Some Tomato Diseases. F. T. Brooks and G. O. Searle. 177 
mycelial stage was concerned. The mycelium was more scanty 
on potato agar than on the other two media. 
Series N was undertaken to test the pathogenicity of these 
twelve forms on the fruit of the vegetable marrow. A large 
fruit was selected and vertical slits about one inch apart were 
made round the circumference, into which the various forms 
were inoculated. In no case did a positive infection occur. 
A few other preliminary experiments were made and will be 
briefly mentioned here. 
Inoculations with forms C, J, and M were made into pears 
under bell jars in the laboratory, pears with sterile cuts and 
tomato fruits with inoculations of C, J and M being used as 
controls. Typical rots with abundant pycnidia were formed on 
the control tomato fruits, but in the pears no rot was caused 
by Form C, whilst Forms J and M both formed large soft 
brown rots although no mycelium noi pycnidia showed on the 
surface. 
Preliminary experiments were then tried for the purpose of 
indicating whether the various forms were wound or non-wound 
parasites of tomato fruits. It was found that the finest prick 
on the surface was sufficient to allow the entry of the fungus 
when spores were sown on the surface, but infection never re- 
sulted when spores were sown on the uninjured surface, even 
when spores were sown in a drop of 10 % sugar solution to 
assist germination or when mycelium was placed on the surface 
of the fruit in a fragment of tomato agar. 
Spore suspensions of Forms C and H were sprayed over 
tomato plants about two feet high in the greenhouse, but no 
infection nor leaf spotting took place. 
ISOLATION OF SINGLE-SPORE CULTURES AND 
EXPERIMENTS THEREWITH. 
During October, November, and December 1919, single-spore 
cultures of all the forms were made. Each form was passed 
through the tomato fruit and back on to tomato agar, single- 
spore cultures being established on the latter by the dilution 
method. As soon as single-spore cultures of all the forms had 
been obtained, the following fourteen series of inoculations and 
culture experiments were carried out to obtain some idea of the 
characters of the various forms on different media with a view 
to their systematic arrangement. 
All the forms were not used in every series, sometimes owing 
to lack of material. The following table shows in brief the 
results of these experiments. 
