New York Agricultural Experiment Station. 
351 
strongly marked by the less spotted and clearer green foliage and its 
greater persistence. It seems probable that much better results would 
have been attained if the main part of the spraying had been done 
during July and extending into August. 
The theory of the action of the fungicide is that the spores are 
prevented by its presence from germinating upon the surface of the 
foliage, and the fungus thus kept from entering the leaf, and that both 
the fungus threads and spores are killed by contact with it. The 
injury, resulting from the growth of a single spore rarely exceeds a 
spot one-eighth of an inch in diameter. The effect of one or a few 
spores upon each leaf is therefore insignificant; it is the great numbers 
that do mischief. While it is doubtless impossible to entirely prevent 
the growth of the fungus in the leaves, yet the feasibility of arresting 
the considerable increase of the spots by suitable topical applications 
seems reasonable. Whether sulphide of potassium will prove 
to be such a preventive must be the work of several years to ascer- 
tain, but the present season's test looks favorable. 
Strawberry Leaf Spot. — A part of a bed of Sharpless strawberries was 
sprayed four times during June with the strength of solution already 
mentioned, with the object of holding in check the spotting of the 
leaves due to the fungus, Ramularia Tulasnei, often described as " sun- 
burn." The object sought was attained, as that part of the bed took 
on a more vigorous growth and showed fewer spotted leaves than the 
remainder. In fact the difference between the sprayed and unsprayed 
portions was so marked that it seems unsafe to ascribe it wholly to the 
fungicide, it being better to content one's self with the strong indica- 
tion that the sulphide is likely to prove a serviceable i^reventive of this 
disease, and to leave the question of its full efficiency to be determined 
by future trials. 
Other Dixease*. — Application of the fungicide was also made at the 
same time and in the same manner as already mentioned to currant 
bushes and quince trees. No results were obtained with the currants, 
where it was hoped to check the common spotting of the leaves caused 
by the growth of a fungus. The results with the quince trees were 
equally indifferent. The object in view was to see the effect of the 
fungicide upon the mildew (Podosphsera tridactyla) and the leaf spot- 
ting (Morthiera Mespili, var.), but neither fungus appeared in sufficient 
abundance to permit of definite observations. After the spraying was 
begun, and before it was ended, another disease took possession of the 
trees — the twig blight, due to the same cause as pear blight — and 
from six inches to a foot or more of the ends of many of the branches 
died. There was no appreciable difference between the sprayed and 
