272 



FUNDAMENTALS OF AGRICULTURE. 



more loss to the farmers of the United States every 

 year than it costs to maintain all the public and private 

 schools, colleges and universities of this whole country. 

 The Two Great Groups of Insect Pests. There are 

 many kinds of insects that pester the farmer and fruit 

 grower. All of them taken together, may be divided 

 into two great groups dependent upon the kind of 

 mouth parts they have, and the manner in which they 

 attack plants. The insects of one group have jaws, 

 and bite off bits of plants and swallow them. These 

 are known as the biting insects. The members of the 

 other group have a beak or sucking tube which they 

 insert into the tissues of plants and suck out the juices. 

 These are called the sucking insects. 



Insects that Bite. The grasshopper is a familiar 

 example of the biting insects. It has biting mouth 



parts composed of two 

 pairs of jaws, one of 

 which is hard and black 

 and easily seen with the 

 unaided eye. With these 

 jaws the grasshopper 

 bites off pieces of leaves, 

 stems, etc., and swallows 

 them much as a cow or 

 horse does. Many insects 

 have biting mouth parts and eat parts of plants; for 

 example, the caterpillar, or " worms " on cotton, to- 

 matoes, cabbage, etc., June-bugs, fig-eaters, potato- 

 bugs, and many others. All such insects are known as 

 biting insects. 



How to Fight the Biting Insects. It is plain that an 

 insect that bites pieces of leaves and swallows them 

 stands a fair chance of being killed if some poisonous 

 substance is placed upon the leaves before they are 

 eaten. After one determines that the pest causing the 

 trouble is a biting insect, it is necessary to decide what 

 poison is best to use and how and when to apply it. 

 Pure Paris green at the rate of one pound to about 



THE JAWS OF A GRASSHOPPER. 



