50 EXPERIMENT STATION EECOED. [Vol.36 



Second progress report on disease resistance in tobacco, J. Johnson (Abs. 

 ill Phytopathology, 6 {1916), No. 1, p. 117).— lu. continuation of a report on re- 

 sistance of tobacco to tlifi root rot organism {Thielavia hasicola) previously- 

 noted (E. S. R., 31, p. 448), the author reports encouraging results of selection 

 for resistance in the White Burley variety. 



Disinfection to overcome the root rot (Thielavia basicola), W. A. Baknet 

 (Canada Expt. Farms Rpts. 1915, pp. 1191-1193).— The sterilization of seed 

 beds by means of steam and formalin is described, the steam sterilization prov- 

 ing very satisfactory, while the formalin treatment under the conditions of the 

 experiment was not a success. Treatment with steam for 30 minutes at 100 

 lbs. pressure is recommended for general practice. Some notes are given on 

 the resistance of varieties of tobacco to root rot infection, and from the au- 

 tlior's observations it is thought that by selection and breeding a resistant 

 variety of tobacco can be obtained that will be commercially profitable. 



Fire blight investigations, H. A. Gossard and R. C. Walton (Mo. Bui. Ohio 

 Sta., 1 (1916), No. 9, pp. 274-276; abs. in Phytopathology, 6 (1916), No. 1, p. 

 lis). — A series of investigations is reported upon in which an effort has been 

 made to determine under what conditions and how long the fire blight organism 

 (Bacillus amylovorus) will live in honeydew as it occurs on the leaves, how 

 long it will retain its vitality in the nectaries of other flowers than' apple, 

 pear, and quince, and how long it will live in honey. 



It was found that the blight organism can live for 7 days in honeydew until 

 the dew is completely dried, and then for at least 3 days longer when moisture 

 is added. In the nectaries of the peach, plum, and cherry blossoms the or- 

 ganism was found to live for 5 days or more and still remain capable of in- 

 fecting trees. In the experiments with honej', a fresh sample of honey was 

 inoculated with bacteria, and beginning 2 days later inoculations were made on 

 apple shoots for a period of 9 days. In this experiment the maximum life of 

 the organism in honey was found to exceed 72 hours, but from the evidence at 

 liand it is not believed to live longer than 100 hours in this medium. 



Longevity of Bacillus amylovonis, J. W. Hotson (Abs. in Phytopathology, 

 6 (1916), No. 1, p. 115). — An attempt has been made to determine the length of 

 time the fire blight organism live.s in infected branches after they have been 

 cut from the trees. 



It was found that the organism existing in branches, when exposed to direct 

 sunlight, remains alive for fron 10 to 13 days, and similar results were ob- 

 tained when the exudate was present on the fruit. When the branches were 

 shaded for part of the day the bacteria remained alive for 27 days in the bark, 

 and when infected branches were left in a field where there was a cover crop 

 of alfalfa, living bacteria were obtained in some cases 29 days after the limbs 

 were cut. 



Arsenate of lead as a fungicide for apple scab, W. J, Mokse (Ahs. in Phyto- 

 pathology, 6 (1916), No. 1, p. 118). — In a series of spraying experiments cover- 

 ing four seasons, in which, the Ben Davis variety of apples was used, satis- 

 factory results are said to have been obtained where arsenate of lead was used 

 alone or in combination with fungicides. The arsenate of lead produced little 

 or no russeting of the fruit, and in three seasons out of four from 12 to 18 per 

 cent more merchantable fruit was obtained than when lime-sulphur was em- 

 ployed. 



Irrigation and bitter pit, C. Brooks and D. F. Fisher (Abs. in Phytopathol- 

 ogy, 6 (1916), No. 1, p. iii).— Attention is called to the relation between the 

 occurrence of corky bitter pit of apples and an increase in the amount of water 

 used. Heavy irrigation throughout the entire season or medium irrigation 

 until August followed by heavy irrigation resulted in a nmch greater amount of 



