CULTURAL DIRECTIONS 285 
upper surfaces. To accomplish this thoroughly seems 
almost impossible with a power machine. 
365. The imported cabbage worm (Pontia rapac) is 
generally recognized to be the most important insect 
enemy of cabbage and several closely related crops. The 
pest was first seen in North America in i860 at Quebec, 
five years later in Maine. Now it is distributed through- 
out the United States. The butterfly is familiar to all 
garden makers. It is white, with a wing expanse of 
nearly 2 inches. There are two conspicuous black spots 
on each fore-wing of the female and only one on the 
fore-wings of the male. The full grown larva is over an 
inch long. It is nearly green and finely dotted with small 
black spots. A faint yellow stripe marks the middle 
of the back with a row of yellow spots on each side in 
line wiih the spiracles. The pale yellowish eggs are de- 
posited singly, and usually on the underside of the leaves. 
The butterflies appear early in spring, and in a few 
days begin laying eggs, which hatch in four to eight days, 
the larvie attaining full maturity in from ten days to two 
weeks. The chrysalis stage during the summer months 
lasts from one to two weeks. The insect also passes the 
winter in the chrysalis form. There are three broods 
in the North in one season. 
Several natural enemies of this pest assist the grower 
in controlling it, but it is often necessary to use insecti- 
cides. All points considered, arsenate of lead is proba- 
bly the most effective poison in destroying cabbage 
worms. Other remedies are hot water, kerosene emul- 
sion, and pyrethrum. 
366. Other insect enemies. — The southern cabbage 
butterfly (Pontia protodicc), the cross-striped cabbage 
worm (Evergestis rimosalis), the common cabbage looper 
(Antograplm brassicac), the imported cabbage web-worm, 
the harlequin cabbage bug (Mnrgantia histrionica), cut- 
worms. flea-beetles and leaf-beetles. 
