REMEDIES AGAINST THE ATTACKS OF INSECTS. 221 



beetles, water-beetles, the larvse of Tenebrionids and of 

 lady-beetles (Coccinella), and those of the lace-winged flies 

 (Chrysopa) which prey on Aphides, though the maggots of 

 the Syrphus flies are more abundant and efficacious as 

 Aphis-destroyers. 



PREVENTIVE AND DIRECT REMEDIES AGAINST THE ATTACKS 



OF INSECTS. 



In applying any remedies against noxious insects, it is of 

 prime importance to become thoroughly acquainted with the 

 habits and transformations of the pests with which we have 

 to contend. It should be borne in mind that insects during 

 their transformations lead different lives, and that practi- 

 cally a caterpillar is a different animal from the chrysalis or 

 the butterfly, with entirely different habits and surround- 

 ings; and so on throughout the other orders of insects. 



Under the head of general or preventive remedies may be 

 enumerated : 



High culture, with the use of plenty of manures and 

 fertilizers. 



Kotation of crops, and early or late sowing. 



Raising crops to last for two years, such as peas and 

 beans, to guard against weevils. 



The breeding of insect-parasites. 



Burning grass and stubble for certain insects injuring 

 field-crops. 



Removal of dead trees or stumps near orchards or in 

 forests. 



Among direct remedies, besides hand-picking, is the use , 

 of the following insecticides: 



Paris green and London purple. 



Kerosene emulsions. 



Pyrethrum or Persian insect-powder. 



Bisulphide of carbon for the grape-root Phylloxera. 



Carbolic-acid soap; whale-oil soap. 



Ammonia or chloroform for insect-bites. 



