9 
damage, were noted. In the present paper the results of the 
investigations on Canker are recorded, as well as observations on 
the other diseases. 
CANKER. 
That a certain number of parsnip roots in all parts of England 
are annually disfigured through surface-injuries on the shoulder 
is common knowledge, and that in some cases serious decay 
follows is also well known. In certain localities this decay, 
which occurs in late summer and autumn, is very prevalent, and 
is termed “Canker”’ or “‘ Rust.’’ The name is loosely used 
and the trouble not easy to define; it has apparently never been 
specially investigated. The brownish-coloured rot shown by 
affected specimens is not a characteristic symptom, but is common 
to other types of injury, being due largely to the oxidation of 
substances in the mucilage present in the parsnip root. The 
term ‘‘ canker’’ as used by growers implies a-more or less open 
wound, at first brownish-red in colour, which affects the shoulde 
or upper part of the root, and frequently leads in bad cases to 
the destruction of the entire root (see plate iii). 
Damage in 1913 crop.—tThe trouble reported from Worcester- 
shire at first seemed to be of a more definite nature, the roots 
but was not found to agree satisfactorily with any described 
species of that genus. It was subsequently ascertained that this 
black rot was a special form of decay, and that canker was not 
associated with any particular fungus, but arose from a surface 
wound, which, invaded by various kinds of micro-organtsms, 
rapidly led to the destruction of the root-tissues. 
In the Evesham district it was estimated that 10 per cent. of 
the entire crop was lost through canker, and this, judging from 
figures supplied by Messrs. Yates, would amount to a loss of 
370 tons of roots from seed supplied by their Evesham branch 
alone. In certain fields the loss was very severe; 50 per cent. 
of the crop in more than one case was stated to have been ren- 
dered unsaleable. 
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