lOO 



THE CEREALS IN AMERICA 



crop, but they may be trapped while migrating to maize fields by means of barriers 



of various sorts. Millet or Hungarian grass is probably the most effective. After 

 the chinch bugs have congregated in the millet, they should be plowed under 

 deeply, — preferably after spraying with pure kerosene oil. Usually, however, the 

 chinch bug has migrated to the maize fields before protective measures have been 

 jiaugurated. The best remedy then is to spray with pure kerosene in the early 

 morning when the chinch bugs will be congregated at the base of the maize plants. 

 The kerosene will do some injury to the maize but not nearly so much as the chinch 

 bugs. 



The chinch bug is attacked by two parasitic fungi which tend to hold it in check. 

 A number of experiment stations have propagated and distributed these fungi to 

 farmers for the purpose of spreading them among healthy insects. It has been 

 found, however, that this method is practically effective only during the moist cool 

 weather when the insects are destroyed without the introduction of the disease 

 germs. While the insects are young, even after they have wings, they are migratory 

 in h.ibit, but when the time for the union of sexes comes they take to wing and are 

 no longer noticed by the casual observer. It happens that this occurs from one to 

 three weeks after they migrate to maize fields. Frequently remedies have been 

 reported effective, when in fact the disappearance of the chinch bugs was due to 

 their midsummer flight. 



152. The Hessian FLV.—The Hessian fly is a small, two-winged, dusky-col- 

 ored insect, about one- 

 eighth of an inch long. 

 It is distinctly a wheat 

 pest, but it will also 

 feed upon barley and 



rye 



,1 On account of 



its small size, the adult 

 insect is seldom ob- 

 served, and less seldom 

 identified. Crane flies, 

 much larger insects, 

 often swarm about 

 wheat fields and may 

 be mistaken for the 

 Hessian fly. 



The Hessian fly is usually two-brooded, although it may be one-brooded in the 

 northern spring wheat districts, or in the more southerly section of the United 

 States may be three-brooded, the third brood living upon voluntary wheat in the 

 summer months. \"S'hen two-brooded, the fall brood reaches the adult stage during 

 the latter part of August, during September and the first days of October, depend- 

 ing upon latitude and other seasonal conditions. The adults probably disappear 

 with the first sharp frost. At any rate, the condition which is most favorable to the 



Hessian fly: A, adult, about three times natural size; 

 B, flaxseed, <^Iightly enlarged ; C, larvae, slightly enlarged. 

 (After Washburn.) 



' Cornell Bui. 194, p. 355. 



