426 



In the following year, sprays were applied at three different times, 

 viz. :— The beginning of December, the beginning of January, and the 

 -end of February ; while other bushes received two applications, either 

 the first and second or the first and third. The results showed the 

 importance of the early spraying, and that the combination of the 

 first and third sprayings was the best, though probably three would 

 have given a better result than two. There was no decided result 

 from the use of lime-sulphur. 



The Breaking up of Grassland. — Roifiamsted Expt. Sta., Rept. for 

 1915-17, Harpenden, 1918, pp. 9-12. [Received 27th July 1918.] 



The breaking up of grass fields for crops has shown that the presence 

 of hedges and trees, though it affords shelter to animals while the land 

 is used for grazing, also affords shelter to sparrows and wood pigeons, 

 which render the results of the gro\\ari'g of experimental crops valueless, 

 while the hedgerow weeds support a number of injurious insects. 



Another and more serious difficulty is the presence of wire- 

 worms in the soil, which has rendered the discovery of some suitable 

 insecticide or method of soil treatment impel ative. The problem of 

 soil sterilisation has been under consideration for some time, it having 

 been shown that if soil is treated with a volatile antiseptic there is 

 a considerable gain in available nitrogen compounds and therefore 

 an increase in productiveness. Toluene and carbon bisulphide have 

 been very effective in pot experiments, but not in the field, where 

 some of the tar acids, especially cresylic acid (the chief constituent 

 of so-called " liquid carbolic acid ") proved to be more suitable. 

 Experiments have shown that carbon bisulphide, in quantities 

 practicable on the farm, has no great insecticidal value. Efforts to 

 put soil sterilisation methods into practice have shown that they are 

 effective, but not economical, compared with the use of cheap 

 ammonium sulphate or sodium nitrate. It would be c^uite a different 

 matter however if a partial sterilisation agent could be found that 

 was at the same time a soil insecticide, and with this end in view tests 

 are being made with compounds of known constitution, and with 

 certain typical waste products now available in quantity at a cheap rate. 



The resistance of wireworms to certain poisons such as carbon 

 bisulphide, toluene and formaldehyde, which ought to be effective 

 but are not, is also being made the subject of study in the hope of 

 gaining information that will be of service. 



Since the most potent soil steriUser and larvicide is heat, attempts 

 have been made to devise a means of heating soil cheaply on a large 

 scale. A machine has been invented by means of which it is hoped 

 that the pre-war cost of £40 per acre already attained by nurserymen 

 in the Lea Valley, a figure nob impossible for market-gardening and 

 nursery work, may be still further reduced. 



Brindley (H. H.), Notes on Certain Parasites, Food and Capture by 

 Birds of the Common Earwig {Forjicula auricularia). — Proc. 

 Cambridge Phil. Soc, xix, July 1918, pp. 167-177. 



The view held during recent years by various naturalists, that the 

 dimorphism exhibited by the forceps of male earwigs is due to the 



