To help prevent roof rats, follow these tips from the Maricopa
County Vector Control:
• Get rid of the roof rats’ food supply by harvesting citrus and
Pick all fruit (ripe or not) on citrus and other fruit and nut
trees and pick up any fallen fruit. Do this promptly and
completely. Fruit and nut trees having the most activity are the
ones which come in contact with other trees, houses, fences or with
power lines running through.
• Donate any excess fruit your family won’t be able to eat to the
closest food bank. Next winter, when the roof rats are under
control or eradicated altogether, enjoy your harvest, but be sure
to pick your fruit promptly and donate what you can’t use. You
don’t need to remove fruit trees from your landscape.
• Manicure your landscape. A clean yard is a deterrent.
• Rake under your trees and shrubbery. Prune fruit trees so the
ground under them is open and visible. Remove wood piles and brush
piles from your yard. Store wood and lumber piles at least 18
inches above the ground and 12 inches away from walls. Thick ground
covers should be thinned.
• Keep your palm trees trimmed. Roof rats nest in the skirts of old
fronds, as well as in piles of debris and hollow trees.
• Thin out bushes until you can see daylight through them.
Oleanders are particularly prone to harbor roof rats in the summer.
Thin bougainvilleas as well.
• Don’t feed the roof rats unknowingly.
• Roof rats will eat anything to survive; this includes pet food
Don’t leave pet food out, especially overnight. Keep dog feces
• It would be best to stop filling your bird feeders for the next
few months. Otherwise, provide just the amount of bird seed that
will be consumed in a day and sweep up fallen seeds on the ground
before sunset. Store bags of bird seed in sealed, rat-proof
• Store bulk foods in sealed, rat-proof containers.
• Keep garbage containers tightly covered.
• Strategically place snap traps and bait stations
• Maricopa County does not provide bait stations or traps to the
public. Bait stations can be purchased at cost through Barry
Paceley at http://www.roofrat.net.
• To prevent rats from entering your property, or to eliminate rats
that have already entered your property, set snap traps in your
laundry room and garden shed baited with creamy peanut butter.
Don’t put much on the bait tab so the rat will have to work at it
to get it off. This will ensure that the trap will trip. • Place
the traps well away from pets and small children. Roof rats are
nervous and cautious of new objects, so leave traps in the same
location for at least a week before moving them.
• Bait stations made of plastic, cardboard or metal provide a
protected place for rats to feed. They allow you to place poison
bait in some locations where it would otherwise be difficult
because of hazards to non-target animals.
• Place two bait stations in your yard, 4 feet or higher off the
ground. Optimal locations are in your citrus tree and anywhere near
potential rat pathways, such as close proximity of wires to house
roofs, trees or oleanders.
• It’s important to close the bait station opening in the morning
to protect wild birds that might be attracted. Open it up in the
late afternoon about sunset.
• The practice of wiring poison bait blocks directly to tree
branches causes accidental poisoning of cats and wildlife. Use
poison bait blocks only in bait stations and slide the blocks all
the way to the back.
• Residents will be responsible for purchasing and placing the
bromadiolone poison in the bait station. Read the entire label
first and strictly adhere to all instructions, restrictions and
• Bromadiolone is sold as “Just One Bite” and can be purchased at
feed and hardware stores. “Just One Bite” is an anti-coagulant that
kills rats in 3-5 days.
• It is important that the resident’s home is properly sealed so
the poisoned rat doesn’t enter the house and die, creating a bad
odor which may be hard to remove.
What doesn’t work:
• Rats quickly learn safe travel routes through yards to avoid
dogs. Cats will kill dispersing juvenile rats, but are rarely able
to handle an adult roof rat.
• There is no evidence that ultrasonic and electromagnetic devices
drive rodents away. There is evidence that ultrasonic devices can
cause hearing loss in pets, especially dogs.
• Maricopa County Vector Control tested Coca Cola (rumor has it
that roof rats can’t burp and die from drinking it), but found that
it was ineffective. In fact, the rats loved it.
• Don’t use d-Con. If pets or wild birds nibble on a rat killed
with d-Con, they can become sick.
• Strongly consider xeriscaping your yard. Xeriscape doesn’t have
to be gravel and a couple of cactuses. There are many lovely
• Combine xeriscape with a citrus-free yard to create a very
effective control against roof rats.
• Maintain a defensive line on your property by continuing the use
of bait stations, keeping a clean yard and removing pet food and
water dishes at night.