152 INSECTS AFFECTING VEGETATION 



duck's back. Furthermore, it is very difficult to reach them when 

 under the foliage. In order to overcome this last difficulty, we have 

 used a short extension, about three and one-half feet long, with a 

 Vermorel nozzle set at right angles to the extension. This makes it 

 easy to reach the underside of the leaves and by simply turning the 

 extension in the hand, one can spray downward on the head of the 

 cabbage. 



The best sprays for the lice that we have been able to find are 

 tak-a-nap soap, used at the rate of one pound to four gallons of 

 water, and Pyrethro-kerosene-emulsion made with whale-oil soap. 

 This is diluted ten times. Both of these sprays killed apparently 

 all the lice that were hit. The difficulty of hitting all the lice with 

 a spray can be appreciated only by those who have made the at- 

 tempt. (Bui. 233, Mich. Agr. Exp. Sta.) 



The Harlequin Cabbage-Bug.* The insects thus far mentioned 

 as attacking cabbage do their injury by devouring the leaves. This 

 one feeds in an entirely different manner, being provided with a 

 beak with which it punctures and abstracts the sap. The effect of 

 the puncture appears to be somewhat like that of the tarnished 

 plant-bug. The leaves wither and turn brown as if scalded. It is 

 very destructive at times, killing in this way the greater part of the 

 plants in a field. 



It is a glossy, flattish insect, about % inch long and nearly ^4 

 inch in greatest width. The general color is black, and the mark- 

 ings are of an orange, or reddish yellow. The wings are ample, and 

 ordinarily lie flat on the back, with the plain black tips overlapping. 

 The young differ chiefly in lacking the wings. They feed at all 

 times after hatching from the egg. 



The calico-back, as it is sometimes called, places its relatively 

 large eggs in two rows, side by side, on the leaves. They are some- 

 what barrel-shaped, each with a dark band about the upper end, 

 and a faint line and dot near the attached extremity. These marks 

 vary a great deal however, and may be wanting, w r hile often ex- 

 tensive blotches appear. When the young hatch they push up a 

 round lid-like piece at the free end of the egg. (Bui. 114, Ky. Agr. 

 Exp. Sta.) 



The adult spends the winter among rubbish in gardens and 

 fields, and comes out very early in the spring to feed on the first 

 plants of the cabbage family to appear. Several broods develop dur- 

 ing the season. Within the cabbage family, it seems to have no 

 preferences. Among other plants, it is known to feed on peas, 

 grapes, and even corn, at times. 



Coal oil in emulsion is about the only thing that can be recom- 

 mended for such insects, since it is necessary to kill them by means 

 of a contact insecticide, except the use of the gasoline torch. Owing 

 to the disposition of the insect to hide among the leaves where it 

 cannot readily be reached with sprays, it is not easy to get rid of. 

 One of the best remedies is the sowing of some trap crop before the 

 regular sowing, then when the bugs have been drawn to it, plants 

 and bugs can be destroyed with hot water, oil, or fire. 



'See page 411, for illustration 



