INJURIOUS INSECTS 121 



pillars. Where smoke from it can be confined around 

 the plants, as in greenhouses and hotbeds, it is common 

 to use it in a smudge, but when thus used it should be 

 kept from blazing. It is also used in powdered form to 

 keep off some insects. A more common and effective way 

 of using it is as a decoction in water at the rate of one pound 

 of tobacco stems, leaves, or dust to two gallons of water. 

 The tobacco should be boiled in the water for twenty 

 minutes. When cold the decoction should be applied 

 undiluted, using a syringe, spray, or other means of appli- 

 cation. The decoction will not keep more than a few days 

 without spoiling. Tobacco is an excellent fertilizer as 

 well as insecticide. Many forms of tobacco preparations 

 are on the market, among which nicofume and nicotocide 

 are used for aphis of various kinds. 



Arsenate of Lead. Arsenate of lead is the best arsenious 

 poison to apply, because it does not hurt the foliage of 

 plants, stays in suspension longer, and adheres to foliage 

 better, sometimes remaining on the foliage in poisonous 

 amounts from June to late in the fall. 



The usual amount applied is three pounds to fifty 

 gallons of water. Five pounds to fifty gallons are some- 

 times used for insects hard to poison. It comes in a paste 

 form which is easily mixed with water. Arsenate of lead 

 may often be applied to advantage with Bordeaux mixture 

 or other fungicides. 



Hellebore. White hellebore is a common insecticide 

 for chewing insects. It is not a lasting poison, since it 

 loses its poisonous quality soon after exposure to the air. 

 It is used for cabbage and currant worms. Hellebore may 

 be dusted on when the plants are moist, or applied in water 

 at the rate of from one to two ounces of powder to two 

 gallons of water. 



