552 EXPERIMENT STATION EECORD, 



cause of the disease, methods of control, and inoculation experiments have been 

 previously noted from other sources (E. S. R., 23, p. 446; 25, p. 450). 



The disease has been known on the Pinellas Peninsula, Florida, for at least 

 30 to 40 years, but has done little damage until recently. It is caused primarily 

 by Cladosporium herbarum citricolum, but is associated with the withertip 

 fungus (CoUetotriclnon glaosporioidcs), which is an important secondary agent 

 in the destruction wrought by the disease. The cultural characteristics of 

 C. herharum citricolum on various media and in comparison with C. herbarum 

 are given. Inoculation experiments with pure cultures of the fungus on young 

 orange trees in the greenhouse and on unripe oranges in the laboratory resulted 

 in the formation of spots similar to scaly bark spots. 



From the experiments conducted on the control of this disease the following 

 conclusions are drawn: (1) The disease yields to spraying with Bordeaux mix- 

 ture; (2) pruning out of the dead wood lessens subsequent infection; (3) car- 

 bolineum, one-half strength, painted over the bark after heading back, is fol- 

 lowed by a vigorous growth free from the disease; (4) neither spraying with 1 

 per cent solution of carbolineum nor spreading copper sulphate in the form of 

 crystals on the ground was found to be of any practical value in controlling 

 the disease. 



In conclusion, it is stated that scaly bark is a disease of the fruit and bark, 

 mainly of the sweet orange, and occurs in only a few localities in Florida. In 

 addition to the other remedies for controlling this disease, it was found that 

 budding or grafting to resistant varieties of citrus, such as pomelo, mandarin, 

 and tangerine {Citrus nobilis) was effective. 



A bibliography is appended. 



The double blossom of tlie dewberry (Fusarium rubi), M. T. Cook (Dela- 

 vare Sta. Bui. 03, pp. 3-12, figs. 12). — In addition to a discussion of the dis- 

 tribution and characteristics of this disease, to which attention had been previ- 

 ously called by the author (E. S. R., 23, p. 453), a study is reported of the 

 penetration of the fungus into the tissues of the host, spore distribution, method 

 and time of infection, damage done by the fungus, and of methods for its 

 control. 



It was found that the mycelium of the fimgus {F. rubi) did not penetrate the 

 tissues, but grew between the various elements of the leaf bud. Later, however, 

 the flower buds are penetrated by the mycelium, and the hyphfe enter the 

 ovaries by way of the stigma and style and form a mass of mycelia in the ovary 

 cavity. Conidia are produced within 48 hours after the opening of the flower 

 buds. These spores fall on the young buds which are forming for the next 

 year, germinate, and grow inward, where the mycelium remains dormant until 

 the following spring. The disease is said to be more severe on the Lucretia and 

 Rathbone varieties of the dewberry, but attacks many species and varieties of 

 the genus Rubus. It is claimed that as the mycelium does not penetrate beyond 

 the base of the buds, the hand-picking of the diseased buds, which are easily 

 recognized by their somewhat more swollen and reddish appearance in the early 

 spring, should prove an effective means of control. Experiments comparing 

 hand-picking and spraying showed that hand-picking kept the disease in check 

 though not eradicating it completely, while spraying proved ineffective in com- 

 bating it. 



Is Bacillus coli ever a plant parasite? .J. R. Johnston (Phytopathology, 1 

 (1911), No. 3, pp. 97-90). — The results of inoculation experiments with this 

 organism on the coconut are reported, as well as inoculation and cultural 

 studies of certain organisms isolated from the bud rot of the coconut palm. 



As a result of these inoculations and the subsequent cultural studies, the 

 conclusion is drawn that at least one organism capable of causing the bud 



