32 Mr. Henry Le Keux on the Turnip Fly. 
perhaps a much weaker solution and a simple immersion without 
permitting them to remain in it any time, would be sufficient to 
render the seed unpalatable to the insect without injuring its vege- 
tating properties. The ant also injures the young plant, but in a 
small degree proportionate to the other two insects. 
The appearance of an injured plant will enable any one examin- 
ing it to decide whether it has been caused by the fly, the ant, or 
the wire-worm. The fly begins by eating a round hole, wide at top, 
and gradually diminishing to the bottom, until the leaf is perforated, 
when it sometimes continues to enlarge the aperture until its appe- 
tite is satisfied. The large holes observed in the leaves were made 
in their early state, and have enlarged with the growth of the leaf. 
The ant does not eat the leaf, but punctures it with its mandibles, 
and then sucking out the juices, produces yellow withered looking 
spots on the spring leaf, which destroys it. The wire-worm begins 
on the edge of the leaf, and eats it away like a caterpillar, and 
often cuts the leaf off at the top of the stalk, and it may sometimes 
be found on the ground half-devoured. One wire-worm will con- 
sume about as much as five or six flies could do in the same time. 
The grub is also a very formidable assailant in the more ad- 
vanced state of the plant, near to which it forms a round hole in a 
vertical direction (in appearance like that of an earth-worm, but 
open at the top) about two or three inches deep in the earth. At 
the bottom of this it remains during the day, (unless it be dark and 
moist,) and at night emerges from its burrow, and commences an 
attack upon the plant by eating round the neck of it, and eventually 
detaching the upper part from the root, or a single leaf is eaten 
through at the stem, and when fallen on the ground the nearest 
edge is dragged to the burrow, where it is drawn in and devoured 
during the day. Last year (1836) the turnips sown on the south 
side of a hill having entirely failed, it was ploughed in furrows, 
and each filled with yard dung, and the earth turned over it by the 
plough ; and on the first rainy day a number of young plants of 
the Swedish turnip (thinned out from a patch in a moist situation 
on the north side) were planted on the ridges eighteen inches 
asunder, and very soon grew remarkably strong and healthy ; but 
after the few straggling plants, in the part left unploughed, had 
been destroyed by the grub, then those at the extreme ends of the 
ridges began to disappear, and plant after plant followed from the 
same cause, until very few were left. Having noticed one fine 
plant at a distance of six or seven yards from any other, and that a 
grub had just formed his burrow and begun to attack it, I dissolved 
