VII 



TOMATOES 217 



Tomato Wilt. Another wilt disease which resembles 

 the one caused by Bacillus solanacearum is very serious 

 in Porto Rico. It works through the fibro- vascular 

 bundle of the plant, and cannot be counteracted by the 

 use of Bordeaux. 



Sclerotium Wilt. This disease is first apparent by a 

 wilting of the tips of the plants. A careful examination 

 of these diseased plants shows Sclerotium Rolfsii, Sacc., 

 a fungus just below the surface of the ground. This 

 fungus finally forms a number of small bodies (sclerotia), 

 about the size of mustard seed, by which it is carried 

 over from year to year. When young, these bodies are 

 white, but when mature they vary from black to red. 

 This fungus also attacks many other plants, such as 

 potatoes, egg-plants, beans, cow-peas, summer squashes, 

 cabbages, beets, melons, and many ornamental plants. 

 The plants can be protected over small areas by spray- 

 ing the soil around the plants with ammoniacal copper 

 carbonate solution. Over large areas it will be necessary 

 to rotate the crops, avoiding where possible the use of 

 manure and decaying vegetable matter for fertilizers. 



Leaf Mould. This disease is caused by the fungus 

 known as Cladosporium fulvum, Cooke. It has been 

 reported from Western Australia and Southern United 

 States, and from Cuba. It spreads rapidly, forming 

 rusty, brown patches on the under side of the leaves. 

 The leaves become yellow, wilt, and shrivel. Poor 

 drainage and moisture are favourable to the rapid 

 development and spread of the disease. The plants 

 should be trellised, and sprayed with Bordeaux. 



Early Blight, Target Board Blight. This disease is 

 due to the Macro sporium solani, E. & M., which has 

 already been discussed in connection with the diseases 

 of potatoes. Prevention is much better than a cure for 

 this pest. The young plants should be sprayed with 

 Bordeaux mixture while yet in the seed-bed ; and if the 

 conditions are such that it can be done with profit, the 

 treatment may be continued in the field (page 208). 



Late Blight or Winter Blight. This disease is due 



