DISEASES DUE TO FUNGI 119 
spraying with Bordeaux or Burgundy Mixture is adopted. 
Thus under cool, moist conditions the disease assumes 
considerable importance. The first symptoms of the 
disease is the appearance of black, water-soaked spots 
on the stem and mature leaves. The lesions rapidly 
increase in size, causing the death of the leaves and a 
rotting of the stem tissues. The malady can easily be 
distinguished from other tomato diseases, for the entire 
plant appears to be suffering from the effect of frost 
and in bad cases turns completely black and dies. Dis- 
coloured sunken areas varying from grey to black are pro- 
duced on the fruit. Such lesions are mainly produced at 
the stem end of the fruit, where the water drips collect. 
An examination of the under surface of diseased 
leaves reveals a white, downy fungal growth, similar 
in appearance to that present on diseased potato leaves. 
This is the spore-bearing portion of the fungus, which 
enables its rapid spread. 
Under normal glasshouse conditions the disease is 
unimportant, and where it has appeared a ready control 
has been effected by increasing the temperature and 
reducing the amount of moisture in the atmosphere. 
In old, leaky houses and out of doors continuous spraying 
with either Bordeaux or Burgundy Mixture is necessary 
to check the disease. 
The Macrosporium Disease of the Tomato.—As in the 
case of the preceding disease, that due to Macrosporium 
solani, which also causes the early blight of the potato, 
is confined mainly to outside tomatoes or to those grown 
in cold, leaky houses, although it is occasionally found 
on the last fruits of the season, when these are picked 
green from the plants and laid on benches to ripen. 
The fungus attacks the leaves, producing brownish- 
black angular spots and blotches, but is chiefly found 
on the fruits, where sunken brownish-black areas are 
produced chiefly at the stalk end. These lesions enlarge 
and become covered by a black, velvety mass of spores. 
