Off-campus UMass Amherst users: To download campus access dissertations, please use the following link to log into our proxy server with your UMass Amherst user name and password.

Non-UMass Amherst users: Please talk to your librarian about requesting this dissertation through interlibrary loan.

Dissertations that have an embargo placed on them will not be available to anyone until the embargo expires.

Date of Award


Access Type

Open Access Dissertation

Document type


Degree Name

Doctor of Philosophy (PhD)

Degree Program



The observations and conclusions reported In the following pages are the results of several years of noro or less continuous investigation on the part of the writer, and deal with the causes, occurrence, appearance and the probable methods of control of this well known disease of the tobacco and related plants iSnough has oeen accomplished so that it is believed wise to add still another paper to the already long list of literature which has been published on this disease. During the time in vhich these experiments have been in progress much new literature has appeared dealing with this subject, some of which has helped the writer by verifying his results and bringing out new facts concerning the disease; but on the other hand some of the work appears to have been done in a hasty manner and possibly erroneous conclusions are drawn in some cases, thus adding to the already large amount of confusing subject matter which has to do with this disease.