TOMATO 



295 



"7. When well supplied with water plants on a sandy loam have 

 developed less disease than those on a clay loam. 



"8. Raising the soil temperature of greenhouse plants has in- 

 creased the disease. 



"9. The writer is of the opinion that the increase in the disease 

 from heavy watering is due to the development of harmful humic 

 and ammonium compounds and an accompanying decrease in ni- 

 trates. 



"10. Susceptible tissue has more starch and more oil than normal 

 tissue and its cell sap has a higher osmotic value. 



"11. The protoplasm in the cells from the fruit of the heavily 

 watered plants is more granular and contains more oil than that 

 of the lightly watered ones." 



Fig. 94. A convenient picking basket. 



Leaf spot or leaf blight (Septoria Lycopersici Speg.) 



sometimes attacks greenhouse tomatoes. It appears on 

 the leaves as numerous oval or circular spots. The in- 

 terior of the spots is light in color while the margins are 

 dark. Bordeaux mixture is recommended for the control 

 of this disease. 



Alternavia solani (E and M) J and G, is another form 

 of blight which is sometimes encountered in the culture 



