150 INSECTS AFFECTING VEGETATION 



some caterpillar about two inches long, when fully grown. It is vel- 

 vety black on the back and has two bright yellow stripes along the 

 sides, which are connected by a series of irregular yellow lines on a 

 black ground-color; the head and feet are reddish. These strikingly 

 contrasting colors render the caterpillar a conspicuous object on the 

 green foliage that it feeds upon, and make it an easy task to pick 

 them off by hand. There are two broods in the year, the moths, 

 which are dull reddish-brown with white underwings, appearing in 

 May and August. The young caterpillars when first hatched feed 

 in colonies and devour the green substance of the leaves, thus pro- 

 ducing white blotches on the foliage and rendering their presence 

 easily noticeable. Should they be too numerous to be destroyed by 

 hand picking, resort may be had to Pyrethrum powder applied as 

 mentioned above, or to white hellebore which may be dusted on the 

 leaves or sprinkled by mixing one ounce in two gallons of warm 

 water, stirring from time to time to prevent the powder from settling 

 at the bottom of the watering can. 



Cabbage Plusia. A pale green caterpillar, with whitish lines 

 running lengthwise of the body, may sometimes be found devouring 

 the leaves of cabbages, lettuce and other vegetables, feeding usually 

 on the under side of the foliage. It is called a semi-looper from its 

 raising the middle of the body when walking, owing to the absence 

 of some of the usual prolegs. In the early part 'of the season they 

 may be got rid of by dusting with a mixture of one pound of Paris 

 green in twenty pounds of lime, applying the powder to the under 

 side of the leaves. A liquid spray may also be used of the ordinary 

 composition. 



Diamond-Back Moth. This is from time to time a serious pest, 

 as its caterpillars appear in large numbers and devour the foliage of 

 cabbages, turnips and other cruciferous plants. These worms are 

 much smaller than those of the preceding species ; are green in color 

 and remarkably active when disturbed ; they will then wriggle about 

 in a violent manner and drop to the ground by a silken thread from 

 the leaf on which they are feeding. As they devour all the green 

 substance of the foliage the plant attacked soon withers and dies. 

 There are usually two broods in the year, the first set of caterpillars 

 appearing at the beginning of July, and the second towards the end 

 of the summer; in favorable seasons there may even be a third. The 

 winter is spent in the pupal stage, the lace-like cocoon enclosing the 

 chrysalis being attached to the under side of the leaves. The moth 

 is a beautiful little creature, dark or 'ashen gray in color, with a 

 series of white marks on the forewings which form, when the wings 

 are closed, a row of diamond-shaped markings down the middle of 

 the back; from this characteristic the moth receives its name. 



The remedy that seems most effective is spraying the under- 

 side of the leaves wherever attacked with kerosene emulsion, at the 

 same time applying fertilizers, such as nitrate of soda, to induce a 

 vigorous growth. As a preventive measure all remains of stalks and 

 foliage, after the crop has been taken in, should be destroyed in 

 order to get rid of the wintering chrysalis. Though the insect is an 



