488 



STATE BOARD OF AGRICULTURE. 



Spots appear 

 on the leaf- 

 lets. Then 

 the leaves 

 (lie, falling 

 from the 

 plant at the 

 least jar. 



The leaves 

 manufacture 

 sugar and 

 starch. The 

 leaf spot 

 disease 

 destroys the 

 factories. 



yellow. The leaves die and drop from the plant at the 

 slightest jar. The disease advances up the plant, and 

 soon all leaves, except a small tuft at the end fall from the 

 stem. The drop})ing of Hie leaves exposes the fruit, which 

 may sunburh badly. 



Spots are also formed on the calyx and stem but rarely 

 on the fruit. 



The damage to the crop comes largely from the loss of the 

 leaf surface. The leaves of plants are the manufacturing 

 organs which produce the starch and sugars which make up 

 the greater part of the solid matter of the fruit. A leaf dis- 

 ease interferes with the manufacturing power, hence, the 



Fig. 



Diseased spots magnified five times. 



Small, sour, 

 watery 

 tomatoes are 

 caused by 

 leaf spot. 



fruit grows sloAvly or not at all. Half -matured fruit fails 

 to ripen. The crop from plants with blighted foliage is 

 small, sour and watery. This last condition is often com- 

 plained of by canners; although they ascribe "watery" 

 tomatoes to a wet season, rather than to a fungous disease 

 made severe by the season. In short, all the general signs 

 are those which go with disturbance of food manufacture by 

 the leaves. 



A fungus 

 steals from 

 the tomato 

 plant. 



THE CAUSE OP LEAP-SPOT. 



Leaf-spot of tomato is caused by a parasitic fungus called 

 Septoria lycopersici which grows and feeds in the tomato 

 leaf. A parasitic fungus is a microscopic plant which makes 



