What Can Be Done About Roaches Coming Up Through a Dishwasher?

Inspection

• German cockroaches are usually found in kitchens and bathrooms because they like warm, moist areas where it’s easy to hide. If you see cockroaches in your dishwasher, you’ll probably find them elsewhere, because cockroaches live in groups, and the German cockroach is a prolific breeder. Look behind other appliances, including the stove and refrigerator. Check under and behind sinks and along the inside frames of drawers and cupboards. Inspect the edges of drop ceilings, especially those located above your dishwasher and stove. Look behind the toilet, shower and bathtub and in drains. In addition to looking for cockroaches, look for the specks they leave on walls and in cupboards.

Baits

• Baits are an effective way to kill cockroaches living in your dishwasher or other areas of your house and they don’t require a lot of preparation like liquid sprays do. However, it will take several weeks before you notice a reduction in numbers. Place baits under the dishwasher and sinks, refrigerators and stove, inside cabinets and beside trash containers. Baits should be placed up against edges or flush into corners, not out in the middle of an area, in order to attract cockroaches that use those paths to move around.

Boric Acid

• Boric acid works as a stomach poison to kill cockroaches that eat it. Apply a thin layer of boric acid powder to the areas you’re treating, including where plumbing pipes enter walls. Don’t make piles of boric acid because cockroaches will avoid them. You should barely be able to see the film of powder you lay down. Boric acid isn’t considered very toxic to adults, but it can be a problem for children and pets so you should take care to keep them out of treated areas. Don’t apply boric acid to any areas used to prepare food.

Dusts

• Dusts like diatomaceous earth and silica dioxide kill cockroaches by damaging the waxy coating on their bodies and dehydrating them. Apply dusts in a thin layer underneath your dishwasher and other appliances and in wall voids. Only use food-grade diatomaceous earth, which is considered nontoxic to mammals. Using a combination of methods will give you the greatest chance for successfully controlling cockroaches.

Other

• Reduce cockroach populations quickly by vacuuming them up with the hose attachment of your vacuum cleaner. Seal the bag inside a plastic bag and dispose of it outside. You can also place the bag inside your freezer for several hours before throwing it out. Temperatures below 20 degrees Fahrenheit kill cockroaches. If possible, place your dishwasher outside and let it remain there for several days.