Scale insects on indoor houseplants
I thought I had these beat on my bay laurel. I found tiny ones on it again last week. This little plant brought these fantastic creatures with it. Nothing like hitchhikers that want to party and spread the joy everywhere they go.
I've been battling these insects on my lemon tree for 3 weeks...they've been bad on it. The tree has been hanging out in the bathtub to kerp it isolated, but it can't stay there forever.
Just now, I finally took off many of the frost damaged leaves from an avocado that I saved from my sister last spring. Guess what I found? (You guessed it!) One of the insects was quite large too. I thought I'd been checking closely enough. I guess I hadn't. I think I found a couple aphids too, but only 2. I squished those. My avocado only has a bit of young new growth left on it now. I was pretty thorough taking those damaged leaves off. It looks very naked but I'm hoping it forces new branches to form.
There could be more scale insects that I missed on other plants. I can't be putting Safers Soap on all of my plants every week. Some would be impossible to do. First of all, it gets expensive. Secondly, it's a pain...so is going over all parts of each plant to lift the insects up and dispose of them. 😡 It's far from enjoyable.
Does anyone have any suggestions, hopefully before it spreads to more plants? Does anything eat these nasty things (if so, where to buy)?
Comments
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I know what you mean. Actually I have these problems, when I bring plants into the house and keep them in the warmth and dry of a heated place. Since two years my laurel, fig, lemon verbena, rosemary and avocado are sitting in the cold winter garden and since then I have no problem. I think those little beasts do not like cold. They prefer warmth. I do not know whether that would help a lemon tree. I have never had one.
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@jowitt.europe It might, but I don't have an option like that to try it out. It will go to +8° on Friday, but I am not sure how wise it is to put the bay laurel & lemon tree out from the house at that temperature. I do also wonder if the insects would just hibernate or something until I brought the plants back into warmth.
I think that I don't have softer mealy bugs as I had first thought, but a different type of scale insect. This type, as I understand it, has an outer armor of sorts. Once the insect crawls to & latches onto their chosen juicy place on the plant, this armor will protect it, even from soap treatments. It lays its eggs underneath this protected place too. It is only vulnerable in the crawling stage. This could be why I'm having ongoing issues. The soap isn't actually accomplishing much.
What I read is that I should try a horticultural oil to smother the breathing pores of the insect. So, I suspect that is my next step. Hopefully I can find some in the stores, or perhaps I will have to see if any nurseries have some to sell.
I just hope it works. I really do not want to throw out my plants. :(
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I have had this same problem every time I bought a bay laurel. I've tried several times and each time within a few weeks (sometimes days), I find scale bugs on it and anything near it. I haven't found anything that helps so I will be watching this for solutions as I'd really like to have a bay laurel.
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Those awful beats have been living on my bay laural for four years! They spread to my lemont seedling and killed it, now theyre happily multiplying on my kumquat seedling and have spread to an ornamental houseplant. They seem to have the ability to cross several feet between plants with ease and nothing stops them. For two years I put all of my infected plants outside on our back porch in the full sun and hit them- HARD and REPEATEDLY - with insecticidal soap and neem. Knocked them down for a while but they ALWAYS came back during the winter. Last two years I couldn't put the plants outside for disinfecting because the sun has become too intense and the temperatures too high. The plants would fry. I'm wondering if rubbing each leaf with isoporpyl alcohol might help? It's a huge job for just even a few plants, though. And the winter temps would kill the plants as well as the bugs if I put them outdoors for even 24 hours. Irritatingly, a friend of mine has a lemon seedling on HER sun porch and NO PROBLEMS!! What's the secret, I wonder???
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@Suburban Pioneer I used isopropyl alcohol on the leaves, along with picking any that I saw off the plant...daily. It took the soap to knock it down for a few weeks on the bay laurel, but they came back. The soap is doing nothing for the lemon tree.
These insects definitely came in with the bay laurel. Then I saw them on the lemon tree (across the house), then on the avocado (mid-house). There are other clusters of plants in each area that I know would be very susceptible...and I would be devastated. I keep checking them, hoping for the best.
I knew to wash my hands well whenever I touched the infested plants (but who knows how kids may have unknowingly spread anything) and was careful to water infested plants last.
No kidding it's a huge job. I am hoping these aren't in my cluster of cacti, as there is nothing I could do with that.
I never put my plants outside for the very reason that I don't want to bring in bugs. People say, oh, just spray them before bringing them in. Well, I have never believed that will solve all the insect issues. It sounded too easy. I suppose this problem confirms that. I too, would like to know others' secret to not having bug problems. Maybe it's like the free range chicken folks who brag that they have never lost a bird to a predator...just a matter of time?
Here is the article I am getting ideas from:
I may go back to isopropyl alcohol every couple days (and picking off what I see) again until I can get the oil. Maybe it will remove the layers of soap now on the plants. My avocado tree has almost no leaves now, which will help go over it. The bay laurel is small. The lemon tree is the most work (and is the most infested). Its lots of work and a tired back is part of it, but it is not a war I wish to lose.
