Using insect traps and careful scouting to monitor pest activity are a good start. But there's another important tool to improve pest management decisions and results.
Degree days are units of measurement reflecting just how hot or cold the weather is.
This is useful because insect, disease and weed pests develop more rapidly when temperatures are warmer. Your past experience tells you that on average, it takes 14 days for a specific insect pest's eggs to hatch. But in colder years, the eggs hatch after the 14th day, and in warmer years, eggs hatch sooner. Degree days express these temperature differences with greater precision. By using degree days, you can time your spray according to the insect's temperature-driven rate of development.