14 



REPORT OF THE FIRST SEMI-ANNUAL MEETING 



the fungi mentioned nor the bacteria penetrate in great quantity 

 into the fruit, nor do they appear to have a very rapid or pro- 

 nounced effect in causing softening and decomposition of the flesh. 

 While they v^ould doubtless spoil the fruit for market purposes, 

 they represent rather superficial decays, and the fruit could be 

 utilized after they had commenced to make their appearance on 

 the surface without great loss, provided they did not become very 

 active until time when the fruit Avas ready to use. As to whether 

 any of these organisms cause the spoiling of the flesh in the early 

 stages of their attack, I have not been able to determine as yet. 



''However, one of the fruits brought to me on September 21st 

 had a rot which from its appearance would lead very promptly to 

 the suggestion that it might be a very important matter for the 

 avocado grower. The fruit of this set was Chappelow and s])eci- 

 mens were very nicely developed individuals of this very attractive 

 little variety. The spot in question was about one and one-half 

 inches in diameter, with the center located near the base of the 

 neck of the fruit. The color was a dull greenish, considerably lighter 

 than the fine deep purple of the normal fruit. In the center of the 

 spot about half the area was rough and somewhat wrinkled and 

 blackish, while the outer part of the spot was Avrinkled somewhat, 

 as though the flesh below had sunken and the skin become thinner 

 and more transparent, but is still as glossy as in the healthy condi- 

 tion. Some whitish tufts of fungus were emerging here and there 

 over the surface, especially near the center of the spot, and it is 

 almost certain that more than one kind of fungus was growing in 

 this area. It seemed apparent at once that we had to do here with 

 some specific rot of the avocado fruit of a rather more violent nature 

 than in the spots which were thickly scattered over the surface of 

 the fruits. 



"On microscopic examination some fruiting bodies were found 

 below the surface in this large rotted area, and spores were found 

 in them which were very pale yellowish, one-celled and formed on 

 short pedicels. 



*'In order to discover the cause of this peculiar rot the surface 

 of the fruit in the outer area of the spot was sterilized by washing 

 with formalin, and with hot needles a little of the flesh was removed 

 from below the surface and planted in an artificial culture medium. 

 Some of this same material examined miscroscopically shoAved 

 large fungus threads here and there passing through the flesh. Bac- 

 teria were not recognized in the deeper layers. Bacteria cultures 

 were also made from this flesh by macerating some of it in Avater 

 and diluting by the ordinary bacterial methods. Only one set of 

 such cultures was made, but absolutely no bacteria grew, indicating 

 that this decaying flesh does not contain bacteria. In two days 

 after planting the pieces of decayed flesh in artificial medium Ang- 

 orous growth of a strong fungus mycelium developed from every 



