Insects require a certain amount of heat to develop from one stage in their life cycle to another (eggs to larvae to pupae to adults). Degree-days measure insect growth and development in response to daily temperatures. The accumulation of these degree-days can be measured over a period of time and used to estimate growth and predict insect development. Calculating degree-days allows us to predict when significant biological events such as the appearance of insect pests may occur or when they may reach a life stage that is damaging to a particular crop.
Fortunately, we have at our fingertips a calculator that can help us calculate degree-days for selected pests. The Pest Degree Day Calculator is a result of a collaborative scientific effort that combines daily weather data collected by the Water and Atmospheric Resources Monitoring (WARM) Program (Illinois State Water Survey, Prairie Research Institute, University of Illinois) and the Integrated Pest Management (IPM) Program (Department of Crop Sciences, University of Illinois) to provide daily, up-to-date information about pest and crop development in Illinois. Many of you may utilize the calculator to predict cutting dates in your area for black cutworm or to identify when rootworm hatch may be occurring.
We are working hard to improve our Degree Day Calculator. Let us know what you like, don’t like, or what you would like to see changed. Take our survey to share your thoughts: https://illinois.edu/sb/sec/1753389. Thanks in advance for your help!