804 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



is known to growers under the name of ' streak ' or ' stripe,' 

 characterized by the presence of dingy yellow streaks or stripes on 

 the leaves and stem." 



Infected soil is the usual source of injury, the fungus being capable 

 of passing through its complete course of development as a pure 

 saprophyte, feeding on the humus present in the soil. " The infection 

 of a new area is in the majority of instances due to the use of manure, 

 on which material the fungus flourishes and reproduces itself at a 

 rapid rate." 



" Commercial formalin (= 40 per cent, formaldehyde) has proved 

 to be the most effective fungicide for sterilizing infected soil. In the 

 United States, where Thielavia proves very destructive in causing 

 a root-rot of tobacco seedlings, the soil of the seed-beds is thoroughly 

 soaked with a solution of formalin in water, in the proportion of one 

 pint of formalin to twelve gallons of water. One gallon of the mixture 

 should be allowed for each square foot of surface. After watering 

 is completed the soil should be covered for two or three days with 

 coarse sacking or canvas, to keep in the fumes. The watering should 

 be done after all digging has been done, and when the seed-beds are 

 in a condition ready for sowing, and a week or ten days should intervene 

 between the soaking of the soil and the sowing of the seed, to allow 

 for the complete escape of the formalin fumes and the drying of the 

 soil." — A. S. 



Sweet Potato, Foot Rot. By L. L. Harter [Phytopathology, 

 vol. iii. pp. 243-245, Aug. 1913 ; figs.). — A new disease of sweet 

 potatos characterized by the yellowing and death of the lower leaves 

 and the blackening of the lower part of the stem ; the roots are also 

 caused to rot. The fungus producing the disease is apparently a new 

 one and is named Plenodomus destruens. — F. J. C. 



Thrips, The Greenhouse. By H. M. Russell (U.S.A. Dep. 

 Agr., Bur. Entom., Circ. 151 ; July 1912 ; 7 figs.). — Fumigation with 

 nicotine or hydrocyanic gas, spraying with nicotine liquids and 

 kerosene emulsion are the usual methods of control, and frequent 

 treatment with a stiff spray of water from a garden hose or syringe 

 will tend to keep this insect down. Whatever method is employed, 

 it should be repeated in from seven to ten days to destroy the young 

 larvae that have hatched from the eggs. This should be sufficient, 

 but it may be advisable to give a third treatment in another week or 

 two. — V. G. J. 



Tobacco Breeding in Connecticut. By Hayes, East, and 

 Beinhart (U.S.A. Exp. Sin., Conn., Bull. 176, 68 pp. j 11 plates). — 

 Treats with great minuteness the problem of the production of an 

 improved tobacco for cigar wrapping. The results are generally 

 Mendel ian, but the large number of characters concerned make it a 

 long and difficult task to associate those desired. 



A summary of previous work with tobacco plants is given. 



E. A. Bd. 



