92 S[JMMA.RY OF CURRENT RESEARCHES RELATING TO 



silver-leaf of Plum and other leaves. It is a disease of which the 

 cause was discovered by Percival to be the parasitism of the fungus 

 Stereum piirpureum. Other workers have made similar infection experi- 

 ments to those carried out by Percival, and with the same results. 

 Oussow sums up the various observations made on the disease, and re- 

 commends methods of avoiding or extirpating the fungus. 



A. Rant* gives an account of a plant disease in Java called Djamoer 

 GJpas caused ])y Corticium javafiiciim, a Basidiomycete. It attacks Dicoty- 

 ledons and Gymnosperms. It is often accompanied by another fungus 

 Necator decretus, which, the writer considers, is part of the life-cycle of 

 the Corticium. Experiments were made on Cinchona with the fungus 

 taken from other hosts, and it was proved that there are no biological 

 species represented in this fungus. Various other biological observations 

 are recorded, and methods of treating the disease are given. 



H. Klebahn f publishes an account of two severe diseases of Celery. 

 A leaf -spot fungus Septoria Apii causes brown spots on the leaves, on 

 which are developed the minute pustules of the fungus. It is the older 

 leaves that are attacked. The spread of the disease is due to leaving 

 diseased leaves undestroyed, and also to the use of seeds that carry the 

 spores of the fungus. The second disease is due to Phoma apiicola, and 

 renders the celery unfit for market. 



Charles Brooks I and Margaret Demeritt publish a report on the 

 cause and nature of apple-leaf spot. The spots, which appear on very 

 young leaves, are at first very small with a purplish tint. Several species 

 of fungi were found on the spots, and from very young stages Sphseropsis 

 malorum (the cause of the disease) was isolated. Several strains of the 

 fungus may be obtained, as was proved by making cultures from apples 

 and leaves affected in different localities. These strains vary in their 

 power to reproduce the disease. Infection takes place from the time 

 the leaves unfold until the end of August. Cultivation, spraying, and 

 the removal of diseased members, are recommended. 



J. Rosenbaum § writes on the disease of Ginseng attributed to 

 Thielavia hasicola which he finds to be identical with the fungus on 

 cotton and tobacco, and this he has proved from morphological characters 

 and by infection experiments. Successful inoculations could only be 

 obtained with young plants, but both aerial and underground parts of 

 the plant suffer from attack. Figures are published of the mycelium 

 and spores taken from the various plants dealt with. 



E. Melhus II publishes a paper of general instructions as to the 

 cultivation of parasitic fungi on living hosts. He describes the various 

 pieces of apparatus that are of use in making the inoculations, including 

 an atomizer, a refrigerator, and a humidity-box. He gives notes of 

 various experiments, and of the success attending his methods of 

 working. 



* Dep. Agric. Ind. Comm. Ind. N6erl. Bull. Jard. Buitenzorg, s6r. 2, iv. (1912) 

 pp. 1-50 (14 figs.). See also Bull. Bur. Agric. lutell. Rome, 1912, pp, 1882-5. 

 t INIitt. Deutsch. Landw.-Ges., 1911, 15 pp. 

 : Phytopathology, ii. (1912) pp. 181-90 (1 pL). 

 § Phytopathology, ii. (1912) pp. 191-6 (2 pis.). 

 II Phytopathology, ii. (1912) pp. 197-203 (1 pi. and figs.). 



