THE Bii()A[)-i!i:A.\ \vi:i:viL. 



lo 



ruduviid bug Zebus renardU Kolcn. Several hyiucnopteroiis para- 

 sites ^ are recorded by European writers, but have not been observed 

 in this country. 



CONTROL MEASURES. 



It is obviously impossible, at least from a practical standpoint, to 

 prevent infestation of the beans in the field by such methods as the 

 application of poisons or deterrents. Any control measures, there- 

 fore, must be toward keeping the adults from getting into the fields, 

 or, in other words, must consist of planting seed which contains no 

 live weevils. 



Mr. W. B, Parker reports good success in treating infested beans 

 with water heated to about 150° F. (160° and over affects germina- 

 tion) for from 15 to 20 minutes. This might do for small gardens, 

 but is obviously impractical for commercial plantings, 



DRY HEAT. 



A series of experiments v;as carried on to determine the degree 

 of heat and the length of time required to kill the weevils. Pre- 

 liminary experiments showed that exposing infested beans to from 

 120° to 160° F. for from 5 to 40 minutes did not kill all the weevils. 

 Following is the result of the final experiment. Heat was supplied 

 by electricity. For each test a sack of about 2 pounds of beans 

 was used in a fumigating box with a capacity of 60 cubic feet. 

 Later the beans were carefully examined to find whether they con- 

 tained live or dead weevils. 



Table XI. — Effect of dry heat on the hroad-hcnn loeevil. 



Date treated. 



Date examined. 



p 



Time 

 treated. 



■Result. 



1917. 

 Nov. 15 



1918. 

 Mar. 2S 



160 

 160 

 IGO 

 170 

 170 

 170 

 170 

 170 

 170 

 ISO 

 ISO 

 ISO 

 180 

 ISO 

 ISO 



Minutes. 

 30 

 40 

 40 

 20 

 20 

 25 

 30 

 30 

 40 

 15 

 20 

 20 

 30 

 30 

 40 





Oct. 24 



do 



Do. 



Oct. 20 



do 



Do. 



Nov. 15 



. ...do 



Do. 



Oct. 24 



Mar. 5 



Do. 



Do 



Mar. 28 



Vll dead 



Oct. 20 



do 



Do. 



Nov. 15 



do 





Oct. 20 



Mar. 5 



AH dead. 



Nov. 15 



Mar. 28 





Do 



Mar. 5 



All dead. 



Aug. 24 



Mar.28 





Sept. 19 



do 



Do. 



Oct. 24 



Feb. 27 



-Vll dead. 



Oct. 20 



Mar. 28 



Do. 









These experiments indicate that dry heat is not a satisfactory 

 remedy for the broad-bean weevil, because in order to be effective 

 it has to be so high that the germinating power of the beans may be 



1 Sigalphus pallipes Nees, SigalpJiiis thoracicus Curt., Chremylus ruhiginosus Nees 

 (1, p. 57). 



