1918] DISEASES OF PLANTS. 455 



Brown spot of Emperor mandarins, G. P. Darnell-Smith (Agr. Gaz. N. S. 

 Wales, 28 {1911), No. 3, pp. 190-196) .—The present article describes in greater 

 detail the experiments (E. S. R., 37, p. 352) conducted during tiie last two years 

 in connection with control of brown spot of the Emperor mandarin due to 

 Colletotrichum glo^osporioides. 



The first essential is destruction of diseased wood. An excellent spray is 

 Bordeaux mixture, which is not injurious at a strength of 6: 4: 50, though half 

 this strength is sufficient after the disease has been brought under control. 

 Early spraying is very essential, but very frequent spraying apparently tends 

 to increa.'^e the red scale. 



Walnut blight in the eastern United States, S. M. McMukran (U, S. Dept. 

 Agr. BuL 611 {1917). pp. 7, pis. 2).— According to the author, walnut blight, or 

 bacteriosis, which has proved very destructive on the Pacific coast, is known 

 to occur in Louisiana, the District of Columbia, Maryland, Delaware, Penn- 

 sylvania, and New York. 



Studies of the organism causing the disease, made in the summer of 1916, 

 gave results similar to those described from California. Based on the single 

 season's observation, the author reports that late infections are the rule. If 

 this condition .should generally hold true, it con.stitutes a striking difference 

 between the di.sease in the Middle Atlantic States and that on the Pacific 

 coast. 



As the results of spraying experiments for the control of the disease in Cali- 

 fornia have not been satisfactory, the author recommends testing and devel- 

 oping resistant varieties. 



Narcissus disease, J. K. Ramsbottom {Gard. Chron., 3. ser., 61 {1917), Nos. 

 1586, p. 207; 1587, pp. 217, 218; 1588. pp. 226, 227).— This is a report of a re- 

 cent study carried out at Wisley on a disease of narcissus which has been 

 attributed to a Fusarium, but is now definitely stated to be due to the nema- 

 tode Tyleiichiis devastatrix. Field observations show that the disease may 

 appear first in the neck of the bulb, the leaves at and below the soil surface 

 decaying and falling over without showing the twisted growth characteristic 

 of a diseased bulb. The nem;itode is an active parasite, but has not been shown 

 to pass from bulb to bulb in storage. The organism has been found in both 

 mature and immature carpels. It may pass from the diseased parent bulb 

 to the offset by way of the basal plate, or vice versa. Fusarium is thought 

 to play but a small part in the production of the disease phenomena observed 

 in this connection. Discussion of preventive and remedial measures includes 

 rotation, trenching, trap plants, heat, formalin, and lime-sulphur. 



The place of origin of this disease is not known. 



Narcissus disease, J. K. Ramsbottom {Gard. Chron., 3. ser., 61 {1917), 2Vo. 

 1586, p. 20.'i). — This is a summary of the work above noted, with mention of 

 other studies on eel-worm or nematode disease of narcissus. 



Oidium quercinum on chestnut, A. Trotter {Alpc [ItaJy], 2. ser., 3 {1916), 

 No. 2, pp. -'{9-53; ahs. in Internal. Inst. Agr. [Rome], Internat. Rev. Sci. and 

 Pract. Agr., 7 {1916), No. 5, pp. 758, 759). — The author notes the occurrence of 

 the oak Oidium (0. quercinum) on chestnut, as previously mentioned by Far- 

 neti (E. S. R., 24. p. 652). In the case now recorded the attack occurred on 

 sprouts growing from stumps of trees cut out of season. This attack may 

 have been conditioned, it is thought, by weakness of the host plants due to the 

 late cutting (not earlier than August 1), the altitude, and the fact that the 

 fungus was then in or near its most actively reproductive stage. 



An epidemic of Cronartium comptoniae at the Roscommon State nurseries, 

 C. H. Kauffman and E. B. Mains {Rpt. Mich. Acad. Sci., 17 {1915), pp. 188. 



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