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What's eating my dahlia leaves?

lyssa13
10 years ago

Help! I have two potted dinnerplate dahlia plants that bloomed beautifully when I bought them. However, they are now sad and the leaves are all eaten with holes.

Based on these pictures what do you think it is? What do I do to fix it. And will my plant come back alive once I fix it or is there a chance it's dead?

Help, I'm very much a beginner at this and trying to learn!

Whatever this is hasnt touched anything else in my backyard, just the dahlias!

Comments (22)

  • lyssa13
    Original Author
    10 years ago

    Second photo

  • lyssa13
    Original Author
    10 years ago

    Oops sorry

  • Noni Morrison
    10 years ago

    Slugs! They love young dahlia plants...As long as your tubers are undamaged they should put out new healthy foliage but you need to get rid of the slugs or snails, which ever you have. Use slug bait, or hand pick them off the plants after dark when htey come out to forage.

    Bait around your plants with either a non toxic to children and pets slug bait or if that is not an issue, try "Deadline". I have an organic garden so I spray my plants with a mixture of 1/3 household ammonia and 2/3 water. Reapply after rain.

  • CCvacation
    10 years ago

    Lizalily,

    I have never heard ammonia used as a preventative, only direct retaliation on browsing slugs. Have you seen a clear difference between sprayed and not sprayed plants? I like the idea of using ammonia spray instead of or addition to the expensive pellets. Someone on the list recently said that ammonia actually is beneficial for dahlias, too, but I'm not sure how that would be.

    Have you had any noticeable decrease in other critter damage as a result of using it as a preventative?

    I've heard you can use full or dilute ammonia on trash cans to deter bear, raccoon and opossum from molesting the contents (with varying success, depending on whether the pest has already formed a habit eating your garbage)

    I wonder if an ammonia solution might work for nibbling rabbits... I've been using two commercial sprays intermittently (one specifically for baby rabbits), and the bunnies seem to think both tastes like salad dressing.

  • Noni Morrison
    10 years ago

    Ammonia IS a high nitrogen fertilizer. The plants love it! I think as long as the odor lingers it works but needs reapplying every few days. And of course the best time to spray it is when the slugs are out enjoying a gourmet feast! But the residue actually will work for a few days if its not raining. Best is to try to capture and dispose of, or poison the slugs before they get to the plant. The two pronged approach as worked well for me.

  • CCvacation
    10 years ago

    Interesting... Thanks for your input!

    I think I'm going to make my own concoction to spray...
    Equal parts Ammonia and commercial rabbit/ deer repellent
    Dissolved epson salts (magnesium for plants)
    Dish soap (surfacant to get solution to stick, and an earwig/aphid deterrent)
    Hot sauce (most the critter deterrent recipes have it in there, so why not)

    The growth month of June makes or breaks dahlias, so I figure, give them as much of an advantage I can!

    I've heard that an old corn cob soaked in vinegar and lain on the edges of the garden deters critters, too, but I'll pass on that technique for now.

    Also, when the plants are grown, trimming bottom leaves off and coating the bottom two inches of the stalk with vasoline helps keep bugs from climbing up to munch on blooms.

  • Noni Morrison
    10 years ago

    By the way, the ammonia spray will kill and defend the plant from aphids too. I first started using it for aphid infestations on my rose bushes.

    Now, 10 years laters, following organic principles as much as possible, I have seen NO aphids on my roses this year, but the garden is full of birdsong..

  • CCvacation
    10 years ago

    Lizalily, how did you come to the conclusion of one third ammonia to two thirds water? Did you experiment with stronger solutions and see leaf damage, or were you following someone else's recipe?

    Thanks!

  • Noni Morrison
    10 years ago

    I was following someone else's recipe from long ago when I used to follow the Cut flower Forum on Garden Web. I tried it, it worked and i like the results. I used this to clear the aphids last year when the ants were farming them on my dahlias.

  • CCvacation
    10 years ago

    Thank you! I'll try to stick to that ratio from now on with the ammonia. I used a bit more then 50/50, and think I burned some leaves. No harm done, but I'd hate to burn buds!

    My concoction above has been mostly working, but if it rains, all bets are off. I was busy this weekend, and wasn't as viligent spraying twice a day (very rainy here), and a good dozen plants were munched half way down to the ground. Very irritating, watching those cute little tails race away from me. No slug damage (I had baited early on in the season), but I have seen earwig damage since spraying.

