INSECTS INJURIOUS TO FRUITS. 79 



of insects is the numerous parasites to which they are sub- 

 ject. These may be either animal or vegetable. Any one who 

 has had much experience in gardening may have seen many 

 instances of the increase of animal parasites until certain kinds 

 of insects were no longer injurious. This is common in the 

 case of the cabbage worm, the tent caterpillar, grasshoppers 

 and many others. 



Animal Parasites. The most common of animal parasites 

 that destroy insects are small wasps and some two-winged flies 

 which deposit their eggs in or on the -eggs and larvae of the in- 

 jurious insects on which the growing wasps feed. These destroy 

 enormous numbers of insects and should be regarded as among 

 the greatest aids to the fruit grower. 



Among vegetable parasites that destroy insects may be 

 mentioned the diseases which destroy the chinch bugs, and 

 which the states of Kansas, Nebraska and Minnesota attempted 

 to introduce on a large scale for the subjugation of this pest. 

 Another instance is the disease which often destroys cabbage 

 worms and -even house flies. A good illustration of this oc- 

 curred recently in the experience of a Minnesota gardener. He 

 found the Cabbage Plusia getting very numerous in his twenty 

 acres of cabbages and got a spraying outfit to kill them with, 

 but had hardly started when he found the worms dying naturally, 

 as the result of a fungous disease. He put up the machine and 

 the disease successfully did the work for him. 



Predaceous insects search out and destroy their prey. In 

 this class of insects may be included the Preying Mantis, Tiger 

 beetles, ladybugs and some wasps and dragon flies. 



The Cottony Cushion Scale was first noticed in California 

 in 1872 and was greatly feared on account of its spreading so 

 rapidly and protecting itself from insecticides by excreting a 

 waxy substance which completely covered the insect. The pest 

 was finally destroyed by a lady bird (lady bug) imported from 

 Australia. 



Insects Injurious to the Apple. 



Affecting the Fruit: 



Codlin Moth (Carpocapsa pomonella). The Codlin Moth 

 is the common cause of wormy apples and makes the infested 



