42 INSECTS INjURIOLS TO N'EGKTAHLES 



a veritable specific for "red spider" on certain plants grown 

 under glass. It is also applied dry mixed with an equal bulk 

 of air-slaked lime, and by means of a powder bellows. It is 

 also used in conjunction with kerosene emulsion or soap washes, 

 added in the proportion of i to 2 pounds to 50 gallons of the 

 spraying solution. It is first mixed into a paste. As a vapor 

 it is exceedingly harmful to plant life, hence should not be used 

 as a fumigant in forcing houses or in a confined structure. 



Bisulphid of carbon {CS-,) , a specific against insects affecting 

 stored grain and other products, has a special value in the treat- 

 ment of some forms of insects afTecting vegetable crops, more 

 particularly aphides, and root-feeding insects, such as root-mag- 

 gots of cabbage and onion. This reagent, when pure, is a color- 

 less liquid and has a powerful and disagreeable odor; it vapor- 

 izes rapidly when exposed to the air, is highly inflammable but 

 not explosive, and is deadly to all forms of animals, including 

 human beings. Its field of usefulness is among such insects as 

 we cannot reach with poisons by direct contact or through their 

 foods. 



The method of applying bisulphid of carbon varies according 

 to the nature of the plants affected and the insects to be de- 

 stroyed. The method of treating the melon aphis and root- 

 maggots will be described in the consideration of those insects. 



PROPRIETARY INSECTICIDES 



Numerous proprietary insect destroyers are on the market, 

 and their number is increasing. Analyses of these are being 

 made, with the result that although a few are not without value 

 they are as a whole decidedly inferior to approved combinations 

 advised by entomologists, of the character that are mentioned 

 in preceding pages ; in fact, they occupy the same relation to 

 standard insecticides that quack nostrums do to the prescrip- 

 tions of reliable physicians, or preparation of recognized value 



