New Yorx AGRICULTURAL EXPERIMENT Station. 199 
CURRANT DISEASES. 
LEAF SPOT. 
The fungi which cause leaf spot of currants in the Hudson 
Valley are Septoria ribis Desm., Cercospora angulata Wint., and 
Gloeosporium ribis (Lib.) Mont. & Desm. During the season of 
1899 none of these did any damage worth mentioning. Only 
traces of fungous leaf spot were found in a few localities. Experi- 
ments by Pammel,™ Goff,* and others have shown that at least 
the first two and most common of these fungous leaf spot diseases 
can be controlled by spraying with Bordeaux mixture. How- 
ever, at various times complaints have been received that spraying 
does not prevent currant leaf spot. 
The observations in the Hudson Valley throw some light on the 
cause of these failures. One of the best informed fruit growers in 
Columbia County called our attention to a bad case of currant 
leaf spot which he had tried in vain to prevent by spraying with 
Bordeaux mixture. Several thousand currant cuttings had been 
sprayed with Bordeaux during the first week in May and again 
about two weeks later. In spite of this treatment the plants 
were severely attacked during the last week in May by a dis- 
ease which the owner did not doubt was the fungous leaf spot 
said to be amenable to treatment. An examination of the 
affected plants revealed the fact that the trouble was entirely the 
work of the four-lined leaf-bug,” Poecilocapsus lineatus. The 
leaves were thickly covered with small, reddish-brown, angular 
spots. In the early stage the spots were black and water soaked 
in appearance, but they soon became brown, dry and transparent. 
(See Plate XVI, fig. 1.) The epidermis, on both sides of the leaf, 
was depressed, but no gnawing of the tissue was evident. The 
insect thrusts its beak into the leaf and sucks out the juices. 
17 Pammel, L. H. Iowa Agr. Exp. Sta. Bul. 13: 45-46; Bul. 17: 419-421; 
Bul. 20: 716-718; Bul. 30: 289-291. 
18 Goff, E. S. Wis. Agr. Exp. Sta. Bul. 72: 30. 
19 For an account of the habits, life history, etc., of this insect, see Cornell 
Agr. Exp. Sta. Bul. 58. O. 1893. 
