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Sowbug & Pillbug


Common names: Pillbug, Roly-Poly Bug, Sowbug

Scientific name: Order Isopoda, Subclass Crustacea. Pillbug--Armadillidium vulgare, Sowbug--Porcellio laevis

Size: Adult--1/4" to 5/8"


Identification: Adults are gray and sometimes brown crustaceans with a segmented armor covering. Seven pair of barely visible short legs. Pillbugs curl up into a ball when disturbed. Nymphs look like small light-colored adults. Sowbugs are larger, flatter, and faster; they have a tail and can't roll up as tight as pillbugs.

Biology and life cycle: Females carry eggs and nymphs in a pouch for several weeks. Nymphs and adults prefer moist conditions and cannot live long in dry conditions. They often explode in populations during the warm spring rains. Snails like the same conditions. Young take a year to reach maturity. Live up to eight years.

Habitat: Moist beds, compost piles.

Feeding habits: Feed mostly on decaying organic matter but can be severe plant pests, especially on young seedlings.

Economic importance: Beneficial to the breakdown of natural organic matter, but they obviously get tired of eating dead brown stuff sometimes and attack plants.

Natural control: Let beds dry out between waterings.

Organic control: Dust hot red pepper powder around plants. Dilute with diatomaceous earth for economy; sprinkle it around young seedlings. Put an apple core or some brewer's yeast in a glass (plastic is safer) countersunk into the soil. Cover it with a dish or pot. Spray with concentrated citrus oil. Add molasses and manure tea for even better results.

Coffee grounds on top of mulch also help.   Broadcast coffee grounds around plants troubled by slugs and snails to run the pest off effectively.  Use anywhere from 2 - 5 lbs of grounds per 1000 square feet.

Insight: Both pillbugs and sowbugs are beneficial in helping to break down organic matter.

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