13S Report of the Department of Botany of the 



no practical difference between the sprayed and unsprayed 

 plants." As far as they go, the results of this experiment are 

 unfavorable to the control of currant anthracnose by spraying. 



Currant growers in the Hudson Valley fully realize the impor- 

 tance of protecting their plants against the ravages of currant 

 worms^i which strip the bushes of their leaves in a surprisingly 

 short time. Of late years they have abandoned the use of helle- 

 bore, the standard remedy for currant worms, and substituted 

 for it Bordeaux mixture containing Paris green, green arsenoid 

 or some other arsenical poison. Promptly upon the first appear- 

 ance of the worms the bushes are given a thoiM3ugh spraying 

 with the poisoned Bordeaux mixture. If the work is well done, 

 and rains not too frequent, a single application suthces for the 

 season. Whereas, if hellebore is used it is usually necessary to 

 make two or more applications, because there are generally two 

 and sometimes three broods of worms during the season and the 



^^Two distinct species of currant worms occur in the Hudson Valley, 

 which not only differ in appearance but also in habits. The one generally 

 known as the currant span-worm, called gooseberry span-worm in some 

 sections (Diastictis ribearia), is single brooded; while the imported currant- 

 worm or currant saw-fly {Netnattis ventricostis), has two broods each year. 

 The larva of the first is a caterpillar. They appear early, sometimes 

 before the currant leaves are even fairly expanded. They grow rapidly 

 and feed voraciously. By the last of May or first of June they are full 

 grown and stop feeding. At this time they are about one inch long, of 

 a bright yellow color, marked with white lines on the sides together with 

 numerous black spots and dots. They can also be distinguished from the 

 imported currant-worm by their habit of looping the body when they 

 travel. These worms leave the bushes about the first of June and go into 

 the ground where they change to the chrysalis form. Early in July they 

 issue as adult moths or millers and can be seen flying over the fields 

 during July and pai't of August. In color the adult moth is pale yellow 

 with dusky spots or bands on the wings. Seen at a distance it could 

 easily be mistaken for the butterfly of the cabbage-worm flying over the 

 currant fields. The eggs are deposited on the branches of the currants 

 and do no-t hatch until the following spring. 



The imported currant-worm is the slug-like catei-pillar of a saw-fly. 

 The flies appear about the time the span-wonn hatches from the egg. 

 They pair first, then lay their eggs ui>on the underside of the currant 

 leaves, usually along the larger veins. The eggs hatch a week or ten 

 days after being deposited. Owing to the time required for laying and 

 hatching the eggs, the worms do not appear until one or two weeks after 

 the span-worm has commenced feeding. The larvoe of the saw-fly reach 



