348 Diseases of Truck Crops 



do they work in deep to form cankers. Spots may 

 also occur on the calyx and on the fruit. The dis- 

 ease, however, is usually a foliage trouble. Of the 

 more resistant varieties maybe mentioned Mikado, 

 King Humbert, Wonder of the Market, and Up to 

 Date. Of the medium resistant varieties may be 

 mentioned Alice Roosevelt, President Garfield, Pre- 

 lude, Ponderosa, and Magnum Bonum. The Trophy 

 and Ficarazzi are very susceptible varieties. 



The Organism. The mycelium of Septoria lyco- 

 persici is hyalin, septate. The pycnidia are globose 

 (fig. 66 b) ; the pycnospores are hyalin, needle-shaped, 

 many-septate, and lose their vitality when exposed to 

 ordinary room temperature for about four days. 



Control. The disease often starts on the seedlings 

 in the seed bed. It is important therefore to start 

 with a clean seed bed soil. Seedlings should be 

 sprayed with 4-4-50 Bordeaux before being trans- 

 planted. In the field the plant should not be worked 

 in wet weather, or when covered with dew. Spraying 

 with 4-4-50 Bordeaux is recommended, especially in 

 wet weather. Since the causative fungus is carried 

 over in pycnidia on dead leaves or stems, the burn- 

 ing of all trash becomes necessary. 



ANTHRACNOSE 

 Caused by Colletotrichum phomoides (Sacc.) Chester. 



Anthracnose is a disease to which ripe tomatoes 

 are especially subject. The losses are often consid- 

 erable both in the field and in transit. 



