DISEASES OF PL.\NTS. 549 



pp. 450, 648). Since that time he has carried on studies on the organism and 

 the effect it produces upon tlie cane, and has proved by inoculation experi- 

 ments that the fungus is actually the cause of the disease. 



The progress of the disease throughout the stalk is traced, and the fact that 

 some varieties seem resistant is pointed out. In the previous account attention 

 was called to the nearly related species of Colletotrichum w^hich have been 

 observed, and infection exjieriments were carried on with C. lineola and 

 C. cereale, but without results. The various natural methods of infection are 

 suggested and discussed, and it appears that infection commonly follows the 

 attacks of the cane borer. It is usually stated that the red rot fungus passes 

 from the diseased stalk to the young plant, but the author found no evidence 

 to show that the young plants are infected by the fungus growing up into 

 them from diseased seed. The injury to the pLint and the losses due to the 

 fungus are discussed, one of the principal effects of its presence being the 

 reduction in the amount of sucrose and the gain in glucose in the infected 

 plants. 



For the control of the disease the author recommends the destruction of all 

 diseased cane material and of the cane borer and more careful attention to the 

 matter of selection of seed cane. 



Notes on tomato diseases with results of selection for resistance, S. H. 

 EsSAEY (Tennessee Sta. Bill. 95, pp. 12, figs. 7). — A brief report of progress on 

 the investigation of the blight disease of tomatoes in Tennessee is given. 



This disease, which is well recognized by growers, is characterized by the 

 yellowing of the lower leaves, followed in a few days by the wilting and 

 dying of these leaves. Within a week from this time the whole plant may wilt 

 and die. The blight, or wilt, as it is more properly called, appears to be due 

 to a species of Fusarium, which enters the plants through their roots. 



A systematic study of the fungus has been begun, and attempts are being 

 made to find a remedy for it. This has led to a study of I'esistance, and marked 

 differences have been noted for different varieties of tomatoes. One strain, 

 characterized as No. 7, is said to be remarkably resistant and to possess a fruit 

 of desirable quality. 



Diseases of citrus fruits, P. H. Rolfs, H. S. Fawcett, and B. F. Floyd 

 (Florida Sta. Bui. 108, pp. 25-47, figs. 14). — Attention is called to the principal 

 diseases to which citrus fruits are subject in Florida. Many of the troubles 

 described affect other parts of the plants than the fruit, and the notes pre- 

 sented were mostly obtained incidental to other studies. 



Among the troubles described are the russeting due to mites, melanose, 

 russeting and tear-streaking caused by the withertip fungus, buckskin, silver- 

 scurf, sun scald, die-back markings, anthracnose, chemical injuries due to too 

 large applications of fertilizers and sprays, various forms of mechanical in- 

 juries, blue mold rot, stem end rot, Diplodia rot, and black rot. Some of these 

 diseases have been reported upon in other publications of the station. Where 

 preventive measures are definitely known the authors describe them. 



Blemishes of citrus fruits, J. E. Coit (Proc. Fruit Growers' Conv. Cat., 

 39 (1911), pp. 22-25). — Some 48 blemishes of citrus fruits are outlined which 

 operate to reduce the profits from the citrus industry. These are divided into 

 4 classes, viz, insect, fungus, mechanical, and physiological blemishes, and are 

 discussed very briefly as to their prevention, most attention being given to the 

 brown spot of the navel orange. 



A Loranthus affecting' citrus trees (Philippine Agr. Rev. [English Ed.], 

 4 (1911), No. 12, p. 679). — The presence of L. secundiflorum on citrus fruit 

 trees, particularly Citrus decumana, is reported. 



