458 EXPERIMENT STATION RECORD. 



disease no methoil of cultivation or spraying can be recommended for its prevention. 

 As the affected plants never produce satisfactory fruit, it is suggested they should be 

 pulled up and destroyed as soon as recognized. The outward appearance of the 

 tomato rosette strongly suggests the presence of nematodes or some insects, but so 

 far no such cause has been observed. The fruit when ripened is abnormally colored 

 and possesses an excess of core. The seed are somewhat peculiar in their position, 

 and it is suggested that such seed should not be planted. 



Bacteriosis of tomatoes, D. McAlpine {Jour. Dept. Agr. Victoria, 1 {1902), Xo. 3, 

 p^ 330).— The author reports having received from various parts of the country toma- 

 toes which were affected by a disease which is believed to be of bacterial origin. 

 The fruit arrives at complete maturity but the blossom end is flattened and dis- 

 colored, ultimately becoming a pale olive tint. On cutting the tomato lengthwise 

 the healthy part is found quite distinct from the diseased area, the latter being 

 watery and of a dark olive-green color. Bacteria are universally present, and are 

 believed to be the cause of the disease, which is to be investigated further. 



The bacteriosis of kohl-rabi, L. Hecke {Ztschr. Lnnchv. Versuchsw. Oesterr., 5 

 {1902), No. 1, pp. 1-21, pi. 1). — A description is given of a bacterial disease of kohl- 

 rabi which has been discovered by the author, and the results of his infection experi- 

 ments are reported at considerable length. It is shown that this disease is of a truly 

 bacterial nature, the bacteria occurring in the vascular bundles of the leaf, stem, and 

 I'oots of the plant. It is believed to be due to the same cause as the black rot of 

 cruciferous plants in this country. The bacteria {Pi<cadomonas campestris) gain access 

 through wounds or the water pores of the plant, and in addition to kohl-rabi attack 

 kale, cabbage, and other allied plants. The disease is said to be rather common and 

 widely spread throughout Austria. 



Diseases of plants and their remedies, D. McAlpine {Jour. Dept. Agr. Victoria, 

 1 {1902), No. 3, pp. 316-325, pis. 2). — Descriptive notes are given of the peach-leaf 

 curl, shot-hole fungus, and scab. Suggestions are given for the prevention of these 

 diseases by spraying, pruning, etc. 



Canker and gummosis of fruit trees, F. T. Brzezinski {Compt. Rend. Acad. 

 Sci. Paris, .134 {1902), No. 20, pp. 1170-1173) . — A summary is given of investiga- 

 tions begun in 1896 on the cause of the canker of apple and pear trees and of the 

 gummosis of peach, apricot, plum, and cherry. The jirimary cause of these diseases, 

 the author states, is bacteria. In all cases of the canker examined no instance was 

 ever found in which bacteria were not present in the diseased tissue. In the case of 

 the canker, inoculations were made in 1899 on branches of pear by piercing with a 

 needle and introducing the organisms from pure cultures. After about 15 days the 

 wounds became healed over, but the following year characteristic lesions of canker 

 appeared at a distance of about 1 cm. from the healed wounds. A number of inocu- 

 lations had progressed so well by the spring of 1902 that there was no doubt of the 

 success of the inoculation. This seems to indicate that the canker is contagious and 

 certain varieties of pear and apple seem predisposed to the disease. A brief descrip- 

 tion is given of the organism, and that occurring on the pear is said to be almost 

 indistinguishable from that on the apple, although in artificial cultures some differ- 

 ences were noted. Their identity has not yet been proved by cross inoculation. 

 The roots of both pear and apple never present cankerous wounds, but show certain 

 excrescences, the cause of which is yet to be determined. 



The gummosis of peach, apricot, plum, and cherry is analogous to that of the 

 canker described above. Inoculations with bacteria in peach produced the charac- 

 teristic gum flow of the disease, and the cause of gummosis in plums and apricots is 

 believed to be the same as that which causes the disease in peaches. The bacteria 

 causing the gummosis of cherries seems to be distinct from the others, its cultures 

 being whiter and more opalescent. 



