Gardening | Organic Treatment for Fire Ants

Many of us have already discovered that nasty fire ant mounds can be home to both red and black species of imported fire ants. Both species are vicious and we can’t ignore them when their mounds show up in our yards.

We don’t have to use toxic chemicals to control them. Organic pesticides that can do the job are available in garden centers and well stocked nurseries. Forget the vinegar, club soda, grits, molasses and other pantry magic that doesn’t work. Scientifically formulated and tested OMRI listed pesticides that effectively control fire ants are available for yard and garden (edible and ornamental) use.

Why apply toxic chemicals to a yard where children play, pets exercise, wildlife visit and adults work or play? People and critters risk ingestion, inhalation, and transdermal uptake of hazardous lawn and garden chemicals that are used in the yard. Those chemicals also come inside the house on shoes, paws, clothes and in the form of chemical dust in human hair and pets’ fur. Consider the health risk.

There are two active agents to look for in an organic fire ant killer, spinosad or d-limonene.

Spinosad is a biopesticide produced from a naturally occurring soil-dwelling bacterium. It is made commercially by culturing these soil borne microbes which produce metabolites toxic to certain insects. Spinosad affects ants’ nervous systems. It can be used on outdoors on lawns, ornamentals, vegetables, fruits and nut trees. In addition to fire ants it controls thrips, caterpillars, leafminers, borers, fruitflies, spidermites, aphids and other pests. Read the package label on the product you choose for a full list.

D-Limonene is oil made from citrus peels. The oil strips away the protective coating on an ant’s exoskeleton thereby causing it to suffocate and die. The product typically comes in a concentrated form and must be mixed with water before use. Follow manufacturer instructions because d-limonene kills grass if applied full strength. Although d-limonene also kills certain other insects, drenches which are applied directly to ant mounds have little effect on non target insects.

Both spinosad and d-limonene are sold under more than one trade name. Baits are spinosad based. Drenches may contain spinosad or d-limonene.

Spinosad based baits include Ferti-lome Come and Get it! Fire Ant Killer, Greenlight Fire Ant Control with Conserve and Southern Ag Pay Back Fire Ant Bait.

For mound drenches containing spinosad look at Bonide Captain Jack’s Dead Bug Concentrate and Green Light Fire Ant Killer with Spinosad Spray,

For mound drench products containing d-limonene consider Safer Brand Fire Ant Killer and Orange Guard.

These products are typically safe on lawns and ornamental gardens, pastures, vegetables, fruits and nut trees. Read the label and make sure the product you choose is safe for your intended use. Look also for OMRI on the label.

Note: In case you are wondering about killing ants by using boiling water on the mounds, the treatment is only about 60% effective and requires three gallons of almost boiling water to reach the reproductive area of a mound. The hot water kills the surrounding vegetation. It also requires a stealth attack by the applicator so that the ants don’t send out their alarm and scatter as they sense imminent danger.

A two step treatment program is the most effective way to control fire ants. First, apply bait granules as directed by the manufacturer. Water ruins bait, so don’t water it in. Don’t apply bait if rain is predicted. If rain occurs within 12 hours, treat again. Look for properly applied spinosad bait to yield results in 2-3 weeks.

Then follow up with a mound drench in cases where an active mound persists or a new one pops up. Don’t disturb the nest before you apply the drench. The amount of drench depends on the size of the mound. One gallon should be sufficient for small mounds, two gallons for large mounds. Consider bait as your foundation for control and drench your follow up for spot treatments.

Time of day and temperature are important for success, too. Follow directions on the label. Read the entire product label before you buy and before you treat.

This story was originally published March 4, 2016 at 9:41 AM with the headline "Gardening | Organic Treatment for Fire Ants."