Figure 25.— Spotted alfalfa aphid, Therioaphis maculata 

 (Buckton). 



Figure 26.— Potato leafhopper, Empoasca fabae (Harris) and 

 E. mexara Ross and Moore. 



Figure 27. — Stem nematode, Ditylenchus dipsaci (Kuhn) 

 Filipjev. 



Northern species, M. 



hapla Chitwood above 



line; southern species, 



M. incognita Chitwood and 



M. javanica (Treub) Chitwood below line. 



Figure 28. — Root-knot nematode, Meloidogyne sp. 



19 



