Ask a Question forum: Identifying pest on house plant (white spots/rice-shaped dots)

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plantproblems
Aug 17, 2016 10:57 AM CST
Hi! I can't figure out what is attacking my house plant (some kind of palm). It lives indoors, though close to a window which is often open. These white dots just appeared in the last few days or so, but I've been pulling off brown leaves for a couple of weeks. Is this scales? Mealybug? Spider mites? They are almost exclusively on the top part of the leaves rather than the underside. They don't seem to be moving around. Some look more like scales (rounder) but most look like tiny grains of rice, some a bit fuzzy, but no webs. I also see the white dots closer to the stem. Any help would be appreciated! I live in Germany. I've put the plant on the balcony for now to avoid the creatures spreading to other plants.


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Name: Sue
Ontario, Canada (Zone 4a)
Daylilies Birds Enjoys or suffers cold winters Native Plants and Wildflowers Butterflies Annuals
Region: Canadian Keeps Horses Dog Lover Plant Identifier Garden Sages
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sooby
Aug 17, 2016 11:13 AM CST
Welcome! They're scale insects, the wide flat ones are the females and the grains of rice are the males. I think the plant is a dracaena.
Name: Rick Corey
Everett WA 98204 (Zone 8a)
Sunset Zone 5. Koppen Csb. Eco 2f
I helped beta test the first seed swap Plant and/or Seed Trader Seed Starter Region: Pacific Northwest Photo Contest Winner: 2014 Vegetable Grower
Avid Green Pages Reviewer Garden Ideas: Master Level Garden Sages I was one of the first 300 contributors to the plant database! I helped plan and beta test the plant database. Charter ATP Member
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RickCorey
Aug 17, 2016 6:16 PM CST
Welcome to NGA, plantproblems!

Sue, would a soapy spray help, or washing the leaves under a shower head, or would you suggest isopropyl alcohol on a Q-tip or cloth? Would Neem oil or other horticultural oil help?

Plantproblems, I'm an amateur when it comes to indoor plant care, but I would FIRST wipe away as many as I could with a bit of cloth, or more likely soak that cloth in soapy water or alcohol first. Do it outdoors. Probably also cut off the leaves that are most heavily infested, and bag them tightly before bringing them indoors to the garbage bucket.

If possible, use a hard fine spray or mist of water to blow more of them away (outside). Repeat these kinds of actions a few times per week so you get rid of eggs as they hatch over time.

After knocking off, wiping off, and spraying off as many as are easily removed, I would spray it with store-bought insecticidal soap, or home-made insecticidal soap.

2-6 Tablespoons of a natural soap per gallon of water
Maybe 2-6 ounces of rubbing alcohol per gallon
water plants the day before spraying
Rinse off 3 hours later.
Don’t spray in sun!

But listen to anyone else before me! I'm going mostly from reading. Experience is a much better teacher. But alcohol wiping and a hard water spray both worked well on something similar that infested some huge Brassicas I was saving seeds from (outdoors).

https://www.planetnatural.com/pest-problem-solver/houseplant...

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[Last edited by RickCorey - Aug 18, 2016 10:37 AM (+)]
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Name: Sue
Ontario, Canada (Zone 4a)
Daylilies Birds Enjoys or suffers cold winters Native Plants and Wildflowers Butterflies Annuals
Region: Canadian Keeps Horses Dog Lover Plant Identifier Garden Sages
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sooby
Aug 17, 2016 6:30 PM CST
There are some suggestions from Cornell here that may help, Rick. It's for a different scale than plantproblems' but that shouldn't make a difference.

http://idl.entomology.cornell.edu/files/2013/11/Scales-on-Ho...

I should add that the few times I've had them on plants they either haven't been bad enough to treat and I've scraped them off, or I've cut off the infested plant parts or disposed of the plant. Sometimes they just get worse if you leave them alone but one year I was surprised to find scales on daylilies which don't normally get them. They didn't persist into subsequent years though.
[Last edited by sooby - Aug 17, 2016 6:36 PM (+)]
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Name: Rick Corey
Everett WA 98204 (Zone 8a)
Sunset Zone 5. Koppen Csb. Eco 2f
I helped beta test the first seed swap Plant and/or Seed Trader Seed Starter Region: Pacific Northwest Photo Contest Winner: 2014 Vegetable Grower
Avid Green Pages Reviewer Garden Ideas: Master Level Garden Sages I was one of the first 300 contributors to the plant database! I helped plan and beta test the plant database. Charter ATP Member
Image
RickCorey
Aug 17, 2016 6:43 PM CST
That was a great link, Sue, thanks!

