DISEASES IN GREENHOUSE 93 



of the same nature as the present work 

 generally discuss fungi, bacteria, and in- 

 sects under different headings. This 

 precedent will not be closely followed 

 here, but all three will be taken up from 

 the point of view of their economic im- 

 portance rather than in the light of their 

 systematic relationship. 



As a rule plant diseases do not spread so 

 rapidly in the greenhouse as in the field. 

 The restrictions of wind currents and the 

 lack of easy access of insects are, no doubt, 

 factors in keeping in check many diseases. 

 There are, however, some indoor condi- 

 tions such as moisture and temperature, 

 which if not properly attended to, will re- 

 sult in great financial loss by favoring the 

 spread of disease. 



Upon proper watering depends much of 

 the success of crops grown under glass. 

 The amount of water and the way it is ap- 



