Ants damaging young(3.5 year) cedar trees in planters

Discussion in 'Gymnosperms (incl. Conifers)' started by Sarah_sa, Aug 9, 2020.

  1. Sarah_sa

    Sarah_sa New Member

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    Hi there,
    I have 16 cedar trees in planters on my open patio. this is the 4th year I am having them, and they have been doing good in general.

    this year I noticed there are a large number of ants moving around the trees and their planters. At first I didnt bother, but now after a few months I found out that ants not only go inside the planters and dig into the planter soil, but also they are constantly crawling up an down the tree trunk and branches - and that the tress which are specifically targeted by ants are losing green/live leaves and stems. To the point that when i shake these trees which are more surrounded by ants, the tree loses a lots of leaves and small branches right away, covering the ground.

    I am now quite sure that the ants are harming my tress. :(

    what can I do to get rid of them?!
     
  2. Arlette

    Arlette Active Member

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    Usually the presence of a large number of ants presupposes the presence of a large quantity of honeydew and, therefore, of parasites that secrete it (Aphids, cochineal - on citrus mostly Cottony scale -, psylla, aleirodidi, leafhoppers .....).
    Cedars are subject to the attack of aphids, in particular of Cedrobium laportei (especially on Cedrus libani and Cedrus atlantica ) and Cinara cedri (especially on Cedrus atlantica glauca and Cedrus deodara). They are both corticles and live in dense colonies arranged in sleeves on the branches with a diameter of less than 2 cm and on the smallest twigs, forming an abundant honeydew which falling, like a very fine rain, smears the soil and the things underlying the plants.
    Abundant fumaggine develops on the honeydew produced by the aphids which, incorporating the solid particles present in the atmosphere, forms thick blackish encrustations which, in addition to disfiguring the ornamental appearance of the plants, exert an asphyxiated action on the vegetation. Furthermore, the needles redden and then fall off the plant and the apical vegetation of the branches dries up.
    This is therefore the first check you need to do on your plants.
    A photo showing part of the branches of a plant affected by the problem and both sides of the leaves would also be useful.
     
    Last edited: Aug 10, 2020
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  3. Acerholic

    Acerholic Esteemed Contributor Forums Moderator Maple Society

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    @Sarah_sa, good morning and welcome to the forum, I agree with @Arlette ants are there because they have found a ready food source. I dont mind ants on my trees, as they point towards the fact that Aphids are there? They are the ones that actually do damage to my maples.
    I have had ants using patio planters and I use chalk powder around the base to deter them. This is a natural non chemical way to stop them. It does work but re application is necessary after rain or watering.
    Ants do not damage trees directly, but they can in large colonies cause disruption to roots of trees. They are also attracted to rotten tree wood and bark.
    So IMO do not worry about the ants but look at the reason they are there.
    Regarding a photo that @Arlette has asked for, I have attached this link in case you are unsure how to do it.
    Attach photos and files from Mobile Device
     
    Last edited: Aug 10, 2020
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  4. Arlette

    Arlette Active Member

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    The ants being greedy of honeydew help us because their presence on the plants makes us doubt that they can be attacked by parasites that secrete it and we can run for cover.
    In the larval stage, however, the ants eat insects that are a protein food to build new tissues, gain weight and therefore grow but I do not know that they eat aphids, indeed, over the millennia a relationship of mutualistic symbiosis between aphids and ants: the workers, in exchange for the honeydew, look after them and push them with their jaws on the tender twigs so that they can feed easily, and "milk" the honeydew, defending them from ladybugs and, during the winter , hosting them in a sort of stable in their nest.
    And this would be the indirect damage on ornamental plants: they favor the survival of insects and parasites that attack these plants with serious damage as very often the presence of honeydew favors the onset of fumaggini that prevent the presence of honeydew favors the onset of smokes that prevent the necessary photosynthesis of chlorophyll by the leaves.
    The problem with fruit plants is different because if they reach the fruiting branches they actually attack the fruits by emptying them of the pulp.
    To eliminate the presence of ants, natural and chemical remedies can be used (but I do not agree with the latter and I do not consider them to be used):
    • cover the bark of the tree with double-sided adhesive coated with adhesive material or brush it with insect mistletoe or with a mixture of soot and linseed oil;
    • level down the pruning of the trees to prevent branches or twigs from touching the ground and favoring the climb of the ants;
    • find the anthill and completely eliminate the portion of earth, to eradicate the nucleus of ants at the origin (placing an overturned terracotta or plastic jar on it, which will be chosen as a new home for the entire colony, allowing it to be transported without damage to another place).​
    Alternatively, you can use a series of aromas or plants whose scent disturbs the ants avoiding the problem of toxicity. First of all the Cinnamon, they can't stand the smell, (I buy bags of the powdered one and I also use it at home) and then lemon juice, Lavender, Marjoram, Mint, Chilli, Garlic, Bay leaf, vinegar, coffee, Chalk. The negative side that following rains the application must be repeated.
    The same drawback occurs with another excellent product which is Diatomaceous earth or diatomaceous earth which is a natural insecticide for the control of parasites and for the treatment of infestations of various kinds. It breaks the exoskeleton of the ants and causes them to die of dehydration. It is not toxic to humans, but it is best not to breathe the particles of this fine dust. You can also create barriers between flower beds with this Diatomaceous earth.
    If, however, the nest and anthill structure were to be more entrenched than it might seem, natural remedies and chemicals do nothing but kill worker ants, but they do not dismantle the insect infestation system. In this case, when the do-it-yourself strategies - from the most harmless to insecticidal products - do not produce the desired results and visibly the ants seem to increase, then you need to turn to professionals.
     
