Garden Column for the Salisbury Post

Darrell Blackwelder

January 26, 2005

     Many would naturally assume that our recent cold weather will reduce the insect population next summer. Cold weather may reduce some insect populations, but it seems it will never completely eliminate insects. Insects are survivors compatible of withstanding the coldest of temperatures. So, when temperatures dip into the low 20’s or even the teens, insects are prepared.

      Some, such as the monarch butterfly, pack their bags in the fall and migrate to the warmer winter climate of Mexico. Beetle larvae can burrow up to six feet to avoid freezing temperatures.

     However, many insects go dormant or hibernate like a bear. Lady beetles, with their respiration and heartbeat almost at a standstill, over winter as adults under tree bark and other hiding places. These insects avoid freezing by depending heavily on antifreeze compounds in their body fluids.  Their bodies produce a compound similar to antifreeze for cars.  Their bodies are all but frozen during the harsh winter months.

     Proper nutrition, temperature, stage of growth and species are an important part of an insect’s winter survival.Smaller insects such as ants or fleas can survive cold temperatures better than larger species, such as grasshoppers. This phenomenon also is true between individuals within a species.  For example, smaller houseflies are often more colder hardy than larger flies.                      

       So, is it a myth that extremely cold temperatures will kill insects?  No, not really. Cold temperatures do kill many species of insects. For example, research on tent caterpillars has shown that extremely cold temperatures can wiped out entire populations of this insect. If this is so, why are they still around after cold winters? The answer is even though many are killed, a few will survive. They find havens in bark, behind shutters, in cracks and crevices in wood and yard debris. Insects are survivors and adapt to the most extreme conditions, but we can help Mother Nature.

     Gardeners can adapt a few cultural practices during the winter to reduce insects in the spring. Tilling before the last freeze of winter helps keep the insect populations in check. Later winter tilling at this time turns up insects and exposes them to killing temperatures. Winter tilling also disrupts tunnels in the soil, leaving some over-wintering insects with no way out.                       

        If you plan to start a garden in a new area, till the ground in late winter or early spring. Planting areas that have not been tilled in a long time, such as old pastures and lawns harbor many insect pests such as cutworms, wireworms, grubs and other soil insects.                  

        Now is an appropriate time to thoroughly clean up old gardens by removing old garden debris and weeds in or near a new garden site.

     Old debris also provides a home for insects, weed seeds and diseases during the winter. Weeds and garden debris should be decomposing in compost pile. If unable to compost, plow the debris under.                                     

       No matter how cold the weather can get, it will never significantly reduce insects, especially in our area. In order to cope with this problem, its best to learn as much about these creatures as we can, both beneficial and bad, to determine the best method of control.