30 
Mr. Henry Le Keux on the Turnip Fly. 
with the ammonia broken into fragments about the size of a pea, but 
when the turnips began to show above ground, my disappointment 
was extreme, to find that the effluvia was destructive to the young 
plant if a bit was lying within an inch of it, and those plants which 
were not injuriously affected by it were attacked by the fly. Not- 
withstanding this remarkable failure, I still think that the antidote, 
if ever found, must be sought for in some effluvia or odour which 
may be either offensive to the insect when near, or so overpower 
the scent of the turnip as to prevent the fly from distinguishing 
and being attracted by it. Or it may perhaps be equally advan- 
tageous, to divert their attacks by a more attractive food, such as 
sowing the white stone turnip mixed with the Swedish turnip ; for I 
have invariably found where this has been done that the former are 
first attacked, and sometimes, indeed generally, nearly destroyed 
before the latter have been touched, and by that time have grown 
to such a size as not to be materially injured by them ; and in sea- 
sons when the fly has not been very numerous, the “ Swede” has 
not had a single puncture upon it, whilst every leaf of a white stone 
turnip, by the side of it, has been pierced full of holes. The last 
experiment which I tried had the appearance of being more suc- 
cessful than any of the preceding ones, but as it was made so late 
in the season, (the latter end of August,) and several days’ rain 
(the best protection) occurred at the most critical time, it can hardly 
be called a fair trial. Having sown a little piece (a yard square) 
with turnips on the hill, swarming with the fly, I poured over it 
(on the fourth day) a quart of a mixture composed of one once of 
tar, one once of olive-oil, and two ounces of strong caustic potash, 
well mixed together, and then shaken up with the requisite quan- 
tity of water. Not many of the seeds came up (probably from the 
lateness of the season), but those were of a healthy colour, and ac- 
quired the rough leaf without any of them being punctured by the 
fly, excepting a few on the windward side of the patch. 
This mixture formed no protection from the slug by which the 
plants were all soon eaten off. Having now left the county, I have 
no means of pursuing the inquiry, but I cannot help thinking this 
experiment would be worth repeating on a larger scale. 
I believe it is not generally known that the Wire- Worm and the 
Ant are both entitled to a considerable share of the odium usually 
cast upon the fly alone ; the latter, however, on account of the great 
devastation committed by it, is justly entitled to be considered as 
the most formidable enemy of the turnip crop. The wire-worm 
seldom feeds above ground in the day-time unless it be cloudy and 
dark ; at such times I have observed them devouring the young 
