What causes these spots on new schefflera leaves?

12 years ago

I started this plant from stem cuttings last summer - actually I started a few of them. There are 3 plants in this pot and only one is affected by these dots on the new growth. Any ideas on what the cause could be?

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tapla (mid-Michigan, USDA z5b-6a)

12 years ago

It's not oedema and it's not from over or under-watering - likely insect-related. It's not unusual for insects to attack one plant in a grouping or even a single branch on a plant. The plant's natural defenses are related to it's metabolism and energy levels which are often variable from plant to plant and even locality on the same plant. IOW - if one plant or plant part is weaker (or more succulent) than another plant or other parts on the same plant, the likelihood of insect attack is increased.

If you do treat the plant, topical insecticides are only marginally effective with little residual effectiveness. Systemics are broader spectrum with a much longer period of effectiveness. I've had excellent results with Bayer's 3-in-1 preparation that contains the systemic insecticide Imidacloprid, the systemic fungicide Tebuconazole, and a miticide, so it pretty much covers all the bases. Don't confuse it with their product that also includes fertilizer. All the chemicals in the 3-in-1 preparation are approved for use on houseplants, but all spraying should be done outdoors. The plant can be moved back indoors as soon as the spray is dry.

What does your plant look like (a full shot of it?). It may be a candidate for a full defoliation a few days after you spray, which will stimulate back-budding (more branches & fullness) and offers the added advantage of having all the newly emerging foliage in pristine condition.

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Comments (8)

tommyr_gw Zone 6
12 years ago
What does the UNDER side of the leaf look like?
tapla (mid-Michigan, USDA z5b-6a)
12 years ago
.... first impression is the feeding sites of a sap-sucking insect (thrips/mites - if you wipe a white tissue across the underside of the leaves, does it pick up a yellow residue?), but if the underside of the leaves looks worse than the surface, it could be the result of oedema, fairly common in scheffs when they are over-watered - especially during periods of high humidity and/or extended heavy overcast or other low light conditions.

Al
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elkay_gw
Original Author
12 years ago
Ok, here's the underside of that leaf.....
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Looks pretty much the same as the top - maybe more pronounced (?) I tried wiping the underside of the leaf with a white tissue and there was no residue. Maybe it IS from overwatering, but I wonder why the new leaves of the other two plants in the pot are not affected?

I suppose using some insect spray wouldn't hurt - just in case, right?
elkay_gw
Original Author
12 years ago
Ok, here's a shot of the whole plant
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And shot looking down at the top
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The plant is about 13" high and 17" wide. It's in a pot that is 4.5" across.

I don't recall seeing that particular Bayer product in any stores I've been in - hope I can find it.

Thanks!
tapla (mid-Michigan, USDA z5b-6a)
12 years ago
It's pretty commonly found in big box stores & most nurseries/greenhouses with any significant retail space devoted to items incidental to plant material. There's no email link on your member page, so I couldn't send the info. Copy/paste this addy to your browser window:

http://www.bayeradvanced.com/tree-shrub-care/products/3-in-1-insect-disease-mite-control/sizes

It comes 3 ways - a hose end sprayer set-up, concentrate, and a hand spritzer. I prefer the concentrate, but for only 1 - a few plants you'll probably find the spritzer packaging the best choice.

Al
ronalawn82
12 years ago
elkay, it seems that one leaf only is affected and I am quite sure that its removal will not hurt the plant or alter its appearance; the whole plant looks quite pleasing.
The condition appears to be insect related and I would guess that the culprit has been long gone.
Aphids or mites do not appear to be the problem and even they can be controlled by cultural methods.
Scales would probably require the application of a systemic insecticide.
countcoco
12 years ago
The new leaves on my schefflera always have some reddish splotches on them. The splotches aren't nearly as well defined or as deep red as the ones on your plant's leaves.

I think it may just be normal. I've had the plant for about a year and the strange looking young leaves always develop into the nice green mature form.