Life Cycle of Sow Bugs

Sow bugs and pill bugs of the order isopoda have jointed limbs and a tough armoured exoskeleton. Both are nocturnal and have 7 pairs of legs. Sow bugs and pill bugs are scavengers. They feed on animal debris and both live and dead plants. They are also called roly poly, woodlice, and potato bugs.

People often confuse sowbugs and pillbugs with each other. However, pill bugs are capable of rolling into a tight ball. They do this to prevent their gills from shrivelling up or to protect their undersides when they feel threatened. Sow bugs can’t roll into a ball when disturbed.

Most sow bugs are grayish in colour. They have an oval-shaped body and their back has overlapping articulating plates. Sow bugs grow to about 15 mm or 9/16" long and 8 mm or 5/16" wide. Pill bugs have a rounder back. They are usually grayish brown in colour and reach less than 1" in length when they mature. 

They’re closely related to shrimp, lobsters, and crabs. Most crustaceans live near or in water. Sow bugs and pills are dry-land crustaceans, so they need damp ground. They have gill-like breathing organs that should be kept moist to function.

Pill bugs and sow bugs prefer moist environments with a lot of decaying vegetation like under logs, grass clippings, leaf litter, boards, stones, bricks or pocks. You may also find them in damp basements.

Life Stages of Sow Bugs

Eggs hatch after 3 to 9 weeks. The young spend 3 to 9 days in their mother’s brood pouch. The female may have 2 to 3 broods every year.

The young moults 4 to 5 times at a regular interval until they become sexually mature. This usually happens within a year. Their lifespan is around 2 years. For pill bugs, moulting occurs in two stages.

They don’t shed their skin at once. The back half of their skin falls off first and the front half follows a few days later. They are extremely vulnerable and often remain isolated during this period.

Sow bugs and pill bugs are mainly herbivores. They feed on the bacteria and fungi that infest rotting and dead vegetation.

These creatures cause damage to the roots of plants as they much on the microorganisms and fungi that live in the root surfaces. Root tissue gets chewed up during their feeding.

Controlling Sow Bugs

There are various ways to eradicate these pests.

·         Natural Methods and Pesticides

Some growers recommend using Sevin, Malathion, or Diazinon when dealing with large numbers of sow bugs and pill bugs. Spray the outer and inner perimeter of plants and the greenhouse.

Pesticides can help control the presence of these pests, but will not completely eliminate them. These products are most effective when used together with other good environmental methods.

If you’re dealing with a minor infestation, you can trap them by placing a hollowed-out potato upside down as near as possible to where these pests have been seen. You can use Neem oil or sprinkle diatomaceous earth (DE) around the base of potted plants.

Other eco-friendly methods include decanting the infested plant and washing its roots with a very mild detergent solution before planting it again. You can also soak the affected plant in a pail of water overnight. Completely immerse the pot and the potting medium.

·         Environmental Controls

Hang orchids in trees and elevate potted plants above the ground. Close cracks near or at ground level with a caulking gun. All doors should be weather-stripped. Place fibreglass window screening over drainage holes inside pots to keep sow bugs and pill bugs out.

Get rid of any plant debris and leaf litter around and inside the greenhouse or in your outdoor growing area. A greenhouse erected on a concrete slab poured on the ground will be vulnerable to pill bug sow bug infestations if there’s no moisture barrier underneath the concrete. The bark of a tree should be kept medium fresh. You can also apply an organic potting mix.

·         Predators

Small mammals, toads, frogs, lizards and spiders are the natural predators of sow bugs and pill bugs. Their own kind might also eat them when they’re still soft during their moulting period.