DISEASES OF PLANTS. 649 



with comparative safety. " Soluble sulphur," even when reduced to f lb. in 

 50 gal. of water, caused serious defoliatiou of the trees, and as a result of this 

 i<nd previous experiments it is not considered safe to use. Where " atomic 

 sulphur " was used, scab control was very efficient and the amount of russctiug 

 was less than that observed on the unsprayed checli plat. The copper lime 

 sulphur did not give any better scab control than ordinary lime sulphur, and 

 the amount of leaf injury and fruit russeting was largely increased by the use 

 of tliis fungicide. The extra fine sulphur did not give as good results as some 

 of the other mixtures employed, although it had considerable efficiency in scab 

 control. With arsenate of lead as a summer spray for apple trees the scab 

 control on the fruit was very efficient. The experiments show that arsenate 

 of lead has an important effect as a fungicide, although the results were not 

 so favorable as those previously obtained. 



In connection with this experiment the effect of omitting the earlier spraying 

 was tested. It was found that if circumstances arise which cause the delay 

 of the earlier application, or cause it to be entirely omitted, this does not neces- 

 sarily imply failure in scab control if the later applications are made in due 

 time. 



Plectodiscella piri, representing a new Ascomycete group, N. N. Woronichin 

 {Trudy Btliro Prikl. Bot. [Bui. Angeiv Bot.), 7 (19U), No. 7, pp. Jf31-U0, pi. 1; 

 Mycol. Centbl, 4 (1914), No. 5, pp. 225-233, pi. 1, figs. 8). — An account is given 

 of the study of a disease of pear and apple leaves in the Caucasus, said to be 

 due to a fungus hitherto unknown. This is described as P. piri n. g. and sp., 

 the representative of a new family which is named Plectodiscellse. 



Silver leaf, T. A. C. Schoevers {Tijdschr. Plantenzielcten, 20 {1914), No. 1, 

 pp. 36-41, pi- !■) — Noting studies on the attack of Stereum purpureum on 

 stone fruits and other plants, as carried out in 1913 at Wageningen, the author 

 states that the exact nature of the connection between the silvered appearance 

 of the leaves and the presence of the fungus in the wood vessels is still undeter- 

 mined. 



Complete destruction of diseased parts is advised, also treatment of wounds 

 with tar or carbolineum. Earth from near trees suffering from the disease 

 should not be placed near sound ones. Material for grafting should be care- 

 fully inspected. Sufficient water supply should be provided, especially for dry 

 weather. Growths liable to harbor the fungus should be removed from the 

 neighborhood of susceptible plants. 



Red raspberry injury caused by Sphaerella rubina, W. G. Sackett ( Colorado 

 8ta. Bui. 206 {1915}, pp. 26, pi. 1, figs. 15).— The author describes the injury 

 .done to raspberries by the fungus ^S. ruMna, and gives an account of spraying 

 experiments for its control. These experiments were carried on for two sea- 

 sons, a 3 : 2 : 50 Bordeaux mixture being used, to Vv'hich 2 lbs. of rosin fish oil 

 soap was added. Three applications were given the canes, only the young 

 canes being sprayed and the old ones being removed and burned as soon as the 

 berries had been gathered. 



As a result of spraying, a net gain of $167.26 per acre was estimated, at a 

 cost of $10.24 per acre for materials and application. 



Notes are also given on the effect of late frost, methods of covering, time of 

 taking up canes, poor cultivation, age of plantations, etc., on raspberry produc- 

 tion. 



Bordeaux mixture as a citrus spray, G. L. Fawcett {Porto Rico Prog., 8 

 {1915), No. 13, pp. 6, 7). — The comparative fungicidal vaUies of fresh Bordeaux 

 mixture, a commercial preparation of the same, and a dry powder of copper 

 sulphate and lime were tested for leaf rot fungus on coffee trees. The freshly 