  • highlandernorth
    10 years ago

    I always have problems with slugs, especially early in the dahlias growth cycle from the time they just start coming up til they are a foot tall, but if they make it through that, I don't have any problems with them later when the plants are bigger. I've never seen any slug damage on leaves above about a foot tall.

    It's been terrible this year, especially since its raining seemingly 4 days a week or more, like right now! That's made using chemicals or bait almost useless because it either wears off or the baits just disolve. Plus they are growing so slowly due to cooler temps and too much rain, so it seems like they just don't want to grow like they should, and some have died due to rot mainly, but at least 2 were completely stripped bare by slugs forcing me to dig them up and replace them. Thankfully I had many extra tubers stored in pots from last year, so I've been able to replace dead plants.

  • gsweater
    10 years ago

    Two words that will help you, will not over fertilize, will not damage beneficials, and works quite well when done strategically:

    Diatomaceous Earth

    Kills 'em all. Nothing else needed aside from NORMAL fertilizer (which Ammonia is not - it's very bad). Anything ammoniacal deteriorates your soil condition, and especially when used with frequency.

    I've used DE for nearly 2 decades in my veggie and show gardens and little to no problems (that is when I actually do it right lol!)

    For pots, I put straw at the top to keep evaporation in check and drastically reduce watering requirements. I sprinkle DE both under and on the straw. I have a set of large buckets I soak my pots in, making sure the water level is below the top of the soil level so as not to wet the DE. The DE scrapes them up when they climb (or ooze) their way in and they're dead the following day. It's crazy how many dead slugs and earwigs I find around the pots. I sometimes have to break out a broom because it looks like a killing zone.

    Another way I control them in the veggie garden is to take old plastic containers (i.e. cottage cheese, etc.) and put a couple ounces of vegetable oil and tuna juice in their. Earwigs literally pile up in there - it's disgusting, but makes me laugh inside >:)

    Bottom line is the damage has dropped significantly and I'd say that those particular bugs are not problems for me any longer - not that they don't exist. Now, SVB... that's one bug that's pi**ing me off - but a different topic altogether. grr...

    Good luck!

    This post was edited by gsweater on Fri, Jul 19, 13 at 22:11

  • Lorna1949
    10 years ago

    salt will kill slugs also but it may harm the plants so be careful

  • Steve555
    10 years ago

    Slugs and snails do NOT like coffee grounds. I place a healthy ring around my dahlia beds along with some crushed egg shell and slugs leave. An organic and safe pellets is Sluggo Plus also gets earwigs but is pricey. I use it only when earwigs attack.

  • CCvacation
    10 years ago

    Steve, I was thinking about setting up a coffee ground collection bin (5 gallon bucket) at a gas station and a local coffee shop, and using it on top of the mulch, working it in the soil with leaf compost after the tubers are dug.

    What say you? Would the grounds next to the stems and applied heavily do any damage to the blooming dahlias?

  • laynie1
    7 years ago

    gsweater you posted three years ago, and this blog came up in my Google search for what's eating my dahlia leaves. I just wanted to tell you that the DE is miracle stuff, and I did the empty tuna can with oil and almost before I stood up there was 5 aphids drowning! And it's not even nighttime yet, it's the middle of the afternoon! Thank you so much for a great tip that I'll remember forever.

  • housedaisy
    6 years ago

    Hi - thanks for the great tips! How would I best use DE with dahlias planted as a cluster in a mixed, raised bed?

  • Teresa Rozich
    6 years ago

    How can you determine if it's earwigs, slugs or something else? I have 2 gardens, and one of them has a dahlia that looks like that. None of my other plants seem to be affected, just the Dahlia. Only 2 Dahlia tubers produced a plant, and only one is viable (the other is barely 1" tall compared to the 18" tall one that's being eaten). The small one isn't being touched, just the larger one. It's putting out blooms, but the leaves look awful.

  • cicivacation
    6 years ago

    Google 'slug damage' and 'earwig damage.' You'll see lots of images that will help you figure it out. Regardless, it is good practice to get slug and earwig bait, and apply it until the plants are over 2 feet. The bait will kill future generations of pests if used late spring through mid-summer.

  • moshguy34
    6 years ago

    I find beer in containers attracts all the slugs, when sunk into garden in various places at ground level. Scoop out loads of dead slugs next morning with an old spoon.

  • Mb Schoening
    9 months ago

    What do you put in the beer containers? Some beer? Or something else?