When Tom Witt, 56, took over the family pest control business from his father, he could say he had worked from the bottom up.

As a boy, he rode in the trucks. At Penn State University, he studied business and entomology (the study of insects).

He became a technician, working to eradicate pest problems. He even cleaned the bathrooms, worked in the warehouse and fixed broken equipment.

"My father was a believer that in order to understand the business, you have to do every task," he said.

Now, as the president of Witt Pest Management he is preparing his own son (his daughter is not interested) to take over from him.

And he has tried to impress upon Adam Witt, 29, that his name is a part of his business.

Attention to the business and to its customers is the only way his small company can compete against Orkin and Terminix, two huge names in pest control that have come into the Pittsburgh market, Mr. Witt said.

In the modern lobby of the Witt building the only picture that hangs on the wall is a 1930 photo of the Harry L. Witt and Company building on Fifth Avenue in the Uptown section of Pittsburgh. The windows of the old store show off the janitorial supplies that Harry Witt sold. Above the door are the words "Exterminator and Janitors Supplies."

The company was 22 years old.

Now, 78 years later and celebrating its 100th anniversary, the company is passing into its fourth generation of family ownership.

The trick behind the successful transfer of the family business isn't a trick at all. It is in parenting.

Tom Witt regards his father, Albert B. Witt, 93, of Boca Raton, Fla., as both a parent and a friend.

The family believed in allowing the successive generations to take the company in the direction they felt was appropriate.

Harry L. Witt and Company was an exterminating company that sold janitorial supplies. Tom Witt has changed that somewhat.

Now the main company is still in the business of pest control, but Mr. Witt also owns Watch-Gard systems, which sells chemicals and provides the manpower to properly clean supermarkets.

Tom Witt and his sister, Wendy, own W&T Investments, which owns property on Polish Hill. One of the family's small companies also developed software to keep track of the pest control company's clients.

Mr. Witt said the family business has changed from the old stereotype of the exterminator walking in with a sprayer on a hose attached to a drum of chemicals. Now the technicians use insecticides in a more limited way, searching for nests of bugs and striking them there. And all the information is recorded on a hand-held computer and sent back wirelessly to the office.

The company technicians also search for how pests could be infiltrating a home or business so that the cracks can be plugged and the bugs kept outside. Their buzz phrase (pun intended) is integrated pest management.

It is one of the ways the Witt family is trying to differentiate their company from its competitors.

At 29 and engaged to be married, Adam Witt said he lives by the lesson his father taught him: that when he walks out the door, his family's name is tattooed on his forehead. And that name is his family's business.

And with his son getting married, Tom Witt is looking beyond Adam and looking forward to passing the family business on to the fifth and sixth generations.