Thursday, April 8, 2010


     I had plans to rant about a number of personal vexations this week:

• Stores (usually supermarkets and big box stores) that sell cool-season annuals alongside warm-season annuals this time of year; 
• Advertising campaigns for pesticides that claim their products are "natural", "lawn friendly", "environmentally friendly" and "safe to use"...when none of those things are true, after reading the label;
• Weed whacker maintenance.

Instead, taking priority, is...ANTS!
The spring indoor migration has begun. Argentine ants, those busy little black ants, are march, march, marching through the kitchen and bathroom.
In years past, we would reach for the spray can and douse those little scavengers. But not anymore.
 Many of those indoor 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 in 2010: 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 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 it may look like they are 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 in late spring or early summer when populations are low.

• Place baits outdoors; avoid indoor baiting as that may attract more ants into the home.

• Place baits near nests, trails, or along foundations.

• 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."

Ant baits contain various active ingredients and attractants. We have tried a variety of different ones, to appease the finickiest of ant diners. One of my favorites is one that uses boric acid, a less toxic alternative.

But again, use it outdoors...otherwise, you will be drawing more ants inside.


  1. It really is quite amazing -- the things I run into -- when I'm turning over the soil in the raised beds.

    Ant colonies would be one of them. And -- fortunately -- those colonies don't extend beyond the one foot base of the bed -- which makes finding and eliminating the queen that much easier. Eliminate the queen = eliminate the colony.

    Unfortunately -- black widows also like the warmth of those raised beds.

    In Madera? We had the red Fire Ants. I made that rather unfortunate discovery after about 100 of them had crawled up my leg while I was installing a rose garden terrace....

  2. Thanks Fred for that great post! I get alot of ants here in Elverta. Everywhere they are! I am also having a huge Black Widow issue! Do you have any thoughts organicly what I can do to get rid of most of them. I have a 6 year old who gardens with me and I would hate for her to come across one.

  3. This is from the UCD IPM website regarding black widows:

    One of the easiest ways to minimize encounters with widow spiders is to reduce clutter around your home, which deprives them of places to make retreats. However, it is impractical to eliminate them completely by removing all clutter.

    Regularly vacuuming or sweeping windows, corners of rooms, storage areas, basements, and other seldom-used areas helps remove spiders and their webs. Vacuuming spiders can be an effective control technique, because their soft bodies usually don’t survive this process.

    In the garage, keep items such as gardening clothes and gloves in bags closed with zipper locks or twist ties. Store seasonal items such as winter clothes or Christmas decorations in boxes that you can tape shut and can place off the floor and away from walls in order to exclude spiders. When cleaning up clutter in garages and other storage areas, be sure to wear gloves to avoid accidental bites.

    Areas of concern include children’s pedal-powered toy vehicles made of molded plastic that have open spaces facing downward where spiders can crawl in. Picnic tables and other large pieces of furniture where you place your fingers underneath to lift also can be a source of exposure.

    Spiders can enter houses and other structures through cracks and other openings. To prevent spiders from coming indoors, seal cracks in the foundation and other parts of the building and gaps around windows and doors. Good screening not only will keep out many spiders but also will discourage them by keeping out the insects they eat. However, baby black widows have no problem crawling through regular window screen mesh.

    Be careful that you don’t carry spiders indoors on items such as plants, firewood, and boxes. Stack woodpiles away from your house, and never pick up pieces of wood unless you are wearing gloves.

    Eliminate places for spiders to hide and build their webs by keeping the area next to the foundation free of trash, leaf litter, and accumulations of other materials. Removing ivy and other heavy vegetation growing around foundations and trimming plant growth away from your home and other structures will discourage spiders, in general, from taking up residence near the structure and then moving indoors.

    Outdoor lighting attracts insects, which in turn attracts spiders. If possible, keep lighting fixtures off structures and away from windows and doorways. Sweep, mop, hose, or vacuum webs and spiders off buildings regularly. Insecticides won’t provide long-term control, so generally you shouldn’t use them against spiders outdoors.

    Because widow spiders are nocturnal, a nonchemical method of eradication is to search for them at night with a flashlight and kill them with a shoe or rolled up newspaper. If you are concerned about wildlife and feel comfortable doing so, you can remove individual spiders from indoor areas by placing a jar over them and slipping a piece of paper underneath to seal off the opening when you life the jar up. Release the spider about 100 feet from your home into a natural area.

    One aspect that makes controlling widow spiders difficult is that they, like many spiders, exhibit a behavior called ballooning. When the spiderlings are very small, on warm days when there is an updraft they climb to the top of a fence post or piece of vegetation, raise their abdomens into the air, and release a small filament of silk.

    When the updraft currents overtake the forces of gravity, the spiderling is carried into the air to another location. This may only be a few feet away, or it could be miles. Ballooning spiderlings have been captured at 10,000 feet from the ground and 200 miles offshore. Because spiderlings will be dropping down on your property continually, eliminating them will be a task that needs to be done repetitively throughout the year.

  4. Thanks for the tips Fred. We encountered an ant infestation a couple of months ago and I was ready to move out the house and leave them there. You are absolutely right on the bait, works well after awhile, but best set outside of the house to avoid attracting more ants :) Lesson learned.

  5. I have rather large black ants on my artichoke and I don't know what they like about the plant. Anyway, what would be a safe and effective way to be rid of them?


  6. They may be harvesting the secretions of certain insects, especially aphids. Place some ant bait traps nearby. Look for boric acid as the active ingredient.