When it gets hot, the ants start marching indoors. When it rains, in come the ants. Too cold? The ants know where its nice and cozy: your kitchen, bathroom and pet food bowls. Outdoors, the pet food bowls and garbage cans are also ant attractants. Argentine ants, those busy little black ants, are in march formation year round.
In years past, we would reach for the spray can and douse those little scavengers. But not anymore.
Many of those spray pesticides are only effective with direct contact on the
ants. And the stronger sprays, with residual action to thwart the next
wave of ants, is potentially harmful to you, your kids, your pets.
So, here is what we are doing now: following the recommendations of the UC Davis Integrated Pest Management Project for Ant Control.
That includes:
• Determine what the ants are attracted to and remove the food source
• Vacuum trails, wipe them with soapy water, or spray with window cleaner
• Locate entry points and caulk openings or plug with petroleum jelly
• Put out bait stations with liquid ant bait or apply gel bait at entry points
• Baits take time to work so continue to clean up trails
• Indoor sprays are not usually necessary.
• Vacuum trails, wipe them with soapy water, or spray with window cleaner
• Locate entry points and caulk openings or plug with petroleum jelly
• Put out bait stations with liquid ant bait or apply gel bait at entry points
• Baits take time to work so continue to clean up trails
• Indoor sprays are not usually necessary.
• Avoid products
packaged as granules that contain the active ingredients cyfluthrin or
permethrin. Although these products may be mistaken for baits, they are
actually contact insecticides that rapidly kill foragers and do not
control the colony.
Before wiping up
(or wiping out) the little critters, follow their trail. Note their
entry point into the house. Seal it up. We have found ants entering the
house in a variety of small avenues: beneath moulding, cracks in the
window frame, behind electrical outlet plates...and one of the ants'
favorite entries: that large holes beneath the sink where the pipes
enter the house.
According to the
UCD IPM page on ant control, "If ants can be thoroughly washed away and
excluded from an area, an insecticide is probably not necessary.
Vacuuming up ant trails or sponging or mopping them with soapy water may
be as effective as an insecticide spray in temporarily removing
foraging ants in a building because it removes the ant’s scent trail,
especially if thorough cleaning is done at the entry points. Some soap
products such as window cleaners can kill ants on contact but leave no
residual toxicity. Certain plant-based oils are also applied for this
purpose, but their odor can be offensive."
Oh, and another
lesson we learned the hard way: if you put those ant baits indoors, you
will attract more ants inside. Look for ants crawling along the outside
of the house, and place the baits there, being sure to follow all label
directions.
What about those
ant sprays that are intended to be used as a perimeter spray along the
outside of the house? Stick with the bait traps, says the UCD IPM page:
"Spraying around the foundation will not provide long-term control
because it kills only foraging ants without killing the colony.
Perimeter treatments may appear to knock down the population, but ants
will quickly build back up and invade again. To try to achieve long-term
control, some pest control companies offer monthly perimeter spray
programs. Perimeter treatments pose more risk of environmental upset
than baits in bait stations and are less effective than a bait-based IPM
program."
Ant baits are
not ant traps, even though some ants may be stuck there. The
whole point of ant baits: they get the stuff on them, take it back to
their nest, where they share it with others...and then croak. Be
patient. It may take a week or so for the baits to work on the ant nest.
More info about
ant baits from the UCD IPM project: "Baits are insecticides mixed with
materials that attract worker ants looking for food. They are a key tool
for managing ants and the only type of insecticide recommended in most
situations. Ants are attracted to the bait and recruit other workers to
it. Workers carry small portions of the bait back to the nest where it
is transferred mouth-to-mouth to other workers, larvae, and queens and
other reproductive forms to kill the entire colony. Bait products must
be slow-acting so that the foraging ants have time to make their way
back to the nest and feed other members of the colony before they are
killed. When properly used, baits are more effective and safer than
sprays."
• Sweet sugar baits such as boric acid (use low
concentrations with less than 1% of
the active ingredient) are highly attractive to Argentine ants
throughout the year.
• Protein baits are attractive to ants in spring when colonies are producing new offspring. (Baits like fipronil or hydramethylnon are effective.)
• Place baits outdoors; avoid indoor baiting as that may attract more ants into the home.
• Place baits near nests, trails, or along foundations, preferably in the shade.
• Baits should be placed in protected areas away from children and pets.
• Offer small portions of each bait to see which one is preferred before employing an extensive baiting program.
• Follow up regularly to make sure bait is working and place fresh bait as necessary.
How baits work:
• Worker ants are attracted to the bait and take it back to the nest where the entire colony, including queens, may be killed.
• Bait must be slow-acting so workers won't be killed before they get back to the nest.
• Results may not be evident for several weeks.
• Bait stations or ant stakes are easiest to use and safest for the environment.
• Sweet sugar baits such as boric acid (use low
concentrations with less than 1% of
the active ingredient) are highly attractive to Argentine ants
throughout the year.
• Protein baits are attractive to ants in spring when colonies are producing new offspring. (Baits like fipronil or hydramethylnon are effective.)
• Place baits outdoors; avoid indoor baiting as that may attract more ants into the home.
• Place baits near nests, trails, or along foundations, preferably in the shade.
• Baits should be placed in protected areas away from children and pets.
• Offer small portions of each bait to see which one is preferred before employing an extensive baiting program.
• Follow up regularly to make sure bait is working and place fresh bait as necessary.
How baits work:
• Worker ants are attracted to the bait and take it back to the nest where the entire colony, including queens, may be killed.
• Bait must be slow-acting so workers won't be killed before they get back to the nest.
• Results may not be evident for several weeks.
• Bait stations or ant stakes are easiest to use and safest for the environment.
For those that prefer a homemade concoction for ant control, Horticulture professor Debbie Flower of American River College in Sacramento recommends this formula:
1 part boric acid (I use 1 teaspoon) - available at most garden centers
9 or 10 parts sugar (so 9 or 10 teaspoons sugar)
Add enough water to make a slurry.
Put slurry in a small container, tuna can size.
Add 2 or 3 cotton balls and rotate them until they are completely covered in the slurry.
Put a lid on the container. Lid must have holes big enough for ants to crawl through. (Lid is not absolutely necessary but it keeps water and dirt out)
Bury in soil so lid is at soil level.
Leave it alone. You won't see dead ants. They visit, take the bait back to the colony, and kill the entire colony.
