240 EXPEKIMENT STATION KECORD. 



eased crops may result from planting apparently healthy tubers, also probably 

 sound crops from diseased tubers. Streak-free tubers descended from those on 

 land previously showing streak in the crop gave rise to very few affected tubers 

 in the descendants, while diseased parent tubers gave a considerable percentage 

 of affected descendants. Planting sound tubers from land previously free from 

 streak disease gave no typical cases of streak, but a small percentage of tubers 

 showing some marks of internal disease. No increase or spread of the disease 

 during the storage period could be detected, a result possibly due to care in 

 storing. 



The efifect of potato scab treatments on seed vitality, T. J. !Maney (loica 

 Sta. Bill. IJfS {lOL'i), pp. 30-60. fi(js. 13). — A suniniary is given of results of 

 investigations carried on for three years to determine the effect of solutions of 

 formaldehyde and corrosive sublimate and of formaldehyde gas treatment on 

 the germination of potatoes. 



All of the treatments were efficient in reducing the amount of scab. The 

 author jconcludes that where whole tubers are treated formaldehyde at the rate 

 of 1 pt. to 30 gal. of water or corrosive sublimate solution, 2 oz. to 16 gal. water, 

 may be safely employed, the tubers to be soaked from 2 to 6 hours. If the 

 tubers are left in the solution for longer periods or are not spread to dry imme- 

 diately, the germination of the tubers is considerably diminished. The for- 

 maldehyde gas treatment was found to be unfavorable for use in the proportions 

 generally recommended on account of its injurious effect on the germinating 

 power of the tubers. The author states that seed tubers should never be cut 

 before treatment for prevention of scab. 



Sorghum smut {Agr. News IBarbadosI, 13 (1914), No. 324, p. 316).— This 

 is a brief discussion of the smut of sorghum noted at Montserrat, ascribed to 

 Sphacclotheca (Ustilago) sorghi, which is said to occur from time to time also 

 on imphee and Guinea corn in the West Indies. 



Infection of sorghum occurs during germination either from the soil or from 

 adhering spores sown with the seed. The fungus first shows itself outwardly at 

 flowering time in small masses of black powdery spores, replacing pollen and 

 seeds. The spoi'es are very resistant and the disease is rapidly cumulative, but 

 the fungus does not enter the seed and is therefore accessible to fungicides. 

 For this purpose commercial (40 per cent) formalin (1 pt. to 30 gal. water), or 

 copper sulphate (1 lb. to 10 gal. water) are recommended. The former is used 

 to soak the seed for two hours. The latter is employeti for three minutes only, 

 after which the seed must be quickly dried. The hot water process recom- 

 mended must employ temperatures between 129 and 138° F. in order to avoid 

 both ineffectiveness and injury to germinability. 



Another smut of sorghum, Sf. {U.) reiliana, which conglomerates the whole 

 head into a smutted mass, and which is said to require measures different from 

 that above mentioned, is not yet certainly known to exist in the Lesser Antilles 



Black rust of Deli tobacco, J. A. Honing (Meded. Deli-Proefstat. Medan, 8 

 (1914), No. 4, PP- 107-111, pi. 1). — This is mainly a brief discussion of the 

 writings of other authors on diseases caused by organisms similar or related to 

 that described by the author (E. S. R., 31, p. 149) as causing black rust in 

 tobacco. 



Diseased tomatoes (Agr. Oaz. N. 8. Wales, 25 (1914), No. 1, p. 26).— It is 

 stated, on the authority of G, P. Darnell-Smith, that bacteria are probably the 

 primary cause of the black spot of tomatoes, the presence of Macrosporium 

 tomato being secondary. It is thought that infection is favored by the presence 

 of the rough scars left by the fall of the styles, by irregular and intermittent 

 water supply, by very bright sunlight, and by heavy applications of sodium 

 nitrate. Some varieties are comparatively free from the disease. 



