DISEASES AFFECTING MANGOLD. 445 



Payen found that the tissues in the upper portion of the 

 root were changed in colour, and had become more or less 

 disorganized, and that these were rapidly carrying the 

 disease downwards into the body of the root. The 

 appearance of the diseased tissues was very similar to that 

 which occurs in the potato murrain. The disease was 

 noticed to progress much more rapidly when the roots 

 were stored together than when they were kept separate 

 and with access to the air. On testing the juice of the 

 diseased portions, it gave an alkaline instead of acid 

 reaction; the sugar had entirely disappeared, and that 

 which remained in the sound portion of the root was 

 materially changed, and rendered quite unfit for the 

 ordinary manufacturing purposes. 



The disease appears to be clue to the influence of a 

 parasitic fungus a species of Botrytis which attacked 

 the leaves, causing them to wither, whence the disease 

 was carried by the spiral vessels of the leaves to the root, 

 where its presence was first indicated by the appearance 

 on the surface of small violet-coloured spots tinged with 

 red. The skin soon became disorganized, and the spots 

 assumed a blackish hue, penetrating the tissues, and thus 

 spreading the disease through the neighbouring parts. 



As the disease appears to be conveyed through the leaves 

 to the root, the latter may be preserved from injury by 

 separating the top directly it is observed to wither. This 

 practice has been followed in the sugar-making districts ; 

 and as the root contains at the mid-period of its growth a 

 larger percentage of sugar than when more fully developed, 

 the loss occasioned by the disease is materially diminished. 

 In this country, where mangold is grown only for feeding 

 purposes, this remedy would not be so available, as its bulk 

 and consequent nutritive value at that period would be 

 much less than at the usual harvest time. The breadth of 

 mangold is increasing with us every year, and with its in- 



