WHEAT 143 



130. The Insects. The Hessian fly is probably the most 

 destructive of the insects that attack the wheat plant. It is 

 found in the main wheat-growing regions of eastern United 

 States, Canada, and many other principal wheat-growing coun- 

 tries of the world. The adult has the appearance of a mosquito, 

 and the female lays her eggs in irregular rows on the lower leaves 

 of the wheat plants soon after they are up. In a few days the 

 eggs hatch and the small, reddish larvae, which later turn white, 

 crawl down the stem between the stem and the leaf sheath, and 

 when located there, cause a small enlargement on the plant at 

 the point of attack. In a few weeks they reach the pupa stage, 

 in which form they resemble a flax seed, and in this form they 

 pass the winter. In the spring the adult appears and lays eggs 

 for another brood. The first indication usually of the presence 

 of the insects is when the young plants turn yellow, and in later 

 growth, when the straw falls. The most effective method of 

 control is the delaying of the seeding of the wheat for a week or 

 ten days after the normal date of seeding, and usually the females 

 will have come and gone before the wheat is up. A trap crop 

 may be seeded early in the season and then plowed under deeply 

 after the eggs have been laid. It is estimated that the annual 

 loss of wheat in the United States from the attacks of this insect 

 is over 4 million bushels. 



131. The Chinch Bug. During the winter the chinch bugs 

 hibernate in the grass or under rubbish, and in the spring the 

 females fly to the wheat fields, where each lays from 100 to 200 

 eggs on the base of the wheat plants. In about three weeks the 

 eggs hatch and the young insects commence to sap the juices 

 from the plants. The bugs pass through six stages before they 

 become full grown. They live on the wheat for some time, or 

 until harvest, when they migrate to the oats or corn. Although 

 the adults have wings, they travel on foot from plant to plant 

 and from field to field. The eggs for the second' brood are laid 

 on the corn plants, and when the insects mature, they fly to the 

 grass lands for the winter. The control of this pest is accom- 

 plished in most cases by burning the grass and rubbish early in 

 the spring, thus destroying the adults before the eggs are laid. 

 Since they travel on foot, it is sometimes possible to keep them 

 from passing from one field to another by spreading a narrow 

 strip of tar between the infected field and the one to be protected. 



