QQ REPORT OF THE AGRICULTURAL RESEARCH 



the affected area. Successful inoculations with the para- 

 site have been secured, and a further study of its life-his- 

 tory made. 



A serious disease of cocoanut palms was reported from 

 Travancore early in 1907, and the Imperial Mycologist 

 visited the State in September and October of that year 

 to investigate its cause. A report on the disease has 

 since been published. 



8. Diseases of Citrus Fruits. — The chief of these in- 

 vestigated were " white rust " which has appeared at 

 Poona, and a disease which is ravaging the valuable 

 orange orchards of Sylhet and Lower Burma. The former 

 is identical with a disease which has recently appeared 

 in Southern Europe. Suggestions for experimental treat- 

 ment have been made. The other disease does not appear 

 to have been previously recorded. The Imperial Mycolo- 

 gist visited Burma in January 1908 to investigate it, and 

 experiments are in progress to ascertain its cause. Tt 

 appears certain that it can be avoided by grafting on 

 stalks of other citrus plants. 



9. Wilt Diseases. — These diseases have engaged more 

 attention during the period under report than any 

 others. Out of the considerable number, all similar in 

 their course, which affect economic plants in India, those 

 of cotton, indigo, pigeon-pea and gram were selected for 

 study. In all, the fungus to which the cotton wilt of the 

 United States is attributed was present, and the assumption 

 was that this fungus which is said to be a virulent para- 

 site in America, was the responsible agent in each case. 

 Detailed experimental work has, however, thrown the 

 gravest doubt on the parasitism of this species, and an- 

 other organism was isolated fiom pigeon-pea which has 

 been shown to be the cause of the disease in this crop. 

 This organism has been called Fusarium udum, Butler. 

 A memoir on the work is now in the press. The cause 

 of the gram wilt disease has also been definitely deter- 

 mined, and successful infections obtained. The investi- 

 gation has been lengthy and troublesome, but the diseases 



