DISEASES OF CULTIVATED PLANTS 567 



points in all directions. The disease occurs usually when the plants 

 are covered, as in a cold frame, or when the seedbed is located in a 

 moist hammock. Damping off is specifically caused, for the most 

 part, by one or more fungi which inhabit the soil. 



In case the seedbed is located in a moist hammock it should be 

 ditched around so as to draw the water off and dry the bed thor- 

 oughly. If the plants are very thick set in the bed it would be best 

 to remove a portion of them so as to let in the sunlight on the ground. 

 In addition to this, a great deal of good can be done by spraying the 

 soil thoroughly with an ammoniacal solution of copper carbonate. 

 Stirring the soil between the seedlings is a further aid towards reduc- 

 ing the loss from these fungi. Seedlings in rows can be easily han- 

 dled in this way. 



Hollow Stem. This diseased condition of the plants manifests 

 itself in the field shortly after they have been set out. The plants at 

 the time of setting out may look perfectly healthy and normal, but 

 after some days or a week, they begin to fall over, remaining green 

 after they have fallen over, but making no growth. Even the plants 

 that do not fall make only an indifferent growth and many of them 

 do not recover. Those that are so weakened as to fall over almost 

 never recover. On examining such plants the stems will be found to 

 be hollow. Many of the plants that are still standing will also be 

 found to have hollow stems. 



The cause of this trouble is that the plants have been grown in 

 a seedbed that has been overfed with nitrogenous material, and which 

 has been given more moisture than is necessary to produce vigorous 

 plants. In short, they are extra forced" plants. These conditions fre- 

 quently arise in years when the seedbeds have been frozen out and 

 uie tomato grower wishes to force his plants with all possible speed to 

 get them large enough to set in the field. 



The tomato growers suffer less loss than they did a few years 

 ago from this trouble, inasmuch as the majority of them know how 

 to handle the plants in the seedbeds so as to prevent this difficulty. 

 If the plants are growing too luxuriantly to be in the best condition 

 for setting out ; that is, if the plants are too tender to stand adverse 

 field conditions, the tomato growers now harden off their plants by 

 withholding a portion of the water from the beds. This must not be 

 done too abruptly, otherwise a large proportion of the plants may be 

 afflicted with hollow stem in the seedbed. If the plants have been 

 thus hardened off for some days or a week, they will be in a condition 

 to plant in the field. (Fla. E. S. B. 91.) 



Other Plants Affected. While it has not been definitely proved 

 that this bacterium may live in the soil from one tomato season to 

 another in Florida, it is possible, in any case, for this disease to bo 

 carried over from one year to another on some of our wild plants 

 which are subject to it. .Consequently, a field that has been severely 

 affected by the bacterial blight one year, should not bo planted either 

 to tomatoes, Irish potatoes, or eggplants during the succeeding year. 

 In addition to these vegetables, the Jamestown weed, black night- 



