108 GARDENING FOR THE SOUTH. 



Nearly all insects have four stages of existence. First, 

 eggs which hatch into larvae; these change into pupae, 

 where they remain dormant for a longer or shorter period, 

 and from which they emerge at last as perfect insects. 

 Some insects, however, bring forth their young alive, as 

 well as deposit eggs. In others, as the Orthoptera, or 

 grasshopper family, the young has nearly the form of a 

 perfect insect. Some insects are injurious only in one 

 stage of their existence; others at all times, when not in 

 a dormant state. 



A knowledge of the habits and transformations of 

 insects is necessary to detect how and at what period of 

 their existence they can best be destroyed, or in what 

 manner vegetation can best be shielded from their 

 attacks. 



By many insects plants are at once destroyed; by others 

 wounds are inflicted that end in a diseased condition of 

 the parts affected, w T hich is communicated to the whole 

 plant. Plants in a weak or diseased state are far more 

 liable to be attacked by insects than those which are 

 healthy and vigorous. 



CLASSIFICATION OF INSECTS AND DISEASES. 



1. Insects which attack the leaves. 



2. Insects which suck the juices from plants. 



3. Insects which bore into the stem and feed upon the 

 wood of the plant. 



4. Insects which attack the roots. 



5. Fungi living on the outside surfaces of plants. 

 (>. Fungi which penetrate the tissues. 



In the treatment of these pests a knowledge of the 

 habits of the insect or fungus is necessary. The remedy 

 that will destroy one group may not check another; so 

 that certain general rules must be followed when efforts 

 are made to combat the enemies. First determine what 



