54 BXPEEIMENT STATION RECORD. 



sion of tlie work and conclusions reported by Lamouroux (E. S. R., 30, p. 24G) 

 regarding treatment of grape stocks witli coal tar for court-noue. 



Spots characteristic of dowiiy mildew, L. Ravaz {Prog. Agr. et Vit. {Ed. 

 VEst-Centre) , 35 {19U), No. 5, p. Ul, pl- i).— Both the yellow or so-called oil 

 spots (often the first indication of the mildew) and the whitish patches (usu- 

 ally seen only on the lower surfaces of the leaves) are shown in natural color. 

 A later discussion of the significance of each is promised. 



Does Cronartium ribicola overwinter on the currant? F. C. Stewart and 

 W. H. Rankin {New York State Sta. Bui. 37^ {19U), pp. 41-53, pis. 3, fig. 1; 

 ais. in Phytopathology, 4 {1914), No. 1, p. ^.3). — The occurrence of this fungus 

 on currants at the New York State Station for several years led to the suspicion 

 that possibly the fungus might winter-over on the black currant. A large num- 

 ber of black currant plants thoroughly infested with Cronartium were divided 

 into six lots and sent to widely separated experiment stations for observation. 

 No Cronartium was to be found on the new leaves and attempts at inoculation 

 by means of infected leaves wintered in wire cages out of doors also failed. It 

 is concluded that C rilncola rarely if ever overwinters on currants. 



In the same connection the authors report the finding of two 15-year-old white 

 pines affected with Peridermium strobi in May, 1913. These trees have been 

 destroyed so as to prevent the further spread of the disease. 



Do dormant currant plants carry pine rust? F. H. Hall {New York State 

 Sta. Bui. 214 (1914), popular ed., pp. 4, fig. 1). — A popular edition of the above. 



A disease of agaves, I. H. Buekill {Gard. Bui. Straits Settlements, 1 {1913), 

 No. 6, pp. 193, 194). — The author reports a disease of agaves in Singapore due 

 to a fungus attacking the mature leaves on the upper surface, rendering them 

 useless for the extraction of fiber. The attack, which is briefly described, is 

 said to resemble in some respects that of a CoUetotrichum, while the spores 

 i-esemble those of a Coryneum. 



Cutting and burning the leaves as soon as the disease is noted is recom- 

 mended. 



Cacao canker, J. Kuyper {Dept. Landh. Suriname Bui. 31 {1913), pp. 29- 

 3S). — The author reports studies on cacao canker pursuant to the work of 

 Rorer (E. S. R., 23, p. 748), Fetch (E. S. R., 2."., p. 46), and Rutgers (E. S. R., 

 29, p. 248), in which all the stem and fruit infections made by him with a 

 fungus claimed to be Phytophthora faheri produced effects characteristic of 

 cacao canker, the control showing no such results. He has not yet succeeded in 

 isolating this fungus from these lesions. 



Citrus canker, H. E. Stevens {Florida Sta. Bui. 122 {1914), PP- 111-118, 

 figs. 4). — A preliminary account is given of a new citrus disease which was 

 first observed in the fall of 1912 and again in the spring of 1913, when leaves 

 and twigs of grapefruit were found badly infected. 



The disease in general has the same appearance on leaves, fruit, and twigs. 

 It appears in small circular spots from one-sixteenth to one-fourth of an inch 

 across, occurring either singly or several together. The spots are raised above 

 the surrounding tissue, are light brown in color, and are composed of a spongy 

 mass of dead cells covered by a thin white or gray membrane, which finally 

 ruptures and turns outward forming a ragged margin around the spot. On 

 the older twigs pronounced cankers are formed. 



The disease at first was thought to be an unusual manifestation of scab, 

 scaly bark, or possibly anthracnose, but it was found to differ materially from 

 any of these. The organism causing it has not yet been determined, but it is 

 probably due to some fungus. A number of species of fungi have been found 

 associated with the spots and some of these are under investigation. The 

 disease appears to be confined mainly to the grapefruit, the sweet orange 



