I certify that I have read this study and that in my opinion 

 it conforms to acceptable standards of scholarly presentation and 

 is fully adequate, in scope and quality, as a dissertation for 

 the degree of Doctor of Philosophy. 



Jerry F. Butj'er), Chairman 



Professor ' O/f Entomology and Nematology 



1 certify that I have read this study and that in my opinion 

 it conforms to acceptable standards of scholarly presentation and 

 is fully adequate, in scope and quality, as a dissertation for 

 the degree of Doctor of Philosophy. 



P. G. Koehler 



Associate Professor of Entomology and Nematology 



I certify that I have read this study and that in my opinion 

 it conforms to acceptable standards of scholarly presentation and 

 is fully adequate, in scope and quality, as a dissertation for 

 the degree of Doctor of Philosophy. 



l9.lO.UUJl 



D. W. Hall 



Associate Professor of Entomology and Nematology 



I certify that I have read this study and that in my opinion 

 it conforms to acceptable standards of scholarly presentation and 

 fully adequate, in scope and quality, as a dissertation for 



i s 



the degree of Doctor of Philosophy. 



e.£.& 



'cW? 





C. R. Douglas 

 Associate Professor of 



Poultry Science 



