What are degree days?
Growing degree days (DD) are a weather-based indicator for assessing crop and pest development. It is a calculation used by crop producers that measures heat accumulation used to predict plant and pest development rates. Growing degrees are defined as the mean daily temperature (average of daily maximum and minimum temperatures) above a certain threshold base temperature accumulated on a daily basis over a period of time. Daily growing degree day values are added together from the beginning of the season. Degree day totals are also used for comparing the progress of a growing season to the long-term average.
Degree Day Development Table
The codling moth, like all insects, is cold blooded. Meaning, the temperature around it determines how fast it grows and how active it is as an adult moth. We can take advantage of this to predict what life stage the majority of the codling moths population are in. Scientists have developed a model that uses degree–days to predict codling moth development. These predictions are summarized in this table.
| Degree day total (+/- 3-5 DD) | Codling moth stage of development |
|---|---|
| 100 | Emergence of 1st brood moths from overwintering larvae |
| 150 | Beginning of 1st brood egg laying |
| 220 | Start of 1st egg hatch (first brood larvae) |
| 500 | End of emergence of 1st brood moths |
| 575 | Start of emergence of 2nd brood moths |
| 650 | End of 1st brood egg hatch |
| 700 | Start of 2nd brood egg hatch (2nd brood larvae) |
| 1140 | End of 2nd brood moth emergence |
| 1160 | Start of 3rd brood moth emergence |
| 1275 | End of 2nd brood egg hatch |
| 1300 | Start of 3rd brood egg hatch |
A complete codling moth degree day development table is also available as a PDF – Full Codling Moth Degree Day Development Table.
More information about the codling moth stages of development, see Codling Moth.
Degree Day Tables
The degree day totals in the table below indicate the predicted stage of development of codling moth populations near specific weather stations located around the valley. Growers and advisors can use the values to determine the life stages of the codling moth in their area. This will help determine the proper time to apply ovicidal and larvicidal products to control each of the codling moth generations if needed.
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2019 Degree Days - South
Data from Osoyoos, Penticton and Summerland comes from Environment Canada.Weather Station Location
Osoyoos Oliver South Oliver Central Cawston Keremeos Penticton Airport Summerland North May 16, 2019 217 234 242 231 236 161 160 May 13, 2019 200 215 224 213 217 146 145 May 10, 2019 172 187 195 179 182 122 131 May 8, 2019 156 170 178 161 163 107 106 May 6, 2019 139 153 161 144 145 94 87 May 3, 2019 117 131 138 123 122 80 78
Data from Oliver south, Oliver north, Cawston, and Keremeos comes from Growers Supply's weather network. -
2019 Degree Days - Central
Weather Station Location West Kelowna Kelowna South Kelowna East Benvoulin Belgo Glenmore Ellison May 16, 2019 168 175 191 190 175 170 169 May 13, 2019 152 160 176 178 160 157 156 May 10, 2019 134 130 144 149 128 140 126 May 8, 2019 108 113 128 134 114 115 114 May 6, 2019 96 101 113 121 101 102 102 May 3, 2019 84 87 99 107 88 90 89 -
2019 Degree Days - North
Data from Salmon Arm comes from Environment Canada.Weather Station
LocationWinfield North Winfield South Bella Vista Vernon North & BX Salmon Arm May 16, 2019 154 149 161 163 119 May 13, 2019 140 135 143 147 105 May 10, 2019 120 114 125 130 92 May 8, 2019 95 91 98 103 66 May 6, 2019 84 79 85 90 56 May 3, 2019 73 69 72 78 46
Data from Oyama, Winfield South, OK Landing & Bella Vista, and Vernon North & BX comes from Growers Supply's weather network.