Apple rust . noted that there were very few appleleaves infected at this time and this is readily accounted forby the fact that measurements of a number of buds in differ-ent sections of the orchard on April 15th showed their averagelength to be only ^ inch to ^ inch. April 18th there was a thunder shower, but this had littleeffect on the cedar galls. York Imperial apple trees were in full bloom April 25thand 26th. April 27th there was an intermittent rain throughout theday and there had been some the preceding night, but therewas no evidence of sporidia discharge or apple leaf infectionas a r
Apple rust . noted that there were very few appleleaves infected at this time and this is readily accounted forby the fact that measurements of a number of buds in differ-ent sections of the orchard on April 15th showed their averagelength to be only ^ inch to ^ inch. April 18th there was a thunder shower, but this had littleeffect on the cedar galls. York Imperial apple trees were in full bloom April 25thand 26th. April 27th there was an intermittent rain throughout theday and there had been some the preceding night, but therewas no evidence of sporidia discharge or apple leaf infectionas a result. The relatively low, and decreasing temperaturewhich prevailed during that day and until ten oclock the [ 1915] Apple Rust 19 next morning, may have prevented sporidia discharge, untilthe sori had dried up sufficiently to hinder it. A section of the chart showing humidity and tempera-ture for that period is reproduced below: FRIDAY SATURDAY SUNDAY MONQ TEMPERATURE HOUR LINES INDICATED IN TOP MARGIN. HUMIDITY HOUR LINES INDICATED IN BOTTOM MARGINHygrotherrnograph record from Friday, April 25th to Monday, April 28th, 1913. There was no more rain until the morning of May 14thbut it continued for about three to five hours at that the afternoon it was cloudy and sporidia were dischargedfrom the cedar apples in great numbers. White cards ex-posed just below good sized rust galls showed a very distinctyellow coating in two hours. There was no evidence of appleinfection as a result of the sporidia discharge which tookplace that afternoon. Twigs of York Imperial apple treesthat were covered with sacks on the morning of May 15thwere as well protected from the rust as others right besidethem which were sacked on the 14th. Conversely, twigswhich had been previously sacked for two weeks to excluderust infection and which were uncovered on May 14th, showedno more rust than similar twigs uncovered on the 15th. Thiscan only be accounted for by the quiet condition of the aird
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Keywords: ., bookcentury1900, bookdecade1910, bookidapplerust154, bookyear1915
