212 Diseases of Greenhouse Crops 



but not so much as to make the soil soggy. They 

 demand a cool, shady house and a rather close at- 

 mosphere. The varieties forced for the Easter mar- 

 ket should be kept in a temperature of 45 to 50 de- 

 grees F., and those forced for Christmas should be 

 grown under a temperature of 50 to 55 degrees. Six 

 to eight weeks before Christmas the plants are given 

 a temperature of 60 to 65 degrees F. In providing 

 ventilation, cold drafts should be avoided. The best 

 time to re-pot azaleas is after blooming. Neglect 

 in this direction may seriously interfere with next 

 year's bloom. Azaleas are very sensitive and may be 

 injured even by the presence of organic matter of a 

 heat producing nature. This means that the ma- 

 nure in the compost must be thoroughly rotted. 



Diseases of Azalea 



The literature on azalea diseases is very scant. 

 This means either that the troubles of this plant are 

 still to be investigated or that it is a remarkably 

 healthy one. 



Leaf Spot 



Caused by Septoria Azale^z Vogl. 



Symptoms. This disease is characterized by red- 

 dish yellow spots on the leaves. It is not of great 

 importance economically. 



The Organism. The pycnidia are immersed, glo- 

 bose, depressed, black. The conidia are oblong, fili- 

 form, straight or curved, 1 to 3 or more septate, and 



