MEXICAN BEAN BEETLE — WHITE 355 



bean beetle insecticide, would reduce the hazard of undesirable resi- 

 dues on the beans. By 1933 sufficient data had been accumulated to 

 warrant the recommendation of the use of finely ground roots of der- 

 ris and cube in water for the control of the bean beetle. Continued 

 investigation with these materials showed them to be the most effec- 

 tive and superior to all others developed for the control of the insect, 

 and they can be used with equally good results in the spray and dust 

 forms, which is a distinct advantage under many circumstances. 

 Since the first important recommendation for the use of derris dust 

 for the control of a leaf-feeding insect which was widely distributed 

 and very numerous in certain areas of the country was made in the 

 case of the bean beetle, the studies on the control of this insect may be 

 credited with having contributed largely to the extended use of this 

 relatively new and valuable insecticidal root as well as other plant 

 roots containing rotenone, such as cube and timbo. 



SUMMARY 



The Mexican bean beetle, although known in the southwestern part 

 of the United States for 75 years or more, was first discovered in the 

 Southeast in Alabama in 1920. Its introduction into the East was 

 probably through shipments of alfalfa hay from an infested region 

 of the West. In the East the beetle spread rapidly by flying in a 

 general northeasterly direction. By 1932 it was present in all 

 States east of the Mississippi River, with the exception of Florida 

 and Wisconsin, and to the north as far as southern Minnesota. Dur- 

 ing the next 8 years its spread was greatly retarded, infestations being 

 found only a little farther north in Michigan, New York, and Maine, 

 and in the South scattered infestations had been reported in the Gulf 

 region from Florida to Louisiana. 



The beetle's presence and spread in the East was viewed with great 

 concern by those engaged in the production of beans, as the crop 

 heretofore had been comparatively free of insect attack. Federal 

 field research laboratories were established in several sections of the 

 United States, and one was set up in Mexico, to study the habits of 

 the beetle and methods for its control. 



The beetle was found to be most destructive to garden beans, 

 occasionally feeding on leguminous crops such as cowpeas and soy- 

 beans. Two broods of the pest may occur in the northern part of 

 its range, whereas four will develop in the southern States. The 

 beetle chooses for hibernation quarters accumulations of fallen leaves 

 of deciduous trees and pine needles. It will, however, hibernate in 

 the open fields in the South under crop remnants and dead weeds. 



Severe damage to the bean crop occurred as the beetle increased its 

 range. This damage was usually very severe during the season that 



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