274 Diseases of Greenhouse Crops 



disease may be introduced into the greenhouse with 

 infected plants. 



Leaf Spot 



Caused by Phyllosticta Jiydrangecz E. and E. 



The disease is characterized by large, rusty, brown 

 spots occurring on the leaves, especially at the edges. 

 The disease is often so severe that it is necessary to 

 cut off the top of the plant. Upon examination of 

 the affected leaves, numerous minute, black pycnidia 

 will be found scattered throughout. The conidia are 

 oblong, hyaline, and one celled, and generally ooze 

 out as minute creamy tendrils. The disease may be 

 kept in check by spraying with a standard fungicide. 



