- 8 - 



IJhen wheat Xiras submerged in a solution vxith a specific gravity 

 considerably below that of sound wheat, 50 percent or more of the ker- 

 nels with internal infestation were separated from the sa^nple by flota- 

 tion in the range between 1.0^0 and 1.190. Frora radiographic examina- 

 tion it was determined that these kernels contained advanced stages of 

 larvae, which is logical since their weight would be decreased to a 

 greater errtent than where small larvae were involved. Furthermore, no 

 lightweight sound kernels appeared in the floating layer in this range. 

 If most commercial wheat, therefore, is similar in respect to the range 

 of specific gravity of its kernels, then it appears that it would be 

 possible to separate that portion of the infestation in any sample that 

 contains mat'jre or nearly mature larvae. For this purpose the single 

 solution would be adequate since no additional information would appar- 

 ently be gained from a 3-layer separation. A3-though the exact degree 

 of internal infestation cannot be determined by this method, an indica- 

 tion of the general severity of infestation can be gained on the basis 

 that if more than one kernel contains advanced- stage larvae, this fact 

 would be evidenced by floating kernels. 



LITERATURE CITED 



(1) Apt, A. C. 



1950. A method for detecting hidden infestation in wheat. 

 Mlling Production 1^(5): 1. 



(2) ^ 



1952. ^A rapid method of examining ijheat samples for infesta- 



tion, nulling Production 17(5): U. 



(3) Dennis, N. M. 



1953. A technique of grain orientation for radiographic analy- 



sis. U. S. Dept. Agr. Bur. Ent. & Plant Quar. Er-310, 

 U pp. (Processed.) 



(U) Frankenfeld, J. C. 



19lj.8» .Staining methods for detecting weevil infestation in 

 grain. U. S. Dept. Agr. Bur. Ent, & Plant Quar. 

 ET-256, h pp. (Processed.) 



(5) Harris, K. L., Nicholson, J. F., Randolph, L. K., and Tra>rick, J. L. 



1952« An investigation of insect and rodent contamination of 

 x^rheat and wheat flour. Assoc. Off. Agr. Chem. Jour. 

 35(1): 115-121. 



(6) Keppel, G. E., and Harris, K. L. 



1953* An evaluation of five procedures for the determination 

 of internal insect infestation of wheat, II. Gelati- 

 nisation in sodium hj^droxide, Assoc. Off. Agr. Chem. 

 Jour. 36(1): mo-liiii. 



