April 13, 1S92.] 



Garden and Forest. 



175 



valuable for bouquets and such like flower-arrangements. 

 Spiraea confusa has crowds of bunches of white Hawthorn- 

 like flowers. Many of the early-flowering shrubby Spiraeas 

 would force well. Guilder Roses are prettier when prop- 

 erly forced than they are out-of-doors. To force flowers 

 simply to get them out of season is a practice with little to 

 recommend it, but to be able to keep up a supply of flow- 

 ers all the year round for the conservatory and indoor use 

 by subjecting suitable plants to a higher temperature than 

 they really require is good gardening. The Royal Horti- 

 cultural Society offered prizes for the best collect'ons of 

 forced shrubs to be exhibited this month, but nothing of 

 special value was shown. There were, however, beautiful 

 pot Roses from the Pauls ; Azalea mollis and Lilacs, be- 

 sides lovely basketfuls of flower-branches of double Peach 

 and Forsythia from Messrs. Veitch. „,. „_ 



London. W. WatSOtl. 



leaf-areas lose their dark green color, and become light 

 green ; these portions soon turn yellowish, and at the 

 same time the leaf begins to curl, the outer edge being gen- 

 erally drawn downward. This causes the leaves to appear 

 considerably smaller, which is quite characteristic of the dis- 

 ease. The discoloration of the leaves progresses slowly, while 

 the portions which were first affected gradually die, giving the 

 leaf a spotted appearance. The spots increase in size and 

 their form becomes very irregular, and in this manner each 

 leaflet succumbs. Upon the fruit the first symptom is a trans- 

 lucent appearance of portions of the outer wall. The centres 

 of these portions turn brown and then black, while the disease 

 spreads more or less rapidly at the outer edges, where a border 

 of the translucent tissue is generally found. The fruit borne 

 by diseased plants also appears to be more irregular than that 

 upon normal plants. 



The Tomato-plants are grown in boxes, and the manner 

 in which the disease spreads from one to the other is not 

 known. The plants first affected were situated at one end of 



Fig. 27 — A Japanese Garden. — See page 170. 



Cultural Department. 



A New Disease of the Tomato. 



ONE of the greenhouses of the Cornell Experiment Station 

 is devoted to the forcing of Tomatoes, and until the past 

 season the plants have been vigorous and have borne well. But 

 last autumn some of the fruiting plants showed signs of disease; 

 they were weaker, the leaves appeared smaller, and the plants 

 assumed a light green or yellow color. The cause of this 

 •change was at first not known, but as the disease progressed 

 it gave evidence of a bacterial nature, and these organisms 

 are now thought to be the cause of the trouble. They are 

 readily found in the tissues of affected plants, and labora- 

 tory-cultures develop them in large numbers. We thought 

 that this bacterium might be identical with the one which is 

 sometimes so destructive to Potatoes, for the appearance of 

 the disease in the two plants is similar, but Professor Burril, 

 to whom specimens were referred, has just reported that the 

 two diseases are probably distinct. It is certain that the dis- 

 ease can be communicated to the Potato, for diseased Tomato- 

 cions have been grafted upon healthy Potato-plants, and the 

 latter are now plainly affected. 



The first indication of the presence of this disease in Toma- 

 toes is shown by the foliage. Small, often vaguely defined 



the house, and those nearest to them were the 'next to show 

 the disease. One plant, standing about fifteen feet from the 

 rest, has remained healthy to the present time. It is quite cer- 

 tain that healthy plants will become diseased if they are set in 

 infested soil, for several have been treated in this manner and 

 all are now affected. One plant had discolored foliage in less 

 than three weeks. Others were set in clean soil and they are 

 healthy, although it is about four weeks since the disease first 

 appeared in the other lot. 



The boxes in which the first diseased plants were grown 

 were used again for the next crop, but they were treated in 

 different ways, in order to discover some method of destroy- 

 ing the disease. Some boxes were whitewashed, some were 

 washed with the ammoniacal carbonate of copper, others with 

 lye, and others were set out-of-doors to freeze. All were then 

 placed in the house with clean soil, and young healthy plants 

 were set in them. No beneficial effects of the treatments can 

 be seen, for the plants are all diseased. Spraying with copper 

 compounds has also proved useless. Undoubtedly, all treat- 

 ment must be preventive and strategic. Care should be exer- 

 cised in securing clean soil, etc., and the immediate removal 

 of diseased plants may prevent the disease from spreading to 

 any serious extent. Possibly this serious disease is identical 

 with the Southern Blight, recently reported by Dr. Halsted in 

 a bulletin of the Mississippi Experiment Station. 



Cornell University. -£'■ G. Lodeman. 



