196 



Tomato Fungi. 



disease. Alter thoroughly trenching the soil, applying a large 

 quantity of unslacked lime before trenching, and well fumi- 

 gating the houses with sulphur, he planted another set of 

 plants, and obtained a satisfactory crop of tomatoes. 

 Similar treatment has materially lessened the ravages of the 

 sleeping disease in Guernsey, though it is by no means 

 stamped out there. 



The minute fungus causing this disease is known as 

 Fusarium l^coperstci. It is produced by resting spores which 

 hibernate in the soil and infect the plants by the medium of 

 their root hairs or rootlets, also by means of the seeds from 

 infected tomato plants containing vegetative parts of the 

 fungus. Mr. Massee, who has made many investigations of 

 this fungus, has not yet been able to find the mycelium in 

 the seeds of infected plants ; but he suggests that it may be 

 in the form of mycoplasma, and believes that the fungus may 

 be propagated by the seed. Mycelium is soon formed, and 

 begins to ascend the stem. If the stem of a " sleeping " 

 plant is cut lengthways, it will be found that the vascular 

 tissues are unhealthy, as shown by their brown colour, while 

 the rootlets become rotten, and the roots on being cut through 

 Avill be seen to be discoloured. In course of time the lower 

 parts of the stems of infected plants are covered with a white 

 growth, like mildew, hardly discernible vv^ithout a glass, 

 composed of branches bearing spores. These spores may 

 reproduce the fungus on other tomato plants, being conveyed 

 to them by the air or by other media. Mr. Massee, in his 

 valuable paper published in the Garde^iers Chronicle, June 8th, 

 1895, on the life history of this fungus, says that the spore- 

 bearhig branches on the stems agree with a genus of fungi 

 called Diplocladi7ij?iy and he terms them the Diplocladium 

 stage of this tomato fungus. After a while the stem becomes 

 much decayed, and then crescent-shaped spores are formed, 

 representing the conidia of the second or Fusarium stage of 

 the fungus. Finally,'' Mr. Massee says, the mycelium 

 that has produced the Diplocladium and Fusarium stages of 

 the fungus in succession at last bears numerous resting 

 spores, which tide the fungus over the winter." 



In an article upon tomato disease in Guernsey, which 



