INSECTS AND PREVENTIVES 



spring will be full of life and vigour. Late fall 

 ploughing, as already recommended on a preceding 

 page, serves to bring it to the surface, exposing it 

 more effectually to the cold and to its natural 

 enemies, thus to some considerable extent reducing 

 its numbers. But the most hopeful treatment yet 

 proposed is that recently put forward by French 

 entomologists, who claim to have discovered a 

 plant-parasite by aid of which lands thoroughly 

 infested with the white grub have been very largely 

 relieved after a two-months' trial, so as to afford 

 a reasonable prospect for the complete extirpation 

 of the pest. This remedy, of introducing a para- 

 site harmless in itself but destructive of the noxious 

 insect, is similar to that which has been so success- 

 fully applied in the case of the scale-insects in the 

 vineyards of California. 



Insecticides in liquid solution may be applied by 

 use of suitable force pumps, or garden engines 

 (according to the scale on which the operation is to 

 be carried out), equipped with spraying nozzles. 



But there are drawbacks and difficulties in the 

 use of liquid solutions; one is that the poison does 

 not actually dissolve in the water, which has to be 

 constantly agitated to maintain a mixture. An- 



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