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Ants are destroying my dahlias!!

Jana Silvia
June 11, 2016

So I've always tried to garden/co-exist peacefully with all that lives in my garden. But the ants have pushed me to my limits lately. They have destroyed 3 of my beloved dahlias. They live in my dahlia bed and have holes right around the bases of my plants. I have noticed that the stalks have been wobbly. Well, just below the soil line the plants are tapered and broken.

I have been applying diatmaceous earth and it's just not doing the trick. The ants go away for a few days and then return to their work. Should I use the borax and sugar combo? Any other ideas??

Thanks in advance!!

Comments (7)
  • Terri Williams

    I certainly am not the most experienced grower here. I bought a little container dahlia in the beginning of May from Lowe's. After a few days of bringing it home, it was covered with those little piss ants that seem to descend upon Asheville every Spring. They were chewing on the blooms and started on the leaves. A gentleman at Home Depot told me that they were pollinating the plant and to leave it alone but the damage kept getting worse. I put my plant on neem oil. I spray every seven days. It seemed to help. I did finally give in and gave a good dose of Sevin insecticide spray. I am trying to be organic this year. This has seemed to help. I have not seen any ants. I am keeping the neem routine because I am getting ready to roll up the sleeves of my old gardening shirt and do battle with the spider mites that I am sure are plotting an attack.
    I hope this helps....

  • cicivacation

    Other then ants farming aphids, I haven't had issues with ants.

    On another dahlia forum, growers are talking about ant problems. They are saying that there are different species that: farm aphids, burrow into the tubers/stalks, cut leaves to drink the sap.

    The solutions that worked for others are: treat for the aphids, use bait stations at the base of the problem dahlias, or use Amdro. (Apparently Amdro is not directly toxic because it interrupts their breeding cycle. I've never heard of it before.)

  • cicivacation

    Sevin is avoided by all the growers I know, as it kills the predatory insects and increases spider mite population. It is also quite bad for honey bees.

  • Terri Williams

    Oh...that may explain the spider's seemingly infatuation with my "problem child".

    I will stay away and continue to neem. I have had some ants but I don't notice much damage. My plants seem to be healthy.

  • HU-3614861919800

    I got my first Dahlias 2 yrs ago, knew nothing about difference variety’s, how to locate eyes, how to dig them up for fall storage etc. After viewing many videos, I have learned a lot. This is the third year I have planted Dahlias, although this year I went crazy and even had a pre spiring greenhouse going for about about 60 Dahlias from Costco, Lowe’s Brecks and Vesseys all later planted in my gardens... you get the picture.

    and this year I am learning about pests other than slugs.

    after reading about advice, I can offer some of my own comments

    earwigs do eat tops of developing buds. Use soap and water spray directly on them or just squish them.

    slugs: all the beer in cup, slug bait, don’t really work that well. Last year I had them all over my Hostas, and Dahlias with leaf holes everywhere, so I would go out every nite and early morning with pair of scissors and snip all slugs in half. Done. No bait no touching them. Did about 15-20 slugs each morning/nite. This year I have continued the practice, but I have hardly any slugs remaining, maybe 0-2 each time I go out.

    On my Dahlias I also have slow green bugs with black stripe and fast moving grey black bugs eating my plants that jump even when you try to spray them with soap and water.

    Many leaves have evenly spaced dotted brown holes on them. I am spraying soap and water on all of them. I have actually delayed deadheading flowers because these quick bugs like the almost dead flowers better than leaves and spraying these wilting flowers zaps them before they can jump/ fly away.

    So, now to ants, of all my 60 plus Dahlias, only one has an ant problem. There is a crack in the stem, and the small ants that you find on your interlocking driveway patio stones are climbing up the stem and entering the stem. The stem below the cracked area is all narrower to the ground than the stem above the cracked area which looks thicker and healthy.

    I keep spraying them with soap and water but they persist. I don’t see any aphids and believe they are entering for the sap. The question is did the ants make the hole/ crack?

    All the advice “eggshells” diatomaceous powders, beer in cups, rolled up newspapers or hoses for earwigs - kills only a few of the culprits.

    - scissors- at early am and last nite for slugs

    soap and water spray for insects.

    I do not have proof of this, however from what I have seen if you spray open flowers with soap and water, they don’t seem to develop as big of a flower or last as long as if you don’t spray the flower directly. My advice is to wait until the flower is done and half dead, before spraying it for the hiding pests between the petals.

    anyone with advice on my comments?

  • cicivacation

    It's awesome that you are accumulating your own tips/tricks, HU. Writing down what you have learned helps you remember it the next time the same problem is staring back at you once again, and can also really help beginners out. Kudos for sharing!

    Here's the FAQ I put together with help from other experienced growers on the same subject... perhaps it will give you additional ideas.
    What can I do about bugs damaging my dahlias?

  • HU-3614861919800

    Thank you cicivacation. Had a read and lots of good info. As an update on my original post, I lost my dahlia that had ants on it. I must say I was not aware some ants do that. I had thought maybe my dahlia had a crack in the stem, and the ants were merely getting fluid/ liquid without hurting plant, til a few weeks went by and the wilting starte on the leaves, and the dahlia is now gone...

    but now, ants are not only climbing one of my fav dinnerplates, you can see brown spots where they are chewing...

    i have sprayed soap and water, put Borax poison out, demataceus powder spread out, and had a company put ant poison stations, but no luck! I am trying Vaseline from ground up in thick 1 inch amount to see if they can get past it.

    If this doesn’t work, I am going to consider systemic insecticides, move my dahlia into a pot, and douse the ground with gaseline amd light a match!! Then discard soil. What I find unusual is these ants are in a small garden in front of the house, and no other dahlias in all of my gardens have ants eating them..

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