DISEASES OF PLANTS. 851 



organism, CoUetotrichum agaves, which is shown to be a wound i>;irasi(c on 

 the sisal plant in British Guiana since 1!)0S or earlier. 



The disease affects first the older leaves, frequently near the tips, spreading 

 to young leaves and finally to all parts of the plant and to neighboring plants, 

 and causing the appearance of yellow patches. 



Careful supervision with immediate destruction of affected leaves and the 

 application of such fungicides as Bordeaux mixture are suggested. 



Leaf spot disease of sisal in German East Africa, K. Braun {Pflanzcr, 10 

 {1911,) No. J,, PI). lSS-191, pi. 1; abs in Intcniat. Just. Agr. [Rome], Mo. Bui. 

 Agr. Intel, and Plant Diseases, 5 (1914), No. 8, p. 1085).— A leaf spot disease 

 of sisal, which has been noted previously (E. S. R., 20, p. 155), was more than 

 usually noticeable in 1913. Investigations have shown that this appearance, 

 which is described, may be produced experimentally by even short exposures 

 to temperatures which frequently occur in this region in sunuuer. It is not 

 known whether other unfavorable factors may not increase the susceptibility 

 of the plant in this respect. 



Occurrence of the bacterial disease of Sudan grass in the Salt Lake Valley, 

 Utah, P. J. O'Gaea (Science, n. set:, 42 (,1915), No. 1079, pp. 314, 315).— It is 

 claimed that a bacterial disease of Sudan grass has been recently observed in 

 Utah. The specimens exhibited elongated reddish-brown blotches on the leaves, 

 many of the lower leaves being entirely dead. On the under surface of the 

 spots were found characteristic reddish crusts or scabs consisting of dry bac- 

 terial ooze, which had come from the interior of the leaves. An examination 

 showed the presence of bacteria, and the author thinks there is little doubt 

 that the disease is due to the broom corn bacterial organism {liacillus sorghi) 

 first studied by Burrill, whose conclusions were later confirmed by Kellerman 

 and Swingle.<^ 



Diseases and enemies of sugar beets and alternating crops in Bohemia, 

 H. UzEL (Ztschr. Zuckerindus. Bolimen, 38 (1914), No. 11, pp. 571-578).— This is 

 a condensed report, dealing with nematodes and other animal parasites of sugar 

 beets, with the leaf fungi Sporidesmium putrcfaciens, PhijUosticta beta', and 

 Cercospora beticola, and with such bacteria as those causing root rot and scab. 



As regards alternating crops notes are given of Tilletia tritici on wheat, 

 Urocystis oceiclta on rye, Ustilago jensenii on barley, and Phytophthora in- 

 festans on potato. 



Control of beet nematodes, H. C. Mtjlleb and E. Molz (Ztschr. Ver. Deut. 

 Zuckerindus., No. 707, 1914, IT, pp. 959-1050, figs. 3).— This is an account of 

 studies bearing upon the control of Heterodera schachtii in relation to sugar 

 beets, including experiments with chemical, physical, and other means. 



Both potassium carbonate and sodium carbonate seemed to favor an in- 

 creased nematode attack. Results were not favorable to the use of sulphur 

 or sodium chlorid. Carbon bisulphid at 3 cm. depth in the soil gave better 

 results than at 20 cm. Formaldehyde gave as good results with employment 

 of a smaller quantity. Allyl alcohol was effective whether used pure or di- 

 luted with water. Several other treatments increased more or less the severity 

 of attack. A modification of the Kiihn method of trap plants is recommende<l. 



Nematodes were found in the greatest numbers at 10 to 20 cm. below the 

 surface, few or none being found at 50 to 60 cm. depth. The vertical or hori- 

 zontal distribution of nematodes introduced into sterile soil was comparatively 

 slow under experimental conditions. 



Sugar cane gummosis, J. Gkoenewege (Meded. Proefstat. Java-Suikcrindus., 

 5 (1915), No. 3, pp. 29-124, pis. 7; Arch. Suikerindus. Nedcrland. Indiij, 2S 



« U. S. Dept. Agr., Office Expt. Stas. Bui. 2, pt. 2, p. 34. 



