678 
Natural Enemies 
The ladybird beetles, Hippodamia con- 
vergens, Megilia maculata and Coccinella 
californica, prey to some extent upon this 
pest. The real check, however, is the in- 
ternal parasite, Diaeretus californicus 
Baker. 
EK. O. Essie 
Cabbage and Radish Maggot 
Phorbia brassicae Bauche 
A. L. Lovert 
This insect is considered a very serious 
pest throughout the Pacific Northwest, or 
wherever cabbages and radishes are 
grown. In the truck crop regions, where 
these crops are grown over considerable 
areas and for a period of years on the 
same soil, the pest is especially serious. 
Plants Attacked 
Besides attacking the cabbage and rad- 
ish, this maggot feeds on the turnip, caul- 
iflower, celery, rape, kale, and a variety 
of the closely allied Cruciferiae. It is 
also found about the roots of some of the 
wild plants of this group, including mus- 
tard and radish. 
Deseription 
The Larva—tit is as a larva that the 
cabbage maggot is injurious and hence 
best known to the grower. At this stage 
it is a footless grub or maggot (see Fig. 
1), waxy white or yellowish in color. The 
Ore EvSte 
Wig. 1. The Cabbage Maggot (Phorbia bras- 
secae), a, adult fly; b, got; ¢c, puparium; d, 
the egg (much enlarged). (Original ) 
body is cylindrical, ending bluntly be- 
hind and tapering to a point at the ce- 
phalic end. When mature, it measures 
about .82 of an inch in length. 
The Pupa-—The pupal or resting stage 
of the cabbage maggot is passed in the 
soil about the roots of the infested plant. 
Exceptions to this rule occur in the forms 
which assume the aerial habit and in the 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
few which pupate in their burrows in 
the root. The pupa consists of a small 
brown case or puparium some two-tenths 
of an inch in length, elliptical-ovate in 
form and without the ability to move. 
The Adult~—The adult insect varies 
considerably from the maggot that de- 
stroys the plant. It is a fly which ap- 
pears to the ordinary observer not 
unlike the common house fly. It is con- 
siderably smaller in size, however, and 
when at rest the wings extend a greater 
distance back of the abdomen and overlap 
‘more. 
The Egg is really very small, measur- 
ing only .04 of an inch in length. It 
is white, however, and by the keen 
observer may be readily seen lying on 
the soil close to the stem of the host 
plant. 
Life History 
This insect passes the winter as larvae 
and pupae in and about the roots of their 
hosts. Possibly some of them pass the 
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Fig. 2. The Cabbage Maggot. Root of wild 
mustard showing larvae, pupae and injury. 
