Insect Pests and Plant Dise.\ses. 201 



and the center becomes gray or nearly white. The fungus passes the winter in the 

 old, diseased leaves that fall to the ground. In setting new plantations, remove 

 all diseased leaves from the plants before they are taken to the field. Soon 

 after growth begins, spray the newly set plants with Bordeaux 5-5-50. Make 

 three or four additional sprayings during the season. The following spring, spray 

 just before blossoming and again 10 to 14 days later. If the bed is to be fruited 

 a second time, mow the plants and burn over the beds as soon as the fruit is gath- 

 ered. Plant resistant varieties. See Cornell Bulletin 79. 



TOMATO. 



is the most destructive foliage disease of the tomato in the 



Septoria, state. The distinguishing character of this fungous disease is 



leaf-spot that it begins on the lower leaves and works towards the top, 



killing the foliage as it goes. It is controlled with difficulty 



because it is carried over winter in the diseased leaves and tops that fall to the 



ground. When setting out plants, pinch off all the lower leaves that touch the 



ground ; also any leaves that show suspicious looking dead-spots. The trouble 



often starts in the seed-bed. Spray plants very thoroughly with Bordeaux, 



5-5-50, beginning as soon as the plants are set out. Stake and tie up for greater 



convenience in spraying. Spray under side of the leaves. Spray every week or 



ten days. 



TURNIP. 



^1 , is the same disease as the club root of cabbage. Same treat- 



Club root 



ment. 



is a bacterial disease, the same as soft rot of cabbage. Plant 

 Soft rot on soils free from the disease. Avoid planting varieties espec- 

 ially susceptible to the trouble. The white turnip seems to be 

 more susceptible than the yellow varieties. 



WHEAT. 



Stinking smut. 



This is usually not detected until harvest time. The affected 

 heads appear nearly normal, only the kernels being attacked. 

 The diseased kernels are composed of a brown, foul-smelling 

 powder. They may be crushed easily between the thumb and 

 finger. Readily controlled by treating the seeds with formalin solution as for oat- 

 smut, which see. See U. S. Farmers' Bulletin 250. 



is conspicuous in the field at "heading" time. Both grain and 

 Loose smut chaff are attacked and transformed into a loose black powder 

 most of whicli is blown away by harvest time leaving the stalk 

 bare. It is common and destructive. In 1907, the average loss in New York was 

 at least 10 per cent. This smut is not controlled by treatment with formalin or 

 other chemicals, but should be prevented by treating the seeds with hot water as 

 follows: Soak sack of wheat in cold water for 12 hours, drain i hour; submerge 

 sack for ten minutes in water held at temperature of 130° F. The temperature 

 must not rise above this as it would then injure the germinating ability of 

 the grain. 



