50 EXPERIMENT STATION. [Jan. 



The tomato leaf blight, caused by Cladosporium, often termed 

 scab, can be perfectly controlled by paying attention to the air 

 moisture and to details of syringing the foliage. The same 

 attention to syringing, ventilation, etc., should be paid in the 

 case of tomatoes as with melons and cucumbers. 



When tomato plants are crowded, and there is an insufficient 

 amount of light and circulation of the air, the lower leaves are 

 frequently attacked by a leaf blight, known as Cylindrosporium, 

 but this will give no trouble if the conditions are kept normal. 

 This leaf blight occasionally occurs in commercial houses, 

 although we have never had a trace of it in our many years' 

 experience in growing tomatoes under glass, both summer and 

 winter. It is more common in winter, when the light is poor, 

 than in the spring and summer. 



The blossom end rot of tomatoes is often a very troublesome 

 disease and furnishes a good illustration of a trouble brought 

 about by neglect of certain details necessary for the normal de- 

 velopment of the crop. This disease is caused by bacteria, one 

 or more fungous growths (Fusarium, Cladosporium, etc.) 

 occasionally accompanying the bacteria. Lack of water in the 

 soil when the fruit is maturing, especially if the atmosphere 

 of the house is more or less dry, will cause the rot, and a liberal 

 supply of moisture, preferably supplied by irrigation, will pre- 

 vent it. Moisture plays an important role here because a too 

 dry atmosphere causes the fruit to crack at the blossom end and 

 become imperfectly developed, and infection follows. This rot 

 is more common near steam pipes, where the air is drier, and 

 in the spring, when the sunlight is more intense and prolonged, 

 than during the late fall or winter. In the spring transpiration 

 is more active, hence the necessity for more soil moisture and 

 more attention to wetting down the house. Sunshine and trans- 

 piration are important factors in causing the rot, and our 

 experiments have shown that slight shading in the spring 

 months is of <^eat value in holding back the trouble. In our 

 experiments in the greenhouse we obtained over 30 per cent, 

 more blossom end rot on plants which were watered on the sur- 

 face than on those subirrigated, and a very material decrease in 

 the amount of rot occurred from the shading afforded l)v the 

 plants. 



