Jan. 2. 1920 Treatment of Cereal Seeds by Dry Heat 387 



disease. Oats in good condition will withstand successfully the 30-hour 

 treatment, but it is probable that even a less severe exposure will be 

 found to control the organism effectively. 



Wheatscab. — The Kubanka and Preston wheats used in experiment 4 

 were heavily infected with scab (Gibberella saubinetii and Fusarium spp.). 

 The seedlings from the treated seed showed no attacks from this disease, 

 while the ones in the control plot from the untreated seed showed numer- 

 ous primary infections. Likewise later, when in head, the plants from 

 the treated seed showed no scab in the head, while the wheat in the 

 isolated control plot showed an abundance of such infections. These 

 data, while yielding encouraging indications, of course point only to the 

 possibility of eliminating seed infection. 



Spotblotch of barley. — The Chevalier barley used in experiment 3 

 was heavily infected with spotblotch (Helminthosporium sativum), as 

 illustrated in Plate 48, A. The thousands of plants in the plot from treated 

 seed were carefully examined, and only four leaf lesions were noticed on 

 the young seedlings. This would seem to indicate that spotblotch was 

 not quite perfectly eliminated in the field, though from the greenhouse 

 experiments previously mentioned its elimination might have been 

 expected. The disease was present in considerable abundance in the 

 control plot planted with untreated seed. 



Netblotch and stripe disease of barley. — Scattering primary 

 infections of netblotch (Helminthosporium teres) on barley and several 

 infections of stripe disease of barley (H. gramineum) were noted in the 

 plots planted with the dry-heat-treated seed. An abundance of both 

 these diseases occurred in the control plot planted with the untreated 

 seed. The same was true of the Helminthosporium leafblotch of oats 

 (H. avenae-sativae) . 



Smut. — The percentage of loose smut infection in barley and oats was 

 considerably diminished by the 30-hour heat treatment. In comparison 

 with the numero'us smutted heads in the control plots only a few appeared 

 in the plots sown with treated seed. 



Work is being continued on the problem. 



SUMMARY 

 

 (i) The work here reported, while only a beginning, suggests promising 



possibilities. 



(2) The data at hand indicate that the various cereals — barley, wheat, 

 rye, and oats — especially when of good quality and well-dried, are able 

 to withstand protracted exposures to dry heat at comparatively high 

 temperatures. 



(3) It is definitely shown that the seed infections from bacterial blight 

 of barley {Bacterium translu^ens) and the bacterial blight of oats {Pseudo- 

 nomas avenae) may both be eliminated by exposing the infected seed to 

 dry heat at temperatures which leave the seed still viable. 



