104 MANUAL OF FRUIT DISEASES 
in many cases for producing wounds through which Clitocybe 
parasitica may enter. 
Control. 
This root-rot disease is subject to the same remedial measures 
as those prescribed for the Armillaria root-rot. (See page 100.) 
REFERENCE 
Wilcox, E. M. A rhizomorphic root-rot of fruit trees. Oklahoma 
Agr. Exp. Sta. Bul. 49: 3-32. 1901. 
Sooty-BLotcH AND FLY-SPECK 
Caused by Leptothyrium pomi (Mont. and Fr.) Sace. 
Certain varieties of apples show this very familiar disfigura- 
tion. The Rhode Island, Peck Pleasant, Rome, Baldwin and 
Northern Spy are regarded as most susceptible, although in 
general the disease is most noticeable on light-colored varieties. 
English growers find that the Newton Wonder is affected more 
than other varieties. This disease is also found on pears, 
particularly on the varieties Anjou and Lawrence. 
The injury produced is not deep-seated, consequently the 
disease is not so serious from the standpoint of destructiveness 
as would first appear. The growth of the affected fruit is not 
checked, nor does the real quality of the fruit seem to be im- 
paired. But the apple is blemished and thus it may be ren- 
dered unmarketable; at all events, fruit affected with sooty- 
blotch is less salable than clean fruit. While the chief loss lies 
in the lowering of the market value of the fruit, it should be 
noted that later ill effects are sometimes shown in the wilting 
of affected fruit and even in the decay induced by organisms 
which are always ready to take advantage of a weakened apple. 
Although no dollar estimates of losses incurred by this disease 
are at hand, its economic importance cannot be questioned. 
