INSEGT8 INJURIOUS TO AGRICULTURE. 205 



while the stalks are sometimes tunnelled by the grub of a 

 weevil (Baridius trinotatus Say), as well as the caterpillar 

 of Gortyna nitela. 



Injuring the Cabbage, Radish, etc. 



The European Cabbage-butterfly (Pieris rapes Schrank). 

 Feeding not only on the outer leaves, but boring into IL 

 heads in all directions, a green, velvety caterpillar with a 

 yellowish stripe along the back and side, and turning into 

 a white butterfly with four (male) or six (female) conspicu- 

 ous black spots. There are two broods of worms, the insect 

 wintering as a chrysalis. It is held in check by a Chalcid 

 parasite (Pteromalus puparum Linn.). 



REMEDIES. Destroy the butterflies by capturing them with a hand- 

 net; trap the chrysalids by placing boards slightly raised from the 

 ground, under which the caterpillars may pupate; also sift over the 

 cabbage-heads a powder composed of one part of pyrethrurn diluted 

 with twenty parts of Hour, or sprinkle a saturated infusion of pyrethrum 

 on the plants. Excellent remedies are applications of hot water, or a 

 solution of one pound of whale-oil soap dissolved in about six gallons 

 of water, or strong tar-water. 



The Cabbage Plusia (Plusia brassicce Eiley). In August 

 and September, gnawing large, irregular holes in the leaves; 

 a rather large, pale-green 

 caterpillar, marked with 

 still paler, more opaque 

 lines, and with three 

 pairs of abdominal feet, 

 being a semilooper, and 

 changing to a grayish- 

 brown moth, whose 

 wings are adorned with 

 a distinct silver mark 

 of interrogation. The 

 moth lays her eggs singly e - eggs. After Riiey. 



or in small clusters on either side of the leaf, the young 

 worms feeding first on the outside leaves, afterwards boring 

 9- short distance into the heads. There are four broods a 



FIG. 218. Cabbage-bug:, a, b, nymphs; c, d, 



