1905.] 



Prevention of the Cabbage Flea. 



299 



A difficulty was met with in the distribution of the sawdust 

 and similar materials. In perfectly calm weather it was found 

 practicable to spread the sawdust and peat litter equally over 

 the ground, but even under these conditions the equal distribu- 

 tion of soot and powdered horse dung was hardly possible. 

 In windy weather it was out of the question. 



In the Sorauer method (No. 3 above) sawdust and peat litter 

 were moistened separately with a 40 per cent, solution of various 

 artificial manures, 1 cwt. of peat being sprinkled with 35 pints of 

 solution, and 1 cwt. of sawdust with 8| pints. The materials were 

 thoroughly mixed, left in a heap to dry for twenty-four hours 

 and then spread on the ground. 



The distribution of the tobacco dust in a dry form was found 

 preferable to its application in a moist stated - * X 



The results of the experiment were as follows :■ — Quicklime, 

 kainit, and also sulphate of ammonia were successful in all cases 

 in preventing the spread of the " flea " beetle, but they injured 

 the condition of the plants, the plots of cabbage which were 

 treated showing after three days many yellow plants, the growth 

 of which was completely at a standstill for a long time. The 

 application, however, of nitrate of soda and super-phosphate 

 had no injurious effect on the plants, while the propagation of 

 the pest was successfully checked. These two manures applied 

 in the proportions, mentioned above are therefore to be preferred 

 to others for this purpose. 



Sawdust, peat litter, and soot did not prove able to restrain 

 the attack, but the sawdust and peat litter had a better effect 

 when impregnated with one of the fertilisers. Peat litter 

 moistened with a solution of quicklime in water proved most 

 advantageous. A strip, about 12 ft. wide, round a large field of 

 rape, of which one side was attacked by the "flea," was able 

 in this way to protect the field from further injury. 



A protective strip treated with powdered horse manure 

 did not prove so successful. It proved excellent at first, 

 but failed after frequent rain. 



The application of tobacco dust and Paris green caused the 

 beetles to disappear almost immediately. 



For practical purposes the employment of artificial manures 

 cannot be recommended on account of the expense, bwt as a 