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  5. Acerholic

    Acerholic Esteemed Contributor Forums Moderator Maple Society

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    @Arlette totally right Arlette re the relationship between Aphids and Ants. The point I was trying to make 'rather badly' I must say, is that ants on a tree tends to point towards the problem of Aphids. Then it is up to us to remove them.
     
  6. Sarah_sa

    Sarah_sa New Member

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    Many Thanks to both of you for your great responses. I will attach some pictures here to show the condition of the trees.
    I could not find any sign of honeydew on any of the trees btw.

    this set of pictures attached to this message, belong to a tree which was formerly invaded by the ants (they can get into the planters from underneath holes) . I tried my best to interfere with ants activities; Now I'm not sure if that was why they left this tree alone, or that they find a better source of attraction (whatever it is) in other trees!


    as you can see the tree has lost a lot of leaves, and many has reddened too.
     

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  7. Sarah_sa

    Sarah_sa New Member

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    The set of pictures attached to this message, belong to a tree which has been recently and sort of still invaded by ants. you can see fresh green needles on the floor, which is due to slightly shaking the tree (accumulated only over the last 24 hours, as I just groomed yesterday and cleared all the needles on th efloor)
     

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  8. Sarah_sa

    Sarah_sa New Member

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    3rd set of pictures attached to this message belong to a 3rd tree - Healthy and in great condition as seen in the pictures - which I believe ants have JUST started attacking/invading. It is also started to loose some fresh green needles, for no reason :(
     

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  9. Sarah_sa

    Sarah_sa New Member

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    Is it possible that the ants come to get food from the soil, and if so why do they crawl up and down the tree trunk and branches?
     
  10. Acerholic

    Acerholic Esteemed Contributor Forums Moderator Maple Society

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    @Sarah_sa, OK you say you cannot see any Aphids. Cyprus aphids will suck all the sap out of conifer needles and be gone before the needles turn brown.
    The ants will colonise the pots and now stay there unless you repot your trees and remove the nests. They will venture to other pots on the look for food.
    The soil in your pots will after 4 years be rather depleted of nutrients so could do with some new soil now. They may well be totally root bound. I would advise repotting in the Autumn ( September) and do not over water. Once a week is ample with a thorough soaking . A root prune will be essential if you are keeping them in the same pots. I repot my maple trees every two years. Your trees can get away with 4 maximum IMO. It will be quite a job to carry out as you have so many, but it is necessary to keep them healthy. A well draining potting soil is also essential.
    A weakend tree is always susceptible to attack, so now ( September) is the time to act against the nest.
    I still do not think the ants are the main problem, unless the nests are so large that the root systems has been compromised severely. The reason is why are the ants there as @Arlette has correctly stated.

    Hope thats of help.
     
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  11. Arlette

    Arlette Active Member

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    Now that I see the photos of the plants I would like to show the state of some internal branches (regarding the first set of pictures) which, I will be wrong, make me think that we are not by now in the presence of an aphid or ants problem.
    It is necessary to check the condition of the roots and the collar and if they were my plants I would have it done by an expert.
    AA.jpg AA2.jpg AA3.jpg

    AA 4.jpg AA 5.jpg
     
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  12. Ron B

    Ron B Paragon of Plants 10 Years

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    Photos show very often purchased Thuja occidentalis 'Smaragd' deteriorating due to being trapped in too small pots. There might also be something like a leaf blight or mites involved as well, but the first thing to do is move the plants on to larger containers filled with fresh potting soil.
     
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  13. Sarah_sa

    Sarah_sa New Member

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    You are all absolutely right; The trees are so overdue for re-potting.
    I have managed them for 4 years now by adding fresh potting soil to the pots in the first year, and also adding manure last year. This year I wanted to get them some more manure, but I missed the spring deadline and so skipped for this year (I suppose manuring should be done in spring time, is it right?)

    I would try my best to repot all the trees in September. I assume I should wait for the temperature to drop, is it correct?
    Just in case, If I wasn't able to repot all of them this year, is it possible to still manage the trees in the same pots, by adding/changing the existing soil with manure? do you recommend manure or fresh soil in general?

    an update on the ants:
    I dont think I have seen any aphids on the trees. I might have seen something similar to mites (based on the pictures of mites I googled) but not a crazy significant number of them - especially speaking of the trees which were targeted by the ants.

    I have been trying to destroy as many ants as possible by moving the pots around. I have not seen any big crowd of them since my last big attack! I am still keeping an eye on them and try to destroy any single one that I see.. :|
    I have put Cinnamon powder around tree pots, and on the paths I figured as their main travel paths. I am still not sure where their nest is. As they seem to shift from one tree to another and then colonize in that area. Their nest might as well be somewhere out of my patio area.
     
  14. Acerholic

    Acerholic Esteemed Contributor Forums Moderator Maple Society

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    @Sarah_sa, I would not use manure but use a slow release fertiliser, mixed into the growing medium. IMO a soiless mix that is very free draining is ideal. You can find good ready bagged gritty compost mixer at garden centres. If not, then you can mix your own. Recipes vary but the most important thing is GOOD drainage. I have found that soil in pots can become too dense and not allow for good drainage and cause root rot. Others may disagree, but that is my experience.
    The temperature will drop in a few weeks, so that is the time to repot.
    You want it warm enough though for the roots to start to take hold before the Winter months arrive. I repot in the South of England in September. Depending on the forecast for your area you may get away with a touch earlier.
    Regarding the ants, when repotting you may come across nests, so that is the time to eradicate these.
    When you do repot, do update the thread with some photos of the root mass etc. I for one will be very interested.
     

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