115 



Called to the fact that the oats had spots of rust on the leaves as soon 

 as the first two leaves had appeared. There is nothing uncommon in 

 this. In seasons when rust is prevalent it often appears on the crops 

 soon after they show above ground. The fact that this observation 

 can be made in any particular season only shows that the season is one 

 rather favourable to rust and that the disease is present ready to take 

 advantage of the fact. It is very uncommon to see a crop of oats that 

 is entirely free from rust in a climate such as that characteristic of our 

 northern rivers. 



Considering the severity of which this disease is capable I do not 

 consider that there is much occasion for alarm, though it is beyond 

 question wise to give close attention to the progress of the disease in 

 various districts. 



The amount of loss is what must govern any action taken. It is 

 -evident that oats are considered as one of the best of winter feeds in 

 .some districts and that anything that threatened this crop would at 

 present be regarded as a serious danger. From what I saw I think 

 we may without fear continue the growth of this crop for that purpose 

 for some time to come, but I fear that the continuous growth of this 

 *crop year after year on the same land for a long time will compel us 

 in the long run to abandon its growth, especially if meanwhile nothing 

 is done to minimise the disease. In the course of this report I intend 

 to suggest some lines of action that will enable dairymen, if they so 

 desire, to continue the growth of this crop for winter feed. At the 

 rsame time I would advise that attention should be given to some other 

 ; sources of winter feed suitable for dairy cattle. 



At a meeting held for the discussion of this question I had the 

 honour to call attention in a pointed manner to the exact nature of 

 the rust disease, I showed with the aid of the microscope that rust 

 is a microscopic plant that propagates in a manner similar to that 

 followed by oats, with this important difference that the " seeds," or 

 .-spores, of the rust are so minute that they can be easily carried on the 

 for long distances. The number of the spores, as I showed, 



Fig. 128. Teleutospores of the common Australian rust of the oat. 

 These occur in linear, black, more or less confluent sori, that remain 

 for a loner time completely covered by the cuticle. As the figure 

 shows, the brow-a cylindroid to conoid spores are borne on very 

 short pedicels, measure 40-60 x 12-20^, and are characterised 



by bearing at the truncate distal end 6-7 blunt irregularly finger- 

 shaped processes. 

 The orange-yellow spheroidal to ellipsoidal faintly echinulate, ure- 



despores are borne in very pulverulent, elongated, often confluent sori. 



Size, 15-20 x 20-28^. 



X400 



-is so great as to be almost beyond calculation. The number of spores 



-on a single leaf of rusty oats might reach millions. It is no wonder then 



that the disease is widespread, especially when we remember that it runs 



its course in a few days' time. Already the rust is so common in some 



-districts that the spores are to be found almost universally distributed. 



J found them. on the fences, high up in trees, and in the dust of the 



jhotel rooms in all parts where the rust was particularly prevalent. 



