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citricola scales, best pesticide?

Gardening Reference » Gardening in 2004
by glam70s on November 10, 2004 05:24 PM
We bought a Meyer's lemon tree a few weeks ago and realized the next day that it was covered in what we found (through the internet) to be citricola scales.. My boyfriend, not wanting to get a pesticide, picked them "all" off (there was no way he could have gotten them all, they're too good at hiding)..

This morning I was looking and saw a couple of them on the leaves.. I told Matt and he kept looking some more, and we discovered that they're covering a couple of stems and are just all over the place, we didn't even see them coming because before they were mainly all over the leaves.. Since the leaves looked like they'd been doing fine, we didn't notice the infestation..

The tree just finished flowering, and is now starting to drop some of its leaves. Any recommendations on the best pesticide to use, and any care that needs to be taken after that?

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Who would have thought it was possible to become addicted to plants?
by papito on November 10, 2004 10:10 PM
Info on Citricola Scale from the University of California.

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Amor est vitae essentia.
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by Will Creed on November 10, 2004 10:29 PM
Scale can be hard to detect. When they are young these sucking insects are slightly oval, slightly raised, translucent bumps about an eighth of an inch long. They can be found along stems and on the undersides of leaves. They don't look like bugs and don't appear to move. As they get older, they develop a hard, dark brown shell and look like a small mole. As the infestation increases, these sucking insects will secrete a sticky substance called honeydew that falls onto leaves, furniture and floors. This stickiness is the most obvious sign of scale and the one that most people notice first.

The key to eliminating scale is to treat even the ones that you cannot see. That means thoroughly drenching all leaf and stem surfaces until they are dripping wet. It is also best if you repeat this treatment all over again in 5 to 7 days to catch any crawlers (the translucent young ones) that you missed the first time. After that, you should check your plant weekly to see if they return.

Soap sprays are not as effective as some other treatments because soap doesn't always penetrate the hard outer shell of the scale.

I do not recommend any pesticides because they are all hazardous to use and not 100% effective against scale. The best non-toxic treatment for mealybug and scale is called Brand X Foliage Cleaner. It is available through Southwest Plantscape Products in California ( Their phone is 1-800-333-7977.It is a silicon-based product so it is very slippery. Its ability to penetrate is probably the key to its effectiveness because it gets into the tiny crevices that other sprays miss.

You may want to try spraying with rubbing alcohol that will help break through the hard outer barrier of the scale and kill it. Mix 1 part alcohol with 8 to 10 parts of water. Add a little liquid soap to help it spread.

Sun Spray Ultra Fine horticultural oil is also mixed with water and effectively smothers the scale. Complete coverage is important.

Another good non-toxic spray is Hot Pepper Wax. Its main ingredient is hot cayenne pepper that overheats the plant pests. There is an information website for it at

Finally neem oil works similarly to horticultural oil. It should be diluted with water and Pine Sol to couneract the onion-like odor. All of these are available nationwide at plant and garden centers and also by mail order.

Important: None of these should be applied to plants in direct sun or in high temps
by glam70s on November 11, 2004 04:07 PM
Thank you, I'll have to look into the treatments you suggested. I don't know about the one in California though, I'm practically on the other side of the continent, it seems a little odd to ship something like that all the way over here..

I did notice the honeydew you mentioned all over the leaves but I've never had a fruit tree before and it was just coming into bloom, I thought that it might be from the flowers.. I guess I'll know better next time, thank you.

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Who would have thought it was possible to become addicted to plants?

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