Build your own ladybug trap for $10


WOOSTER, Ohio – Joe Kovach has built a better ladybug trap – simple and inexpensive to make – and people may soon beat a path to his door, or at least to his Web site.

Kovach, coordinator of Ohio State University’s Integrated Pest Management program, and colleagues recently developed a new home trap for multicolored Asian lady beetles – just one part of a much-wider effort aimed at battling the non-native bugs.

In the past 10 years, multicolored Asian lady beetles – introduced to the United States as beneficial insects, ones that eat pests – have become a major headache.

Hundreds or even thousands of the orange-colored, black-spotted, pea-sized bugs invade people’s homes in fall. Living, crawling clusters form in attics, corners and basements.

Until now, the bugs were thought to be simply a nuisance. But recent research by Kovach and his team showed that 25 percent of the people who live with high populations of multicolored Asian lady beetles report an allergic reaction to them.

Furthermore, it’s also now known that the beetles bite people, although, fortunately, not too often. Tiny, sharp mandibles do the work.

“I’ve been bitten,” said Kovach, who works at the Ohio Agricultural Research and Development Center’s Wooster campus. “It felt like someone dragging a pin on my arm, like a cat scratch. Anyone who says (multicolored Asian lady beetles) don’t bite has never been bitten.”

Kovach and other scientists still aren’t sure why the beetles bite. It might be by accident. It might be to get moisture: sweat. Or it might be that they’re grazing on microbes on your skin.

Lamp and milk. Building Kovach’s trap takes less than $10 worth of common materials: a clamp-on lamp, two plastic milk jugs, several sheets of clear transparency plastic and hardware.

The device catches about 70 percent of the lady beetles in a room.

It can be rigged to a timer so it only comes on at night, for instance, or only when you’re not in the room.

Plans are available from the Integrated Pest Management program at 330-263-3846, from county offices of Ohio State University Extension and at

Commercial traps – costing around $175 and up to 99 percent effective (according to research by Kovach and team) – are available, too.

They’re best for situations where nearly complete control is needed: restaurants, food-processing plants and other places where it’s important to be bug-free.

Looks like a cliff. Why do ladybugs swarm into homes, barns and offices? They think the buildings are cliffs. That’s where the beetles overwinter in Asia.

Houses with woods on two or three sides have it worst. They present a silhouette that the bugs see as a cliff. The color of a house doesn’t matter much, Kovach found.

“If you’re going to get them you’re going to get them,” he said.

But there are ways to minimize infestations. Start by caulking small holes in buildings and putting small-mesh screens over large holes.

Install or fix door sweeps and window screens. And consider applying a pyrethroid pesticide or camphor-based repellent around potential entry points.

Indian summer. Applying pesticides and repellents takes good timing. So Kovach and colleagues are developing a model to predict when ladybugs will swarm, making sprays more precise and efficient.

The work isn’t done yet. So far what’s known is that swarming depends on three factors: day length, “chilling hours” (including a freeze) and a warm spell.

In Ohio this can happen almost any time in October or early November.

“What generally happens is that a cold front comes in, it’s rainy, it moves through,” Kovach said. “Then the next day is a beautiful Indian-summer day – clear, blue skies, 65 or 70 degrees – and that’s when they’ll swarm, and they’ll swarm as long as the temperature stays in that range.”


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