PUBLISHED ON February 29th, 2012
As any Oregon pest control professional can tell you, it’s difficult to predict insect populations according to weather patterns because there are many different factors to consider for each species. Weather impacts everything from soil moisture levels to survival rates for insect predators and parasites. Still, as passionate Portland pest control gurus, we enjoy thinking about how different weather trends could affect pests.
The truth is that it’s probably too early to accurately forecast what influence Oregon’s dry, warm winter will have on insects and rodents. After all, if March’s weather is cold and wet, pests will have an entirely different set of variables to contend with. However, our extensive pest control experience has taught us a few things about how different pest populations could be impacted if our weather stays dry and warm.
The first thing to recognize when trying to predict springtime pest populations is that insects are cold-blooded. Because they cannot create their own internal source of heat as warm-blooded animals do, insects must deploy overwinter survival strategies. Otherwise, if the temperature drops below the melting point of their body fluid, insects risk freezing to death.
Some insects, such as the Monarch butterfly, actually migrate to follow warmer temperatures. Others, including ladybugs, increase their chances of survival by piling on top of each other to share body heat. A few species “hibernate” underground as adults – beetles and ants are included in this category. (The scientific term for this state is diapause.) Finally, many insects bury their eggs below the frost line. The eggs hatch when temperatures grow warm enough to sustain cold-blooded creatures.
Therefore, mild winter temperatures could cause some insects to appear earlier than usual here in Oregon. Pest control professionals in the balmy mid-south are already seeing this pattern. ABC reported that Weir Pest Control in Memphis, Tenn., was fielding requests for ant pest control in late January – much earlier than usual. Like the Pacific Northwest, the mid-south has had an unusually temperate winter. Oftentimes, warmer-than-usual winter temperatures cause underground insect eggs to hatch earlier and pest populations to grow sooner than they would have otherwise.
Bees, wasps and ants are a few of the species that overwinter as adults; they also time their springtime emergence with warming temperatures. If the entire winter is mild and warm, more of these “hibernating” insects will survive the winter, and homeowners could see an increase in pest control issues.
We could also see higher rodent populations, as more rats and mice will survive the cold months. Furthermore, warm temperatures allow rodents to continue breeding all winter long. This spring, Oregon pest control companies could be fielding many requests for rodent eradication.
At the same time, our relatively dry winter conditions could limit the amount of natural food sources available for pest populations. Less moisture means less plant growth, so pests that sample from both natural and human-provided food sources could face a food shortage going into the summer and fall. (By the way, Portland pest control experts recommend that homeowners keep an extremely clean kitchen and pantry to avoid providing pests with easily accessible sources of human food.)
Ultimately, upcoming weather conditions will determine much of our Portland pest control experience. If March is cold and rainy, as it was in 2011, we could see a die-off of any insects that have emerged earlier than usual. Rodent populations will also decline if temperatures drop, as breeding levels decline.
Predictions aside, homeowners can discourage pest populations by establishing a few good pest control habits. Keep a clean home to decrease the amount of food available for pests. Maintain a plant-free zone around your home’s foundation to prevent insects from taking up residence there and then moving into your home. Seal up all cracks in your home’s exterior. Remember that rodents and insects can squeeze through very small openings to gain entry into your home. (A mouse can push itself through a hole with a dime-size diameter, for instance.) Also, make sure the lid to your trash can is tight fitting and your firewood pile is stored away from the house. Eliminate any standing water, which attracts mosquitoes and other irritating pests. Finally, if pests do invade your home, call your local Portland pest control professional immediately.