Temperatures and Insect Activity

Wake Up Sleepy Head!


It is that time of year where the last remnants of winter are slowly fading and melting away. Plants and insects seem to be slowly becoming more active. You may be asking yourself, why? How do they know to get going on their life cycles? The answer is simply temperature.


All Plants and insects develop in response to temperature. The warmer the weather, the more quickly they develop, and the cooler the weather the slower they develop. Not all trees and insects develop at the same time or rate.  All species have a cutoff temperature below which no development occurs. This base temperature differs depending on species.


Silver Maples are one of the first trees in our area to flower. You may have noticed this start to happen already, especially in Waukesha County. As the average temperature increases above the cut off temperature, development occurs in both trees and insects. The higher the temperature, the faster the development moves.  The most common cut off temperature is 50 degrees F. This is the temperature at which dormancy is broken in plants and when many insects become active. This base temperature is often noted following the abbreviation for degree day, DD.


Degree days are accumulated whenever the temperature exceeds the predetermined developmental threshold. Wow, that seems kind of complicated! It really is not so bad; the basic procedure for calculating degree days is very simple. First determine the daily average temperature by adding the daily high temperature and low temperature together and dividing by two. Next take that number and subtract the base temperature.


To keep track of degree day accumulation simply keep a total of degree days starting from the first of the year. In Wisconsin we do not typically start collecting degree days until the beginning of April. If this seems like a lot of mumbo jumbo to keep track of you are right.


That is our job at Hoppe Tree Service. Our plant health care manager Brad Hill keeps track of accumulating degree days so that we can be out at the correct times to properly protect your high value plants from our common and uncommon disease and insect issues. By using degree days in our custom integrated pest management programs, we can be more accurate, use less chemicals in our environment, and produce results that are in line with our clients’ expectations.







If you are interested in more information check out the links below.

-Computerized degree day calendar:


-Degree Days for common landscape insect pests:


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