264 EXPERIMENT STATION RECORD. 



On account of tlie resemblance between the two, infection experiments were con- 

 ducted in which mycehum from cacao trees and pods was transformed to sugar cane 

 and the sugar-cane fungus to the cacao. The cross-infection experiments were very 

 successful and leave no doubt as to the identity of the two fungi. In suggesting 

 remedial measures for checking the ravages of this fungus, it is stated that all cacao 

 pod husks should be removed and burned, and all the diseased pods noticed on 

 trees should be similarly destroyed. In the cultivation of sugar cane, the diseased 

 canes should be regularly collected and burned. In this way there will be less 

 chance for infecting a new crop. The systematic position of the fungus is discussed 

 at some length. 



Observations on the mosaic disease of tobacco, A. F. Woods {U. S. Dept. 

 Agr., Bureau of I'luut Indudry Bui. IS, pp. 24, pis. 6). — A sununary is given of the 

 author's investigations on the cause of the mosaic disease of tobacco and similar dis- 

 eases of other jjlants. The work of a number of other investigators is reviewed, and 

 the author's publications relative to this disease (E. S. R., 12, pp. 216, 217) are sum- 

 marized. The author claims to be able to artificially produce the disease, and that 

 it is due to a (listurl)ance of the normal physiological activity of the cells. The 

 reduction of the available nitrogenous reserve food may cause the disease, and rapid 

 growth caused by too mucli nitrogenous manure is favorable to it. It may also be 

 caused by a severe cutting back of plants or by transplanting when rapidly growing. 

 When once started the disease is believed to be continued by the action of the oxidiz- 

 ing enzyms as previously noted. 



Black rot of g-inger, A. Howard {Bui. Bot. Dept. Jamaica, 9 {1902), No. 3, p. 

 4S). — The occurrence of black rot on a number of specimens of ginger roots is 

 reported. In continuation of the suggestions of the paper mentioned above, the 

 author calls attention to the necessity of isolating the diseased patches by trenches, 

 throwing the soil on the affected areas, and destroying the diseased plants by burn- 

 ing. In planting, care should be taken to select perfectly healthy rhizomes from the 

 best fields and tf> soak these for a few hours in Bordeaux mixture. 



A new banana disease in Egypt, A. Preyer {Jour. Kliedir. Agr. Soc. uud School 

 Agr., S {1901), X(i. 5, pj). 242, 24-'^). — For about three years a peculiar disease has 

 Ijeen noticed spreading among the bananas cultivated in the vicinity of Alexandria, 

 Egyi)t. The first symptoms of the disease are observed in a sudden checking of the 

 growth, after which the tips of the leaves and the young central leaves become black 

 and die. The stem does not die immediately but is rendered unfit to bear fruit. 

 The great damage done by the disease led to its investigation. A badly infected 

 stem was dug up and together with its roots cut in longitudinal direction. In the 

 upper part the youngest leaves were all black and rotten, while the outer layers were 

 white and seemed sound. The lower part of the stem and root stalk showed no sign 

 of disease. The roots themselves exhibited toward their ends small excrescences 

 usually accompanied by a resin-like* material. Sections of these knob-like growths 

 were examined and found to be filled with-nematodes, and further investigations 

 showed that the banana disease was due to infection of the roots by the nematodes 

 which in this case belonged to the genus Tylenchus, the species resemV)ling T. acvto- 

 caudatus. The nematode was found to l)e not only present in the roots, but was met 

 with in consideruble numbers in the upper parts of the stem. Experiments are 

 being conducted for the prevention of the disease, ])ut as yet no definite results have 

 been obtained. 



Observations on the mulberry dwarf troubles, a w^idely spread disease in 

 Japan, U. Suzuki {Bid. Col. Agr. Imp. Utiir. Tokgo, 4 {1902), No. ,'j, pp. 359, 360).— In 

 a previous publication. (E. S. R., 13, p. 866) the author reported on the relation 

 between oxydizing enzyms in healthy and diseased mulberry leaves. Numerous 

 tests have been made in continuation of his previous investigations, and as a result 

 the author concludes that oxidase and peroxidase are present in larger quartities in 



