IN junior s INSECTS AND FUNGI. 265 



cide at the rate of from 1 Ib. to 3 to 5 gals, of water, ac- 

 cording to the insect. 



PYRETHRUM OR PERSIAN INSECT-POWDER. This sub- 

 stance is made from the flowers of two or three species of 

 pyrethrum or feverfew-plants, the flower-heads of which 

 are ground to a fine powder, known in the markets as 

 pyrethrum, Dalmatian, Persian, or Buhack insect-powder. 

 When dusted upon some kinds of insects in the latter part 

 of the afternoon or evening, it will paralyze them and those 

 remaining under its influence during the entire night are 

 killed. Many of these insects would soon recover if it were 

 applied in the morning or middle of the day. Young 

 insects are more susceptible to its effect than older ones, 

 but as most of the aphides and other sucking insects are 

 short-lived, several applications at intervals of a few days 

 or a week will destroy most of them. 



Fungi or Fungous Growths. 



The use of fungicides becomes necessary to protect many 

 of our trees and shrubs from fungous growths, i.e., mil- 

 dews, rusts, blights, etc., which often do serious injury, 

 and copper in one form or another is the substance most 

 commonly used to destroy these pests. When once a 

 fungous growth has become established in the tissues of a 

 plant, nothing will kill or dislodge it that will not destroy 

 the host plant, but the ppores or seeds of the fungus may 

 be killed or be prevented from germinating by a very small 

 amount of copper solution coming in contact with them. 



To prevent the growth, therefore, of the spores of rusts, 

 smuts, mildews, etc., it becomes necessary to have the 

 copper solution on the parts of the plants likely to be 



