Family Solanaceae 347 



possess a thin wall; the pycnospores (fig. 65 i) are 

 hyalin and one-celled. Jamieson 1 failed to find an 

 ascus or winter stage. Should the disease become 

 serious, spraying with Bordeaux is recommended. 



LEAF SPOT 

 Caused by Septoria lycopersici Speg. 



The disease is generally known as late blight, or 

 blight, both of which names are misleading. Recent 

 investigations by Levin 2 confirm the belief that leaf 

 spot is widely distributed. It is found in Alabama, 

 California, Connecticut, Delaware, Illinois, Louisiana, 

 Massachusetts, Maryland, Michigan, Missouri, New 

 Jersey, New York, North Carolina, Ohio, Penn- 

 sylvania, Virginia, Tennessee, Texas, and Wisconsin . 



Symptoms. The first indications of the disease 

 are minute water-soaked spots on the underside of the 

 leaves. With time these increase in size and become 

 circular in outline with a definite margin (fig. 66 a) . 

 The spots become hard, dry, dark, and shrunken, and 

 when numerous they coalesce into large blotches, in- 

 volving the entire leaflets and leaves ; the latter soon 

 droop, dry, and cling to the stalk, until broken off by 

 the wind or by any other jar. Within the spots are 

 formed minute black glistening pycnidia and the 

 spores exude as yellowish mucilaginous drops. 



On the stems the spots are similar to those on the 

 leaves, although they are not so clearly defined, nor 



1 Jamieson, C. O., U. S. Dept. Agr. Research, 4 : 1-20, 1915. 



2 Levin, E., Michigan Agr. Expt. Sta. Tech. Bui. 25 : 7-51, 1916. 



