113 



plants, the same being excluded by the water. Such instances would be 

 less common if the soil were rendered more porous by deep culture, the 

 small improvement secured in this way being sufficient to permit the 

 waters of small storms to sink in rapidly enough to allow the plants to 

 escape " drowning." These slight depressions in the paddock may in 

 some cases be gradually filled in by the right method of ploughing, 

 which constantly turns the soil from their margins towards the centre of 

 the depression. I have seen extensive areas subject to " Take-all " 

 that could be dealt with in this manner and cured in the course of a 

 few years, but of course such a combination of circumstances is 

 not common. 



Since dealing with the matter in 1893 I have found that the follow- 

 ing treatment is almost invariably followed by good results. At a 

 time when the disease is showing, which it always does in patches of 

 greater or less extent, mark the patches with stakes, and after harvest 

 and before the following ploughing apply lime, or wood ashes known to 

 have a large proportion of lime, at the rate of at least one ton to the 

 acre, better more. Of course only the diseased areas need be so treated. 



This treatment is based on a general knowledge of the causes of 

 the trouble and the fact that the disease continues from year to year 

 in the same place. It is possible that if one year is very favourable 

 to the disease and it is followed by a year that is very unfavourable 

 to the disease the patch will not persist, but this is exceptional and 

 does not upset the rule. If the season is very favourable to the 

 disease or there is a succession of such seasons, the disease may appear 

 so as to cover large areas. It appears that such was the case in 1903 

 in some districts. 



While on the subject of " Take-all '' it may be well to mention that 

 Sorghum has been known to suffer from the attacks of Cladosporium 

 in the same way as wheat and other cereals. The appearances of the 

 cases examined by me are much the same as those formerly described in 

 connection with wheat and oats. I have seen Sorghum dead and dying 

 in patches with no other signs of parasitic growth than the abundant 

 growth of Cladosporium, so that it seems a fair inference that this 

 grass is also subject to " Take-all." 



VARIOUS BUSTS. 



MORE interesting than destructive is the rust of the White Clover. 

 Though not uncommon, it is never, so far as I have observed, so 

 prevalent as to do very much damage. Not infrequently it happens to 



Fig. 126 Aecidium of the rust of the common White Clover (Tn/olium 

 repens). Magnified 10 diameters. 



Aecidio-spores. The nearly colourless, closely verrucose, polygonal 

 or rounded secidio-spores measure 16 to 18 by 20 to 25 /j, and are borne 

 in cup-shaped pseudoperidia, having everted whitish dentate edges. 

 The diseased spots are about two millimetres across. 



attract the attention of some observant person, who, influenced by its 

 general resemblance to other more destructive rusts, makes inquiry as 

 36567 H 



