SUMMARY OF INSECT CONDITIOITS DURING 1921. 



9 



unusual abundance in 1921, the lighter shading indicating appre- 

 ciable damage in 1921, and the black dots, localities of serious 

 infestation in previous years drawn from literature. 



Table 1. — Estimated damage to field coi-n hy the corn earioorm. 



state. 



Bushels in 

 crop, 1921. 



Percentage 

 infested 

 in 1921. 



Percentage 

 damaged 

 in 1921. 



Estimated 



bushels 



damaged, 1921. 



Illinois 



Indiana 



Ohio 



Missouri 



Minnesota 



Kansas 



Michigan 



Virginia 



West Virginia 



New York 



New Jersey 



Massachusetts 



Total for above 12 States 



United States 



306, 000, 000 

 169, 800, 000 

 159, 300, 000 

 182, 900, 000 

 140, 500, 000 

 102, 100, 000 

 66, 400, 000 

 47, 600, 000 

 20, 100, 000 

 36, 700, 000 

 11,300,000 

 3, 100, 000 



100 

 20-30 



90-95 

 30-40 



5 



17 



7 



110 



11 



4 



11 



4 



14 



12 



115 



12 



15,300,000 



11,886,000 



11, 151, 000 



18, 290, 000 



1, 405, 000 



4, 084, 000 



664, 000 



1,904,000 



804, 000 



734,000 



1, 695, 000 



62,000 



1, 245, 800, 000 



67,979,000 



3, 080, 400, 000 



175,612,000 



1 Estimated. 



HESSIAN FLY. 



{Phytophaga destructor Say.)* 



The Hessian fly outbreak which threatened during the summer and 

 fall of 1920 has declined to a point that warrants the assumption 

 that but little damage will be done by this pest during the summer 

 of 1922. The fly was of minor importance in comparison with the 

 great outbreak of 1915 and 1916. 



In the territory east of the Appalachian Mountains the spring 

 brood was very serious in North Carolina, South Carolina, and tide- 

 water sections of eastern Maryland. In North Carolina the damage 

 was confined to the west-central part of the State, while the outbreak 

 in South Carolina was contiguous with that in North Carolina. In 

 the latter State the crop failure was complete in places. The fall 

 brood was generally verj^ light over this region, with the exception 

 of a few localized infestations in New York and tidewater Maryland. 

 In New York the average infestation in the 14 principal wheat-grow- 

 ing counties amounted to 7.33 per cent. 



Among the East-Central States, Ohio reported that a midsummer 

 survey, carried on in 31 counties, showed an average of 17 per cent 

 infestation as against 44 per cent infestation in 1920. In nine north- 

 western counties the infestation ran as high as 35 per cent. In these 

 counties, however, parasitism was very high, averaging from 50 to 

 60 per cent. 



1 From reports of W. 

 the several States. 



111610—22 



R. Walton, Bureau of Entomology, and survey collaborators iu 



