324 Landscape Gardening 



thrum, 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-hved, several applications at intervals of a few days 

 or a week will destroy most of them. 



Fungicides 



(Fungus-destroyers.) 



The use of fungicides becomes necessary to protect many 

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

 dews, rusts, blights, etc., w^hich often do serious injury, 

 and lime sulphur solution or 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 spores or seeds of 

 the fungus may be killed or be prevented from germinating 

 by a very small amount of copper solution or other fungicides 

 coming in contact with them. 



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

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

 fungicides on the parts of the plants likely to be affected 

 whenever the spores (seeds) come in contact with the plant 

 under conditions of high temperature and moisture. These 

 spores are produced in immense numbers, an illustration of 

 which may be seen in mass of spores forming the large fruit- 

 bunches of the "corn-smut" or the dust of the puffball, 

 the black substance of the first and the fine gray powder of 



