Volume II MAY, 1915 No. I 



A BACTERIAL DISEASE OF THE MANGO. 

 BACILLUS MANGIFERAE n.sp. 



By ETHEL M. DOIDGE, M.A., F.L.S., 



Mycologist, Division of Botany, Pretoria. 



(Thesis approved for the Degree of Doctor of Science in the 

 University of the Cape of Good Hope.) 



(With Plates I— XIV and 3 Text-figures.) 



For some years past, fruit growers in certain districts of this country 

 have been troubled by a disease of mangoes which is causing considerable 

 havoc in their orchards and threatens to seriously affect the export 

 trade. 



All parts of the tree are attacked, the affected areas becoming dis- 

 coloured, while in fruit and stem deep longitudinal cracks also occur; 

 the disease has been described by farmers as resembling in appearance 

 the anthracnose of the grape vine caused by Gloeosporium ampelophagum 

 Sacc, and its external effects are not dissimilar to those caused by that 

 fungus. A large percentage of the fruit falls to the ground whilst yet 

 immature, and the mangoes which remain on the trees are rendered 

 unsightly and unfit for the market. 



The disease was first reported in December, 1909, as occurring at 

 Barberton in the Transvaal, and as being unchecked in its progress by 

 repeated applications of Bordeaux mixture. It was soon found that 

 most of the mango-growing districts of. the Union were similarly affected 

 and it was considered advisable to make a more detailed study of the 

 disease and the organism causing it, with a view to formulating, if 

 possible, some method by which its progress might be checked. This 

 purpose has not yet been fully carried out as no effective remedy has 

 been found, but the work has progressed to a point where it seems 

 advisable that the results which have been obtained should be placed 

 on record. 



Ann. Biol, n 1 



