[harrison-sadlerJ a bacterial SOFT ROT OF TURNIPS 93 



Both Yellow Tankard (S.F.A.) and Bortf elder (Sv.) show only 0-7 

 per cent, diseased roots in the A series. In the B series, again, the 

 Yellow Tankard strain still has a comparatively low figure, or 2 • 1 per 

 cent, diseased roots, but the Bortfelder strain has been badly attacked 

 in this part of the field, showing 9-3 per cent, diseased roots. The B 

 plots in general suffered more from the disease than the A plots. 



Although all classes were more or less attacked in different parts 

 of the field, the figures seem to indicate that the long-shaped turnips 

 in general possess a slightly higher power of resistance than the globe- 

 shaped. This may perhaps be accounted for by the circumstance 

 that the relative proportion of 'true root' or primary root is higher in 

 the long-shaped turnips, whereas the 'hypocotyl' dominates in the globe- 

 shaped varieties. There is at least an indication that the hypocotyl 

 part of the root is less resistant against the disease than the true or 

 primary part of the root. Thus the lower part (the true or primary 

 root) of a long-shaped turnip which has been attacked by the soft 

 rot is still sound in many cases, but a globe-shaped turnip (mainly 

 consisting of hypocotyl) is generally entirely destroyed. 



The outside bast layer of the turnip withstands the attack fairly 

 w^ell, and instances were found when an outwardly sound root was 

 absolutely hollow inside of a thin layer of skin and bast. Another 

 feature worth mentioning is that the crown very often keeps green 

 even after the greater part of the inside root has been destroyed. 



The infection seems to spread from the pith of the root and often 

 starts from the middle of the hypocotyl. How the organisms gain 

 entrance to these deep tissues has not been demonstrated experiment- 

 ally. 



Whilst the rot appears in dry as well as wet years, the seasons 

 1910 and 1912, which may be described as wet years were characterised 

 by much soft rot. On a rough estimate, 40 per cent, of the turnips in 

 1910 were diseased. The conditions of the trial plots on the College 

 farm were similar to those found on farms throughout the country, 

 and we have received many reports of the prevalence and destructive- 

 ness of this rot from Quebec and Ontario. 



Signs of the Naturally Occurring Disease. 



Early manifestations of the disease are rare. In an advanced stage 

 the leaves wilt, hang down, dry and wither. The rotted material at 

 times breaks through the skin, giving rise to a very distinctive and 

 putrid smell. The natural turnip odour seems to be exaggerated to 

 offensiveness. In many cases the root looks sound on the outside, 

 and the crown of leaves is erect and healthy looking; but a smart tap 



