1908.] 



PUBLIC DOCUMENT — No. 33. 



139 



Under all conditions of disease, however, the leaves are much 

 distorted and stiff, and often very badly curled, never possess- 

 ing the flexibility of healthy, normal leaves. 



The Growing of Plants used in Experiments. 



As the mosaic disease seldom if ever occurs on field-grown 

 tomatoes, and as these experiments were carried on in the green- 

 house, a standard greenhouse variety of tomato, the Lorillard, 

 was used in the work. This variety is of medium size, and 

 possesses strong growing qualities. 



The seed used was carefully selected and of uniform size, all 

 being over 2.5 millimeters in diameter. The seed was first 

 planted in drills in a seed plot in which no tomatoes had previ- 

 ously been grown, and which could in no way contain any roots, 

 decayed or otherwise, of diseased plants. After the seedlings 

 had reached a height of 4-6 centimeters they were transplanted 

 to 4-inch pots, and then once more transplanted, when they had 

 reached a height of 15-18 centimeters, to the boxes containing 

 the coal ashes, mention of which will be made later, and to the 

 benches into soil which had not previously produced tomatoes. 



The plants transplanted to the boxes were used to ascertain 

 the action of excess of various plant fertilizers on the produc- 

 tion or intensifying of the disease after it had once been con- 

 tracted. The plants transplanted to the benches were used for 

 inoculation and various other minor experiments. 



Action of Excess of Fertilizers on the Production or Intensi- 

 fying of Mosaic Disease. 

 To test the action of excesses of various fertilizers on the 

 pruned and unpruned tomato plants, a fertilizer containing all 

 the necessary plant food for tomatoes was used. The fertiliz- 

 ing constituents in tomatoes, given in parts per thousand, are 

 as follows : ^ — 



Moisture, 

 Nitrogen, 

 Ash, 



Potassium oxide. 

 Sodium oxide, 

 Calcium oxide. 

 Magnesium oxide, 

 Piiosplioric acid. 



Parts. 

 9-iO.O 



1.7 



3.6 



.3 

 .2 

 .4 



1 Hatch Experiment Station report, 1902. 



