First, I would like to share background on millipedes and centipedes. The first thing to clear up is that they are not insects and are actually more related to items like crayfish and shrimp. They are found in areas with high humidity and good moisture, but note that millipedes and centipedes are land dwellers.
They do not carry diseases that would bother humans, animals or plants. They are considered a nuisance pest because when they invade a dwelling, they can do so in large numbers. When in the home, they can stain items if they are crushed and can leave a bad odor if handled.
Millipedes are called rain worms or 1,000- legged worms. They can vary in length from less than an inch to over two inches. They are wormlike and have rounded body segments with each segment having two pairs of legs. They have a rounded head with short antennae. Millipedes are not poisonous, but can produce fluids from glands that can cause allergic reactions in some folks. Note, there are some millipedes that can put out a defensive spray of hydrochloric acid according to Gray that can burn the skin and cause discoloration. The fluid can also hurt the eyes so the best suggestion is to not handle millipedes bare handed. Another reason to not handle them bare handed is due to a bad odor they can leave on your hands. If you do have bare contact with your hands, wash with soap and water till odor is gone.
Centipedes are also called the 100-legged worm. One difference is they have only one pair of legs on each body segment compared to millipedes with 2 pair. They have a more flat body with a distinct head. The head will have a pair of long antennae while millipedes have a short antennae. Centipedes do have poison glands and use this and powerful jaws to kill small insects. They can bit humans and for most folks this will be similar to a bee sting, but some people who are allergic to insect venoms and other toxins could have a severe reaction to centipede venom.
For the most part, millipedes feed on decaying vegetation and leaf litter, but they can do some feeding on plant roots. Millipedes spend most of their life in the soil. Centipedes like dark areas and can be found under rock, logs, bark and leaf matter. One cool note is that some species of centipedes have been known to live up to six years.
For the most part, millipedes and centipedes cause little problems. When they start coming in the home in large numbers then they are a nuisance for some. The easiest way to control is to do your work outside the home by finding and removing objects that are considered hiding places for them.
Gray suggests to remove trash piles, rocks, boards, leaf piles, compost piles and anything similar that may be close to the dwelling. If it is something that needs to be gone, remove it or just move your compost pile farther away from the home for example. Another suggestion is exclusion. Make sure that windows and doors are secured properly and that you caulk cracks and crevices. Applying pesticides labeled for the specific pest correctly around the foundation and around doors and windows may help for a short time. You may also need to treat flower beds or even turf area with heavy thatch if numbers are very high. Note to always read the label of any pesticide purchased for proper use and safety.
For more information contact Gordon County Extension at 706-629-8685 or email firstname.lastname@example.org.