129 



Parasitic Plant Diseases Reported for Indiana. 



Fraxk D. Ki:rx. 



The following summary of plant diseases in Indiana has been made up 

 from information which has been accumulating during the past few years 

 at the Botanical Laboratory of the Indiana Experiment Station. 



In this list only the more important diseases have been considered 

 from the standpoint of the cultivator. The information at hand is far from 

 complete, since the diseases are invariably reported by common names, and 

 as it is impossible to investigate or verify each case there is a probability 

 that disturbances in growth and health do not always have the proper 

 causes assigned. An effort has been made to classify the diseases according 

 to their pathological effects, fifty six in all being discussed. Such a group- 

 ing is difficult, owing to the lack of knowledge concerning the exact manner 

 in which many of the parasites act. 



Before taking up the detailed account it will be of interest from the 

 point of view of the mycologist to consider the parasites which are held 

 responsible for the various diseased conditions of root, stem, leaf and fruit. 

 Out of fifty species under discussion forty -five are fungi, five bacteria, and 

 one a sUinc-mould. Three species are causes for two separate diseases each, 

 while three have no cause assigned, thus bringing the total up to fifty-six, 

 the number selected for consideration by this paper. The fungus parasites 

 are divided among thirty-two genera belonging to classes as follows: As- 

 comycetes, nine ; Basidiomycetes, nine ; Pliy corny cetes, one ; Fungi Imper- 

 iecii, thirteen. Under the general term of Fungi Imperfecti are included a 

 misceiianeous lot of forms whoso life histories are imperfectly understood; 

 some may have no other stages, while others may have connections not 

 yet discovei'ed. Comparatively recently three which were formerly classed 

 here have had their perfect stages identified and have been transferred to 

 the class Ascomycetcs. These are the Bitter-rot fungus of the apple, the 

 Scab-fungus of the apple and pear and the Brown-rot fungus of the peach 

 and pium. The bacterial parasites are divided among two genera, both be- 

 longing to the same family, Bacieriacrae. 



9— A. OF SCIKNCE. 



