DISEASES OF PLANTS. 661 



A cherry disease, F. Corboz {Chron. Agr. Canton Vaud, 14 {1901), No. 15, pp. 

 387-389). — Notes the occasional occurrence of (Inomonia erythroMoma upon cherries in 

 Switzerland. The fungus attacks the leaves, sometimes very severely, but is seldom 

 found upon trees where lisht and air are sufHcient. 



Fungus and insect enemies of citrus fruits and means for their preven- 

 tion, G. d'Utra {Bol. Agr. SCio Paulo, 2. ser., 1901, No. 6, pp. 55jf-565).— Brief descrip- 

 tions are given of a number of fungus and insect enemies of the orange, with direc- 

 tions for their prevention. Among the diseases described are gummosis, which it is 

 claimed is caused by MifcospJiarella Icefgreni, as well as a second form caused by 

 Aphionectria corcicola, Did)/mella citri, Colletotrichum glceosponoides, Glceosporium spe- 

 gazzini, and Fumago citri. Of the insects described most of them belong to the group 

 commonly known as scale insects. 



Collar rot in citrus trees, W. J. Allen {Agr. Gaz. New South Wales, 12 {1901), 

 No. 6, p. 728). — The occurrence of mal-di-goma or collar rot is mentioned and the 

 removal of the diseased bark, after which the wound is treated with carbolic acid, is 

 recommended as a treatment. 



A cure for orange root rot {Agr. Jour. Cape Good Hope, 19 ( 1901), No. 3, pp. 

 185, 186). — Recommends digging up diseased trees, cleaning off all adhering dirt, and 

 exposing the roots for a week or 10 days to the air under shade, after which cut the 

 tree back severely and replant. This method, it is said, has been repeatedly fol- 

 lowed with success. 



Diseases of pineapples, C. W. Mally {Agr. Jour. Cape Good Hope, 19 {1901), 

 No. 3, pp. 171-180). — The author agrees with Schonland that the mealy bug is neither 

 the originating cause nor an important factor in pineapple diseases. 



Report of the agricultural chemical experiment station in Spalato, F. 

 GuozDEXovic {Zlschr. Landw. Versuchsiv. Oesterr., 4 {1901), No. 3, pp. 254-272). — 

 Among the investigations pursued were experiments on the prevention of a number 

 of plant diseases. Grape peronospora, oi'dium, and white rot are described, and 

 experiments reported in the use of various fungicides for their prevention. Among 

 the substances used were solutions of various compounds of zinc, cadmium, nickel, 

 and copper. The Bordeaux mixture proved the best suited to use in combating dis- 

 ease. Experiments on the efficiency of sea water as a fungicide M-ere continued and 

 indicated that the use of this substance is not to be recommended, as it has a 

 decidedly injurious effect. A disease of olives, due to Cydoconium oleaginum, was 

 decidedly injurious, but experiments with a 1 per cent solution of Bordeaux mixture 

 or with a potassium permanganate solution showed that the disease could be readily 

 controlled. Analyses of a large number of samples of wine are reported, as well as 

 investigations in fertilizers, minerals, oils, etc. 



Comparative effects of lightning and gelivure on grapevines, L. Ravaz and 

 A. Bonnet {Compt. Rend. Acad. Sci. Pari.% 132 {1901), No. 12, pp. 805-807).— The 

 effect of electricity upon plants, as shown by the shattered trunks of trees when 

 struck by lightning, is described at some length. The authors conducted a series of 

 experiments in which growing grapevines were subjected for a short time to power- 

 ful electric currents from a dynamo, after which the plants were replaced in the vine- 

 yard, where they were subject to the ordinary conditions. The changes produced by 

 the electric currents were compared with those produced by lightning, as well as 

 those produced by the disease known as gelivure, which has been attributed to freez- 

 ing and to bacterial agencies. The authors found in the plants subjected to electric 

 currents that there was a drying, beginning at the summit of the branches. The 

 bark was broken and crevices formed to various depths. Within the branches the 

 tissues were dried and more or le.ss destroyed. These conditions are identical with 

 those produced I)y the disease in (]uestion, and the authors believe that what luis 

 l)een attributed to the bacterial disease or to freezing is really due to the effect of 

 lightning upon the vines in the vineyard. 



