PLANT DISEASES DUE TO FUXGI. 57 



Infection trials of sound bulbs during the winter failed to cause 

 infection. 



It appears likely that if the disease has to be eradicated, growers 

 will have to adopt some method of soaking the bulbs before they are 

 dried and put away, and again before they are sent out. For this 

 purpose formaldehyde is worth experimenting with, the bulbs to be 

 soaked in one pint of formaldehyde mixed with thirty gallons of water, 

 and allowed to remain in the fluid for an hour and a half. Experi- 

 ment only will prove the right strength of the fluid, and the proper 

 length of time to leave the bulbs in. 



ORNITHOQALUM BLACK MOULD. 



Heterosporium ornithogali (Klotsch). 



A severe attack of the Black Mould on Ornithogalum umbellattim 

 is worthy cf record. 



The disease appears as minute, irregular, brownish sooty-like 

 spots, irregularly distributed on areas of varying extent on the leaves. 

 They quickly spread and the leaves rapidly decay. 



When examined microscopically the sooty-like patches are seen to 

 consist of a mycelium and dark thread-like bodies. These latter 

 appear in tufts, consisting of short, thick cells, with their walls, some- 

 times branched, and bearing at their apices the conidia. The conidia 

 are of variable size, some being elliptical with a single transverse 

 division, whilst others are elongated and divided into three, four, or 

 more cells ; they have a rough surface with minute points. 



If attended to in time, spraying with potassium sulphide will 

 arrest the spread of the disease. All diseased leaves should be burnt. 



