224 



Austrian Silesia. The injury is characterised by the fact that the 

 ears remain totally or partially hidden in the sheath, the whitish 

 transparent mites being found on the inner side of it. The injury 

 usually appears towards the end of June and spreads slowty, continuing 

 up to the harvest. Shade favours the spread of the injury. The 

 damage has been reported as amounting to 2-10 per cent., but in 

 Holland 90 per cent, has been said to occur, and in France a 100 per 

 cent, infestation has been recorded, involving a loss of perhaps three- 

 quarters of the crop. White varieties of oats suffer less than black 

 or late-ripening ones. Winter oats are seldom affected, and only in 

 very dry years. Wheat and barley are not much attacked, and there 

 is no record concerning rye. In wet years T. spirifex is said not to 

 occur. Korff supposes that the mite hibernates in the sheath and 

 is brought to the fields in manure, but it is possible that hibernation 

 also occurs in the field, wild plants allied to oats being the natural 

 food-plants from which the mite migrates to oats. A succession of 

 oat crops increases the trouble. 



Remedial measures include thorough manuring with saltpetre, 

 irrigation, crop rotation (lucerne, etc.), early sowing (ensuring vigorous 

 growth at the critical time), deep ploughing, and the avoidance of all 

 straw and seed from infested fields. 



Gleisberg (W.). Gefahren fur den Kohlbau. [Dangers to Cabbage 

 Cultivation.] — Deutsche Landw. Presse, Berlin, xlvii, no. 103, 

 29th December 1920, pp. 705-706, 2 figs. 



The gall-midge, Contarinia torquens, de Meij., which destroys the 

 hearts of cauliflowers, causes such serious losses in Upper Silesia that 

 cultivation of this crop has been given up in many cases. As it occurs 

 in other parts of Germany, attention is drawn to the severe outbreaks 

 in Holland between 1897 and 1901. 



Owing to its preference for sheltered situations, C. torquens does 

 more injury in early beds than in open fields. In 1920 March was a 

 warm month, and the first plants set out were infested, so that the 

 second generation of the midge appeared in June, when the first 

 usually occurs. The resulting increase is a menace to cultivation 

 in 1921. 



In the district under observation areas treated with lime suffered 

 least. It seems established that the cultural malpractices that favour 

 the disease Plasmodiophora brassicae and the presence of Phorbia 

 {Anthomyia) brassicae (cabbage fly) also favour C. torquens. 



Success was attained in Holland by spraying once a week with a 

 tobacco decoction (6 parts by weight of tobacco leaves in 100 parts 

 water). This treatment should begin with the first seedlings to 

 prevent oviposition, and seedlings must be carefully watched for any 

 signs of infestation, any affected plants being destroyed. 



Brethes (J.). La Vaquita de la Acacia. [Chalepus medius, Chap., on 

 Robinia.] — Anales Soc. Rural Argentina, Buenos Aires, Iv, no. 2, 

 15th January 1921, pp. 39-41, 2 figs. 



The Hispid, Chalepus medius. Chap., causes considerable 

 damage in Argentina to Robinia pseudacacia, upon which it is 

 found almost exclusively. A general description of the adult beetle 



