482 CITRUS FRUITS AND THEIR CULTURE. 



The cause of the trouble is a fungus, the scientific 

 name of which is Leptothyrium Pomi, common in apple 

 districts, where it develops on th.e fruit, both on the tree 

 and in storage. 



The sooty spots consist of a formation of the fungal 

 threads ; on the rind they are black, but viewed under the 

 light, they are light brown in color. The minute spots 

 appear to consist of more closely-woven strands of fun- 

 gus, as though a small spore case were in process of form- 

 ation. Whether this is the case or not, spores, by means 

 of which most fungi are disseminated and propagated, 

 have not yet been discovered in this fungus, and appear 

 in all cases to be entirely lacking. 



Anything which may be said regarding the way in 

 which the fungus spreads must be more or less conject- 

 ural. The fungal threads may become detached and blow 

 about, or it may be that spores, not yet discovered, may 

 be produced. Since citrus fruits frequently grow ic 

 clusters, the fungus may easily spread from one fruit to 

 another. 



So far as has been observed, no damage is done the 

 fruit, but when the fungus is present in abundance, it 

 renders the fruit unsightly, and, consequently, depre- 

 ciates the market value. 



Treatment. Nearly all traces of the fungus may be 

 removed if the fruit is washed, and since it makes its 

 appearance about the time the fruit matures, this is the 

 best possible treatment. It will yield readily to an ap- 

 plication of solution No. 1, but this treatment can 

 scarcely be recommended. 



Melanose. This disease was first brought to notice 

 by Webber and Swingle in 1896. It was quite prevalent 

 in the vicinity of Gitra, Fla., at that time. Since then, 



