DISEASES OF PLANTS. 777 



Powdery mildew and early pruning-, L. Ravaz {Prog. Aijr. ct Vif. (Ed. U Est), 

 23 {lUOJ), No. 40, pp. (ii'iS, (U'>9). — The value of early pruning of grai^evines as a 

 nieanp for combating powdery mildew is mentioned and attention called to the fact 

 that in order to be successful the affected shoots should be pruned wiiile still carry- 

 ing their leaves. Later pruning was shown by experiments to be without value. 



Powdery mildew and early pruning, L. Degrully {Prog. Agr. et Vit. {Ed. L'Esl), 

 23 {1902), No. 46, pp. 570, 571). — In an editorial note the author attests the efficacy 

 of early pruning as a means of checking attacks of grajie powdery mildew. It is 

 recommended that grajievines l)e severely pruned early in the season following a 

 destructive attack of the disease. This procedure will not obviate the use of fungi- 

 cides, which should be applied later in the season. 



Recent investigations in combating the plant and animal enemies of tlie 

 grape, F. Gvozdenovic {Separate from Allg. Wien. Ztg., l'.)02, pp. 20). — A l)rief 

 account is given of experiments conducted in combating the grape downy and 

 powdery mildews, whether occurring singly or simultaneously upon a plant, the 

 grape anthracnose, and the leaf rollers. 



Diseases of cultivated chrysanthemums, P. Voglino {Malpighia, 15 {1902)„ 

 jyp. 329-341, pi- 1; abs. in Jour. Poi/. Micros. Soc. ILondori], 1902, No. 5, p. 596) .—k.n 

 extended study has been made of the diseases of cultivated chrysanthemums, par- 

 ticular attention being given to one that has proved quite destructive to jilants in 

 Italy. The disease first appeared in July. In August and September there had not 

 been much spread of the disease, but in the two following months it increased with 

 great rajiidity, killing many plants. The leaves were disfigured by irregular brown 

 spots which gradually extended over the whole leaf surface. On these spots small 

 pycnidia were formed by a fungus which the author called Phoma chrysanthemi. 

 Specimens of Phyllostida leucanthemi were occasionally found present, forming gray- 

 ish spots, and at a later stage the Phoma was rej^laced by Septoria chrysanthemi, which 

 continued to develop, and during the latter part of the season was the chief form of 

 disease. By culture and infection experiments the author believes that the Phoma 

 and Septoria are successive stages of the same fungus, and while the spores of the 

 Phoma are short lived, the Septoria spores germinate after long intervals and are 

 able to resist quite low temperatures. 



Chlorosis in palms {Gard. Chron., 3. ser., 32 {1902), No. 822, p. 232).— AiiQwiion 

 is called to the rather frequent occurrence of yellow foliage in some palms, particu- 

 larly Kentias. No very satisfactory explanation has been offered as a cause of this 

 phenomenon, and as a possible explanation the writer refers to a recent annomice- 

 ment of Laurent in which he attributes the chlorotic condition to the fatty degener- 

 ation of the chlorophyll corpuscles. In healthy green leaves the chloroplasts are of 

 a deep green color and there is no trace of the yellow bodies always present in cases 

 of chlorosis. The inference is drawn that these yellow bodies result from degenera- 

 tion of the chlorophyll. Some of the conditions for producing this state are said to 

 be cultivation at low temperature with an excess of moisture, and growing plants 

 from seed which have been gathered in an unripe condition, possibly from unhealthy 

 plants. 



Witches', brooms on the barberry, J. Eriksson {Beitr. Biol. Pflanz. [Co/«i], 8 

 {1902), pp. 3-127, pis. 3; abs. in Jour. Roy. Micros. Soc. [London], 1902, No. 5, p. 

 592) . — The author has shown by experiment that the abnormal branch development 

 ot the barberry is due to JScidium graveolens, the Puccinia form of .which is found on 

 the tall oat grass. The region of attack is the central bud of the tender rosette of 

 leaves. According to the author, the tissue entered by the fungus is not suppressed, 

 but is excited to a quick, strong branch development followed by a condition of 

 weakness which renders the abnormal branches unfit to resist the cold of winter, 

 hence these parts are especially subject to winterkilling. 



