Questions on: Ants
Ron Smith, Horticulturist, NDSU Extension Service
Q: A client has ant problems in his carrots. The ants ate his red and orange carrots, but left the yellow carrots alone. One could say just plant yellow carrots, but I don't think that's the answer he wants. What can be done to prevent this from happening again? (e-mail reference)
A: In my dealings with ants, it is effective to tempt them with another source of food that has a poison in it. Being foragers, they will take the bait back to their nests for use as food, which kills them. The client needs to find bait that can be used in vegetable gardens. Whether this will stop them completely this fall remains to be seen, but I would sure use it next spring when planting carrots.
Q: I have a huge anthill at the base of my lilac. Do you have any suggestions as to what I might do to get rid of the ants, but not harm the lilac? Will the ants harm the lilac? (e-mail reference)
A: Iíve never known any North American ant species that would hurt woody plants, so I think the lilac is safe. The ants may have taken up residency there because of an infestation of aphids on the lilac at one time or even now. Try Tempo or Bayer Advanced Garden Multi-Insect Killer. These and other products are available in national chain stores or at good quality local garden center outlets.
Q: We have a row of lilacs that we are taking out. I have noticed that there are many red ants around the base of the lilacs. Is this normal? (e-mail reference)
A: Red ants are omnivorous, which means they eat flora and fauna in the environment. Any nursery stock you bring home should be inspected carefully to be sure that no red ant colonies are developing. Count yourself lucky if you never have been stung by these aggressive predators! To get rid of the ants (makes me itch just talking about them!) you will need to use an insecticidal drench on the soil or mound. Insecticidal mound drenches with common insecticides usually are effective against fire ant colonies. The mound is flooded with a large volume of liquid containing a contact insecticide, such as carbaryl, diazinon or dursban. Numerous insecticides are labeled for this use. A major problem with this method is that the queen is sometimes too deep within the colony to be contacted by the toxicant. Care must be taken not to disturb the mound prior to applying the drench. A disturbance will alert the colony and the queen may be taken deeper into the mound. Insecticidal surface dusts or granules have a limited effect on a colony if they are not watered in. The dissolved granules must come into direct contact with the ants. As in mound drenches, care must be taken not to disturb the colony prior to application. Take care and good luck!
Q: We have many ant hills in our yard. They are the small ants (much smaller than carpenter ants). We have many oak trees and our soil is very sandy. The ants are causing problems on newly seeded areas and are a pest when they get on backyard beverages! We live on a lake, so I am looking for an organic way to control them. All pesticides I read about are too toxic for the lake, our children and our new puppy. (e-mail reference)
A: Any pesticide will have some toxicity to non-target organisms. The question comes down to the dose and longevity. Try a boric acid solution. Mix a cup of water, 1/2 cup of sugar, 1 1/2 teaspoons of boric acid and shake well. Fill small bottles with cotton balls and saturate the cotton with the toxin. Poke small holes in half the lid so ants can get in. Turn the bottles on their side in heavily infested areas. The ants will bring the bait back to the nest and eventually kill off the colony. Some people have claimed success with sprinkling boric acid around each ant nest.
If you have any large ant nests, try the boiling water approach. Another idea is to mix mint tea with Saferís or Schultzís insecticidal soap. Follow the mixing directions on the bottle and then put the mix in a spray bottle. It kills ants on contact and repels survivors.
A: Try grits. I read somewhere that they will take those in as food, eat them, and because of the expansion that takes place in their gut, the ants die. It won't happen overnight like a poison will, but is supposed to work to get rid of them. Give it a try and report back to me. Simply sprinkle it around the mounds you see them making.
A: Plants attract bugs too, so should we eliminate plants around the home? Carpenter ants are not particularly attracted to wood chip mulch. Even if they were, they are easily controlled. I have used and recommended wood chip mulch for decades with no negative consequences like carpenter ants.
A: Since ant species are not my speciality, I took your sample to Phil Glogoza, NDSU extension entomologist. He immediately IDed it as a carpenter ant. As the name implies, this creature dwells somewhere within your housing structure. He suggests contacting a local pest control company and ask them to use Advanceģ, a registered carpenter ant bait that is effective in controlling them. It is safe around warm-blooded animals, but to be effective the bait needs to be placed where the ants are active.
A: Try boric acid. It is a proven stomach poison for ants and roaches. Mix some with foods they find attractive -- sugary or high-protein. Or, you can use commercial preparations, like Drax or others.
Q. I have two whiskey barrel planters that are full of ants. I have tried using traps, but it is not solving the problem. Would taking the soil out and replacing it help or would spraying the soil help, or do I need to get new planters? (Williston, N.D., e-mail)
A. Ants are there most likely because there is a source of food for themmost likely aphids that are feeding on the roots or stems of your plants, and the ants are "tending" them to collect the aphids' honeydew. If you apply the insecticide Sevin or diazinon, you should get control. Follow the directions on the label. You shouldn't need to replace those expensive whiskey barrels!
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