68 Second Report on Economic Zoology. 
but also radishes. In 1872 it did much harm to them in the Nether- 
lands ; it is also recorded as spoiling them in Great Britain and in 
North America (Slingerland). The larvae also live in turnips 
(Fig. 8, a) and swedes, and even in horse-radish. In some cases 
they have been recorded from beans, clover (Ormerod), etc., but in 
all such cases there has undoubtedly been some error in determina- 
tion ; for instance, the Bean Boot-maggot has been shown to be 
Pliorbict fusciceps , Zett. 
The Cabbage Boot-maggot confines its attention to Cruciferre 
alone, as far as all accurate information and records go (but one 
exception, viz., Dr. Lintner bred this pest from maggots mining the 
leaves of beetroots). This is an important point in dealing with 
the treatment of this pest. As would be imagined, Pliorbict brassiere 
does not confine itself to cultivated Cruciferse only, but attacks 
various wild kinds, as Shepherd’s Purse, Charlock, Jack-by*the- 
Hedge, Wall Mustard, etc. As an instance of its attacking orna- 
mental plants, the Stock (. Mathiola ) may be named. 
Although this insect is looked upon essentially as a cabbage pest, 
the damage it does to the turnip crop is often as great as that done to 
the cabbage. In 1901 swedes were badly injured in Tyrone and 
County Down, and in County Clare the turnip crop was so badly 
injured as to be, to a large extent, abandoned (‘Mourn. Dept. Agri- 
culture,” vol. iii. No. 1, p. 109, Dr. Carpenter, 1902). 
Miss Ormerod (“ Manual Inj. Insects,” p. 26, 1890) says the 
maggots are found in dung, but she gives no direct evidence ; none 
have been seen in dung, and under such circumstances such reports 
need confirmation before being accepted. I have tried to hatch these 
larvae when kept in rank manure, but in all cases they speedily died. 
That they have frequently been worse where the fields have been 
heavily manured is no proof that they come with the manure. 
Methods of Maggot Attack. 
The larvae of the Cabbage Boot Fly, as the name implies, mainly 
live in the roots of plants, but this, as will be pointed out later, is 
not invariably the rule. 
The first invasion is often upon the seedling plants before they are 
set out ; in such cases the maggots simply gnaw the young roots, and 
the plants are killed right away. But usually it is not until the 
plants are set out that the pest commences its ravages. After feeding 
pro tern, on the surface of the roots they gnaw their way into the 
substance of the roots and tunnel in all directions. The tunnels 
allow moisture to get into the root and soon cause decay. They will 
