714 Agricultural Journal of Victoria. 



them^ apai't from size and structure, is that tlie wheat-plaut obtains 

 its nourishment from the soil on which it grows and the air which 

 surrounds it, while the other obtains it from the living plant, the 

 wheat. In other words it is a parasite which lives within the wheat- 

 plant and exists at its expense. We know exactly how the rust- 

 spores or minute seed-like bodies germinate and enter the plant by 

 means of little threads or tubes, how these tubes grow and branch 

 inside the plant a,nd drain the tissues of their contents, until they are 

 ready again to produce their spores at the surface. All this round 

 from spore to spore may take place during eight days, so you can 

 understand why and how the rust spreads so rapidly. 



All the power for mischief lies in these spores, and if we could 

 only destroy them there would be no rust. In the case of the smut 

 spores, which are on the seed, we can destroy them or 

 prevent them gaining an entrance by steeping the seed in 

 bluestone or formalin, but we know from sad experience that this 

 method does not ap])ly to the rust. The spores are so small and so 

 numerous that they are readily wafted about, and you may have some 

 conception of this when I tell you that it takes about 900 of them end 

 to end to cover an inch. 



How is the rust spread and continued from season to season is a 

 most important question, for if we could find out where and under what 

 conditions the rust is lying dormant from the time the crop is reaped 

 till it is sown again, then we might be able to destroy it at this stage 

 and prevent its reappearance. 



Although the question may thus be simply stated it is by no 

 means easy to answer. 



1. For a long time there was a suspicion in the minds of many 

 practical farmers in older countries that the barberry bush had some- 

 thing to do with its spread, and so firmly was this believed in that 

 the State of Massachusetts passed an Act as early as 1760, compelling 

 the inhabitants to extirpate barberry bushes. And curiously enough 

 it was afterwards scieutifically proved that there was a connection 

 between the fungus appearing on the barberry bush and the rust on 

 the wheat, so that it was thought by many that we had simply to get 

 rid of barberry bushes in order to get rid of the rust. 



The black form of the rust which often appears late in the season 

 is the stage concerned in the production of barberry rust. The 

 spores undergo a period of rest and then germinate, and if the 

 secondary spores that are formed alight on the barberry leaves they 

 may give rise to another stage of the fungus. Although barberry 

 bushes have been imported into Australia and the black rust strewn 

 all around them, yet no infection of any kind has hitherto taken 

 place. 



But it is well known that here in Australia, where barberry bushes 

 are not native and are comparatively unknown, the rust is particularly 

 bad, so that there must be other causes to account for the prevalence 

 of rust. 



