120 VEGETABLE GARDENING 



very abundant some other method of destroying them 

 must be employed. 



INSECTICIDES AND OTHER INSECT DESTROYERS 



Pyrethrum is the insect powder of the stores. It is 

 made by grinding the flowers of the pyrethrum plant, which 

 closely resembles the common oxeye daisy. It is not 

 poisonous to higher organized animals although very 

 destructive to many kinds of insects. It is frequently 

 adulterated and can seldom be obtained of good quality. 

 It also deteriorates very quickly when exposed to the air. 

 On these accounts it is often difficult to get satisfactory 

 results from powder obtained at the stores. When used 

 it should be diluted with about five times its bulk of flour, 

 with' which it should be kept in a tight vessel for at least 

 twenty-four hours before using, in order to get best results. 

 When thus confined the flour takes up the poisonous prin- 

 ciple of the pyrethrum. It should always be kept in an 

 air-tight receptacle. 



Paris green is a refuse product composed of arsenious 

 acid and copper and is probably as safe as any arsenic com- 

 pound. It is only very slightly soluble in water, and is 

 used with water at the rate of one ! pound to one hundred 

 or more gallons of water; it is also used mixed with dry 

 substances, at the rate of one pound to fifty pounds of 

 flour or one hundred pounds of land plaster, road dust or 

 sifted coal ashes. In using it with water the addition of 

 an equal amount of milk of lime often prevents injury 

 to leaves. The mixture should be constantly agitated to 

 insure applying a mixture of even strength. 



Tobacco is very useful for destroying some kinds of 

 insects in the garden and greenhouse. It is especially 

 effective against plant lice and soft-skinned hairless cater- 



