Garden Guide

Millipedes are here, weather or not
Jul. 31, 2013 @ 04:58 AM

Crunch ... that’s the sound of stepping on millipedes. Each year we seem to battle creepy, crawly, crunchy millipedes. However, each year is different and in some years populations are worse than others. This year we have seen more than usual because of the wet conditions. 

While millipedes sometimes enter homes in large numbers, they do not bite, sting or transmit diseases, nor do they infest food, clothing or wood. However, they can be quite a nuisance. They look bad, smell bad when squished and make for an unsightly mess when present in large numbers.

Common points of entry include door thresholds (especially at the base of sliding glass doors), expansion joints and through the voids of concrete block walls. Frequent indoor sightings of these pests usually means that there are large numbers breeding outdoors. Since they don’t live long once indoors, insecticides are usually a temporary solution to keeping them out of your home. The vacuum cleaner is often your best weapon. 

The most effective, long-term measure for reducing entry of millipedes (and many other pests) is to reduce excess moisture and hiding places, especially near the foundation. Remove leaves, grass clippings, heavy accumulations of mulch, wooden boards, stones, boxes and similar items laying on the ground beside the foundation. This does not mean you can’t have mulch around the foundation; simply keep it 6-12” away from the wall. Seal cracks and openings in the outside foundation wall, and around the bottoms of doors and basement windows.

If you choose to use chemicals in this battle, be sure you only apply chemicals labeled for outdoor use, outside and not indoors. And remember to always read the label carefully. Outdoors, you can use any of the common products made by Ortho, Spectracide, Bayer, etc. Granular insecticides may help but usually fail because it is not properly watered into the lawn after applying the product. Liquid insecticides can be applied to the foundation: about 18”-24” up the foundation wall and 3-5 feet out. The critical point in this process is water; you need to apply the chemical in sufficient volume to saturate the soil. For that reason, a garden hose sprayer is a desirable tool. Spraying around windows may also cut down on millipede entry in these areas; in this situation, a pump sprayer (the 1-2 gal. tank or backpack sprayer) is most effective. When making any pesticide application outdoors be sure to avoid chemical drift and contaminating yourself, children’s toys, barbecue grills, etc. Insecticidal dusts (particularly Sevin Dust) can be applied in a 6-12” band along the foundation. However, dust formulations are not the best choice when children and/or pets are likely to play in that vicinity. For those of you wishing to use gentler choices, you can use diatomaceous earth but it probably will not be as effective. 

For more information on millipedes and their control, call the Extension Office at (919) 775-5624 and ask for the Publication on Controlling Millipedes In and Around Homes.

Want more pertinent horticulture information delivered directly to your home computer? Subscribe to the Lee County home horticulture e-mail list. Simply send an e-mail to mj2@lists.ncsu.edu with subscribe leehomehort in the body of the message. You will then be a member of leehomehort@lists.ncsu.edu.