Pests in Gardens and Landscapes: Quick Tips


Published   5/21

PDFSpanish version of this Pest Alert

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German cockroach adult (top) and nymph.

German cockroach adult (top) and nymph.

Various life stages in oriental cockroach colony.

Various life stages in oriental cockroach colony.

Dead cockroaches caught on a sticky trap. Credit: CA Reynolds.

Dead cockroaches caught on a sticky trap.

Cockroaches thrive in both indoor and outdoor environments that provide food, water, and shelter. During the day, roaches hide in dark, moist areas like cracks, water meter boxes, sewers, and crawl spaces. They come out at night to feed. Good sanitation and exclusion are important for effective control; pesticides alone will not solve cockroach problems. When using insecticides, baits provide better control than sprays.

Identify the cockroach species before taking action.

  • Effective management options vary according to species.
  • Cockroach sticky traps are useful in catching roaches for identification.
  • Some cockroaches live outdoors but can invade indoor spaces (American, oriental, and Turkestan) while others live and breed entirely indoors (German and brownbanded).

Remove food and water sources.

  • Store food in tightly sealed containers.
  • Keep trash in containers with tight lids.
  • Fix plumbing and irrigation leaks to reduce sources of water.
  • Regularly vacuum indoor cracks and crevices, clean behind kitchen appliances, and clean floors and counters, since even tiny crumbs or liquids provide good food sources.

Exclude roaches and remove their hiding places.

  • Seal cracks and other openings in walls, under and around doors, and around windows to prevent invaders coming in from outside.
  • Use door sweeps and weather stripping on doors and windows.
  • Seal cracks in false bottoms of cupboards and other indoor hiding places.
  • Remove old papers, cardboard boxes, and other clutter, especially in kitchens and bathrooms.

Use traps to identify and track cockroach populations.

  • Cockroach sticky traps are available in garden and hardware stores.
  • Place traps on the floor around edges of walls, in cupboards, and other places where you think roaches are foraging. Place traps near exterior doors to catch invading outdoor species.
  • Check traps daily until you can tell where the most cockroaches are being caught.

What about pesticides?

  • Avoid using foggers, bombs, or aerosol sprays; these products can be hazardous and may repel and disperse cockroaches to other areas without actually killing them.
  • Insecticide sprays do not provide long-term control. Sprays are not necessary if cleanup and removal of hiding places is combined with effective baits and boric acid powder.
  • Boric acid powders and desiccant dusts may be applied within hollow walls, under refrigerators, and other undisturbed hiding places. This approach is very effective but may require a pest control professional. These materials must remain dry and undisturbed in order to be effective.
  • Insecticide gels and bait stations placed near cockroach hiding areas can be effective if other food sources are removed. It may be 7 days or longer before you see fewer cockroaches.
  • To control outdoor cockroaches, place baits in water meter boxes, drains, or under concrete slabs.
  • Contact a pest control professional for very serious infestations.

Read more about Cockroaches.

Minimize the use of pesticides that pollute our waterways. Use nonchemical alternatives or less toxic pesticide products whenever possible. Read product labels carefully and follow instructions on proper use, storage, and disposal.

Statewide IPM Program, Agriculture and Natural Resources, University of California
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