38 BULLETIN 395, U. S. DEPARTMENT OF AGEICULTUKE. 



meteoric water appears to be peculiarly well adapted to the perform- 

 ance of this function. 



OBSERVATIONAL DATA. 



Careful field observations extending through several seasons yielded 

 results which accord thoroughly with those of the preceding experi- 

 ments. Examinations of large numbers of typically affected fruits, 

 usually upon midseason and late varieties where the disease had 

 reached its fuU development, showed two distinct types of infection, 

 viz, (1) abundant infection extending from the depressions about the 

 peduncles well over the wettable surfaces of the fruits and (2) sparse, 

 scattered infections rather uniformly distributed over the wettable 

 surfaces. In the former type, the lesions, numbering usually about 

 200 to 300, were uniformly most abundant about the attachment of 

 the peduncles and over the proximal portions of the wettable sur- 

 faces of the fruits, frequently becoming confluent over considerable 

 areas, but normally occurring less abundantly toward the distal por- 

 tions. In the latter type the lesions usually numbered less than 50, 

 while their position showed no relationship to the peduncles. Fruits 

 of the former type were, almost without exception, borne in close 

 proximity to twig lesions, in such position that spores could be washed 

 down the twigs to the peduncles and thence over the wettable sur- 

 faces of the fruits. Those of the latter type were as uniformly borne 

 in positions which precluded this method of dissemination. When 

 infection is very severe, as upon badly diseased late varieties, these 

 types have been observed to merge into each other. 



In order to secure definite data, observations were made at Cor- 

 neha, Ga., on July 23, 1913, upon 50 fruits selected at random from a 

 large number of trees in a badly diseased imsprayed Elberta orchard. 

 Notes were made concerning the approximate number of infections, 

 the areas upon which they occurred, the areas upon which no infec- 

 tion occurred, the proximity of lesions upon the subtending twigs, 

 and the facility with which spores from the twig lesions might be 

 transferred to the fruits by means of meteoric water. The results 

 are summarized in Table VIII. 



Certain striking relationships which can not be brought out in the 

 table are here set forth : 



Notes supplementing Table VIII. — No. 34 was borne in a horizontal position upon 

 a short spur, with no chance of infection by means of water-borne spores from the 

 subtending twig. About 5 cm. above the wettable surface of the fruit, however, 

 numerous lesions occurred upon a horizontal twig. Thus, it is obvious that the abun- 

 dant infection was induced by water-borne spores from this source. 



Nos. 38, 37, 36, and 35 occurred, in the order here given, almost in contact (peduncles 

 at intervals of about 10 cm.) upon a single twig which sloped at an angle of about 15°, 

 with the distal end lower. The striking differences in infection are worthy of special 

 emphasis. In the case of No. 38, the fruit nearest the base of the twig with no chance 



