﻿Mycological Notes. 



By Byron D. Halsted. 



The Checking- of Hollyhock Rust. — There was rejoicing in the 

 Plant Hospital over one fungus that appeared there late in autumn 

 for the first time. For two years it has been watched for and the 

 plants treated to sprayings in anticipation of its advent. 



The year 1889 may be set down as the time when the holly- 

 hock rust {Puccinia mahaccavum Mont.) made its appearance in 

 a general manner in the United States. This is one year in ad- 

 vance of the outbreak of the carnation rust (Uromyces caryo- 

 phyllinus Schr.) which came generally to the notice of the florists 

 in 1890, and has remained as a serious menace ever since. In like 

 manner 1896 is the year in which the asparagus rust {Puccinia 

 asparagi DC.) came to us in a violent form and without any 

 abatement during the past year. All three of these genuine rusts 

 had been previously known in Europe for a long time, and came 

 to us in a way that is not yet not fully understood. 



But to return to the hollyhocks, it may be written that a row 

 of plants were grown from seed and when three months old were 

 set in the experiment area, and certain ones sprayed and others not, 

 all through the growing season of 1896 without a single sorus of 

 the rust appearing upon any plant either check or sprayed. 



In passing it may be recorded that there was a large amount 

 of the leaf spot {Cercospora althacina Sacc.) and reward for the 

 treatment was ample, for the fungicides worked admirably and 

 kept the sprayed plants comparatively clean. During 1897 simi- 



lar results were 



■cospora 



but, best of all, the enemy for which the plants were set to catch 

 appeared in October. It is worthy of remark thajt it came no 

 earlier than this, the plants being closely watched. When first 

 discovered the sori were quite young, but they increased rapidly 

 in number, and soon became mature. The chief fact to be 

 here recorded and to which all that has preceded is somewhat 

 introductory is, that of the eighteen plants that were sprayed 



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