Some Tomato Diseases. F. T. Brooks and G. O. Searle. 179 
In using Dox’s medium it was found that the normal amount 
of cane sugar, 7.e. 30 grms. per litre, produced a too profuse 
mycelial growth, so that fruit bodies, specially of the pycnidial 
type, were obscured and such details as the colour of the spore 
mass could not be determined. 
The amount of sugar was therefore first modified to 15 grms. 
per litre and later to 7:5 grms. per litre. This latter medium 
appeared to give the most satisfactory results. 
On duplicating the whole series on the medium containing 
7-5 grms. sugar no appreciable difference could be discerned 
between the two tubes of each form, an effect which was not 
seen when working with other media such as tomato agar. 
The formula used in this modification of Dox’s medium was 
as follows: 
Magnesium sulphate ... ae OFS SE: 
Potassium acid phosphate ... I-0 ,, 
Potassium chloride... eft Os ay 
Ferrous sulphate ae Sem BOSOM 5, 
Sodium nitrate “ta 20 | 2O-ormc: 
Cane sugar: © %.: 3 
Made up to 1000 c.c. with 2 % agar. 
The acidity was + 13:6. 
DESCRIPTION OF THE MACROSCOPIC CHARACTERS 
OF THE VARIOUS FORMS ON TOMATO FRUITS. 
The following gives the appearance of these fungi on tomato 
fruits about ten days after inoculation: 
Form A. A black spot roughly circular about 3-1 inch in 
diameter, slightly sunken towards the circumference, generally 
raised in the centre at the point of inoculation. Shades off in 
colour towards the uninjured part of the fruit. Very numerous 
black pycnidia aggregated round the centre and erumpent 
through the epidermis of the fruit, giving the surface a roughly 
punctate, carbonaceous appearance. 
Form B. Large brown spot, with numerous brown pycnidia 
erumpent through the epidermis of the fruit. 
Form C. Large brownish black spot, about one inch in dia- 
meter, raised in the centre and sunken towards the circum- 
ference. Very numerous, densely gregarious pycnidia, varying 
from brown to black in colour, covered with dull greyish pink, 
slimy, spore masses. 
Form D. Watery-looking, rugged canker about one inch in 
diameter, entirely covered with closely aggregated black acer- 
vuli, surrounded by a circle of younger acervuli covered with 
pink spores. 
