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Degree Days - long description file

Title of table: 2010 Degree Day Monitoring Results

Monitoring start date was March 17th; table heading is “Cumulative Degree Days” (using a base temperature of 50°F)

First location in the table: Columbia Falls; April 9th = 3.7 degree days; April 30th = 14.6 degree days; May 7th = 60.1 degree days; May 17th = 80.5 degree days; May 17th = 80.5 degree days; May 23rd = 131.7 degree days and May 27th = 221.5 degree days (this last value of 221.5 is denoted with double asterisks after it, which a note below the table explains as follows: tipworm eggs & larvae found (in the tips of brand new shoots – brand new shoots were everywhere in the beds, rising up from the runners).

Second location in the table (2nd row): Deblois; April 9th = 47.2 degree days; April 30th = 64.1 degree days; May 7th = 144.1 degree days (this value is followed by a single asterisk, which a note below the table explains as follows: 1 male tipworm fly found (female tipworm flies were found on May 13th in Deblois and the degree day total at that time was only 168.7) – So they appeared earlier than expected; target number was 228 based on my findings from 3 years of monitoring their emergence at a site in Troy; begs the question, ‘How reliable is degree days at predicting tipworm fly emergence?’ – it seems that the number of degree days needed is far too variable from year to year to place much faith in it. Next date is May 17th = 197.6 degree days; May 23rd = 279.5 degree days; May 27th = 398.8 degree days and this entry also has the double asterisks for the same note that corresponds to the Columbia Falls May 27th date when tipworm eggs and larvae were found in the tips of brand new shoots.

Third location in the table (3rd row): Aurora; April 9th = 23 degree days; April 30th = 56.1 degree days; May 7th = 138 degree days; May 17th = 196 degree days; May 23rd = 286.4 degree days; May 27th = 386.8 degree days followed by a diamond which signifies that “No tipworm found (not even flies); Plants did not have new shoots yet; they were still in the bud-break stage (even though the degree days were very high—well past the value when the tipworm should have been present).”

Fourth location in the table (4th row): Etna; April 9th = 31.6 degree days; April 30th = 40.5 degree days; May 7th = 110 degree days; May 17th = 145.2 degree days; May 23rd = 208 degree days and May 27th = 293.7 degree days. The May 23rd value of 208 has a triangle after it to denote the following: “Tipworm eggs & larvae found on tips from Troy (near Etna), on May 21st [But degree days through May 21st in Etna were only at 183.5 and given how close Troy and Etna are on a map, you would expect the degree days to be similar, meaning the number of degree days in Troy would also be expected to be somewhere around 183.5 when the tipworm eggs and larvae were found, but 183.5 is a fair amount less (i.e. sooner) than the ‘fly’ target of 228, when the first flies would be expected, say nothing about eggs and larvae]

Finally, there is a note in parentheses beneath the table that says: “Large amount of variation between some of the sites”

 


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