Bui. 1058, U. S. Dept. of Agriculture. 



PLATE IV. 



Wisconsin No. 22 Oats, Sprayed on June 29, 1918, with Water Suspension 

 of "Stock" Halo Organism after Injury by Needle Pricks. 



Collected in July, 1918. Photographed in January, 1921. Three-fourths natural size. 



