70U THE FAHMEBS' HANDBOOK. 



The trusses of bloom which give the fruit are thrown out along the main 

 fetem. Care must be taken not to injure these when pruning. When the 

 main stem reaches the top of the lath it may be pinched off, but not before. 

 This pruning should be practised regularly, about once a week. Wherever 

 laterals appear they should be pinched off. 



The tomatoes will start to ripen from the base of the plant, and the ripen- 

 ing will proceed gradually towards the top. 



Watering and Spraying. 



The tomatoes, whether in the seed-box, hot-bed, or in the field, must be 

 regularly but not excessively watered. The soil should be kept always in a 

 moist, growing condition. Harm can be done by too much watering, but 

 soil should never be allowed to get dust-dry. At the College we irrigate 

 tomatoes and vegetables with the effluent from the septic tank. 



If there is danger of frosty nights, the best practice is to water the young 

 seedlings in the mornings. If the plants are watered in the evening and a. 

 cold night follows, the plants will receive a check. In warm weather, how- 

 ever, watering at night is the rule. 



The plants are sprayed occasionally with Bordeaux mixture, 6 — 4 — 50 

 formula, to check fungus diseases. The method of manufacture is described 

 in connection with potatoes. 



If the weather is wet, spraying is carried out once a fortnight; but in fine 

 weather it is not necessary to spray so often. 



Diseases of Tomatoes.* 



Black Spot. 



Black Spot usually makes its appearance first at the flower end of the 

 South Wales, and probably no tomato disease causes greater loss. 



Black Spot usually makes its appearance first at the flower end of the 

 fruit as a small brown discoloration.' The discoloration spreads, and 

 the spot becomes more distinct and definite in outline. At the same time it 

 becomes depressed and darkens in colour. The larger spots, which may be 

 an inch or more across, have a dark-brown or black appearance, and are 

 often somewhat velvety in texture. Later the whole blossom-half of the 

 fruit may be involved. The affected tissue collapses and becomes firm and 

 leathery. This collapsing of the diseased tissue, together with the continued' 

 development of other, parts of the fruit, may produce a definite depression 

 on the blossom end of the fruit, or often it results in only a flattening of 

 the surface. 



The first effects of the disease are not always superficial. Fruit that 

 appears entirely normal from an external view often has the tissue of 

 several, or sometimes all, its placenta? collapsed and blackened in the parts 

 nearest the blossom. The velvety appearance that develops later on the sur- 

 face is due to a growth of a fungus, a species of Maerosporinm. This 

 fungus is not, by itself, capable of Producing the rot, and is apparently a 

 secondary infection. The disease is not due primarily to bacteria or fungi,, 

 but to various physiological conditions, and is not infectious. 



* Compiled by Officers of the Biological Branch. 