You know, I had an Asian ladybug in the house and it prefers the cold window to the bay laurel plant. I suspect that that is due to the soaps. Maybe I should see if it likes the avocado better, but I think it won't make any difference.
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@LaurieLovesLearning @Suburban Pioneer you reminded me of alcohol. Yes, I read somewhere that it might help.
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I have unfortunately waged this war. I recommend cutting off the thorns of the lemon tree first (they hurt). I used a cotton ball with the isopropyl alcohol and they come right off. It kills them on contact. They are protected by ants (they feed them sugar 🙃) so that could be why you can't get rid of them outside. You can also hose them off with decent water pressure and then wipe down with the alcohol. I would repeat once every 2 weeks for a little while. I hope this helps!
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@Cornelius Maybe I'll cut off the thorns so I can treat the trunk more effectively with this oil. The insects are so hard to see on the maturing bark. I've been able to avoid getting skewered so far. These trees are indoor plants.
I tried the isopropyl alcohol & a cotton swab, and it only shut them down for a few weeks and they reappeared. I had to do this treatment often with my bay laurel over a few weeks. I picked them off then went over my plant, totally going over it with the alcohol.
My aunt says they hibernate and not even the cold of winter kills them. They will hide in the soil too and then re-infest, which I've read about. Supposedly she has this issue too in her houseplants. If only I'd known that before possibly bringing in extra with plants from her house too. Sigh.
I was told at the nursery where I got the horticultural oil (99% mineral oil...not so sure of the 1%) from to use it once every 3 weeks for 9 weeks, using a cotton swab to directly cover the insect in oil. It is supposed to smother them. I suspect that I may have to do more than just once every 3 weeks, and hopefully I can spot them all. They start tiny.
I think that sounds like an awful lot of time between treatments...and if they are in the soil, well, I will have to continue to be vigilant. I have no idea if these are now on any other plants & I am just not seeing them when I look. It's possible.
At the one particular nursery, I found out that they are using biological controls on their insect pests. Right now, one large jade is being treated for mealy bugs. Nothing has worked, so they are hoping the fly they brought in will destroy them. The assistant manager said they are now on their second generation, so it is looking hopeful.
I can order beneficial insects through them if I wish to in the future. That is awesome!
A bonus (and it would be cool if I brought good insects home on this), we found a pitcher plant & brought it home. They had the most interesting houseplants for sale there. 😍
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I did find two beneficial insects that are supposed to be good for scale. I may look into them further at some point, but will give the horticultural oil a try first because I have it (although I think I'd rather do the insects first). I just don't need a huge number of them in the house for a few plants!
This place is out of the US, but posting it as it is very relevant to this discussion and is helpful to those who may wish to research or get these for bio control. I still have to find the Canadian suppliers again.
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I had few insect problems in the house until I started growing sprouts and shoots every winter.
Now I have a fruit fly infestation every winter. They aren't harmful, but are a real nuisance, especially in the kitchen.
I'm trying a trap that I bought at Aubuchon Hardware. Its a spherical cup with small holes in the upper half. You squirt a liquid attractant that is supposed to entice fruit flies inside, but keep them from getting out. It's supposed to be good for 45 days.
Is there some way you can set up traps that will attract scale insects and aphids? Perhaps some kind of flypaper?
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@VermontCathy I haven't heard or read of any attractants for scale insects.
I'm not overly concerned about aphids and not too concerned about the leafhoppers. I only found two of each and they were destroyed upon finding them.
I should say, the scale that I am battling isn't soft bodied like a mealybug that can be killed by isopropyl alcohol or insecticidal soaps. These particular insects have an armor, a waxy coating, that protects them from most things. It could easily be black scale, but there are many types of scale insects.
I read oil is likely to work on these...but it is not always foolproof. This is why I have continued to search for further solutions so that I have another possible solution.
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I did a little reading on scale insects. Nasty buggers! Any attracting and killing would have to occur in the nymph stage, before they settle down to suck the life out of your plants.
Bay Laurel appears to have a widespread problem with these pests. "Laidbackgardener" appears to have had them on every one she ever bought.
Https://laidbackgardener.blog/2015/12/09/another-bay-laurel-bites-the-dust/
I think she made a mistake composting the affected plants. Better to burn them to Ash to prevent more infestation.
One of the commenters at the laidbackgardener URL above suggested the following:
"Take your bay tree to the sink or tub and lay it on it’s side so you can get the leaves, especially the undersides, right under the running water. Use a paper towel to literally scrub the leaves while they are under the water…or use your fingers or nails to scratch the buggers right off. You’ll feel a sadistic satisfaction watching them spiral down the sink drain. It’s a happy time indeed. But don’t think you’re off the hook yet…
The very next night, do this again…to get the few babies that may have hatched. Do it again…and the fourth night too. Each night you will see less and less scale on your leaves, until one day soon, there will be none at all.
