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larva are white or greenish maggots which mine the leaves 
of those plants. ‘There may be several larvae in a leaf and 
by their devouring the middle layers of tissues transparent 
patches result, covered only by the upper and lower 
epidermis. After a while these patches become brown and 
the functions of the leaves are very greatly reduced. The 
larve: turn into yellow or yellow-brown pupa shaped some- 
what like minute barrels, and are found sometimes in the 
leaves but mostly in the soil. The Insect winters in the 
pupa buried a few inches beneath the ground. This fact 
1s of value with regard to preventive measures and deep 
trenching in winter between the original rows and burying 
the soil therein containing the pupe will destroy many 
of the Flies which would otherwise emerge. The mixing 
of gas lime with the soil adds to the effectiveness of this 
measure. Screening the young plants with cheap muslin 
when first put out protects them from the Flies until they 
are well established, and less liable to suffer severely from 
the Insect. Picking off and burning the mined leaves will 
destroy the larva, but in bad attacks the depletion of the 
foliage by this method would be too great. All infected 
celery tops should be burnt and not cast aside on refuse 
heaps. heobald recommends spraying with nicotine; a 
useful formula is 4 0z. of 98 per cent. nicotine, and } Ib. of 
soft soap to 10 gallons of water. Various preparations of 
nicotine are obtainable and so long as the above propor- 
tions are maintained it matters very little which is used 
(15). It is best to spray in the evening and when the 
foliage is not too dry, the spray is said to soak through 
the epidermis and kill a large number of the larve. 
The Cabbage Root Fly (Chortophila brassicae) (7) is 
one of the worst pests of cabbage and cauliflowers, and 
may also attack radishes, turnips, swedes and _ stocks. 
Growth of the affected plant is checked, the leaves flag and 
discolour, the roots are largely destroyed, and the plants 
die. The Fly is an ashy-grey Insect not unlike the House 
Fly in general appearance and measures about jin. long. 
(he winter is passed through in the pupa stage and the 
first brood of Flies appear in April or the beginning of 
May and there are most probably three generations in a 
year. The eggs are visible to the naked eye, and are laid 
close to, or on the plant, usually just below the surface of 
the soil. The larve are typical Fly maggots, white or 
pale yellowish, and about }in. in length when mature. 
