A large amount of insect mortality occurs in winter. Insects perish because of cold temperatures and natural diseases that attack them while they are in the resting stage.

Many pests are impacted by winter's climate conditions. For the most part, fungus spores are highly resistant to winter conditions, but are much more sensitive to tillage than certain weeds and insects.

Grubs, for example, exist as larvae during winter and many are killed by a pathogen that infects their outer skin, which desiccates (dries out) the body.

Some insects, which normally during winter are in surface residue (leaves, weeds, etc.) or soil, don't locate themselves deeply enough in the soil to survive winter and can be killed by cold temperatures.

The winter of 2013 - '14, since it was so severely cold, may have caused a decrease in the number of insects and may bring decreased insect pressure this growing season.

In a winter of mild weather, some insects start growing and then, if temperatures turn sharply cold, many insects will perish. A lot depended on the temperatures in February, the particular insect and the amount of snowfall. Snow insulates the soil and lessens the mortality of insects.

Flea beetle populations are elevated when February temperatures are mild. Insect hatches usually occur when the host (preferred food of the insect) is present. If the host is not present in sufficient quantity to support the insects when they hatch, then the insects will die. This is why crop rotation is critical because by rotating the crop, the insect life cycle is broken and the insect population plummets.

Since the brown marmorated stinkbug will "hibernate" in our homes and other sheltered areas, the cold winter probably did not have any effect on cutting back on their numbers.

We will just have to wait and see if the the recently-concluded brutal winter has had a significant effect on the Lehigh Valley insect populations.

"Growing Green" is contributed by Lehigh County Extension Office Staff and Master Gardeners. Lehigh County Extension Office, 610-391-9840; Northampton County Extension Office, 610-746-1970.