166 Proceedings of Indiana Academy of Science 



sprayed check trees was very prevalent and in certain cases was found 

 so severe as to kill the leaves outright. Petiole infection is an impor- 

 tant feature in the life history of this fungus since it has been found 

 that a very high percentage of the twig cankers are at leaf scars and 

 are the result of mycelial invasion from petiole lesions (19). Thus by 

 controlling petiole infection, canker formation will be largely prevented. 

 Observations at Knightstown show that spraying has practically pre- 

 vented all canker formation on the wood formed the years the sprays 

 were applied. R. A. Simpson, at Vincennes, likewise has prevented 

 canker formation with frequent Bordeaux sprays. The importance of 

 spraying every year, regardless of crop, is, of course, evident. Obser- 

 vations indicate that as a summer spray lime-sulphur is not as effective 

 against blotch as Bordeaux mixture. 



Burkholder reports that the disease occurs here and there in north- 

 ern Indiana, mainly on the Mann and Oldenburg varieties, both of which 

 are frequentlj' grown in home orchards. The same observer noted 

 blotch this year in DeKalb, Allen, and Noble Counties and it has been 

 reported from Elkhart and Marshall counties. 



Scab caused by Venturia inuequalis was worse than usual on the 

 foliage this year, not only owing to the early wet spring weather but 

 on account of the great difficulty experienced in properly applying the 

 sprays because of the protracted blooming period which, according to 

 Cullinan, covered almost a month in some localities. In some cases the 

 pink spray or first summer spray was entirely omitted. Undoubtedly 

 the June-July drouth checked scab. H. H. Swaim reported that in spite 

 of its early severity, the disease was well controlled later. Burkholder 

 reports scab woise in northern Indiana than in 1920, especially on Win- 

 ter Banana in DeKalb County and in Wabash County. Gregory re- 

 ported scab severe on Floyd, Decatur, and Shelby counties. Complaints 

 accompanied by scab specimens were received in June from Allen, Clay, 

 Ripley, Steuben, Hendricks, and Wabash counties. Severe foliage in- 

 fection was noted at Mooresville, Paoli, Peru, and Vincennes early in 

 the season. 



Some observations upon varietal susceptibility to scab were made 

 in an unsprayed orchard near Mooresville in September. Foliage infec- 

 tion was severe on Maiden Blush, Pewaukee, Chenango, Benoni, Wealthy, 

 Northwestern, Stark, Jonathan and Indiana Favorite, and was present 

 to some extent but not severe on Grimes, Winter Maiden Blush, and 

 York, while none was noted on Transparent. Fruit infection was noted 

 on Maiden Blush, Wealthy, York, and Jonathan. Burkholder reports 

 severe scab on the Delicious variety. At Peru scab was noted much 

 worse on Ben Davis than on Grimes — in fact practically none was noted 

 on Grimes foliage in October. Unsprayed Ben Davis trees showed very 

 abundant foliage infection of scab in May and in October the disease had 

 caused severe defoliation and a total loss of the crop because of the 

 undersized, malformed, scabby fruit. The Ben Davis fruit responded 

 in a peculiar manner to scab infection in that there was marked hyper- 

 trophy of the tissue beneath older lesions resulting in conspicuous pro- 

 tuberances on the fruit. In other cases old lesions had checked the 



