The Homeowners Column

The Homeowners Column

Minute pirate bugs- little bug with a big bite

Photo of Sandra Mason

Sandra Mason
State Master Gardener Coordinator
slmason@illinois.edu

As I was working in my garden the other day it became painfully clear as to what I should chat about today. Recently you may have also experienced the bite of a bug so tiny it easily fades into oblivion among a sea of freckles. These little bitsy guys are minute pirate bugs.

The minute pirate bug, Orius tristicolor, is less than one eighth of an inch long, oval to triangular in shape, somewhat flattened and black with whitish marks on the back.

Most of the time minute pirate bugs are good guys. They are true generalist predators feeding on many different prey including thrips, aphids, spider mites and many insect eggs. They can consume as many as 30 spider mites per day. They are reportedly important predators of corn earworm eggs in cornfields.

Minute pirate bugs are present all summer in fields, woodlands, gardens and landscapes going unnoticed by us. I haven't been able to come up with a definitive reason for why these guys go Dr. Jekyll and Mr. Hyde on us at the end of the season. Why do they suddenly decide to bite something a zillion times bigger than they are after they have spent the summer munching on tiny spider mites? Oh the insect mind. Perhaps there is not enough prey at that time of the year for the numbers of pirate bugs present. Maybe it's the moisture we provide. Maybe they are just mean.

Their bite is amazingly painful for something so tiny. When they bite they are actually probing us with their short blunt beak. They do not feed on blood or inject venom or saliva.

Everyone seems to react differently to his or her bite and some people seem to be more apt to be bit. I get bit more often when I am working and sweating (or is it glowing?) Bites on some people swell up like a mosquito bite, some turn into a hard red bump and for others there is no reaction at all. Minute pirate bugs are not quick to fly following biting, so you usually see what just bit you so hard.

Trying to control minute pirate bugs is really not practical. Their biting occurs for a very short time and tends to be more abundant some years. Also since they are overall beneficial by eating many pests, it is best just to put up with their split personality. Reportedly wearing dark clothing on very warm days when pirate bugs are abundant may help. Keeping covered with long sleeves and long pants will also definitely help. Repellents have mixed reviews as to how well they help with pirate bugs but may be worth a try.

Asian Multicolored Ladybugs may also bite this time of year: probably for the same reasons as pirate bugs. The same control and prevention measures would apply to ladybugs.

Hover flies can also be common this time of year. Unfortunately hover flies share the characteristic bee coloration of black and yellow which means they must endure unnecessary swats and screams from humans. They are flies and not bees. They don't sting and actually can't sting even if they had the urge. Just as their name implies, hover flies often hover around flowers or around people. They are 3/8 to 3/4 of an inch long often with black and yellow stripes. Some people call hover flies sweat bees since the flies enjoy a little tasty drink of sweat periodically.

Hover flies and their relatives syrphid flies are also good guys in the garden. Their young are ravenous predators of bad guys such as aphids, thrips and small caterpillars. The adult hover flies do not eat other insects, but feed on nectar and pollen.

Get to know the good, the bad and the bugly of the insect world.

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