352 AJSTNUAL REPORT SMITHSONIAN INSTITUTION, 1940 



central Alabama. In the coastal area of the Carolinas, Georgia, 

 Maryland, and Virginia, its occurrence in damaging numbers has been 

 sporadic. Judging from the reports on outbreaks south of central 

 Georgia and Atlanta the infestations in this area have been localized. 

 The bean-growing areas of Michigan and southwestern New York 

 have not been seriously affected by the insect, and the two infesta- 

 tions discovered in 1933 and 1935 in Minnesota and Iowa, respec- 

 tively, apparently have not become of any importance to the bean 

 crop. Studies have shown that during the hibernation period the 

 lack of proper coverage to protect the beetle from rapid changes in 

 temperature and moisture increases winter mortality and during the 

 active season high temperatures, accompanied by drought conditions, 

 will rapidly reduce populations of the insect and it is probably these 

 latter factors that have been largely responsible for the variation in 

 the seasonal abundance of the bean beetle in many sections. Winter 

 mortality, although undoubtedly an important factor in the survival 

 of the insect in any given area does not appear to be of paramount 

 importance in relation to the seasonal abundance of the insect. 

 Spring conditions following a high survival of the pest during the 

 winter may result in low populations of the first generation of the 

 beetles. Yet on the other hand, spring conditions following high 

 winter mortality may promote a rapid development of the first gen- 

 eration of the beetles. Considering these factors then, it is hazardous 

 to venture a prediction as to bean beetle conditions, based upon winter 

 survival. 



CONTROL 



Quarantine. — In the early days of the infestation the entomolo- 

 gists' knowledge of the insect's ability to spread under its own power 

 was limited, and it was first thought that a rigid quarantine of the 

 infested area would prevent the insect's spread or at least retard 

 it. Consequently, a Federal quarantine was imposed on May 1, 1921. 

 It was soon learned, however, that because of the insect's ability to 

 make strong sustained flights and its inherent urge to move, even in 

 the presence of an adequate supply of favorable food, regulations 

 on the movements of farm produce and other materials would not 

 prevent its spread. Upon recommendations of J. E. Graf, who was 

 in general field charge of the work for the Government, the quaran- 

 tine was lifted 2 months later, July 23, 1921, and the money appro- 

 priated for its enforcement was returned to the United States 

 Treasury. 



Insecticidal studies. — At the outset the problem of control appeared 

 to be one in which insecticides would play an important part, the 

 insect being a gross feeder and developing on the exterior of the 

 plant. It appeared to be simply a problem of determining which 



