1915.] PUBLIC DOCUMENT — No. 31. 55 a 



REPORT OF THE BOTANIST. 



A. VINCENT OSMUN. 



The writer of this report has been in charge of the depart- 

 ment of botany and vegetable physiology and pathology only 

 since October 13. It has been necessary, therefore, to depend 

 upon other members of the staff for information concerning the 

 particular work conducted by each. 



During 1014 the botanical work has been mainly along lines 

 previously reported. Information concerning plant diseases 

 and methods of control has been in increasing demand. Several 

 diseases formerly considered relatively unimportant have come 

 into prominence, and a few diseases previously unlisted as oc- 

 curring within the State have been reported. Among the former 

 may be mentioned a bacterial root and stem rot of celery, which 

 Ijecomes especially troublesome in storage ; a similar rot of onion 

 bulbs, sooty blotch of apple caused by Leptothyrium pomi 

 (Mont. & Fr.) Sacc, and anthracnose of snapdragon caused by 

 C olletotrichum antirrhirii Stewart. The first two mentioned 

 diseases present rather difficult and important problems and 

 need investigating. Sooty blotch of apples is a common disease 

 which usually is readily controlled by spraying. During the 

 last season it was more than commonly prevalent, and several 

 growers reported a large percentage of loss from it. The severity 

 of the outbreak may have been due in part to the dusty 

 atmosphere of a dry summer, but more data carefully collected 

 are needed. 



Powdery scab of potatoes was found in several market lots 

 said to have come from Maine, but no occurrence of the disease 

 in Massachusetts-grown potatoes was reported. This disease is 

 a serious one in Europe, and has become established in Canada 

 and Maine. Although Federal inspection and quarantine laws 



