Plant Pests: Bugs in Disguise

I have high hopes every spring when I bring home new plants.  My new plants usually look bright and green.  By the end of the summer, though, some of them are ready to just give up.  That’s ok.  At least I’ve learned a little more than I knew before.  This summer I’ve been learning about plant pests and how to recognize them.  I’ve certainly had plenty of opportunity!  My plants have all kinds of issues, as you’ll see.

I used to have a gardenia.  It died a long, slow death.  I didn’t know what the problem was, so I didn’t know how to treat it!  In hopes that it might save other plants from the sad, sad fate of my gardenia, here are a few pictures to help you identify a few plant pests.

1.  A squiggly line on a leaf might look like some kind of plant disease, but it is actually from a leaf miner.  Leaf miners are larvae of moths or flies, and they tunnel through the leaf, leaving their trail behind them.  I pluck off the leaf if I see something like this:

20080528 - Leaf miner damage

2.  A dark woody bump on the stem or underside of the leaf might look like a natural part of the plant, but it is actually an insect called scale.  What you see is really a hard shell over a bug that feeds on the plant sap.  Scale varies in colors and size.  Sometimes you can just scrape or flick it off the plant stem.  Other common advice is to apply rubbing alcohol to it with a cotton swab.

This plant has a bad case of scale. The leaves are sticky with a honeydew residue as a result. For this one we cut off the branches with the worst of it, scraped the remaining scale off as best we could, and washed it with soapy water.


Another type of scale:
20080528 - Scale pest on plant

3.  I think these are the worst.  What looks like some kind of white fungus is really mealybugs.  These white, fuzzy bugs cause a mess.  They feed on the plant sap, weakening the plant and eventually killing it.  If you notice these, you can wash them off with water or wipe them off with a cloth to get rid of them.

29989526 - Mealybugs

4.  A pest that is hard to see is spider mites.  These bugs are tiny, red dots that reside on the dry underside of leaves.  When they feed on the plants, it gives the leaves a speckled, stippled appearance. The leaves eventually become dry and yellowed. You might also notice a few strands of web around the leaves.  Spider mites can be hard to treat once they become established.  If you catch them early enough, you can wash them off with water.

20080526 - Spider mite damage

Using water is a common preventive measure against pests.  The water washes off the dirt or dust that can harbor mites, and it usually takes care of the bugs and eggs that hide among the leaves.  This is especially important for house plants that don’t get rained on regularly.  I’ve had some success spraying or dunking my plants in soapy water.  On my last post about plant pests, Jessica mentioned that garlic spray seemed to help with bugs in her garden.  Any more ideas for how to take care of plant problems?

About Rachel

I write about practical tips that will help you simplify at home. Connect with me on Pinterest and Twitter.

Comments

  1. I have no suggestions because I am new to gardening, but I am finding these posts so helpful. I would think that the white plant had cobwebs ;) Seriously, that is what I thought. Great tutorial and I am loving your environmentally-friendly solutions!!

  2. OK…the mealy ones are really gross ;p I have heard of that garlic spray works and so does a spray witht soap and water.
    I have a TON of ladybugs in my garden, and apparently they eat all of those icky aphids ( which killed our collard greens), so we are trying to keep them around….course that doesnt help for house plants…you don’t want lady bugs inside ;)

    • This spray with water and soap (the soap we wash the dishes?) wont’ do any harm to the plants? I have to prevent this mixture from reaching the soil of the plant?? otherwise I’m afraid that it will be the same as watering the plant with soapwater.. I’m thinking of it as a poison.. please tell me if I’m overreacting.! Thanks in advance!

      • You don’t want to water a plant’s roots with soapy water, but you can spray some on the leaves. A couple of applications can make a difference against small pests like mealybugs and spider mites, from my experience.

        I’ve used a natural dishwashing soap, and there are insecticidal soaps.

        It’s better than using something toxic if you’re trying to grow herbs and vegetables, and it’s better than damage the pest would cause.

  3. This is awesome! Your photos are great. I will do a post on the garlic spray I used soon.

  4. Looking forward to seeing how to make garlic spray. Mealybugs are the ones that got to my gardenia, so I really have it out for them. :)

  5. I live in the South. A common squash fungus called powery mildew overtakes plants when there is high humidity with very warm nights. I found a recipe that at least slowed it down.

    1 quart water
    1 teaspoon baking soda
    a few drops of dishwashing detergent

    Spray on top and bottom of leaves.

    And wouldn’t you know, I have mealy bugs on my parsley. Going to mix up some garlic spray…

  6. Thank you for the pictures; it is so difficult to tell if I found the answer using only symptoms and descriptions. The pictures were helpful. Happy to know my jade does not have scale. I think I gave it too much water, not enough light. Good news, I might be able to get her to stand up again.
    Thanks again,
    Mr. G
    George@mrgsteriyaki.com

  7. grrr. We have spider mites eating our rosemary and basil right now. hoping they don’t cross over to the veggies. i can never actually see them so it’s very frustrating! will try hosing them down a little more vehemently. :) thanks, Rachel!

    Katie ~ Simple Organic´s last post…An Introduction to Traditional Wet Shaving: Good for the Earth, Great for Skin!

  8. I’ve found sprayed Neem oil to work very well.

    Matthew´s last post…First contact- not appealing

  9. Today I found mealybugs on the Basil I purchased from the local Safeway grocery store. I was a little shocked when I saw the little powdery gray things crawling around. I lost my appetite for pesto.

    If I remember correctly, a roommate and I treated some insect pests in our garden with a water/flour mixture spray. This was several years ago, but I think the point was that the water would dry, leaving the flour to clog the pores of the insect, causing death.

    Hope this is not nonsense.

  10. does anyone have an eco-safe way to get rid of fire ants. when i first moved to florida, someone suggested grits. but these are southern ants and they flourished. i have tries every kind of hardwarestore product without result.