72 Wheat Rust in Australia. 



the rust. At Port Fairy, in Victoria, where rotation is regularly prac- 

 tised, and where I have had crops grown the same st^ason, sometimes 

 after mangels, or potatoes, or onions, there was no perceptible difference 

 in rustiness from those crops of wheat grown in succession. From the 

 stand-point of good farming, it is to be recommended ; but cropping year 

 after year does not seem to affect the liability to rust further than this, 

 that self-sown wheat is likely to appear in the interval between the two 

 crops. Such "volunteer" wheat, if not killed in cultivating, is much 

 more forward than sown grain, and on account of its earliness may escape 

 the rust, but on the other hand, there is a risk attending it, for it is some- 

 times more rusty than the ordinary wheat, and appears earlier, so that 

 it is one of the means of carrying over the rust from one season to another. 

 All such wheat should therefore be kept down by means of sheep. 



Fallowing. This practice is similar in its effects to rotation as regards 

 rust. Professor Lowrie, speaking from a large experience, in South Aus- 

 tralia, considers that the apparent exemption which fallow-land sometimes 

 enjoys from rust is due to the fact that it is customary to sow bare f allow - 

 land first, and the crop ripens sufficiently early to escape the rust in some 

 seasons. 



Burning Stubble. It is sometimes recommended to burn the stubble 

 in order to destroy any spores of rust that may be about ; but as a matter 

 of experience, this has not been found to produce any appreciable differ- 

 ence. Theoretically, the burning of the surface of the soil should destroy 

 a number of spores, and to that extenti is beneficial ; but, practically, the 

 difference in result is not marked. As far as most wheat-soils are con- 

 cerned here, the loss of vegetable matter is much more serious than any 

 possible increase of rust. 



Soils. Soils are sometimes said to be rust-liable and rust-free, like the 

 wheat itself; but on closer investigation, it will be found that the soil 

 is only one of several factors that require to be taken into consideration. 

 Rich soils are said to surfer most, and in rusty years the best crops have 

 sometimes been raised from the poorest soils. On the rich soils the crop 

 is naturally heavier and more luxuriant than on poor soils, and the softer 

 and more susceptible tissues are easily invaded by the parasite. Hence 

 it is that the rust may sometimes be worst in the best crops. The mallee, 

 in Victoria, vis said to be particularly rust-free ; but in some seasons the 

 crop has to be cut for hay, in order to save it from being completely 

 destroyed by rust. The reason for general freedom from rust lies not 

 so much in the soil as in the light rainfall and the early ripening of the 

 crop. But if " muggy " weather should prevail when the wheat is flower- 

 ing, then the crop is just as liable to rust here as elsewhere. At Port Fairy 

 the low-lying black soils more readily produce a rusty crop than the sandy 

 soils, and this may be partly due to the fact that the dark-coloured soils 

 absorb more heat, and are more likely to preserve the spores in a fit state 

 for germination, or because they grow a heavier crop, which often lodges 

 and thus encourages the rust. 



Manures. Perhaps no means for the prevention of rust have been 

 more thoroughly and continuously tested than the application of different 

 manures. In all the States, as well as in New Zealand, experiments 

 have been conducted to this end, and the general opinion has been expressed 

 by a late Director of Lincoln College, New Zealand: " No manure has 

 yet been discovered that is a preventative of rust in cereal crops." The 

 tests were carried out under varying conditions, and, as might be expected, 

 the results of one year were often contradicted by those of the next; 

 till, it was generally found that nitrogenous manures favoured the rust, 

 while phosphatic ones had a tendency to diminish it. Nitrogenous manures 



