NOTES AND ABSTRACTS. 



801 



cost of 88 c. each tree ; 530 trees, many of them very scattered, were 

 sprayed. The elm sawfly leaf-miner (Kaliosysphinga iilmi) was 

 attacked very successfully by the use of a contact wash. The larch 

 case-bearer (Coleophora laricella), which hibernates in the larval form, 

 was attacked by spraying with lime-sulphur (29 degrees Baume, 

 diluted with seven times its volume of water). The spraying was 

 done just when the larvae began to move, and it was found that at 

 this stage they were effectively checked. — F. J. C. 



Silver-leaf Disease. By F. T. Brooks (Jour. Bd. Agr., vol. xx. 

 No. 8, pp. 682-690 ; 5 plates). — The author, who has conducted a 

 number of inoculation experiments, concludes that whilst silvering 

 of the foliage is a manifestation of ill-health which may be due to 

 different causes, it is usually caused in the case of fruit trees by the 

 fungus Stereum purpureum. 



The disease is fully described, and the various means by which 

 trees may become infected are indicated. It is pointed out that 

 Stereum purpureum must be looked upon as a potential agent in 

 causing silver-leaf on whatever substratum it may be found ; e.g., 

 fruits of the fungus taken from a silvered Laburnum will cause silver- 

 leaf in Plums, and vice versa, and it has also been shown that fructi- 

 fications taken from a dead Birch stump in the midst of a wood are as 

 effective in causing the disease as those taken from a silvered Plum 

 tree. 



The treatment advised consists entirely of preventive measures, 

 for whilst " other kinds of treatment have been suggested for the 

 amelioration of silvered trees, up to the present time none of them 

 have been commercially successful when tried on a large scale." 

 " Cases of natural recovery of trees which are slightly silvered are 

 not infrequent," and " in view of the possibility of recovery without 

 treatment it is difficult to lay any stress on the results of experiments 

 which have not been carried out on a large scale." — .4. S. 



Soil, Investigations on "Sickness" in. I. — Sewage 

 Sickness. By E. J. Russell and J. Golding. II. — In Glasshouse 

 Soils. By E. J. Russell and F. R. Petherbridge (Jour. Agr. Sci. 

 v. pp. 27-47, 86-11 1 ; Oct. 1912 ; plates). — In the former article 

 the condition of the soil of a sewage farm, in which the sewage failed 

 to percolate satisfactorily and the effluent came through less pure 

 than formerly, is discussed. Three causes for the trouble are shown 

 to exist, but the authors appear to attach the greatest weight to a 

 biological factor which checks the increase of bacteria in the soil. This 

 factor can be removed by treatment of the soil with any volatile 

 antiseptic (toluol and carbon bisulphide were used in the experiments) 

 with excellent results, both in the laboratory and on a large scale. 



In the second paper the well-known phenomenon of " sickness " 

 in glasshouse soils in which tomatos and cucumbers had been growing 

 was investigated. The authors consider the "sickness'' to be due to 



vol. xxxix. 3 g 



