SMUT EXPERIMENTS IN VICTORIA. 597 



those from rye grown in Gemiany. Finally, lye seed was infect-ed 

 with the spores of flag smut from rye, and another portion with 

 those from wheat. These plots were sown on 23rd May, and on the 

 L'Sth of October, three wheat plants were found out of twenty badly 

 affected with flag smut, the infection having been brought about by 

 the spores of wheat flag smut. The plots were finally examined at 

 the end of the year, but there was no further development of disease. 

 Although in this experiment there was no disease in the rj-e it was 

 not owing to the spores being non-germinable ; for when placed on a 

 slide in tap-water, and kept under 'a bell-jar, they germinated freely 

 in three days. 



A- third experiment was carried out in pots similar to the last. 

 Only one wheat plant was diseased, and that was infected with flag 

 smut from wheat, and one rye plant infected with flag smut from 

 rye. 



The conclusion to be drawn from these experiments is that the 

 flag smuts of wheat and lye are not mutually infective, that the one 

 is incapable of infecting the other, and that, therefore, the name 

 given to this smut by Koeraicke, in 1877, who received specimens from 

 R. Schomburgh, in South Australia, should be retained — viz., 

 Urocystis tritici. 



II. — Infection Confined to the Seedling Stage. 



For this experiment the seed wheat was planted in pots con- 

 taining ordinary garden soil. There were three pots — one used as a 

 check, in which the seed was uninfected, a second, in which the 

 seed was thoroughly dusted with spores, and a third in which the 

 spore-s were dusted over the plants when about 6 in. high. The result 

 was that the smut developed only when the seed was dusted with 

 spores, showing that it is the young seedling which is attacked, and 

 that there is no infection when the plant is above gi'ound. The 

 experiment of dusting the seed with spores was repeated, with a 

 similar result, and when in another experiment the young plants about 

 3 in. high were also dusted with spores, and kept moist by being 

 covered with a bell-jar, there was no infection. 



The experiments recorded in connection with wheat and rye, in 

 which the seed was infected and the disease produced, also prove the 

 same point. 



III. — Infection by Spores in the Soil. 



If infection Avas confined to the spores adhering to the seed, then 

 the probability is that seed-treatment would be found as effectual in 

 this disease as in the case of Stinking Smut of wheat. But I had 

 found in my field experiments, that even after treatment of the seed 

 with bluestone, formalin, and hot water respectively, the disease still 

 appeared! where flag-smutted crops had previously been grown, and 

 this pointed to so*he other method of infection than that of the spores 

 adhering to the grain. 



By sowing clean wheat along with diseased straw it was sought 

 to pi'ove whether the diseased straw of one crop was able to infect 

 the following one. 



On 28th June, fifty clean grains of Federation wheat were sown, 

 and fragments of diseased straw sown with them from the ci'op of 