After you rid them, you will do maintenance showers once a week. The showers will be less tedious each time because you’ve banished the infestation at this point."
Personally, I think I would just give up on bay laurel.
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@VermontCathy Composting them would not be wise.
I did take the nasty little ones off often when I first found them, put those down the sink, then I coated the leaves with rubbing alcohol. It was tedious, but did temporarily work.
If I showered them, I'm convinced that our municipal water would kill the plant. It's nasty, considering the source of the water and the junk they put into it.
I did read that you could put double sided tape on the stem to catch the young crawlers (thats to see if you have any young ones). I wonder if this is effective if you rid the plant of them on everything above the tape? But then there is still the issue of them possibly making their way to other plants. The thing is, you can't put double tape on every type of plant.
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If your municipal water is that toxic, what do you use to water your indoors plants?
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I use live spring water that we get from a local spring. This is also what we use to drink.
The municipal water comes from a slough. This slough is surrounded by grain land. So, you get poor quality slough water, ag chemicals & chemicals put into the water to kill everything. We suspect that contains choloramine. When I watered my houseplants years ago, I wondered why they were dying off. Water in our area is very hard if you can get any at all (extremely few wells).
We suspect that the water & additives are affecting our livestock negatively as well, but we have no other source at the moment.
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Great photo images. When we bring in our plants to change from summer/fall to winterize them, first we place them in the garage for a couple of weeks. It depends on when the frost will be. Then we apply an indoor insect spray that gets applied while in the garage. Wait. Couple of days before bringing them into the house as they are stored in the basement. Then the larvae of insects, and other insects and/or eggs do not survive as we have lots of various indoor plants.
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I wonder if watering with a 1:1 water to peroxide solution would kill the eggs and larvae in the soil?
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@Cornelius I would have no idea. Would that harm the plant or affect the soil negatively in any way?
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@VermontCathy to remove fruit flies I have been trying one part vinegar one part water and a drop of dish soap. The fruit flies get trapped under the liquid by the soap and die there.
@LaurieLovesLearning and everyone — for all the other plants, perhaps strengthen the plants. I just watched a video about composting, that suggested to keep grasshoppers in something like a worm farm (paper with egg cartons and cardboard for little holes they can hide in) and feeding their poop to your plants. He says the plants get strong from this poop that is full of something that the males the plant create more bug repellent.
—Christina
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Hydrogen peroxide won't hurt the plants. At least not at a 4:1 water/peroxide mixture which is what I used to get rid of fungus gnats and a few other nasties that were in the soil. It actually give the plants a bit of a boost to their root growth and they were quite happy.
I have battled scale on my bay laurel off and on for a few years. Wiping the plant down with isopropyl alcohol has been the main deterrent but you have to basically be willing to do each and every leaf and stem once a week for about a month and a half. I also watered it after each wipe down with the hydrogen peroxide 4:1 mixture. This eliminated it for me. Since then I have made sure to use a good potting soil mixed about 3 or 4:1 with worm castings when I repot and every couple of months I put a layer of worm castings on the top of the soil to keep the plant healthy and happy. Make sure you water when the soil is dry to the first knuckle on your finger and that should help keep the plant unstressed and hopefully less susceptible to the nasty little boogers!
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Oh my, that sounds like something my oldest would do. She already kept crickets as pets for a couple years.
I wonder if it would smell?
That would be an interesting experiment as long as the grasshoppers never got loose when you went to get the poop.
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@Sheila THANK YOU.
This sounds like a complete and successful plan.
They are minimal at this point, but still present. I've since found a few black ones (instead of the brown ones) on my hibiscus & another plant as well. I've just picked the hibiscus leaves. It has plenty enough. I just took the other tiny ones off the other plant. I haven't opened the horticultural oil bottle yet.
So do you still wipe down your plants on occasion or is it totally gone now?
I wish I could donlots of worm castings. My bin is small because I don't have much room, but when I give it to the plants, they thrive!
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@LaurieLovesLearning I do a monthly check and if I see any I either scrape them off with my fingernail or give a quick swipe with alcohol but generally unless I put them outside in the summer I seem to be keeping it away :)
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@LaurieLovesLearning I am not sure about starting grasshoppers in the winter, as they need to be 80-90 degrees Fahrenheit! Not easy to take them outdoors in the snow to collect the poop (cricket frakis?). If you put down vermiculite or maybe dirt it’s not supposed to smell. I heard in different Asian countries they have crickets as pets because they like the noise in the house. We will see!
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@LaurieLovesLearning I'm glad to hear that you seem to have having success. I had never heard of scale insects before this thread.
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@VermontCathy I hadn't heard of them before either. I just hope you never have to deal with them.
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I like to use a mild dish detergent on scale and if their shells have already hardened, I use a soft toothbrush.
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