156 GARDENING FOR THE SOUTH. 



the plant they cover, as they would conduct the heat away 

 from what they touched. The main object of. these cov> 

 erings is to confine the air and protect the surface from 

 radiating heat. 



All plants will endure more frost uninjured in a dry, 

 well-drained soil. In low, damp locations, plants, else- 

 where considered hardy, are frequently killed by frost. 

 They are also much more easily injured directly after a 

 mild term starts them into growth. 



CHAPTER XV. 



INSECTS AND VERMIN. 



To these numerous and most destructive foes all our 

 gardens are exposed. ISTo plant and no part of a plant is 

 exempt from their attacks. One devours its tender leaf 

 as it issues from the ground ; another preys upon the root, 

 and the plant perishes ; another burrows into the stem, 

 boring it in every direction until it is broken off by the 

 wind. The caterpillar preys upon the leaves when it gets 

 more mature, while the black grub cuts off the young 

 plant just as it is shooting into growth. Some feed upon 

 the flowers, while others devour the matured fruit or seed. 



Insects are on the increase in American gardens, partly 

 from the fact that the destruction of forest trees and wild 

 plants has driven them to the cultivated ones for food, 

 (the apple tree borer, for instance, originally subsisting on 

 the thorn,)partly from being constantly imported from all 

 other countries from which seeds and plants are brought, 

 and partly from the diminution of birds and other enemies 

 by which they are naturally held in check. 



