Cold weather effects on insect populations?
7) Southwestern corn borer: The hard winter should give us some help here. Cold definitely hurts this critter. Thus, it rarely gets much further north than Kentucky and southern Illinois. I expect reduced problems in Tennessee during 2014.
8) European corn borer: This corn borer does just find in both northern and southern geographies. It has a history of being a major pest in the upper Corn Belt.
9) Threecornered alfalfa hopper: Tennessee is about this insect’s upper limit, and I’ve seen slow starts for this pest following previous cold winters. Expect the same for 2014, but populations may still rebound enough to be a problem in wheat beans.
10) Fall armyworm, beet armyworm, soybean looper, and velvetbean caterpillar: These pests typically do not make it through the winters in the U.S., except for extremely southern areas where it does not freeze. Our infestations originate from migratory moths in places like Puerto Rico, Mexico and South America. Thus, mid-southern temperatures do not predict much about the occurrence of these critters.
11) Green cloverworm, yellowstriped armyworm, corn earworm: These are native species with a broad distribution. I do not expected a predictable, negative effect from our hard winter. The corn earworm (i.e., bollworm) may have a little trouble making it through this last Tennessee winter, but it is a very capable migrator. How well it fares on spring hosts to our south probably will have a bigger effect.
12) Fire ants: Yeah, the winter should knock these guys back a good bit in Tennessee. Down but not out! Their distribution will likely continue to ebb and flow northward depending upon how harsh or mild the previous winters have been.
13) Twospotted spider mite: Nah, they will do fine despite the cold winter.
14) Japanese beetles: First found in the Northeast (New York, etc.) about 100 years ago. They have been moving our way ever since. Enough said!
We know less about the survival of the many important beneficial insects that help control insect pests. But bad effects on important beneficial insects favors a rapid build-up of pest populations. So there is some give and take here. Because most insect and mite pests have a high capability to reproduce, they can overcome initially low populations if conditions are favorable during the first generation after winter breaks. In my business, we call this job security!