FUSARIUM. 521 



tomatoes. This tomato disease has .proved very destructive 

 during recent years in Britain, particularly in the Isle of 

 Wight and the Channel Islands. Plants are attacked when 

 quite young, but the disease seldom manifests itself outwardly 

 till the plant is full grown. The first symptom of disease 

 is drooping of the leaves, with or without discoloration. At 

 this stage the roots of attacked plants will be found to have a 

 yellowish brown colour in the wood region. The mycelium 

 of this fungus will be found in the vessels and other elements 

 of the root. They are believed to originate from resting-spores 

 which have hibernated in the soil and given off germ-tubes by 

 which young rootlets were infected. The mycelium makes its 

 way up the tomato stem, discolouring the vascular, bundles as it 

 goes. The conidia are produced on all diseased organs as a 

 whitish bloom on the epidermis. The earlier conidia {Diplo- 

 cladium) are oval and one- or two-celled, but they are soon 

 replaced by pale orange crescent-shaped conidia of the true 

 Fiisarmm type. The resting-spores are produced on the hyphae 

 in the tissues of the decaying host- stem ; after hibernation, they 

 germinate and produce hyphae which give off the Diplocladium 

 stage. Massee found that only the germ-tubes from resting- 

 spores were able to infect tomato plants The same author 

 does not consider fungicides of much avail on account of the 

 disease beginning from the roots. Careful removal and destruc- 

 tion of all infected material, and a liberal application of lime 

 to the soil are measures recommended. 



Fus. limonis Briosi {lusisporium limonis Briosi). This is 

 given by Briosi as the cause of " mal-di-gomma " of orange 

 and lemon trees in Italy and elsewhere ; ^ Webber and Swingle ^ 

 ascribe the disease of the orange and lemon in Florida known 

 as " foot-rot " to the same fungus. In Florida the damage done 

 is great and much more serious than that caused by any other 

 disease of the same plants. It may be recognized by the 

 exudation of gum from patches near the base of the tree. The 

 patches enlarge and the disease spreads round the trunk and 

 downwards into the roots, passing inwards from bark to cambium 

 and wood, killing the tissues as it goes. Other symptoms 



'Briosi, "Mai di gomma," Memoria della S. Acad, dei lAncei, B.orae, 1878. 



2 Webber and Swingle, " Diseases of citrons fruits in Florida." U.S. America 

 Depi. of Agrkidlure. Bidletin, No. 8, 1896. (Edit.) 



