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Ready, Set, Grow: Protect against ants this fall

October brings to mind images of pumpkins, chrysanthemums and falling leaves to many gardeners and homeowners.

It makes me think of ants… mean, devilish, fire-biting ants.

That’s because it’s one of two seasons (along with late spring) when it’s most appropriate to apply long-term ant-eliminating baits.

While treating ants mound-by-mound can be effective in eliminating individual colonies (AKA “ant piles”), much broader and longer-lasting control can be achieved by adding baits to your arsenal. And the larger an area is treated, the longer the control will last.

If you’re in a rural area, you may choose to treat your entire property or perhaps the first acre or so around your house. Some subdivisions and neighborhoods have achieved great success by treating the entire neighborhood as a whole.

In neighborhood programs it’s best to organize. Baits are most effective when applied to a broad area within the same two-day period. You might talk to your neighbors and agree to all apply bait on the same weekend. Also, be sure not to apply the baits within 24 hours of a rain – either before or after application.

Baits work by a variety of biochemical methods that effectively disrupt ants’ ability to reproduce. Most do not actually “kill the queen” as many advertise, at least not directly. Instead, the colony as a functional unit dies by attrition.

They cannot replace older ants as they die off. Therefore control takes up to six weeks. In the meantime, go ahead and treat any mounds you see with short-term contact insecticides.

Baits don’t seem very attractive so far, but consider all the mounds you don’t see. Ants will forage up to 100 feet in search of food, and they will find your delicious bait. So you’re establishing a buffer zone and it will take the ants some time to get back in. The bigger area you’ve treated, the longer their return is thwarted.

Ever kill an ant mound, only to see it “move” a few feet over? In many cases, you did kill the mound.

The “move” you saw was probably another colony moving into the area. Ant colonies send scouts out all the time, just looking for new real estate.

When you kill the first mound, the scout finds a vacancy in the area and invites the whole gang over. The baits solve this problem, since the scout brings bait back to the nest, even if you don’t see the nest. (Many are small and unnoticeable.)

Baits come in a variety of brands, chemicals and modes of action. The LSU Ag Center has a list of those we recommend (on our website, or contact me). Common brands include Over and Out, Extinguish Plus, Amdro, Ascend and Award. Many others exist, but the “bait” claim on the label is often inaccurate. Do refer to our list if in doubt.

Even if you’ve applied baits, do continue to treat individual mounds. Contact insecticides kill ants immediately and are quite effective. Carbaryl (Sevin) is the probably most commonly used contact insecticide, and it’s safe for vegetable gardens. So is Rotenone, d-limolene, and the pyrethrins. Spinosad is approved for gardens too, and it’s organic-approved.

If you want to know more about gardening, landscaping, or anything else horticultural, contact the St. John / St. James Parishes County Agent André Brock at abrock@agcenter.lsu.edu. Also, the LSU Ag Center’s website can be accessed at lsuagcenter.com with lots of user-friendly information, including this article.