Niban, homemade bait can weed out the cockroaches

Q:I have a cockroach "problem." I have a compost bin in my backyard that attracts them. I have few visible during the day, but if I go out at night, I can hear them, and if I turn on the yard light there must be hundreds within 20 to 30 feet of the bin.

Only a few venture into my house and garage. I would like to know if there is some safe way that the roach population could be kept down. I do keep them under control at the front of the house by sprinkling boric acid into my water-meter access hole every few weeks.

P.L., Walnut Creek

A: Cockroaches are very interesting and important insects. There are more than 3,500 species of cockroaches worldwide, but only a very few interact with people.

Roaches are the most despised of all of our household visitors, unjustifiably so, in my opinion. Although large populations of cockroaches in urban areas can cause some people to develop asthmatic conditions, generally their potential danger is overrated.

I would submit that all pesticides developed to control roaches have done more harm to the environment than all the cockroaches combined.

You can help prevent cockroaches from coming into your home by inspecting all incoming food products, all boxes and any used furniture or appliances for the presence of cockroaches or their egg capsules.

Do not store paper bags anywhere in the kitchen. Seal any holes or crevices around plumbing under sinks and behind toilets. Regularly vacuum and clean floors under the kitchen appliances. Keep all drains closed at night to prevent them from coming up from the sewer system. If you don't have a drain cover, fill a sandwich-size Ziploc bag with water and place it on the drain.

Get your attic and crawl space, if you have one, dusted with food-grade diatomaceous earth.

There are a number of good baits for controlling cockroaches. Put equal amounts of baking soda and sugar out in flat containers and they will take it. Or make a roach dough by combining 1/2 cup powdered sugar and 1/4 cup shortening. Add 1/2 cup onions, 1/2 cup flour and 8 ounces baking soda. Add enough water to make a dough-like consistency. Make balls of bait and put them where you see roaches.

There is a very good roach bait available commercially, Niban Bait, made from boric acid. It is available online. One good supplier is www.pestcontrolsupplies.com.

Richard Fagerlund promotes the least toxic methods of pest control. Go to www.askthebugman.com or e-mail comments to home@sfchronicle.com.