448 EXPERIMENT STATION EECOKD. 



rot. These organisms, when inoculated into healthy green tomatoes, have 

 failed to produce tlie disease. The development of the disease is said to be 

 favored by heavy applications of commercial fertilizers and greatly increased 

 by the addition of stable manure. It is decreased by the application of sodium 

 nitrate, and is worse on heavy than on light soil. Its development may be 

 favored by a lack of water and also by excessive watering, depending upon the 

 condition of the plants at the time of the change. Lime has been found to be 

 a partial preventive and it also serves as a remedial agent on plants already 

 predisposed to the disease. 



Diseases of tobacco, J. Johnson (Wisconshi Sta. Bid. 237 (1914), pp. 1-27, 

 figs. 7). — The author gives descriptions of the more common and injurious dis- 

 eases affecting tobacco in the seed bed. field, and curing house, and suggests 

 methods for their control. 



The most serious troubles of the seed bed are said to be the bed rot or damp- 

 ing off and the root rot or black root. The first-named disease is due to 

 Pythiiim dcbaryanum and Ilhizoctonia. while the second is caused by the fungus 

 Thiclavia basicola. For the control of the diseases of the seed bed sterilization 

 of the soil is recommended, and the steam sterilization by the inverted-pan 

 method is said to be the most efficient and economical of any method tested. 



The root rot may also attack tobacco in the field, causing large losses. The 

 author believes that this disease is. in some cases at least, responsible for the 

 so-called running out of tobacco soils rather than a depletion of fertility. 



Descriptions are given of rusts of the leaves, which are due to a number of 

 causes, the mosaic disease or calico, shed burn or pole rot, stem rot, wet butts 

 or fat stem, white vein diseases, black rot occurring in sweating tobacco, etc. 



For most of the troubles of the curing house, proper attention to ventilation 

 and temiierature, it is said, will reduce the loss. 



Two new diseases occurring in the field have been observed and studied in a 

 preliminary way. These have been called black leg or canker and hollow stalk. 

 The first is characterized by the decay of the stalks at or above the surface of 

 the ground and seems to be due to the same organisms which cause the damping 

 off of seedlings in the plant beds. The hollow stalk is said to be a decay of 

 the pith of the stalk, which sometimes extends out into the midrib and veins 

 of the leaves, causing them to droop. A bacillus of the soft rot type has been 

 isolated and the disease produced by inoculating healthy plants, which seems 

 to indicate that it is of a bacterial nature. 



Disease resistance in tobacco to root rot, J. Johnson {Abs. in Phyto- 

 pathology, 4 {1914) y ^0. 1, p. ^S). — The root rot of tobacco, due to Thielavia 

 basicola, is said to be becoming of economic importance to tobacco growers. In 

 1913 the author studied the " Burley sick soils " of Ontario and the "deterior- 

 ated tobacco soils " of V>'isconsin, upon which root rot was found very preva- 

 lent. Marked differences in resistance were observed for different varieties, 

 White Burley being very susceptible to root rot, while the variety I>ittle Dutch 

 was found to be very resistant. The Connecticut Havana is approximately in- 

 termediate between the other two varieties in resistance to disease. A large 

 acreage was examined for resistant plants and a number were found sufiiciently 

 resistant to warrant bagging and preserving for seed. These are to be tested 

 for further selection and breeding in 1914. 



Some diseases of nursery stock, M. T. Cook {New Jersey Stas. Circ. 35, 

 pp. 24, figs. 15). — A description is given of some of the more serious diseases 

 which are likely to be carried by nursery stock, attention being drawn to them 

 in order that growers and nurserymen may be on their guard concerning their 

 introduction and dissemination. 



