This method of control necessitates a thorough knowledge of 

 the life history of the insect concerned, in order that such 

 cultural methods may be applied at a time when they will be 

 most effective in reducing the numbers of the pest. 



INSECTICIDES AND THEIR APPLICATION. 



Insecticides fall, roughly, into two classes: (1) internal or 

 stomach poisons, and (2) external or contact poisons. The 

 former kill by being eaten with the insects' food; the latter, by 

 direct contact with their bodies. 



Stomach Poisons for Chewing Insects. 



Arsenate of lead, or lead arsenate, is one of the cheapest and 

 safest arsenical poisons for use against insects which destroy 

 foliage. This insecticide is placed on the market in two forms, 

 — as a heavy white paste and as a fine white powder, both 

 being efficient poisons and non-injurious to foliage under normal 

 conditions. 



As a spray, use at the rate of 2 pounds of powder or 4 

 pounds of paste to 50 gallons of water. Where only a few 

 plants are to be treated use 10 level teaspoonfuls of powder 

 or 3 teaspoonfuls of paste to 1 gallon of water. As a dust 

 this poison may be applied to the foliage without being diluted 

 with inert substances. The powder should be used early in 

 the morning, when the plants are wet with dew, or immediately 

 after a light shower. 



Paris green is a green crystalline powder which was formerly 

 much recommended for chewing insects, but which is now being 

 largely superseded by arsenate of lead. This condition has 

 resulted from the fact that Paris green has proved very in- 

 jurious to tender foliage unless applied under ideal conditions 

 and with extreme care. 



Resin-soap Sticker. — Upon the smooth and waxy foliage of 

 such plants as cabbage and asparagus it is exceedingly difficult 

 to stick arsenate of lead when used as a spray. To obviate 

 this a resin sticker is usually added. Such a "sticker" can be 

 made by boiling together for about one hour 2 pounds of resin 

 and 1 pound of sal soda (crystals) in a gallon of water. This 



