63 



period ; the pupae should be taken when required and kept under 

 netting permitting the Tachinids to escape. 



A good method of breeding Tachinids is to place the host cocoons 

 in flowerpots or wire-gauze cylinders sunk in the ground and covered 

 with moss, etc. 



Kleine (R). Die Wintersaateule, A^yyotis segetiim, Schiff., und ihre 

 Bedeutung als landwirtschaJtlicher Schadling. [Euxoa segetum 

 and its Importance as an agricultural Y'est.]—Zeitschr. angew. 

 Entom., Berlin, vi, no. 2, February 1920, pp. 247-269, 1 map. 

 [Received 2nd December 1920.] 



The severe outbreak of Euxoa {Agrotis) segetum in Germany in 1915 

 was followed by one of a ruinous character in 1917. In 1918 very little 

 damage was done. The investigations here described were made in 

 Pomerania ; Zimmermann's observations in Mecklenburg have 

 already been noticed [R.A.E., A, vi, 444]. 



The outbreaks are quite sudden, as the individuals normally found 

 are capable of increase within a year to devastating multitudes. 



Weather exercises more influence than has been supposed, and may 

 be almost the sole cause of a severe outbreak. In 1915 and 1917 the 

 weather was dry ; in 1916 and 1918 it was wet. The winter of 1916-17 

 was cold, and a cold winter is favourable to this moth. Warm winters 

 are unfavourable, because the caterpillars remain near the surface 

 of the ground, and are more liable to be affected by damp and 

 pathogenic fungi. 



Rape {Brassica rapa) suffered the most from this cutworm, and 

 potatoes, which covered a larger area, nearly as much. The great 

 injury to rape seems to be due to the fact that seedhngs are planted 

 out in stable manure recently ploughed under. If instead of planting 

 seedlings seed is sown in drills, the danger will be less, because the 

 manure will have been ploughed under some time before, and because 

 the plants will be vigorous in July, the chief danger period. Potatoes 

 are not a preferred food ; other root crops are more attractive. Both 

 sugar and fodder beet suffered severely. In dry years young tobacco 

 plants have been attacked. Winter cereals are not seriously infested. 

 On light soils rye has been injured. 



Rolhng and harrowing are useful measures in the case of potatoes, 

 and rape must be well hoed. The plough is only directly useful when 

 ploughing manure, the important thing being to work the ground in 

 autumn, at least in dry years. Stable manure should be applied in 

 autumn or early spring, just before planting or sowing. In any case 

 it must be ploughed under immediately, so as to prevent eggs being 

 deposited. 



E. segetum does not appear to be parasitised to any degree. Only 

 about 1 per cent, were attacked. The Braconid concerned was not 

 identified. 



The use of artificial manures, such as kainit, seemed promising. If 

 the manured ground is wet these substances appear to kill the cater- 

 pillars, though dry conditions prevent their action. Practical con- 

 siderations, however, give httle hope of this method being of use. 

 In dry years the crops should be watched, and centres of infestation 

 must be isolated by a steep-sided trench strewn with kainit. In wet 

 years there is little to fear, especially after a warm winter. 



