Brooks : The Fruit Spot of apples 437 



than in other directions. Free-hand and microtome sections of 

 the brown tissue of the inoculations showed that but one fungus 

 was present. There was a good growth of this, and its character- 



istics and its relations to the host cells were the same as are later 

 described for the fungus in the pockets of the host tissue (see page 

 450). Upon transfer to culture media, inoculation tissue gave pure 

 cultures of the above-mentioned fungus. 



The rate of development of the inoculation spots varied greatly 

 with the apple. All of the spots on a particular apple might be 

 as fully developed at the end of two weeks as those on another 

 apple, inoculated on the same day, from the same test-tube and 

 placed in the same moist chamber, were in four weeks. Notes were 

 taken on the acidity, dryness, and texture of such apples, but no 

 conclusion could be drawn as to the cause of the difference in sus- 

 ceptibility of the different apples of the same variety. The results 

 upon other varieties were the same as on the Baldwin except 

 on the Greenings, Yellow Transparents, Astrachans, and Por- 

 ters the browning of the spot developed more rapidly. This fact 

 would suggest that a soft tissue and a readily available water- 

 supply are favorable to the rapid development of the fungus. 



Attempts were also made to inoculate ripe unspotted apples by 

 spraying spores over their surface and by dropping them into solu- 

 10ns that were full of spores, also by placing small pieces of spore- 

 earing agar on the lenticels. The apples were placed in a moist 

 c amber and left until decay began. Only negative results were 

 tamed in such cases. The apples used were Porters and Bald- 

 ns - Unfortunately, the above test has never been made when the 

 a PPles were passing through the "after-ripening " stage. 



that 



Field work 



rom tne theoretical as well as the practical standpoint it was of 



e rest to determine when and under what circumstances the fun- 



gUS gained entrance to the apple and how this infection could be 



v ented. Spraying experiments made in the summer of 1906 



furnish 



ttents 



ed some suggestions in this matter. 

 ' Un ^cides. — The Bordeaux mixture used in these experi- 



to fif WaS made W ' th five P ounds each o( lime and C0 PP er suI P hate 

 ty S all °ns of water. The " K. L. B. P." was similar Bordeaux 



