INSECT ENEMIES OP WHEAT 173 



annual damage to wheat is thought to average 10 per cent of 

 the crop, that is, over 50,000,000 bushels. In some localities 

 an injury varying from 50 per cent to total failure is not in- 

 frequent. In 1901 the loss in New York was about $3,000,000, 

 and the loss in Ontario was nearly as great. In 1900 it was 

 $16,800,000 in Ohio, and nearly two-thirds of the Indiana wheat 

 was not harvested on account of the fly. The outbreak of the 

 Hessian fly in 1900 was the most notable of recent years. The 

 total loss for the United States was estimated at $100,000,000, 

 and milling operations were seriously hampered in the worst 

 affected region. The damage which the fly does is often laid 

 to rust, drought or other causes. In 1904 there was little com- 

 plaint of damage from the insect, yet many fields in the Ohio 

 valley were injured to the extent of over 50 per cent. 



REMEDIES. There are a number of natural enemies which 

 attack the Hessian fly in the larval and pupal stages. Some 

 are native, and others are being artifically introduced. While 

 they limit the damage, they are useful mainly where other 

 preventives are neglected. The best remedy for a field of wheat 

 severely attacked is to plow deeply, and plant a spring crop. 

 In case of mild infection, the prompt use of fertilizer may in- 

 crease the tillering of the wheat so as to produce a partial 

 crop. If the crop has a good growth pasturing or cutting in 

 the fall may be beneficial. When injuries from the fly may 

 be anticipated, moderately late planting of winter wheat is 

 perhaps the best preventive. Seeding for this purpose should 

 be about the middle of September in the northern districts, 

 during the first half of October in Kentucky, and during the 

 first half of November in the extreme south. The rotation of 

 crops should be practiced. Burning or plowing under the 

 stubble is of great advantage. The fly can be starved out 

 almost completely over a district of any size by abandoning 

 for one year the culture of wheat, rye and barley. Volunteer 

 grains should also be destroyed. Early plantings of trap or 

 decoy crops will attract the flies, and, after ovipositing, these 

 crops may be plowed under deeply. While no varieties of 

 wheat are absolutely "fly proof," some tiller more and are 

 less injured than others, such as Underbill, Mediterranean, 

 Red Cap, Red May and Clawson. Preventive measures reduce 

 the annual loss from the Hessian fly by an amount estimated 



