l'Rl-:SIDENTIAI. ADDKKSS SKCTION C. 8.^ 



are not of apparent economic ini])ortance. The aj^pearance of 

 the citrus canker lesions has hcen known for many years in 

 the East. 



In the herbarium of the Hon.q;-Konfij Botanic Gardens there 

 is a collection of Citrus iiobilis Lour made in 1863 at Naei^asaki. 

 Japan, by Maximowicz. This specimen shows a number of citrus 

 canker lesions, and proves the early occurrence of the disease 

 in Japan (33). 



In 1904 there appeared in a ja]:)anese publication a descrip- 

 tion of " a new kind of Pathogenic microbe, being No. 8 of 

 the organisms injurious to citrus " ; no name is given to the 

 organism by the author, but his description leaves no doubt that 

 he is referring to the disease now known as canker. The lesions 

 on the host are accurately described, but these had only been 

 noted on nursery stock, and the application of Bordeaux mixture 

 was recommended for the prevention of the disease. 



It was in 1905 or 1906 that the nursery stock was imported 

 into this country which introduced the disease, and in 1908 and 

 1909. when canker became serious at Warmbaths, the study of 

 the disease was dropped when canker was apparently controlled 

 there, owing to the pressure of work on the two plant patholo- 

 gists then at work in the Transvaal, and owing to the lack of 

 proper equipment, there being no greenhouse facilities for 

 infection work. Had it been possible to complete the investiga- 

 tion at the time, the disease could have been checked at a much 

 earlier stage of its progress, and at a much smaller cost to the 

 country. 



Bacterial Spot of Citrus. Bacillus citrimaculaus 

 Doidge (19). 



This disease is of minor importance as compared with ihe 

 citrus canker. It is limited in its distribution, occurring only in 

 the Groot Drakenstein valley in the Western Province. It 

 causes sunken sp'ots or pits in the fruit, and in some seasons 

 causes considerable loss. The fruit lesions are similar to those 

 of black pit, a disease described as occurring in California (48b), 

 but apparently caused by a different organism. The stem .lesions, 

 which occur as brown patches round the base of the thorns, are 

 similar to the Californian " Citrus blast," which is caused by 

 still a third bacterium (39). 



Bacterial Blight of I'ear Blossoms. Hacteriuin 

 ncctarophilum Doidge (18). 



Another trouble which ap|)ears to be confined to the Western 

 Province is a bacterial blight of pear blossoms, which is trouble- 

 some in the Stellenbosch district, and to which some varieties are 

 much more susceptible than others. This closely resembles a 

 blight of fruit blossoms occurring in England (5a), but does not, 

 like the American fire blight, attack the twigs and leaves. Up 



