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July 13, 2015

Will the cicadas kill my trees, shrubs or flowers?

Filed under: FAQs | Magicicada | Ovipositing — Dan @ 2:41 pm

The primary focus of this article is 17 and 13 year cicadas (Magicicada). Most other cicadas are nothing to worry about, with some exceptions1.

People ask: “Will the cicadas kill my trees, shrubs or flowers?” The short answer is “maybe”, particularly if your trees are pathetic weaklings. Here are some ways to defend your trees, other than chemical warfare.

Read on for more information:

First, it is important to mention that cicadas do not cause damage to plants by chewing leaves like other insects do, such as caterpillars. These are not the locusts associated with destroying the entire food supply of nations, nor are they the locusts mentioned in the Bible.

Damage from cicadas occurs during ovipositing, or in some extreme cases, when they feed on the roots of trees4.

Grooves made by a cicada during ovipositing:
An illustraition of egg nests:

The weakest limbs of a tree are often temporarily damaged or killed off, the result of which is called flagging, as the leaves of the branch will turn brown and look like a hanging flag. In many cases, they are doing the trees a favor by pruning their weakest branches.

An image of Flagging caused by cicadas:
Brood II 2013 Periodical Cicada Flagging

Cicadas are technically parasites of the trees, and they need the trees to survive throughout their life cycle, so killing trees is not in the cicadas best interest. If cicadas were tree killers, there would be no trees, and no cicadas left.

Big, Hearty North American Trees:

Deciduous trees, like elm, chestnut, ash, maple, and oak, are the preferred host trees of periodical cicadas. They will flag the branches of these trees, but only young ones are at risk.

Don’t believe me? Read this quote from the paper Periodical Cicada (Magicicada cassini) Oviposition Damage: Visually Impressive yet Dynamically Irrelevant by William M. Hook and Robert D. Holt (Am. Midl. Nat. 147:214-224).

The widespread oviposition damage from periodical cicadas did not have any important effects on successional dynamics of the host plants, suggesting that the trees appeared to compensate sufficiently for physiological damage during the emergence.

Periodical cicadas avoid evergreen trees for egg laying because the sap interferes with their egg nests.

Fruit trees: Farmers expect every branch of their fruit trees to yield fruit. They will not tolerate ovipositing & flagging by cicadas.

Cicada Lawyer
Cicada Laywer

The smaller species of Magicicada, ‘cassini & ‘decula, like ovipositing on trees on the edge of a forest, probably because their offspring will be more likely to find grass roots when they leave their egg nests (cicadas initially feed on grass roots until they are big enough to reach and feed on the larger rootlets of trees). An orchard is all “edge of a forest” because of the rows between the trees, so it ends up being what the legal system would call an “attractive nuisance” for cicadas, because the farmers are baiting the cicadas by providing the ideal egg-laying environment, only to kill them with pesticides.


Another consideration is that many fruiting trees are not native to North America. Apples, for instance, are from Asia and are not prepared/evolved for the egg-laying behaviors of cicadas.

Small or Ornamental Trees: Cicadas pose the largest threat to small, weakling, ornamental trees, and young deciduous trees. These trees will have the fewest branches, and will not be able to suffer a heavy loss. These are the trees you can worry about, but there are ways to defend them. It makes sense to avoid planting ornamental, fruit or or other deciduous trees the year before and of a cicada emergence — make it the year you concentrate on pavers and low, ground-covering plants like vines and pachysandra.

Shrubs, Vegetables, & Flowers: Given a choice, cicadas will avoid ovipositing on shrubs and long stem flowers, but if the emergence is particularly heavy, they’ll give it a try, out of desperation.

Small flowers, like marigolds, pansies and zinnia will have the best chance of avoiding cicada egg-laying behavior since their stems are so short and unappealing for egg laying.

Personal experience:

I’ve experienced the full duration of two emergences of Brood II. During neither event did I witness the loss of a small tree, shrub or flowering plant. I saw a dogwood tree withstand two emergences, although it did experience ovipositing on nearly every stem, and it lost multiple branches due to flagging. In 1996, our small ornamental red maple withstood the cicada emergence without memorable issues (that plant was lost to a fungal blight many years later). I cannot remember any damage to scrubs such as boxwoods and forsythia, or garden flowers. Your personal experience might be different.

And of course: Good Luck!

Some references, if you are interested in this topic

1 Certain cicada species in Australia will damage sugar cane and grape vines, but not in North America.

2 Periodical Cicada (Magicicada cassini) Oviposition Damage: Visually Impressive yet Dynamically Irrelevant by William D. Cook & Robert D. Holt.
American Midland Naturalist, Vol. 147, No. 2. (Apr., 2002), pp. 214-224.

3 Spatial variability in oviposition damage by periodical cicadas in a fragmented landscape by William M. Cook, Robert D. Holt & Jin Yao. Oecologia (2001) 127:51–61.

4 Periodical Cicadas in 1963, Brood 23 by D.W. Hamilton & M.L. Cleveland. 1964. Proc. Indiana Acad. Sci. for 1963, 72; 167-170.

