531 



Remedy. Spray the young vines with Bordeaux mixture or 

 sulphide of potassium, and then periodically every few weeks 

 especially the young fruit. 



LEAF RUST (Cladosporiumfulvum,Cooke). This disease spreads 

 with great rapidity. It is caused by a fungus which forms rusty 

 brown patches on the under-side of the leaves. These patches con- 

 sist of closely packed clusters of coloured coniodophores. As these 

 patches spread the leaf becomes yellow and wilted, the margins 

 curl, and the leaves shrivel and die. Bad drainage and moist situa- 

 tions favour the growth of the fungus, which requires plenty of 

 moisture. Trellising, by lifting up the plants into a drier atmos- 

 phere, lessens the liability of attack. Spraying with Bordeaux 

 mixture or with sulphide of potassium (liver of sulphur) will hold 

 the disease in check. 



TOMATO WILT. This trouble is caused by two different agents, 

 viz., a fungus (Fusarium lycopersici, saccJ] and a bacillus (^Bacillus 

 Solanacearum). The symptoms of both diseases are much alike. 

 The first, which is known in the Channel Islands as the " sleeping 

 disease," at times causes great damage. This disease is indicated by 

 the drooping of the leaves, followed by that of the plant, hence the 

 name given to it. If the plants are only attacked when the fruits 

 are green, these ripen and there is nothing in their appearance to 

 show that they are in any way infected. The fungus gains access 

 to the plant through the rootlets and gradually extends to the tap 

 root and lower portion of the stem. When it gets this far, a brown 

 discolouration of the vascular bundles takes place, and the plant 

 droops or "sleeps." Shortly after this stage, says Prosser, the 

 portion of stem just above ground is more or less covered with a 

 very delicate white mould which consists of fruiting branches or 

 conidiophores, which bear conidia at the tips. These conidia fall to 

 the ground and there germinate, producing a mycelium, which 

 attacks the rootlets of tomatoes, potatoes, egg fruit, and plants of 

 that family, owing to the mode of attack. Spraying with fungicides 

 is of little use. Rotation of crops minimises the trouble, liming of 

 the soil is recommended, and above all, seeds from fruit ripening on 

 diseased plants should not be used. 



The Bacterial disease of the Solanaceae is very similar to the 

 previous one. The foliage first wilts, then the plant collapses 

 wilts and dies without sign of disease upon it. As the germs are 

 in the circulation and not outside, no external treatment is of any 

 avail. A section of a diseased branch discloses a brown discoloura- 

 tion of the woody cylinder, and from the vessels ooze out yellowish 

 drops carrying the bacteria. 



The disease is propagated by inoculation, generally by nibbling 

 insects, whereas in the previous disease the fungus cannot be 

 inoculated 011 the stem or the leaves, and only enters the plant 

 through the rootlets. In the case of the bacterial disease, spray 

 with Paris green to check leaf eating and leaf -puncturing insects. 



