Bui. 703, U. S. Dept. of Agriculture. 



Plate I. 



FiQ. 1.— Yellow Thistle (Cirsium horridulum), a Common Weed in Uncultivated 



Fields in Louisiana. 



It is closely related to the globe artichoke, and some ot the aphids which attack the latter feed 



on the thistle. 





Fig. 2.— Globe Artichokes on which Aphids, Myzus braqgii, have been Con- 

 trolled BY Spraying. 



WILD AND CULTIVATED FOOD PLANTS OF MYZUS BRAGGII. 



