PEACH SCAB AXD ITS CONTROL. 



39 



of infection by water-bome spores from lesions upon the subtending t^vig, only about 

 2.5 uniformly scattered infections occurred. In striking contrast, the three fruits 

 immediately adjacent, with excellent conditions for infection of this tj-pe, developed 

 about 225 lesions each. Instead of being uniformly scattered over the wettable sur- 

 faces of the fruits, as would be expected had they resulted from wind-blown spores, 

 these lesions were massed about the peduncles and over the proximal portions of the 

 wettable surfaces, gradually becoming less abundant toward the apices. Again, had 

 the infecting spores been wind blown, the infection should have been practically 

 equally prevalent and similarly situated upon the four fruits in question. 



Table VIII. — Summary of observations concerning the occurrence and location oj scab 

 lesicms on unsprayed Elberta fruits and twigs in relation to spore dissemination, 

 Cornelia, Ga., July 2-3, 191S. 



[The observed infections were on the wettable surfaces of the fruits, while the protected surfaces were not 



infected.] 



Fruit 

 No. 



Esti- 

 ma- 

 ted 

 le- 

 sions. 



Distribution 

 of lesions. 



1 I 

 Distance Facilities 

 from pe- for infec- j 

 duncle to tion by 

 nearest water-borne | 

 lesion on , spores from 

 subtending subtending ! 

 twig. twig. 



1 



Fruit 

 No. 



Esti- 

 ma- 

 ted 

 le- 

 sions. 



Distribution 

 of lesions. 



Distance 

 from pe- 

 dimcle to 

 nearest 

 lesion on 

 subtending 

 twig. 



Facilities 

 for infec- 

 tion by 

 water-borne 

 spores from 

 subtending 

 twig. 



1... 

 2... 

 3... 



4... 

 5... 

 6... 



7... 



8... 



9... 

 10... 

 11... 

 322.. 

 13... 

 14... 

 15... 

 16... 

 17... 

 18... 

 19... 

 202.. 

 21... 

 22... 

 23... 

 24... 

 252.. 



Xum- 

 ber. 

 2.50 

 250 



20 

 225 

 225 

 250 



12 

 2.50 



12 

 250 

 250 



20 

 225 

 225 

 250 



20 

 250 

 250 

 250 



25 



25 

 250 

 250 

 250 



12 



Aggregated . 

 do 



Scattered.. . 



Aggregated . 



do 



do 



Scattered... 



Aggregated . 



Scattered.. . 



Aggregated.. 

 do 



Scattered.. . 



Aggregated.. 



do 



do 



Scattered 



Aggregated. . 



do 



do 



Scattered... 

 do 



Aggregated. . 



do 



do 



Scattered... 



Cm. 

 0.5 

 .5 



": 



.5 

 1 



(1) 

 .5 



^^5 

 .5 



2 

 .5 

 .5 

 .5 



4 

 .5 

 .5 

 .5 



6 



6 

 .5 

 .25 



1 

 16 



Excellent . . 

 ...do 



None 



Excellent . . 



...do 



...do 



Kone 



Excellent . . 



None 



Excellent.. 

 do 



None 



Excellent . . 



...do 



...do 



None 



Excellent . . 



...do 



...do 



None 



Poor 



Excellent . . 



...do 



...do 



None 



26... 

 27... 

 28... 

 29... 

 303.. 

 31... 

 32... 

 33... 

 34... 

 35... 

 36... 

 37... 

 38 3.. 

 39... 

 403.. 



412.. 



42... 

 432.. 

 44... 

 45... 

 46 3.. 

 47... 

 48 2.. 

 49... 

 50... 



Num- 

 ber. 



25 

 250 



10 

 250 



12 

 250 



40 



60 

 200 

 225 

 225 

 225 



25 

 250 



20 



25 

 250 



10 

 100 

 250 



12 

 250 



25 

 225 



30 



Scattered... 



Aggregated . 



Scattered.. . 



Aggregated . 



Scattered.. . 



Aggregated . 



Scattered... 



do 



do 



.Aggregated.. 



do 



do 



Scattered... 



Aggregated.. 



Scattered... 

 do 



Aggregated.. 



Scattered... 



Aggregated.. 

 do 



Scattered.. . 



Aggregated.. 



Scattered. . . 



Aggregated.. 



Scattered... 



Cm. 

 16 



.5 

 20 

 .5 

 (') 

 .5 

 4 

 (1) 



'\ 



1 



1 



4 



.25 



G) 



(') 



.5 

 (1) 

 1 

 .25 



«1 



.5 



Poor. 



Excellent. 



Poor. 



Excellent. 



None. 



Excellent. 



Poor. 



None. 



Do. 

 Excellent. 



Do. 



Do. 

 None. 

 ExceUent. 

 None. 



Do. 

 Excellent. 

 None. 

 Excellent. 



Do. 

 None. 

 ExceUent. 

 None. 

 ExceUent. 



Do. 



1 No lesion on subtending twig. , 



2 Fruit, apex up, borne upon a short spur. 



3 Fruit in favorable position for infection by water-borne spores from lesions on subtending twig, but not 

 such lesion present. 



These data shovr (1) that every badly diseased fruit observed 

 developed under excellent conditions for infection by means of 

 conidia from twig lesions; (2) that in all cases where conditions were 

 favorable for the passage of water-borne spores from lesions on the 

 subtending twigs down the peduncles and over the wettable surfaces 

 of the fruits severe infection resulted, the disease uniformly appearing 

 most abundantly on the areas obviously most subject to this type of 

 dissemination; (3) that in all cases where conditions precluded this 

 type of dissemination only sparse infection occurred, the lesions being 

 miscellaneously scattered over the wettable surfaces of the fruits in a 



