July 15, 1920 



Presoak Method of Seed Treatment 



385 



Currell wheat seed was inoculated with a bacterial suspension of Bac- 

 terium translucens var. undulosum, isolation No. 850, treated with forma- 

 lin for the periods given in Table XIII, planted outdoors, and the percent- 

 age of infected seedlings determined 27 days after planting. 



PERCENTAGE OF GERMINATION 



JO 20 30 40 50 60 70 80 



Fio. 7. — Graph showing effect of formalin i to 320 treatments for various periods, with and without pre- 

 soaking: A, control, tmtreated; B, seeds soaked in formalin i to 320 for 15 minutes drained, covered 2 

 hours, dried overnight, and planted ;C, seeds soaked in water 10 minutes, covered 5 hours, then treated 

 with formalin as in B; D , seeds soaked in formalin i to 320 for 15 minutes, drained, covered 3 hours, and 

 dried overnight; E, seeds soaked in water 10 minutes, covered 5 hours, then treated with formalin as in 

 D ; F, seeds soaked in formalin i to 320 for 30 minutes, drained, covered i hour, and dried overnight; G, 

 seeds soaked in water 10 minutes, covered 5 hours, then treated with formahn as in F; H, seeds soaked 

 in formalin i to 320 for 30 minutes, drained, and dried overnight; I, seeds soaked in water 10 minutes, 

 covered 5 hours, then treated with formalin as in H; J, seeds soaked in water 10 minutes, covered 6 hours, 

 then treated wit h formalin as in H. Records of germination were made on the sixth day after planting 

 and are the averages of three experiments. 



Table XIII. 



'Effect of shortened presoak method of treatment on infected wheat seed under 

 field conditions 



Treatment. 



Inoculated seeds dried and planted Vi'ithout further treat- 

 ment 



Inoculated seeds soaked in water 10 minutes, drained, 

 covered 5 hours, soaked in formalin i : 320 for 15 minutes, 

 covered 2 hours, dried, and planted 



Inoculated seeds soaked in water 10 minutes, drained, 

 covered 5 hours, soaked in formalin 1:320 for 15 minutes, 

 covered 3 hours, dried, and planted 



Inoculated seeds soaked in water 10 minutes, drained, 

 covered 5 hours, soaked in formalin i : 320 for 30 minutes, 

 covered i hour, dried, and planted 



Inoculated seeds soaked in water 10 minutes, drained, 

 covered 5 hours, soaked in formalin i : 320 for 30 minutes, 

 dried , and planted 



Inoculated seeds soaked in water 10 minutes, drained, 

 covered 6 hours, soaked in formalin i : 320 for 30 minutes, 

 dried, and planted 



Number 

 of plants 

 exam- 

 ined. 



215 

 196 



231 

 211 

 246 



Number 

 of plants 

 infected. 



40 



Percent- 

 age of 

 infection 



after 27 

 days. 



