98 



from 0"6 to 0*8 mm. in width and leading into oval excavations fiom 

 2 to 3'6 mm. wide. The economic importance of this type of injury 

 is as yet unlvnown. 



The data collected in Sweden during recent years show that 

 oviposition commences at the beginning of July and continues through- 

 out the summer, possibly until the beginning of September, and that 

 the beetle decidedly avoids newly felled trees, being in consequence 

 mainly a secondary pest. 



RoSTRUP (Sofie). Undersogelser over Kaalfluen, dens levevls og 

 bekaempelse. [Investigations in the Life-History and the Methods 

 of controlling the Cabbage Fly, Phorbia brassicae, in Denmark.] — 

 128 Beretning fra Statens Forsogsvirksomhed i Plantekultur , 

 Kobenhavn, 1918, pp. 255-313, 9 text figs. 



A detailed account is given of the experiments conducted against 

 Phorbia brassicae in Denmark during the years 1913-1917. This is 

 a serious pest in a country where the cultivation of cabbage and 

 turnips plays such an important part as in Denmark. When the flies 

 make their appearance in the spring there are always radishes and 

 cabbage to maintain a supply of food for the larvae of the first 

 generation, even if the turnips are insufficiently forward for this 

 purpose. Those of the second generation live on both turnips and 

 cabbage, the latter plant being often left in the fields during the winter. 

 It is therefore necessary to clear the fields thoroughly in the winter 

 of cabbage and turnip plants and their refuse. The injury is always 

 more severe in loose soil, in which the flies prefer to oviposit. A dry 

 autumn seems to diminish the attack during the following spring, and 

 drought and cold weather in May and June has the same effect on the 

 pest dm'ing the summer. 



Preventive methods include : — Early sowing and thinning of the 

 plants, which renders them more capable of resisting attack ; thorough 

 fertihsing is also useful, but there seems to be reason to beheve that 

 the spreading of manure in the spring will attract the flies ; watering 

 the plants and hilling them renders them also more capable of resisting 

 attack ; and it is advisable to lay out new cabbage beds as far away as 

 possible from the old ones. 



Direct remedial methods for this fly include the placing of tarred 

 paper discs around the plants as soon as possible after they have been 

 set out in the field. Tobacco dust and nicotine spray are not refiable, 

 but watering with parafiin emulsion has given promising results ; 

 carboHc acid emulsion on the other hand has proved to be useless. 



SuDA (K.). Sanran to Kanki. [Silk-worm Eggs and Cold.}— Dai- 

 nihon Sanshikwaiho [Report of Japan SericuJtural Association]^ 

 Tokyo, xxviii, no. 324, January 1st 1919, pp. 27-29. 



Considerable differences of opinion exist among sericulturists as 

 to the temperature at which the eggs of silkworms should be stored. 

 Some consider that temperatures under 0° C. [32° F.] affect the develop- 

 ment of the embryo, while others believe that low temperature may 

 prevent damage to eggs caused by sudden change of climate. The 



