6 BULLETIN 684, U. S. DEPARTMENT OF AGRICULTURE. 



year the fungus is usually to be found. However, neither furnished 

 a good medium for the fungus, and as a result the number of spores 

 (usually conidia) produced is quite small compared with the number 

 which the fungus produces when growing in a newly rotted fruit of 

 the current season. The size of the spores is usually somewhat re- 

 duced also, 



A mummy hanging on a tree furnishes a medium which is de- 

 ficient in moisture and in plant food. In the case of the rotted 

 apples on the ground the bitter-rot fungus must compete with many 

 of the mold and rot fungi and bacteria which are less susceptible 

 to cold and which are true saprophj'^tes. In examining rotted fruits, 

 one finds a mixture of the spores of the bitter-rot fungus and those 

 of various molds, together with numerous bacteria. 



In both Virginia and Arkansas orchards, mummies and rotted 

 fruits undoubtedly are important sources of infection. The writer 

 has examined infected orchards in Arkansas in which bitter-rot 

 mummies and rotted fruits of the preceding year were abundant in 

 the trees and on the ground and in which no other sources of in- 

 fection could be found. Some of the most seriously infected or- 

 chards which the writer has seen, however, were Arkansas orchards 

 from which the mummies and rotted fruit had been removed. Gen- 

 erally, in Arkansas few mummies are to be found in the trees, and 

 as nearly all growers practice clean cultivation throughout the 

 earlier part of the season those which have fallen to the ground 

 have been turned under. It has been a common practice, too, for 

 the grower to gather up and haul to evaporating plants the best of 

 the dropped fruit and to sell the rotten and diseased fruit to the 

 distilleries. 



The writer agrees with Alwood and Scott that mummies are the 

 chief sources of infection in the orchards of Virginia. In that State 

 the Yellow Newtown variety, known locally as the Albemarle Pip- 

 pin, is the commercial variety which is damaged to the greatest 

 extent by the disease. This variety is grown for the most part in 

 coves of the Blue Eidge, situations which usually do not admit of 

 cultivation. These trees do not come into bearing until they are 

 about 15 years old, and they are very long lived. Accordingly, most 

 of them are rather old and quite large. The dropped fruits 

 have no economic value. There are many reasons, therefore, why 

 rotted fruits should be left on the ground. There are usually some 

 mummies also to be found hanging on trees of such size. The writer 

 counted more than a hundred on one tree, which, however, was an 

 unusual number. In Virginia he was easily able to trace the source 

 of clumps of rotted fruits to mummies hanging in the trees. This 

 is readily done if examination is made shortly after the first out- 

 break of the disease. 



