BULLETIN 1103, U. S. DEPARTMENT OF AGRICULTURE. 



caused considerable loss. In the coast region about San Francisco- 

 Bay the corn earworm has become so serious a pest that the grow- 

 ing of sweet corn has been discontinued. 



One of the striking features of this year's corn earworm outbreak 

 was the rather unusual damage occasioned to alfalfa, reports of 

 serious damage to this crop having been received from Illinois, 

 Kansas, and Kentucky. Injury to vetch was reported from Alabama. 

 Another unusual feature was the serious damage done to greenhouse 

 crops in Indiana ; roses, chrysanthemums, carnations, and geraniums 

 suffered severely from the feeding of these larvae on the flower buds 

 and stems, the damage ranging from 10 to 90 per cent of the crop. 



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Fig. 1. — Geographical distribution of the corn earworm in the United States: Heavily 

 shaded area, very seriously infested in 1921 ; lighter shading, area of appreciable dam- 

 age in 1921 ; black dots, localities where serious outbreaks have occurred previous 

 to 1921. 



Table 1 gives some impression of the seriousness of this pest dur- 

 ing the past season. The figures on the bushels of field corn pro- 

 duced in 1921 were provided by the Bureau of Markets and Crop 

 Estimates. The percentages of damage were obtained from actual 

 counts by the entomological collaborators of the survey, or were esti- 

 mated from the percentage infestation obtained by actual count. No- 

 attempt has been made to reduce this loss to dollars and cents, but 

 the damage to corn ran well over 175,000,000 bushels. 



The figures on sweet corn are very fragmentary, but in the four 

 States sending in estimates the damage amounted to over $1,500,000. 



The accompanying map (Fig. 1) indicates the localities from 

 which this insect has been reported, both in the past and during the 

 season of 1921, the heavily shaded area indicating the region of 



