52 MASSACHUSETTS HORTICULTURAL SOCIETY. 



gall has been established. The organism is a species of bacteria 

 and the disease is proving second to none in the category of those 

 with which the horticulturist is concerned. It shows a natural 

 range of host plants and a power of cross infection which is truly 

 discouraging. Here in New England one of the more common 

 fruit diseases, generally known as the Baldwin fruit spot, has been 

 traced to a specific fungus. A carnation bud rot has been dis- 

 covered, and several other important diseases of floricultural plants 

 have been successfully investigated. The organism producing the 

 well-known canker of the apple has been shown to cause, throughout 

 the country, the widespread spot of the leaves of this plant. A study 

 of sub-tropical fruit diseases has received a new impetus. In the 

 line of treatment we may note improvement in the methods applic- 

 able to the refractory peach rot, the anthracnose of bean and many 

 other maladies. 



It is to be hoped that no other field of work will for some time 

 lessen the effort which may be devoted to a more complete under- 

 standing of the life histories of fungous diseases. Such work should 

 become more searching and thorough, and be able to stand the test 

 of time. The work in this country is not yet old. It had its begin- 

 ning about 1876, at which time there appeared from the Bussey 

 Institute those well-known papers on the black knot of the plum 

 and the downy mildew of the grape. It is true that at times over- 

 ambitious investigators have proceeded with undue haste, and the 

 result has been that an enormous number of fungous diseases has 

 been half discovered and others discovered and described would 

 require a considerable imagination to rediscover. 



From time immemorial, it has been observed that one condition 

 or another of the environment is favorable to the perpetuation and 

 spread of fungous diseases. In general, the close relation which 

 exists between weather and disease has been recognized by every 

 person interested in plant life. It has been little more than a genera- 

 tion since many producers held the weather directly responsible for 

 the severe annual losses now known to be due to fungi. Today a 

 careful discrimination is made between the weather as a complex 

 set of factors conditioning a disease and a parasitic fungus which, 

 under the conditions, is able to infect, and directly to produce and 

 spread a disease. 



