34 
refusal to yield to the treatment for rust mite, however, led to the dis- 
covery that it is distinct from rust.! 
The disease is undoubtedly of very recent origin or introduction. 
It has spreat rapidly in the region about Citra, and many of the 
groves there are badly affected. The malady has also been found to 
occur to some extent at Ocala, Stanton, and Sanfor d, and is apparently 
spreading rapidly. 
The foliage of trees attacked by this disease is greatly injured, and 
consequently the general vigor and productiveness of the tree much 
reduced. The growth of young trees is retarded, and they are appar- 
ently permanently stunted if the disease is allowed to continue. The 
fruit produced is mostly disfigured, some of it so badiy as to be unsala- 
ble. This is particularly the case with lemons, they, unlike russet 
oranges, being almost wholly unsalable. At Stanton, where the malady 
occurs in lemon groves to some extent, from 3 to 4 per cent of the fruit 
was affected in 1894 and about 2 per cent rendered unsalable. On badly 
affected grape fruit and orange trees fully 90 per cent of the fruit may 
be more or less disfigured by melanose. Probably 1 per cent of these 
arerendered unsalable. The total damage produced by this malady is 
as yet slight, being about $5,000 annually. It appears to be spreading 
rapidly, however, and may ere long become one of the most common 
and most injurious diseases. Great care should be taken to prevent the 
introduction of this malady into California and other orange- growing 
countries where it is not yet known to occur. 
Symptoms.—The most conspicuous symptom of melanose is the oceur- 
rence of small, dark brown spots on the leaves, young stems, and 
fruits (Pl. VIIT). On the leaves and fruits the individual spots, when 
distinct, are nearly round and are slightly elevated above the surround- 
ing surface. On the stems the spots are usually roundish, but are fre- 
quently somewhat elliptical or oblong and elevated, as on the leaves. 
Only the elevated spot is discolored, the surrounding tissue being of 
normal color. The spots are at first very minute and yellowish. They | 
gradually increase, however, and swell up, changing to dark brown or 
nearly black. Many of the spots finally burst near the center and show 
a small, irregular fissure. Very commonly the under side of the leaves 
show minute depressions, corresponding to the spots located on the 
upper surface. On young, partially grown leaves this latter character 
is usually very evident, each brown spot occurring on a slight eleva- 
tion of the leaf. The spots vary considerably in size, ranging usually 
from 4 to 1 mm. (;3> to =; inch) in diameter. On the common sweet 
orange and sour orange they range in size from 4 to $ mm. (745 to 3) inch). 
On the grape fruit they are from 4 to 1 mm. (5 to =: inch) in diameter, 
the individual spots being usually much larger and more conspicuous 
than on common orange or sour orange. On the common orange 388 
1A eee buenos of the ae ene i ane Fveoe ae a hates feeding 
mite, Phytoptus. 
