Walton, W. R. <br/><br/>
The green-bug or spring grain-aphis  :   how to prevent its periodical outbreaks  / 
W. R. Walton 
 - Washington  :   Department of Agriculture 
 - 11 p. 
 - EUA. Dep. of Agri. Farmers' Bull.; 1217 .
<br/><br/><label>LCCN: </label>203855 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Coccus viridis  Toxoptera graminum  Cereales -- Plagas