74 VEGETABLE GROWING PROJECTS 



after they are attacked. It may be checked by thorough ventila- 

 tion and avoidance of overwatering. The application of potash 

 also seems to check the disease to some extent. Inasmuch as it 

 is spread by infected seed, great care must be exercised in select- 

 ing the fruits from which seed is to be taken. The diseased 

 seeds may be detected by cutting open the ripened fruits and 

 examining for brown or blackish spots. If spots are present on 

 even a few seeds such fruits should be discarded. 



Damping off and root-rots are diseases caused by fungi, which 

 live in the soil and attack the tomato plants while they are in 

 the seedling stage or before they are fully established in the field. 

 They are most destructive as seed-bed diseases and as such may 

 be controlled by sterilizing the soil in the seed bed each year 

 with steam or formaldehyde. They are most often brought on 

 by overwatering the young plants, and the condition can be par- 

 tially corrected by limiting the water supply. 



Wilt or sleepy disease is an extremely destructive disease which 

 is most prevalent in the warmer climates. It is caused by a 

 fungus, Fusarium lycopersici, which lives in the soil and attacks 

 the plants through the roots. The vascular system of the plant 

 is invaded and the supply of water thus limited, which causes 

 the plants to wilt. Several strains of tomatoes have been 

 developed which are highly resistant to this disease. Among 

 such varieties are Marvel, Arlington, and Columbia, which are 

 well worth growing where wilt is a factor in tomato production. 



There are several fruit rots that attack the tomato late in the 

 season. They are caused by various fungi, which are favored in 

 their attack by injuries that break the epidermis. Keeping 

 the patch clean of old plant refuse and training the plants on 

 stakes to keep the fruits off the ground are the best means for 

 combating these troubles. 



Blossom end rot is a common disease, characterized by a dry 

 decay, which always starts at the blossom end of the fruit. 



