Cold weather effects on insect populations?
Hey, let’s face it. The reason we have more kinds of bugs in the South is because we have a warmer environment. However, not all insect pests are equally affected. Some are very tolerant of cold weather while others take a hit during a hard winter. Below are some examples.
1) Boll weevil: I know this one is eradicated in the Mid South, but this pest is one reason this question arises so much. Most people recall that boll weevils are sensitive to winter kill, and populations would be substantially reduced the year following a harsh winter.
2) Tarnished plant bug: Sorry, they can tolerate very cold winter, and this species actually occurs well into Canada. Don’t expect much in way of a winter kill, but a cold winter can definitely delay the weedy hosts that support early plant bug populations. How this affects populations that will occur in cotton is much less predictable.
3) Southern green stink bug: This species does not like the cold and rarely occurs in Tennessee except late season and/or after 2-3 consecutive mild winters. We will certainly see reduced populations across much of the South this year. I don’t expect to see one in Tennessee!
4) Green and brown stink bugs: They don’t mind the cold too bad and populations persist well north of Tennessee. They tend to have fewer problems with stink bugs in the Midwest because they have fewer generations and less time for populations to build to economic levels. I’m not expecting much winter impact in Tennessee.
5) Brown marmorated stink bug: An invasive pest from Asia, this species is well established in Pennsylvania, Virginia, Delaware and other surrounding states. It is also well established in the Knoxville and Nashville area. It is invading from the north and appears to do well in the cold. Indeed, hot summers may negatively affect the spread of this pest in the South.
6) Kudzu bug: Another Asian invasive that does not appear too sensitive to cold weather. We will find out more this year. However, both kudzu bug and brown marmorated stink bugs like to overwinter in homes and other structures, so we know some will make it through the winter. Based on its distribution in its native home range, this pest should make it just about anywhere kudzu is common in the South. However, the kick off to seeing the first generation will occur later as you move northward. I expect there is a place where only one generation (as opposed to two) occurs each year. This could be a help, but we don’t know where that line is yet.
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