Orchid Diseases 299 



There are other Nectria recorded on orchids: 

 Nectria vanda Wahrl on root of Vanda suavis, 

 Nectria goroshankianna Wahrl., Nectria {Dialo- 

 nectria) binotiana Sacc, and Nectria (D.) phyllo- 

 gena Sacc. on leaves of epiphyte orchids in Brazil. 



Anthracnose of Orchids 



Caused by Physalospora cattleya Maub. and Las. 



Symptoms. This trouble is manifested as yellow- 

 ish light spots the tissue of which becomes soft. 

 When the epidermis is torn away from one of the 

 spots a clear liquid will ooze out. At this stage 

 of the malady infected leaves lose their normal 

 color, collapse, and drop off. Ordinarily there is 

 no fruit of any fungus formed on the spots, but 

 under moist conditions the acervuli of the causal 

 fungus appear. The disease, although attacking the 

 foliage, does its greatest damage to the stems. In- 

 fection can take place only through a wound made 

 in the epidermis. 



The Organism. It is only the summer stage of 

 the fungus, Gloeosporium macropus Sacc, which 

 causes the disease on orchids. The same stage also 

 produces a similar disease on foliage of Haya car- 

 nosa. Citrus aurantium aiid Aloes. Its occurrence on 

 orchids was called attention to by Mangin,* who 

 found it to be a serious disease of greenhouse orchids 



* Mangin, M. L., Jour. Soc. Nat. d'Hort. de France 19: 449-452, 

 1897. 



