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greenmanok

Insects infestation and treatment

greenmanOK (Zone7)
10 years ago

Hi all. I'm having some trouble with something infesting my verbena, rudbeckia, and Shasta daisies in my full sun garden. Especially in the verbena I see little white jumping bugs when I ruffle the foliage. Based on what I've read on here it might be spider mites, whiteflies or springtails? I suppose all the moisture in the past several weeks has contributed. One patch of verbena has really suffered - browning, wilting, dying... Another nearby verbena patch is also heavily infested but they do not appear to be harming the plants, since they are blooming and growing nicely. I've resorted to pulling some daisies, and I'm getting some leaf and stem wilting and browning on the rudbeckia. I treated with neem oil last night and as of today it doesn't seem to have made a dent. In fact, the already struggling verbena looks worse and I'll probably pull it out. Interestingly, I have a big ole lantana right in the middle of all this and it is unaffected and thriving. Any guesses on what the we are or suggestions on how to treat? I read Dawns post on spider mites, but I'm not sure that's what I have. Guessing it is though. Thanks. Eric

Comments (4)

  • Okiedawn OK Zone 7
    10 years ago

    Hi Eric,

    Normally, most spider mites are so small you cannot see them move. The two-spotted mites I have on my cucumber plants and tomato plants pretty much every year are so small that they are about the size of the dot over the letter "i". One way to confirm if you have spider mites is to hold a white sheet of paper or cardboard underneath the foliage and thump the leaves. A good thumping will knock the spider mites to the white sheet of paper or cardboard, and they then will very slowly move around looking for a safe place. It will look like a lot of little dots, not large enough to really even tell it is a pest. Some mites are so small that they are invisible to the naked eye, and you need a magnifying glass to identify them.

    Because you mentioned that they are white, I instantly thought of whiteflies. They would like like teeny tiny white moths. In fact, they look more like moths than like flies. Mealybugs also are white.

    I don't think I've ever seen springtails.

    It is interesting that whatever you have is infesting the verbena and not the lantana because they are subject to several of the same pests.

    About the only pests I actually see on the plants you listed are spider mites and aphids. I'm going to link a fact sheet from TAMU that discusses pests of verbena and lantana. Maybe something on that fact sheet will sound familiar to you.

    Some years verbena does great and other years it just isn't happy. I have less trouble with the tall verbena (verbena bonariensis) than with the mounding types.

    You also could go to bugguide.net and see if you can find anything there that resembles the pests you're seeing. They have great photos and the site is pretty easy to navigate.

    If you are in the part of OK that has had a lot of rain in recent weeks, your plants might actually have a fungal or bacterial disease and the pests you are seeing might not be the real problem. Rudbeckia only does well for me in well-amended clay soil that drains really well and even then the wet years can kill it, and doesn't do well at all in the unamended clay. I am wondering if your soil has just been too wet this year.

    Keep searching for an answer and don't give up. Be careful spraying anything on foliage at temperatures over 90 degrees. Once the temperatures are really hot, leaf burn can occur when you spray plants with products. It is real hit-and-miss type stuff where one type of plant might not be bothered at all, and another type will burn, discolor and wilt.

    Dawn

    Here is a link that might be useful: Pests of Verbena and Lantana

  • greenmanOK (Zone7)
    Original Author
    10 years ago

    Thanks, Dawn, all useful information to have. The more I read the more I think they are whiteflies. I'm reading up on how to treat them, but I think the soil also just got too wet in July. It is amended clay soil but it is a fairly new bed so not THAT amended. That's proably what is getting the rudbeckia at least.

  • greenmanOK (Zone7)
    Original Author
    10 years ago

    They are whiteflies. There seem to also be a lot of just regular houseflies, too. Maybe they are attracted to the whiteflies' secretions. Anyway, last night I used a hose and sprayer to knock them all off the undersides of the leaves and it seems to have helped. I think I'll just have to stay on top of it - spraying with water and occasionally treat with neem or something. Thanks for the info, Dawn.

  • Okiedawn OK Zone 7
    10 years ago

    Eric,

    You're welcome. Always happy to help.

    I'm glad you figured it out. Most regular flies actually are helpful and normally not a problem at all. Some of them prey on harmful pest insects and some of them serve as pollinators. Whiteflies, of course, can be a big problem. Good luck with them.

    One more thing....if you have any containers of plants that you overwinter indoors, check them carefully for whiteflies before you bring them inside. The whiteflies often will overwinter on plants brought into a house, greenhouse, etc. for the winter and then those that overwintered get off to a really early start on infesting outdoor plants after you move the plants back outside in the spring.

    Dawn

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