Remembering Ruth

Everyone who has lifted a board or flowerpot outside has probably encountered a "roly-poly" or sow bug. They are actually two different creatures - a pillbug or roly-poly will roll up in a ball, and a sow bug will not. Both sow bugs and pillbugs are isopods and are more related to lobsters than they are to insects. Only a few families of isopods are terrestrial; their brethren are marine creatures and a few live in fresh water. As such, they breathe by means of gills and that's why we find them in moist places.

Female sow bugs and pill bugs have a marsupium, or brood pouch, in which approximately 50 eggs are incubated until they hatch. The young leave the brood pouch and typically molt soon after, usually within 24 hours. The molt takes place in two stages; the back half is lost first, followed two or three days later by the front. This method of molting is different from that of most arthropods, which shed their cuticle in a single process. After leaving the marsupium, they live in family groups until the young are grown. Each family has a chemical "badge" which distinguishes it from the rest of the population (Linsenmair 1984).

These little isopods are not generally regarded as a serious household pest because they do not spread disease and do not damage wood or structures; however, their presence can indicate dampness problems. Their preferred diet is organic matter so that they assist in reducing mulches and leaf litter to plant nutrients. They are are not good at digesting living plant material therefore will not attack healthy plants if other preferred food is available.

"Sow bugs and pillbugs get blamed for more damage to garden plants than they actually do," says Oregon State University Extension entomologist Glenn Fisher. "They are deemed guilty by association, as they are often found feeding in decaying or damaged garden produce," says Fisher. "Actually, diseases, slugs and other pests often inflict the initial damage. Sowbugs enter later to take advantage of the feast. They are great opportunists."

If you would rather not live with an army of little armadillo look-alikes, here's some suggestions:

Clean up organic debris, boards, boxes and piles of leaves around the yard and garden to limit moist, dark hiding places.
Water early in the day so plants and the soil surface dries out by the evening when sow or pillbugs are active.
Mulch with coarse materials, so water passes through to the soil quickly.
Elevate fruits and vegetables off the ground. Black plastic mulches are good because they get too hot in the summer to provide desirable shelter for sowbugs.
Seal cracks around the house and eliminate the dark, damp hiding places next to your foundation if sowbugs are entering your home and buildings.
Place a rolled up newspaper tube on the soil surface and leave it overnight. In the morning, shake out the tubes into a pail of soapy water.
Sprinkle food grade diatomaceous earth directly on the row where seeds have been planted to dry the soil surface enough to discourage sow bugs. Experiment with the amount of diatomaceous earth, as too thin a layer will not be effective and too thick a layer can become like plaster if it becomes wet.