7 2 Second Report on Economic Zoology . 
Natural Enemies. 
I have never come across a single natural enemy of this pest in 
England, but Dr. Carpenter records a small insect belonging to the 
Gall Elies (. Euccela ) as having been reared from cabbage maggots 
found in County Down some years ago. Slingerland refers to 
Euccela anthomyise working in a similar way in America and also 
to a small Eove Beetle (Aleochcira nitida ) preying upon them. This 
latter occurs commonly in dung, haystack refuse, etc., all over Great 
Britain, and may do the same good work, but has not been observed 
to do so. I have found several mites ( Acari ) in company with these 
maggots. 
Prevention and Treatment. 
This pest is undoubtedly worst where cabbage, etc., are grown 
year after year on the same land. When land becomes fouled by 
this pest it can to some extent be cleaned by the application of gas 
lime, but so uncertain is this substance in its action that it is 
scarcely advisable to recommend it. In some cases it works 
admirably, in others it is a complete failure. If it is used it must 
be allowed to stand on the land after being spread for at least a 
month. The quantity depends on the nature of the soil, but from 
3 to 6 cwts. to the acre may safely be used anywhere. 
It would be far better to deeply plough or dig two spits deep 
land that had been infested and grow no cabbage on it for two years, 
but some crop other than of a cruciferous nature. 
All cabbage stumps and other roots after an attack should be 
burnt. This is seldom done, and as many larvre pupate in the 
stalks which are left about in heaps, they can only tend to help 
forward the advances of the pest. 
Broadcasting soot and lime after planting out has met with some 
success, but I have seen fields and gardens badly attacked later in 
the year when this has been done. A small amount of soot and lime 
may also be put in with the plants when dibbled out. In America 
a plan which is the best we have is being adopted by growers of 
“ discing ” the plants when they are set out. It is not very trouble- 
some, nor costly, and it is certainly very successful. It consists of 
placing discs of tarred paper or card around each plant. They can 
be cut out by machinery at little cost, and are so easily applied to 
the plant that no objection can be raised in regard to cost of extra 
labour. 
