Try to think of one good thing that came from the couple of bitterly cold stretches we’ve had so far this winter…I know…it might be difficult…I’ll give you a minute! 😉
Agronomically, there might not be many. Could soils have gotten cold enough to initiate freeze-thaw cycles to help alleviate compaction? Possibly. Maybe a few insect pests froze, reducing next season’s feeding pressure? Not likely.
Insects actually handle cold pretty well. For those overwintering in soil (wireworms, Japanese Beetles, etc..), soil itself actually provides them with good insulation against the coldest temperatures. The snow cover prior to the cold snap helped buffer soil temperatures even further. In fact, data from Kansas Mesonet (https://mesonet.k-state.edu/) stations in Corning (7 day chart above) and Oskaloosa (7 day chart below) confirm soil temperatures have barely reached freezing much below the surface. Soil temperature at these stations is taken under grass so are buffered a bit, but neither the two or four inch soil temperature has yet touched the freezing mark.
Bean leaf beetles overwinter in more exposed areas with a greater potential for exposure to cold injury, but even they find ways to protect themselves against cold. Natural body mechanisms (European corn borer larvae produce glycerol, a biological antifreeze) can help, but even many freeze susceptible insects won’t experience much mortality until temperatures drop to -4 F – and often lower. We don’t see soybean aphids, but they overwinter as eggs and can tolerate temperatures as low as -29 degrees F!
Remember: many insects don’t overwinter here and are therefore unaffected by our cold temperatures. Fall armyworm, black cutworm and corn earworm all prefer warmer climates and tend to migrate north during the growing season.
That’s not a very positive outlook, but remember: if the damaging insect has survived, beneficials likely have as well. That’s good news for parasitoids and other natural predators that can help us keep damaging pests at bay.
