254 Journal of Agriculture. [8 April, 1907 



the control of diseases are what our farmers and fruit-growers require and 

 these can only be devised as the result of comprehensive field experiments. 



At present we know that the take-all fungus produces little black flask- 

 shaped bodies,' called perithecia, on the sheath of the wheat, containing an 

 immense number of spores, and these spores are capable of germinating 

 at once if sufiicient moisture and air be present. As was shown by experi- 

 ment three years ago if diseased stubble be placed in a pot and healthy 

 wheat sown with it, the young seedlings are seen to- be diseased almost 

 as soon as they appear abo've ground, and in as short a time as two 

 months from date of sowing the plants may be all dead and their 

 blackened butts covered with the perithecia of the fungus. Thus if wheat 

 be sown on land bad with take-all the previous year we may expect the 

 resulting crop to be diseased, in all probability much worse than in the 

 first case, since the conditions favoring germination of the seed also favour, 

 germination of the spores. As this result invariablv occurs in farming 

 practice it is clear that the disease known as take-all arises from the 

 spores of this fungus remaining in the ground from the previous year. 



Some consideration will be given tO' the methods generallv adopted for 

 combating the disease and an effort made to show the reasoning on which 

 they are based. Summed up the measures may be described as starving 

 the fungus, which is achieved as follows: — 

 (i) Avoiding wheat after w-heat. 



(2) Burning badly-affected stubble. 



(3) Early fallowing with thorough working after rain. 



(4) Replacing wheat with some crop, such as oats, not liable to 



the disease. 



The Value of Early well- worked Fallow. 



Of late years the practice of taking off only one wheat crop every 

 three vears has become fairly general in the Northern districts, the stubble 

 being allowed to stand after harvest, such feed as. may spring up serv- 

 ing as pasture. In the second winter or spring succeeding the 

 wheat crop, the land is fallowed and in the following autumn wheat 

 is again sown. This year take-all has been worse than in any 

 year since 1903 when, the first wet season after the drought was ex- 

 perienced. Bearing in mind the frequent practice of one wheat crop 

 in three vears we find that many of the paddocks in which take-all was 

 so bad this year were seriously affected in 1903. Taking such a paddock 

 to illustrate our argument the conclusion is obvious that the fungus has 

 bv some means survived in that land for three years, for we are certain 

 it is not carried by the seed. What we have to find out is, Ho'W has it 

 survived ? We have a few facts to guide us in seeking an answer to this 

 question but must depend largely on conjecture. We may dismiss at 

 once the possibility that any of the spores produced on the wheat stubble 

 of 1903 have survived till the autumn of 1906 and then infected the 

 newVy-sown wheat-, for the remains of that crop, stubble, fungus, and all, 

 must long since have been merged into the general substance of the soil. 

 Of course during the year the paddock was in grass there must have been 

 a number of self-sown wheat plants many of which would be diseased. 

 These would give us, on their dead remains, spores in the autumn of 1905, 

 capable of attacking wheat but there is no likelihood that there were anv 

 Ihnng w^ieat plants in the paddock during 1905 for these spores to 

 attack, so that unless the fungus was able to grow on some plants other 

 than wheat it would be starved out, hence we should expect a year in grass 



