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What you need to know about rodents?


Rats are some of the most troublesome and damaging rodents in households. They consume and contaminate food, damage structures and property, transmit parasites and diseases to other animals and humans. Rats live and thrive under a wide variety of climates and conditions; they are often found in and around homes and other buildings, farms, gardens, and open fields.

Damages cause by rats:

Rats consume and contaminate foodstuffs and animal feed. They also damage containers and packaging materials in which foods and feed are stored. Both species of rats cause problems by gnawing on electrical wires and wooden structures (doors, ledges, in corners, and in wall material) and tearing up insulation in walls and ceilings for nesting.


Norway rats may undermine building foundations and slabs with their burrowing activities. They may also gnaw on all types of materials, including soft metals such as copper and lead as well as plastic and wood. If roof rats are living in the attic of a residence, they can cause considerable damage with their gnawing and nest-building activities. They also damage garden crops and ornamental plantings.


Among the diseases rats may transmit to humans or livestock are murine typhus, leptospirosis, trichinosis, salmonellosis (food poisoning), and ratbite fever. Plague is a disease that can be carried by both roof and Norway rats, but in California it is more commonly associated with ground squirrels, chipmunks, and native wood rats

Managing rat problem:

Three elements are necessary for a successful rat management program: sanitation measures, building construction and rodent proofing, and, if necessary, population control. Below are number of ways to overcoming rodent issues.

1) Sanitization: Sanitation is fundamental to rat control and must be continuous. If sanitation measures are not properly maintained, the benefits of other measures will be lost, and rats will quickly return.


Good housekeeping in and around buildings will reduce available shelter and food sources for Norway and, to some extent, roof rats. Neat, off-the-ground storage of pipes, lumber, firewood, crates, boxes, gardening equipment, and other household goods will help reduce the suitability of the area for rats and will also make their detection easier.


Garbage, trash, and garden debris should be collected frequently, and all garbage receptacles should have tight-fitting covers. Where dogs are kept and fed outdoors, rats may become a problem if there is a ready supply of dog food. Feed your pet only the amount of food it will eat at a feeding, and store pet food in rodent-proof containers.

2) Building construction & rodent proofing:  The most successful and long lasting form of rat control in buildings is to “build them out.” Seal cracks and openings in building foundations, and any openings for water pipes, electric wires, sewer pipes, drain spouts, and vents. No hole larger than 6mm should be left unsealed to exclude both rats and house mice.


Make sure doors, windows, and screens fit tightly. Their edges can be covered with sheet metal if gnawing is a problem. Because rats (and house mice) are excellent climbers, openings above ground level must also be plugged. Rodent proofing against roof rats usually requires more time to find entry points than for Norway rats because of their greater climbing ability. Roof rats often enter buildings at the roof line area so be sure that all access points in the roof are sealed. If roof rats are travelling on overhead utility wires, contact a pest control professional or the utility company for information and assistance with measures that can be taken to prevent this.

3) Trapping:  Trapping is the safest and most effective method for controlling rats in and around homes, garages, and other structures as traps can be used over and over again. Traps can be set and left indefinitely in areas where rats have been a problem in the past, such as an attic.


The kind of bait used for the trap is important. Nut meat, dried fruit, or bacon make excellent baits for rats. The bait should be fastened securely to the trigger of the trap with light string, thread, or fine wire so the rodent will spring the trap in attempting to remove the food. The best places to set traps are in secluded areas where rats are likely to travel and seek shelter.


Droppings, gnawings, and damage indicate the presence of rodents, and areas where such evidence is found are usually the best places to set traps, especially when these areas are located between their nests and food sources. Place traps in natural travel ways, such as along walls, so the rodents will pass directly over the trigger of the trap. If a rat sets off a trap without getting caught, it will be very difficult to catch the rat with a trap again.

4) Glue boards: One of the alternatives to a snap trap is a glue board. Glue boards work on the same principle as flypaper: when a rat or mouse attempts to cross the glue board, the rodent gets stuck. Glue boards are much more effective for mice than for rats. Also, one of the major drawbacks with glue boards (and other live-catch type traps) is that the trapped rat may not die quickly, and you will need to kill it. For this reason, glue boards are not a good alternative for many people and their use is not recommended. Also, cats and dogs may get into the glue and track it around the house, creating additional problems.

5) Live traps: Live traps are not recommended because trapped rats must either be killed or released elsewhere. Releasing rats outdoors is not recommended because of health concerns to people, pets, and other domestic animals. Because neither the roof nor Norway rat is native to this country, their presence in the wild is very detrimental to native ecosystems. They have been known to decimate some bird populations.

6) Toxic bait: While trapping is generally recommended for controlling rats indoors, when the number of rats around a building is high, you may need to use toxic baits to achieve adequate control, especially if there is a continuous re-infestation from surrounding areas. If this is the case, consider hiring a licensed pest control applicator, who is trained to use rodenticides safely.

7) Bait station: Bait stations or boxes are often used with baits of all kinds. These enclosures protect the bait from weather and restrict accessibility to rodents, providing a safeguard for people, pets, and other animals. Bait stations should be large enough to accommodate several rats at a time and should contain a bait-holding compartment. Each station should have at least two openings for rats to enter and exit.


Place bait stations next to walls or in places where rats will encounter them. Commercial bait stations are available in a variety of sizes and shapes. Stations that may be accessible to children or pets must be made of sturdy, tamper-resistant material and be secured in a way that they cannot be tipped. See the product label for additional information. All bait stations should be clearly labelled.

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