Gwiddonyn cotwm

Gwiddonyn yw'r gwiddonyn cotwm (Anthonomus grandis) sy'n bla ar gnydau cotwm.

 Darllen pellach 
 Lange, Fabian, Alan L. Olmstead, a Paul W. Rhode, “The Impact of the Boll Weevil, 1892–1932,” Journal of Economic History, 69 (Medi 2009), 685–718.

Categori:Pryfed