The most common centipedes found around structures are fast-running predators of other arthropods, such as insects, as well as earthworms and snails. They generally are nocturnal, hiding under boards, rocks, or vegetation on the soil during the daytime and seen only when they are disturbed and uncovered. Centipedes do have the ability to inject venom through the pair of appendages directly behind the head, called maxillipeds. The North American species are relatively harmless to humans, while species in tropical Latin America may cause a serious reaction. At least one large western species also can cause severe pain with its bite. Some species may live up to 6 years. Females lay their eggs one at a time, usually burying it under a shallow layer of soil to protect it from being eaten, possibly even by the males.
Centipedes are very long and narrow, and flattened from top to bottom. There may be a great many pairs of legs, but they will have a single pair on each segment of the body, separating them from the millipedes. Color is usually dark reddish brown, although some kinds have a bluish-green tint on a tan background. They have a pair of very long antennae and the last pair of legs is often much longer than the ones before it and they project backward.
Control consists of habitat modification and possibly pesticide applications. Elimination of the debris and objects on the soil that provides harborage sites will reduce populations, along with the control of insects and other small animals that centipedes feed on. These are highly beneficial arthropods, and they should be encouraged in landscape whenever they are not invading the structure.
Millipedes are slow moving vegetarians, feeding on both decaying vegetation as well as live plant tissues. They are essentially harmless to humans in North America, while some species in South America are able to exude a cyanide-like spray from their bodies when disturbed. North American species do exude an unpleasant smelling secretion, and they also may lose body fluids as they die, causing staining on indoor surfaces. The secretion is a combination of irritating chemicals that may cause skin rashes on people and even be toxic to small animals. The larger species are capable of living up to 8 years, sometimes requiring up to 5 years to reach sexual maturity. Eggs are laid in the soil in batches of from 20 to 300 eggs, and newly emerged nymphs are very small with only around 7 body segments and only 3 pairs of legs. As they grow they add more sections and legs. In addition to the foul odor they can give off, millipedes protect themselves by rolling into a tight coil when disturbed, protecting the more vulnerable ventral parts.
The larger millipedes are elongate and cylindrical, getting up to more than 4 inches in length. The smaller garden millipedes are usually less than ¾ inch long and are more flattened in appearance. They all have 2 pairs of legs on each body segment, differing from the centipedes. There is a pair of short antennae.
Habitat modification to remove the objects and debris on the soil that millipedes use for harborage is needed. These animals require areas of fairly high moisture, and reduction of unnecessary moisture also reduces the attraction of an area. Invasions of structures may occur when surrounding areas dry out in the summer, driving millipedes to the green, moist landscape around the structure. Treatment of the perimeter of a landscape, as well as the building perimeter, with a residual insecticide will help to kill migrating millipedes.
If you have a centipede or millipede problem and would like to have a Craig Thomas Pest Control, in partnership with Orkin Pest Control, representative speak to you, give us a call! Contact us by phone 800-255-6777, email for your free inspection today!
We at Craig Thomas Pest Control, Inc. are grateful to Univar Profession Products and Services for pest information incorporated into this work.