440 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



life cycle requires from thirty to fort}' days, so tluit there may 

 be several generations in a year, Professor Cornstock having 

 observed three generations. In central Texas the beetles hiber- 

 nate over winter, but in south Texas they continue to breed in 

 the bins during the winter. 



Control. The following measures of control are recommended 

 by Professor A. F. Conradi, who has studied the species in Texas.* 



" When the insect is known to be present, tubers should not 

 be allowed to remain exposed, and should be covered with soil. 

 Where beetle attack is anticipated, deep planting should be 

 practiced, and if conditions will permit the planting should be in 

 flats, because outbreaks will be more readily noticed than when 

 planted in ridges. Such planting will permit of cultivation that 

 will keep the cracks in the soil closed during drought, thus shut- 

 ting up all entering channels by which the adults may reach the 

 tubers. When the crop is known to be infested, it should be 

 harvested as soon as possible, for every day the infestation will 

 increase and the value of the crop will decrease. All tubers 

 showing no sign of infestation should be separated from the 

 infested ones. The former should be placed in a weevil-tight 

 bin [and fumigated with carbon bisulfide if not sold immediately 

 E. D. S.], and the latter destroyed absolutely. The vines should 

 be gathered and burned, and the grower should convince him- 

 self . . . that no vines or tubers remain in the field." The pest 

 may be disseminated in sweet-potato sets intended for planting, 

 and may be spread great distances by the tubers on the open 

 market, so that seed potatoes or slips should be secured from 

 localities known to be free from it or should be thoroughly fumi- 

 gated. The weevils often gnaw the plants, and Professor Conradi 

 advises thorough spraying with Paris green or arsenate of lead 

 while they are feeding. Potatoes in bins should be thoroughly 

 fumigated with carbon bisulfide, 5 pounds to 100 bushels for 

 thirty hours (see page 57). 



* See Bulletin 89, Texas Agr. Exp. Sta., p. 40. 



