The Canadian Horticulturist 



305 



BLACK ROT OF THE TOMATO. 



Sir, — I send you a couple of tomatoes affected with the black rot, which seems to have 

 affected all varieties in this section. I would be obliged if you can give a cause and remedy 

 for it. It affects those upon the ground as well as those suspended. I would be glad to 

 know, too, if the sound portions of those affected would be injurious to those eating them. 



J. G. FiazGiBBON, Norwood. 



The specimens of diseased tomatoes sent by Mr. FitzGibbon present an 

 appearance only too familiar. The tomato rot has been wide-spread during the 

 last five years, not only throughout Canada, but also throughout the United 

 States. Some growers report that as much as one-third of their crop has been 

 destroyed by it. 



The causfe of this rot is very difificult to explain, but it is a fungus growth 

 which first affects the tomato at the apex and gradually spreads over a large 

 portion of the fruit. (See Fig. 53.) The parts affected soon harden and the 

 whole fruit becomes dried and shriveled, rendering it unfit for market. So far 

 as we know there is nothing injurious to the health in the sound portions of 

 those tomatoes which are slightly affected. 



Prof. Bailey is of the opinion that the tomato rot is made worse by the 

 abundant use of stable manure, and the general opinion is that some varieties 



Fig. 53 — Tomato Affected with Rot. 



are more subject to it than others. Thus the Acme and the Mikado are very 

 badly subject to it, while the Perfection, Paragon and Trophy are not so easily 

 affected. 



To scientists the fungus is known as Macrosporium tomato, and consists of 

 a dark-colored mycelium and vegetative system, the growing tubes of which can 

 be readily traced to the cells of the sound tissue of the tomato (see Fig. 54 d) ; 

 and of spores, which are borne on the ends of the branches, called hyphae, all of 

 which are plainly represented in Fig. 54 a and fi. These are at first dark brown, 

 but at- length turn olive-black. When these spores come in contact with either 

 ripe or green fruit they germinate rapidly under favorable circumstances, such as 



