LYRASIS Members and Sloan Foundation

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the windapparently distributes most of the infection to the surroundingtrees. On the other hand, if the diseased area of bark at the centerof an infection is large and has produced a great number of peri-thecia, and the climatic conditions have been favorable for theejection of ascospores, a large number of incipient infections arevery apt to be left in the surrounding trees at tlie time of the firstremoval cutting. Just how long after cutting it takes these incipient infectionsto develop so that they can be detected in scouting depends on anumber of conditions, such as the location of the diseased area onthe tree and the height above ground where infection occurs, sizeof the tree, season of the year and climatic conditions followingthe occurrence of infection, location of the spot infection relativeto topography, etc. Probably the most important factor govern-ing the number of new infections after a removal cutting is thecharacter and quality of the man who scouted the area. Certain
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Healthy sprouts growing around a burned stuiap. 87 men have much better scouting ability than others, and in some ofthe spots examined, at least, this factor alone is suflficient to accountlargely for the conditions found on reinspection. However, eventhe best scout cannot detect small twig infections in the tops of talltrees before they have girdled the twigs, and it is frequently veryeasy to miss w^ell developed cankers either at the base of large treeswhen no fruiting bodies have been produced, or on the upper trunksof tall trees before the tops have been girdled. It was very noticeable that new infections appearing in a spotwhere the original infection had been properly removed were al-most always within a short distance of the original infection. Prob-ably half of the new infections found, even after the second inspec-tion, were on trees that grew on the same stump or in the same treegroup as an original infected tree, and 90 per cent, of the newlyinfected trees were so close tha

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