14 FARMERS’ BULLETIN 766. 
Tt was introduced from Europe and has been known in the United 
States since 1865. It has become a most serious drawback to the 
cultivation of cabbage, cauliflower, turnip, and related crops in this 
country. 
The first generation is produced on wild cruciferous plants, and the 
second attacks crop plants. It is capable in the warmest weather of 
developing from egg to adult or butterfly in 22 days. Even in its 
northernmost range it is triple-brooded, and southward there may be 
as many as six distinct generations. 
Two natural enemies contribute considerably to the decrease of 
this species, otherwise it would be a pest of still greater severity. 
The best remedies are the arsenicals, of which arsenate of lead and 
Paris green are the most efficient; the former, being cheaper at the 
present time, is recommended at the rate of 2 pounds in powder form 
or 4 pounds in paste form to 50 gallons of water. Adhesiveness is 
enhanced by the addition of about the same amount by weight of 
crude resin soap or resin-fishoil soap. 
The best form of spraying machinery should be used, with special 
attention to nozzles in order to secure a mist-like spray. 
The arsenicals are harmless when properly applied as directed. 
In addition to the persistent use of arsenicals, clean farming should 
be pursued in cooperation with neighboring cabbage growers to obtain 
the best results. 
It is advisable to encourage the parasites above-mentioned accord- 
ing to the directions given. 
Finally, cooperation in the use of arsenate of lead as a spray and in 
maintaining clean farming and other methods is highly desirable in 
all communities. If this could be practiced on an experimental scale 
under proper supervision the results would soon be apparent. It 
must be kept up year after year, however, owing to the constant 
migration and invasion of this cabbage worm from other sources. 
