110 
the water will have no effect on the maggots except to remove some 
of them, the hellebore may kill them all. 
For the prevention of maggot attack after transplcinting, prob- 
ably the most successful measure is the use of tarred-paper cards. 
Those ordinarily used are made of a thin grade of tarred felt-paper, 
and are about two and a half inches in diameter. They may be of 
any shape, but, as a matter of economy, are usually hexagonal, with 
a slit from one side to the center. The card is placed on the plant 
by separating the two edges of the slit and slipping the card around 
the plant so that the stem comes in the middle of the card. The card 
must then be pressed close to the stem and flat on the ground. This 
being done, the female fly must lay her eggs either on the card — 
where there is small chance of their hatching — or on the stem — and 
if the card is close to the stem the young larvse hatching from them 
W'ill be unable to reach the roots — or else on the ground beyond the 
card, in which case the young larvae, hatching so far from the plant. 
W'Ould probably be unable to reach it. 
A carbolic acid and lime mixture (see page 155) has been rec- 
ommended by others, but in our experience it proved w^orthless, the 
coat of lime cracking and leaving places for the deposit of eggs. 
After 24 hours the carbolic acid loses its value as a repellent. The 
mixture is applied along the rows with a sprinkling-can or sj^ray- 
nozzle as the plants are transplanted, and in such manner as to coat 
the entire surface thinly around the plants. 
Tobacco dust placed around the base of the i)lants has been 
found to prevent the female from depositing her eggs on or near 
them. 
When these maggots have once gained a foothold in a cabbage 
field it is difficult, if not impossible, to exterminate them. The only 
practical insecticides which have been recommended are the carbolic 
acid emulsion, a decoction of hellebore, and carbon bisulfid (see 
pages 153, 154 and 158), and these have given quite variable results. 
The carbon bisulfid has been used with success, but the expense of 
application prohibits its use in large commercial gardens. Helle- 
bore decoction has given us very good results. A third of a pint 
should be poured at the base of each plant when transplanted, and 
each week thereafter for three or four weeks. 
In using these insecticides it is necessary to make thoro appli- 
cation at the base of the plants before the maggots have had a 
chance to enter the root and protect themselves. 
The application of commercial fertilizers is of much value. 
They stimulate the plant and make it more resistant to maggot 
attacks. 
Clean farming and fall plowing aid in preventing maggot 
attack. 
