CURRANT AND GOOSEBERRY INSECTS 345 



The Gooseberry Span-worm 

 Cymatophora ribearia Fitch 



Although generally distributed throughout the Atlantic 

 and Middle states and eastern Canada^ this measuring-worm 

 becomes troublesome only occasionally. It attacks gooseberry, 

 red and black currant and the blueberry. 



The eggs which have remained on the branches through the 

 winter hatch in May about the time the leaves become fully 

 expanded. The larvae are measuring-worms or loopers, whitish 

 in color with yellow stripes on the back and sides and conspicu- 

 ously marked with numerous black spots of various sizes. 

 They begin feeding on the tips of the leaves, and, if numerous, 

 soon strip the bush and sometimes attack the tender branches. 

 When disturbed they let themselves down by a silken thread. 

 They become full-grown in three or four weeks and are then an 

 inch or less in length ; they leave the bush, enter the ground a 

 short distance and transform to a nearly black pupa about -^ 

 inch in length. The moths emerge in about two weeks, the 

 last of June in New York, and deposit their small, beautifully 

 sculptured, elongate oval, dull yellowish-gray eggs on the bark 

 of the branches more often near the base of the plant. The 

 eggs do not hatch till the following spring, there being but one 

 generation a year. The female moth has an expanse of over 

 an inch, is of a pale yellow color and has the fore wings crossed 

 by two irregular interrupted bands of brownish ; the outer 

 band continues across the hind wing. In the male the yellow 

 is darker and the markings more distinct. 



Hellebore has not been found effective against this pest, but 

 4 pounds arsenate of lead, or 1 pound Paris green in 100 gallons 

 of water may be used effectively while the larvae are small. 

 When nearly full-grown they are not easily poisoned, and re- 

 course must be had to the more tedious and expensive operation 

 of hand-picking. 



