850 EXPERIMENT STATION RECORD. 



The Cycloconium on the olive, G. De Michele (Italia Agr., 1911, No. 15, 

 pp. 3'/7-3o2, figs. 3; abs. in Riv. Patol. Vcg., 5 (IDll), No. 7, pp. 103, 104).— On 

 account of reports that spraying olive trees with Bordeaux mixture failed to 

 reduce the leaf fall due to C. olcaginum, the author investigated the subject 

 with somewhat contradictory results. Solutions of copper sulphate were found 

 to be not altogether efficient in preventing the defoliation, but this is attributed 

 to the physiological effect on the olive tree and not to the effect on the fungus. 

 It is believed that the presence of lime or potash renders trees less subject to 

 the fungus and that the lack of these elements favors leaf fall. 



A solution of copper sulphate is said to have proved very eflScient against 

 fumagiue of the olive. 



The present knowledge in regard to the nature of peach yellows disease, 

 E. W. Morse and L. W. Fetzek {Abs. in Sdcnce, n. set:, 35 {1912), No. 897, p. 

 S93). — The authors present a summai-y of the present state of knowledge regard- 

 ing the disease of peach trees known as yellows, and conclude that it is a consti- 

 tutional disease which is inheritable. The symptoms of the disease, such as 

 premature ripening of the peach, the appearance of superficial red spots and 

 streaks throughout the flesh, and the yellowing of the leaves, are held to point 

 to the hypothesis that the disease is a metabolic one, due to a disturbance of 

 equilibrium among the enzyms of the plant. 



Investigations on the dying of plum trees, E. Rabate {Pr-og. Agr. et Vit. 

 {Ed. I'Est-Centre), 32 {1911), Nos. 33, pp. 191-202; 5//, pp. 2U-222) .—An inves- 

 tigation was made of the cause of the rapid destruction of plum trees during 

 1911 in certain portions of France. The conclusion was reached that the trouble 

 was due to the asphyxiation of the roots through a prolonged saturation of the 

 soil, to root rot fungi, or to both causes acting together. 



Most of the recent loss is attributed to saturation of the soil, and draining 

 and a better sanitary condition of established orchards and more careful selec- 

 tion for new plantings are recommended. 



Double blossom of the dewberry and the blackberry, F. C Reimeb and 

 L. R. Detjen {North Carolina Sta. Rpt. 1911, pp. 41-50, figs. 5). — In continua- 

 tion of a preliminary report on this disease (E. S. R., 25, p. 849), the authors 

 give an account of their investigations which have led to the conclusion that it 

 is due to the fungus Fusarium rubi. 



This fungus lives in the leaf buds of the young canes, and as the buds develop 

 it spreads and involves the entire rosette. Later, instead of normal shoots 

 growing from the bud, an indefinite number may appear, giving it the appearance 

 of witches' broom. 



For the treatment of the disease spraying experiments, although not carried 

 on sufficiently long to give conclusive results, indicate that spraying will not 

 prove a practical remedy. It is suggested ^-hat probably the best treatment 

 would be cutting the canes at the surface o' .,he ground as soon as the picking 

 season is over and burning them. 



The leaf spot fungi of currants, E. Voges {Centbl. BaJct. [etc.'], 2. AU., 30 

 (1911), No. 21-24, pp. 573-579, figs. 5). — The results are given of a study made 

 by the author of a fungus found in the early spring of 1909 on the leaves of 

 currants that had remained green over winter. This fungus he pronounces to 

 be the pycnidia stage of the Mycosphgerella, the same species that is found in 

 nature in the leaf spots of gooseberry and raspberry and known on the former 

 as Phyllosticta grossularice and on the latter as P. ruboriim and P. rubicola. 



The unlikeness of the leaf spots is attributed to the differences in the hosts, 

 also possibly to the presence of other parasites associated with this in the 

 affected spots, such presence being both effect and cause of weakness in the 

 leaves affected. 



