Does a warmer winter mean more pests to manage during spring and summer?  Actually, there are a few other factors to consider before concluding this theory.

  1. Insects that overwinter below ground (Japanese beetle grubs) might not be affected by a mild winter because soil temperatures tend to be more constant. If the frost layer is deep, the survival rate may be lower.  If the frost line is shallow, there may be more survivors.
  2. Temperature is the key to all insect development. Have you seen a slow moving fly a few weeks ago, on a warm winter day? The higher winter temperatures “wake up” and activate the insects such as the common house fly, or woolly bear (caterpillar). They are using up stored fats they depend on to survive until the spring. Without access to food, these active insects could starve to death before food becomes available.
  3. Most insects adapt to cold winters by slowly preparing in the fall and staying dormant until the spring. Therefore, large temperature swings can be detrimental to insects… (There was at least one day this winter, from what I remember, where the temperature dropped a total of 50 degrees within just two days!).  We could expect some insect mortality due to cold intolerance when regularly fluctuating from 0-50 degrees.