DIVISION OF BOTANY 491 



SESSIONAL PAPER No. 16 



A ' STORAGE ' SPOT OF THE APPLE. 



Apples in storage are liable to a variety of maladies which often give serious 

 trouble and result in much depreciation in value. A case of spotting of stored apples 

 was brought to the notice of the Division during the year and investigated by Mr. 

 Eastham who contributes the following account: — 



In the Fall of 1912 a correspondent sent in some Gravenstein apples from North 

 Sydney, N.S., affected by a peculiar spotting, with the enquiry whether this could be 

 due to the use of arsenate of lead as an insecticide. Later, this correspondent sent 

 apples similarly affected from his own orchard, together with the following state- 

 ment : — 



' The lime-sulphur I used was made by the Niagara Spray Co., Kentville, N.S., 

 and tests almost 32. 5B. Swift's arsenate of lead was also used, about 6 lbs. to 100 

 gallons. As far as I know all trees were sprayed in the same way. The weather con- 

 ditions were noteworthy in this respect, that following a very hot spell for ten days 

 the 1st of July we then for the next six weeks had one of the wettest seasons on record, 

 and consequently a very great growth of Black Spot. Only the late sprayed and well 

 sprayed orchards escaped. You will notice no Black Spot on sample sent. I have not 

 noticed this injury on any other apple except the Gravenstein. 



I first noticed the injury in Montreal at The manager had 



just opened some barrels of N. S. Gravensteins. He said the apples were not keeping- 

 well and he had put the price down 50 cents a barrel in consequence. I asked to see 

 them and found the apples in the top of the barrel that had stood opened the day 

 before as a sample, covered with this rusty injury. This did not extend to the fruit 

 further down in the barrel, and on opening other barrels it was not found, but the 

 manager said if exposed to the air they would show it in twenty-four hours. These 

 f,ppl6s were only just beginning to ripen. The injury did not appear on my own 

 apples home for six weeks to two months afterwards." It was also stated that .->: 

 sprayings were given. 



The spots varied in size from J m.m. up to 5 m.m. in diameter, those of the latter 

 size being circular, triangular or irregular. They were depressed, brown in colour, 

 darkest in the centre round what, in many cases, appeared to be a lenticel. The smaller 

 spots were by far the more numerous, as many as thirty-five being counted to the 

 square centimeter but more commonly five to ten. In the case of the very smallest 

 spots, the injury did not appear to go through the skin, the underlying tissue being 

 sound. In the other spots, however, the underlying tissue was brown. The spots were 

 much less plentiful and less conspicuous on the side of the apple exposed to the sun, 

 being often hardly observable on the ' coloured ' area. They seemed to be slightly 

 more abundant at the calyx end. Where they were very numerous there was a tend- 

 ency for the entire surface to show discolouration. 



On December 3rd, after the apples had been placed in cold storage twenty-four 

 hours, two similar ones were taken out and treated as follows: On one a circle 15 m.m. 

 in diameter, was drawn in ink enclosing twenty spots, none move than half a m.m. 

 in diameter. This apple was placed under a bell-jar and kept at the ordinary labora- 

 tory temperature which varied between 60° and 80° F. The other was similarly 

 marked with a circle about 12 m.m. in diameter, and enclosing fifteen spots of a size 

 similar to those of the first specimen. This apple was placed in cold storage. On 

 December 23, none of the spots in the areas marked showed any appreciable enlarge- 

 ment in either of the apples. However, both apples by this time, but especially the 

 one kept at room temperature, were badly rotted, although the rot had not extended 

 into the areas marked. Whether the rot had started from similar spots as well as 

 from bruises and abrasions could not be positively determined, although I think it 

 likely. 



Cultures were next made as follows: The apple v/as wiped, immersed for one 

 minute in 1-1000 mercuric chloride and then rinsed in sterile water and 



