Questions about fire ants in the garden are common around the Extension office. Fire ants can be a nuisance and they can damage some vegetable crops such as okra and Irish potatoes. Fewer fire ant mounds would result from tilling your garden but a few mounds may persist in heavy mulch or close to vegetable plants. In these cases fire ant baits or mound treatments may be in order.

One of the best ways to keep fire ants out of your garden is to do a good job keeping them out of the lawn. Gardeners can apply labeled fire ant baits in a 50 to 75 foot wide band around the outside of the garden.  The bait needs to be applied two to three times a year and will hopefully result in fewer issues in the garden. Worker ants will forage for food outside the garden making parameter treatments successful.

Gardeners need to make sure to read the label of baits because a lot of them are not labeled for use in gardens. Active ingredients of some products that can be labeled for use in the garden include pyriproxfen and spinosad.  Pyriproxyfen is an insect growth regulator that reduces the production of eggs and it prevents the development of worker ants. Spinosad is a natural metabolite product that affects the ant nervous system. Many spinosad products are approved for organic vegetable production and are pretty fast acting.

If you are going to use a mound treatment, do not put the product directly on top of the mound but sprinkle it around the mound. Baits are best applied in the spring and fall when temperatures are in the 70s. Apply baits in the late afternoon or early morning when the ants are foraging. To determine if fire ants are foraging, crumble a few potato chips and place them on the ground beside the mound. Check for ant activity in about 30 minutes and see if the ants have taken off the chips. Apply baits when there is no threat of rainfall within 24 hours, as rain will dissolve the bait.

You can also use liquid drench products. Mound drenches usually have quick activity on ants. Spinosad products have been very effective when used as mound drenches. Check the label for directions.

When applying drenches, gardeners need to apply enough water to soak the mound. Depending on the size, this could be 1 to 2 gallons of solution. First apply about one quarter of the total volume in a circle about 12 inches from the outside of the mound. This will prevent the queen or workers from escaping. Then apply the rest of the drench directly onto the mound. When applied properly, mound drenches will eliminate a mound within a few hours.

Some brands of carbaryl can be used as mound drenches in gardens. Please check specific labels on these products.