214 Report of the Department of Botany of the 



■ 



apples the injury usually appeared in the form of lenticel spotting 

 while on Baldwin it more frequently resembled " scald," a trouble 

 of stored apples in which the skin becomes brown over large irregular 

 areas with indistinct boundaries. 



That formaldehyde, also ammonia, may cause lenticel spotting 

 of apples has been announced previously by Norton 42 who points 

 out that on the variety Jonathan the injury closely resembles the 

 Jonathan fruit spot disease described by Scott. 43 



EFFECT ON GERMINATION AND GROWTH. 



Throughout this bulletin lenticel spotting is referred to as injury 

 and when no lenticel spotting occurred it has been stated that there 

 was no injury. The question naturally arises, are tubers which show 

 only lenticel spotting really injured for seed purposes? It may also 

 be asked if tubers which show no lenticel spotting are certainly 

 unharmed for use as seed. Our experiments have not been carried 

 far enough to enable us to answer these questions fully. The 

 sprouting of the tubers has been observed in all of the experiments 

 and in a few of the experiments the tubers were planted in the green- 

 house and kept under observation until the plants were about six 

 inches high, but none were followed through to maturity. Judging 

 from, the observations made we are of the opinion that there may be 

 considerable lenticel spotting without material injury to the tubers 

 for seed. No matter how severe the lenticel spotting, sprouting 

 usually appears to proceed normally provided there are no areas of 

 dead brown tissue surrounding the eyes. However, exceptions to 

 this have been seen occasionally. Treated tubers which are free 

 from lenticel spotting may be regarded as safe for planting. 



IS FORMALDEHYDE SOLUTION WEAKENED BY 



REPEATED USE? 



The discovery that potatoes exposed to formaldehyde gas adsorb 

 or hold upon their surface large quantities of the gas caused 

 the writers to inquire if in the liquid treatment of potatoes for scab 

 the formaldehyde solution might not be materially weakened by 

 repeated use through the removal of formaldehyde adsorbed by the 



^Norton, J. B. S. Jonathan fruit spot. Phytopath. 3:99-100. Ap. 1913. 

 « Scott, W. M. A new fruit spot of apple. Phytopath. 1:32-34. F. 1913. 