They make it much more dilute, and use detergent INSTEAD OF real natural soap:
"Use two teaspoons of a mild dish detergent (not soap) per gallon of water."

Also, about hand-picking and wiping:
"Repeat every few weeks as needed."

plantproblems
Aug 18, 2016 12:44 AM CST
Thank you so much! :)
Couple follow-up questions:
How long should I leave the plant outdoors after to cleaning it and treating it? For a couple of weeks? Until I no longer see the scales appearing? Or is it safe to live indoors after the initial cleaning? (The plant isn't close to other plants inside.) It's still fairly warm here in Berlin, but it can get to the low 50s at night.
Do these critters pose any health risk to humans or dogs? I'm hoping they don't spread to our other plants too. :/
The scales also seem to be in and around the thicker branches and trunk--in places that are difficult to clean. At what point is it a hopeless effort to save the plant, for those of you with experience with scales?
So very grateful to everyone for your responses!
xx from Berlin!
[Last edited by plantproblems - Aug 18, 2016 12:50 AM (+)]
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Name: Sue
Ontario, Canada (Zone 4a)
Daylilies Birds Enjoys or suffers cold winters Native Plants and Wildflowers Butterflies Annuals
Region: Canadian Keeps Horses Dog Lover Plant Identifier Garden Sages
Image
sooby
Aug 18, 2016 5:31 PM CST
If you're sure you've got rid of the scales there's no need to leave it outside. Depending what species of scale it is it may not affect your other plants anyway unless maybe they are related to the first plant. Do you think the scales came with the plant? Scale insects do occur outdoors, they're not only indoor plant pests.

I'm not aware of any health issues from them with humans or dogs.

Whether to continue fighting with the scales is a personal decision - if you have the patience to keep working at getting rid of them there's no reason why you can't save the plant.


plantproblems
Aug 19, 2016 7:24 AM CST
Thanks, Sooby!

The scales must've come with the plant, I would imagine, unless something got in through the window. I purchased it maybe 5-6 months ago from a Home Depot type store here in Berlin. It's the only plant in that room, but it sits near a window that is often cracked open. I'm monitoring my other plants to make sure they don't develop the scales. Any tips for preventative treatment? Gentle washing? Plant oil?

I'm going to try save it, though it's pretty tricky removing all the scales, because some are deep in the folds of the palm branches and trunk. :(

Thanks again!
Name: Sue
Ontario, Canada (Zone 4a)
Daylilies Birds Enjoys or suffers cold winters Native Plants and Wildflowers Butterflies Annuals
Region: Canadian Keeps Horses Dog Lover Plant Identifier Garden Sages
Image
sooby
Aug 19, 2016 2:11 PM CST
I would just inspect the other plants thoroughly every so often, they may not even be susceptible to that scale. Do you know the names of the other plants you have?

If you have a large tub you could try inverting the whole affected plant in soapy water, say 1% hand dishwashing liquid to water (not dishwasher machine detergent). Wait a couple of weeks and then do it again. I don't know if that plant is damaged by soaps, maybe someone else does. You might want to take the risk anyway.
Name: Will Creed
NYC
Professional interior landscaper
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WillC
Aug 20, 2016 10:26 AM CST
Your plant is a Dracaena marginata. Scale insects and mealybugs are closely related and can be treated similarly. You can safely use liquid dish soap or alcohol or a combination of the two diluted in water. The key to success is thoroughness of coverage. Wiping will help remove the residue (dead carcasses), but it is not effective in penetrating small spaces where the juveniles are. Spray thoroughly all leaf and stem surfaces until they are literally dripping wet. Pay particular attention to the leaf axils where the leaves are attached to the stems. This is a messy job and best done outside, but not in direct sunlight. One thorough treatment is usually sufficient if you are really thorough. If you miss a few critters, they will slowly reproduce and come back to haunt you several months down the road. After treatment, there is no need to quarantine the plant. Do check other plants for signs of pests. Treating pests is always easier when detected early.
Will Creed
Horticultural Help, NYC
[url=www.HorticulturalHelp.com]www.HorticulturalHelp.com[/url]

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