Invasion of Soft Brown Scale

4 years ago

I have a Madrid Lemon tree my daughter gave me years ago that is about 6' tall now and produces nicely.

Every year in February, we get a nasty crop of soft brown scale. We have tried neem oil spray and soak, horticultural oil, soaps with zero luck at stopping them. We tried a very dilute insecticide and that nearly killed the tree. So far the only solution is to manually remove them via a toothbrush. As you might imagine this takes hours over several days to do. Note the oval shapes with the black cross in the center.

We have put tanglefoot every 6" on the branches to catch the 'crawlers' that come to attach themselves and suck the tree's lifeblood. That has cut them back to about 60% of last year with some branches untouched, but this is really frying our brains for some type of solution. Their bodies are soft, flimsy and come right off with a little toothbrush scrub, but three or four passes are needed to break their attachment into the stems. If I don't get 95% of them off in the first couple weeks, the tree will be completely defoliated. This happened about three years ago because I didn't see it soon enough. Somehow it managed to straighten up and come back. So I have been keeping after it.

I would like to eventually build a greenhouse and let it grow 8-10', but it is almost impossible to clean the scale off at this size.

I have to think there is someone out there that knows a way to kill these buggers without killing the fruit tree. There has to be some out-of-the-box way to get these guys to move on to the next life.

All comments and suggestions are appreciated!!!!

Bruce

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Comments (7)

CA Kate z9
4 years ago
You don't say where you are or if the tree is indoors or out. Mine is in a large pot outside and only gets scale when the ants bring them in to farm. I have had to clean off each scale and then stop the farming by stopping the ants by spreading DE - diatomaceous earth - on the ground under the tree and even on the lower trunk. It does work if one is watchful for the ants because the DE does go away after awhile.
bcavender
Original Author
4 years ago
North Central TN here. We keep the tree outside, except for the winter. I almost wonder if ants carried them to the pot and they are now sustained in the soil? Hmmm. A DE soil treatment would be a good experiment

Thanks for the response!

Since the scale is soft, i wonder if direct dusting DE might be effective.

Great Thought Kate!!!

Best regards,

Bruce
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CA Kate z9
4 years ago
I haven't tried dusting the Scale itself with DE. There is a coating of sorts made by the Scale for protection. I wonder if the DE can get thru' that? It sure its worth the try. Please let us know how if it works.
Silica
4 years ago
A spay with horticultural oil or neem oil will easily get rid of scale.
bcavender
Original Author
4 years ago
I have tried several brands of each with zero effect.

Do you have a brand to reccomend which you have actually applied that was effective?

Thank you!
bcavender
Original Author
4 years ago
Kate, I just went through a cleaning session, but i’ve probably missed some. I will give it a look for a place to do a direct spot treatment.

Like you, i think the matures may not be susecptible to DE since they appear not to move after attachment, but only a test will tell. OTOH, maybe the ’crawler’ stage buggers will be during their next expansion session. They are exceptionally small and i have never seen them directly.
gardengal48 (PNW Z8/9)
4 years ago
Most sources will recommend Neem oil or other lightweight horticultural oils. But It is not a once and done thing. It may require repeated treatments every week to 10 days or so to effect complete eradication.

Or use a systemic. Bonide and Bayer BioAdvanced are both registered for the treatment of scale.