298 Prevention of the Cabbage Flea. [aug., 



(2.) Potato "sets" should not be cut, but the tubers should 

 be planted entire. 



(3). Care should be taken to obtain seed from districts where 

 the disease does not exist. 



(4.) Lime, or strong nitrogenous manures, especially nitrate 

 of soda and sulphate of ammonia, should not be used. 



Several experiments have recently been carried out on a 

 large scale in Germany, by Dr. Kleberger, of Giessen, for the 

 purpose of testing the measures usually 

 Experiments in recommended for the prevention of the 



the Prevention Cabbage Flea (Haltica oleracea)* which, 



Cabbage Flea. m consequence of the dry weather, has been 

 very destructive in Germany this year. 



The remedies which were tested, were (1) the application of 

 artificial manures, such as quicklime, kainit, nitrate of soda, 

 sulphate of ammonia, and super-phosphate, which, in con- 

 sequence of their corrosive action, tend to keep the insect 

 at a distance ; (2) substances, such as sawdust, peat litter, and 

 fine soot, which make it difficult for the fleas to move about, 

 and so prevent their spreading ; (3) a combination, suggested by 

 Dr. Sorauer, of (1) and (2), in which sawdust and peat litter are 

 moistened with a 40 per cent, solution of quicklime or of kainit, 

 or of nitrate of soda and sulphate of ammonia, and then applied 

 so that the hindrance to movement is combined with the 

 caustic effect of the manure ; and (4) tobacco dust and horse 

 manure, finely powdered, as well as the^ use of Paris green for 

 spraying the leaves. 



The experiments were carried out at four centres, on plots 

 each of 600 square yards. The quantity of artificial manure 

 applied amounted to 50 lb. per plot, or about 3J cwt. per acre. 

 It was distributed along the rows, as near as possible to the 

 plants. The sawdust, peat, soot, and horse dung were spread 

 equally over the whole area. The tobacco dust was in one case 

 put on with a large brush when the dew was on the plants, and 

 m another case sprayed on in a moist state. The Paris green 

 was sprayed on as a 5 per cent, solution. 



* This insect is dealt with in Leaflet No. 3, " Flea " Beetles. 



