(News article for June 4, 2022; edited)
Red imported fire ants plague us in many locations in Louisiana, and vegetable gardens are no exception.
Treatment options – including baiting, using a contact insecticide, or a combination of both – are similar to those for other locations, but only insecticides labeled for use around vegetables, and the specific types of vegetables you grow, should be used.
Baits contain small amounts of insecticide mixed with materials that attract ants. If used correctly, worker ants bring the bait back to their colonies so that other ants are exposed to the insecticide. Because ants distribute it, using bait effectively doesn’t require knowing exactly where colonies are located.
Baits should be used when fresh and applied when the ground is dry, with rain not expected within the next 24 hours. The temperature at the time of application is important. Fire ants do not seek out food as actively when temperatures are hotter than 90 degrees F or cooler than 65 to 70 degrees F.
Fertilome Come and Get It! is a fire ant bait containing the active ingredient spinosad and labeled for use around many types of vegetables in home gardens. It will likely take around two to four weeks to see results after using a spinosad-containing bait.
Some baits with insect growth regulators, including methoprene (Extinguish Professional Fire Ant Bait, but not Extinguish Plus) and pyriproxyfen (Esteem Ant Bait), allow use around some or all vegetables, but it can take several months for these to have their maximum effect.
While the number of bait products that can be used in vegetable areas is limited, ants will travel some distance while foraging. If you use a fire bait product in the lawn area close to the vegetable garden, this can also help manage fire ants nearby.
Baits are useful when long-term fire ant management is the primary goal. Where immediate control of ants is needed and the location of the colony can be identified, contact insecticides are helpful.
When choosing a contact insecticide to use in a vegetable garden, it’s not only important that the product be effective against fire ants and labeled for use around the types of vegetables you’re growing but also that it be labeled for fire ant mound applications around vegetables. Treating fire ant mounds is different from just spraying plants for protection from plant-feeding insects. To control fire ants, you need to be able to apply the product in such a way that it gets down into the ant colony.
Several spinosad-containing contact insecticides, including Bonide Captain Jack's Dead Bug Brew Concentrate, Bonide Colorado Potato Beetle Beater Concentrate, and NaturalGuard Spinosad are labeled for mound treatments around many types of vegetables. Orange Guard, which has the citrus extract d-limonene as its active ingredient, is another option for mound treatments and can be used around all vegetables.
If you want long-term control of fire ants but also need to get rid of them quickly in one or more spots, you can take a two-step approach: Apply a bait, wait a few days to give ants time to carry it back into the mound, and then apply a contact insecticide.
Be sure to read and follow all label instructions when using any insecticide.
Let me know if you have questions.
Contact Mary Helen Ferguson.
Reference to commercial or trade names is made for the reader’s convenience and with the understanding that no discrimination or endorsement of a particular product is intended by LSU or the LSU AgCenter. In some cases, other brands are available.
Red imported fire ant. (Photo source: USDA APHIS PPQ - Imported Fire Ant Station , USDA APHIS PPQ, Bugwood.org)