In my experience, unexpected cold temperatures do very little to impact our most common garden pests. Yes, it may kill the active adults....but eggs and nymphs are how these critters overwinter, even in very frigid temperatures.

I lived in a semi-tropical area for many years. Aphids, for example, were active all year long! Every once in awhile, after deep, sub-freezing temperatures, everyone would be proclaiming a reprieve from pests.

Ha! Within a day of normal temps, aphids would be back.

Depends, I would think. If the pest is something that normally overwinters, then maybe a little extra predation and other death might happen compared to a mild winter. But if the pest is something that has really blossomed in numbers because of recent mild winters, then a long cold winter should knock them back considerably. I'm thinking of the nematodes in particular. Where I am is a borderline area for them since they don't withstand freezing well. Hopefully this winter will knock them back to the almost unnoticable population of a few years ago, after our last freezing winter. And of course that depends on whether the weather stays cold. Can't rule out another 80ð January/February yet.

I agree with sunnibel7. If you live in a warmer climate and the pests are used to having mild winters, I would think the severe cold would have an affect on the next year's pest population. However, like here in Michigan where it usually gets cold the pests are used to it. So a quick cold snap like this isn't going to due much in terms of pest control. The adult pests have laid their eggs already, the adults are dead, and the immature stages of the bugs are already overwintering.

Rodney