228 Diseases of Greenhouse Crops 



Bud Rot 



Caused by Sporothrichum poe Pk. 



Symptoms. This disease seems to be confined to 

 the floral buds only. Ordinarily the affected buds 

 fail to expand or only open part way (fig. 47, a 

 and b.). A close examination will show that the 

 interior of the affected bud is browned and moldy. 

 The rotted tissue may be found in the center of the 

 bloom or on the petals. The stamens, styles, and 

 pistils are also frequently affected. Where yoimg 

 buds are diseased the calyx, too, will be involved, 

 otherwise it is usually sound, although the other 

 parts of the flower may be decayed. 



The Organism. The hyphse are creeping, vary- 

 ing in thickness, hyaline, and septate. The conidia 

 are of two kinds: Microconidia — one-celled, globose 

 or broadly ovate; Macroconidia — abimdant, one, 

 rarely two, septate and several times larger than the 

 microconidia (fig. 48, g to i.). Stewart* claims 

 that Sporotrichum pocz Peck found on diseased tops 

 of June grass and S. anthophilum, which causes the 

 bud rot of carnations are the same. The fungus is 

 spread about in the greenhouse by a mite {Pedicu- 

 lopsis graminum Reut.). 



Control. According to Heald t and others the 

 most susceptible varieties to bud rot may be men- 

 tioned — the Lawson, Enchantress, Queen Louise, 



• Stewart, F. C, and Hodgkiss, H. E., New York (Geneva) Agr. 

 Expt. Sta. Tech. Bui. 7: 84-119, 1908. 

 t Heald, F. D., Nebraska Agr. Expt. Sta., Bui. 103:3-31, 1908. 



