226 Diseases of Greenhouse Crops 



a great degree by growing resistant varieties. The 

 Scott and the Jubilee are two varieties very sus- 

 ceptible to rust. On tb ^ other hand, the Enchantress 

 and the Lawson are h "^Vy resistant. 



A Parasite of Ca'j^,'^.^^i^on Rust. Most parasites 

 have others to live on them. The carnation rust 

 seems to be no exception. The fungus Darluca 

 filum (Bin.) Cast, was found by Blodgett* to para- 

 sitize the carnation rust fungus. The presence of 

 the Darluca is manifested by a dwarfed and weak 

 development of the rust pustules. The pycnidia of 

 Darluca (fig. 46, b and c) are found scattered on 

 the rust pustules and are flask shaped, the spores are 

 two-celled (fig. 46, e and f), colorless, and when 

 ripe escape in masses of long tendrils, held together 

 by a gelatinous substance in the outer cell wall of the 

 spore (fig. 46, d.). The latter readily germinate in 

 water. Darluca filum also attacks the asparagus 

 rust fungus. It is possible to grow Darluca in pure 

 culture and to inoculate its spores on the carnation 

 rust fungus. In nature, however, it has not proved 

 abundant enough to keep the rust in check. 



Septoria Leaf Spot 



Caused by Septoria dianthi Desm. 



Symptoms, Leaf spot is characterized by light 

 brown patches on the leaves and stems. On the 

 latter, the spots are usually found midway between 



♦Blodgett, F. H., New York (Geneva) Agr. Expt. Sta., Bui. 

 175: 1-13, 1900. 



