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BULLETIN OF 

 MASSACHUSETTS BOARD OF AGRICULTURE. 



THE PREVENTION OF FUNGOUS DISEASES PECULIAR TO 

 GREENHOUSE PLANTS. 



By Dr. George E. Stone, Professor of Botany, Massachusetts Agricultural 



College. 



The diseases to which plants are subject uuder glass require 

 different methods of prevention than those in common use out of 

 doors, since in greenhouses the crop conditions are largely under 

 control, whereas in outdoor crops they are left to the mercy of the 

 weather and the whims of the season. To meet the unforeseen 

 seasonal conditions to which outdoor crops are subject it is neces- 

 sary to resort to methods of prevention each year. Such methods 

 consist of spraying crops, or applying other treatments before cer- 

 tain pests have made their appearance. There is, however, very 

 little need of the application of spraying mixtures to greenhouse 

 plants, since the conditions which give rise to diseases can be and 

 are controlled by expert gardeners to a very large extent. The 

 recommendations, therefore, for a general system of spraying for 

 indoor crops, such as is expedient at the present time for outdoor 

 crops, would be irrational, and would constitute a step in the wrong 

 direction. Every skilled and intelligent grower realizes this, and 

 the more skilled a gardener is, the fewer diseases he has to con- 

 tend with. The gardener who can turn out a nearly perfect crop 

 as regularly as a manufacturing establishment turns out its products 

 is qualified for the severest tests of proficiency. 



The inci'eased production of high-grade greenhouse products in 

 Massachusetts has been the means of training and developing a 

 large class of men as efficient growers, and with this increased 

 skill and knowledge there has come about a better understanding 

 of the causes of diseases and methods of controlling them. The 