26 Comments »

  1. Eleni Constance Scott says:

    thank you for this helpful article. Preparing to wrap a small Yoshino Cherry we planted in March. Do we need to cover an evergreen Viburnum? Boxwoods?

    1. Dan says:

      From personal experience with cicadas and evergreens, I would say no, but double-check with a local arborist.

  2. Becca says:

    Here in Arlington VA (bullseye for Brood X 2021), I have a 4 yr old European Hornbeam that is 20’ tall. However, due to the type of tree, 80% of the branches are pencil-sized or smaller. I’ve been calling all the local arborists and tree companies, but none of them offer tree wrapping services. Is there anything else I can do to help this tree? Do cicadas have preference for European hornbeams? Thanks for your time and sharing your knowledge!

    1. Dan says:

      No idea about European hornbeams.

  3. RaShonda says:

    I’m in the process of planting 15 Arborvitae Emerald trees… are they at risk of damage form the 17 year cicada?
    If so..How can I protect them?
    Thanks…
    Concerned

    1. Dan says:

      Talk to a professional arborist about your concerns. Personally, I’ve never seen a negative evergreen/cicada interaction, but your results may vary, so get professional advice.

  4. peggy wiley says:

    I have a 50 year old dogwood in my yard that is usually full of buds this time of year. this year it is leafing out but very few buds. My neighobor have apink one and very few buds also. 17 years ago I have 2 50 year old Noway Maples about thirty feet away. Could the lack of flower buds be caused by the 17 yr cicada
    chewing on the roots?

    1. Dan says:

      Not sure. Technically they don’t chew on roots, they tap into them and drink from them, and they’ve been there for the past 17 years all the time. If it’s any consolation, my dogwood has weathered 2 cicada Brood emergences.

  5. Jim says:

    We planted hardy hibiscus a couple of years ago that took root and bloomed beautifully last season, but no stalks have emerged yet this year. Although they are flowering plants, are they likely to fall victim to ovipositing? Should we wrap the stalks in netting within the next couple of weeks?

    1. Dan says:

      I’m not certain about this because I have no personal experience or anecdotal knowledge of cicadas & hibiscus. Generally speaking, they do not trifle with garden flowers. However, if hibiscus has woody stems, they might try to oviposit on them. You can wait to net them once the cicadas start appearing because they don’t start mating & egg laying right away — but that said, you should not delay in purchasing netting supplies, as they may run out.

      1. Jim says:

        Sounds “iffy,” but perhaps best not to take chances (although I asked our landscaper and he said not to worry… and I’m still a little worried). The truth is that hardy hibiscus ARE woody — mature bushes grow to about 6-7 feet and are… well… HARDY. So, while they may be regarded more as bushes than trees, younger plants like ours may provide an attractive habitat for ovipositing. I’ll play it safe and buy some netting, but I’ll look for other forums that may provide answers specifically (there are a bunch of forums, since caring for hibiscus is pretty specialized). I’ll be happy to repost info if I learn anything. Thanks for your help.

  6. Susan Hoffmann says:

    Is it safe to plant 2 foot Nellie Steven’s hollies in late April 2021, just before the cicadas appear? Thanks.

    1. Dan says:

      Not sure about hollies. They didn’t bother my hollies in 2013, but your experience may vary. Consult your local arborist.

  7. Jeanne Capelli says:

    Hi We have a small lavender farm in South Central Kentucky and would like your opinion
    Do you think we should cover our lavender plants they are 1 to 2 years old.
    Appreciate your insight on how Cicadas interact with herbal plants such as lavender.

    Thank you for your time and help on this
    J & M

    1. Dan says:

      Periodical cicadas are interested in trees, and the damage they cause comes from their egg-laying behavior. I am not sure, but I don’t think lavender is woody-stemmed or tree-like, but I do not know, so I cannot say for sure. Please consult the professionals you normally consult when dealing with pests.

  8. Kimberly Clifton says:

    Will the Cicada hurt the peach trees?

    1. Dan says:

      Their egg-laying will kill branches.

  9. Jamia Sharp says:

    I am seeing alot of flagging right now on our trees it was 17 years ago this year I learned what was happening.

    Jamia Sharp
    Salem Missouri

  10. David says:

    I have a maple in my front yard. It was doing great for 20 years until last year. Now there is not a leaf to be found on it while others are full green. Cicada issue from last summer?????

    David

  11. Melissa says:

    Planted a weeping cherry in April..what can I expect?

    1. Dan says:

      did you consult your local arborist?

  12. pamela Christensen says:

    we have some Dappled Willow
    Salix integra ‘Hakuro Nishiki’ and the cicadas have ‘killed’ the tips of some of the branches…..should we prune them or let them alone, till at least the cicadas leave? and will the whole plant die?

  13. Lynnda Gress says:

    Should the branches on a small dogwood tree be removed where the cicada’s have made their slits in the branches?

    1. Dan says:

      Only remove them if they die. Sometimes they live. My Dogwood lost some branches, but most lived.

  14. Lynnda Gress says:

    should you trim the small branches off the dogwood where the cicada’s made their slits in the branches or just leave them alone?

    1. Dan says:

      Only remove them if they die. Sometimes they live. My Dogwood lost some branches, but most lived.

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