Green-bug or spring grain-aphis
Walton, W.R.
Green-bug or spring grain-aphis How to prevent its periodical outbreaks - Washington 1921 - 1-10 p. - Spring, Grain United States Department of Agriculture. Farmers Bulletin No. 1217 .
Green-bug or spring grain-aphis How to prevent its periodical outbreaks - Washington 1921 - 1-10 p. - Spring, Grain United States Department of Agriculture. Farmers Bulletin No. 1217 .