INSECTS WHICH ARE CONTROLLED BY NATURAL 



ENEMIES. 



While all insects are controlled by natural enemies to 

 a greater or less extent, a few instances may be given to 

 show how this manner of control affects some of the most 

 widely known of our West Indian pests. 



THE MOTH BORER. The moth borer of the sugar-cane, 

 although it is abundant every year in the West Indies, is 

 probably controlled to a very considerable extent by 

 natural enemies. During the time that the eggs of the 

 moth borer are exposed on the leaf of the cane they 

 are liable to attack by a very small hymenopterous insect. 

 (Fig. 182.) 



Fig. 182. Hymenopterous parasite of eggs of moth borer. 

 Greatly enlarged. (Imperial Dept. Agric.) 



The eggs of this insect are deposited in the eggs of 

 the moth borer. The parasite grub hatches and begins to 

 feed on the substance of the moth borer egg, and thus 

 causes the death of the young moth borer caterpillar. 



Probably many, if not all, moths and butterflies which 

 lay their eggs unprotected in an exposed situation are 

 subject to attacks of this kind by similar parasites. The 

 moth borer is also attacked by a parasitic fungus (see 

 Fig. 179) which destroys a certain number of the larvae. 



THE COTTON WORM. The eggs of the cotton worm are 

 attacked by an egg parasite, or perhaps more than one, in 

 a manner similar to that already mentioned in the case of 

 the moth borer. The cotton worm is also attacked by a 



