caveman
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Sticky Lemon/lime.

We have three small bushes in our conservatory, grown from pips. Two lemon and one Lime (we've forgotten which is with) and one of them has developed very sticky leaves. In fact it gets everywhere.
There is no sign of any infestation, it's only on the top of the leaves and only on the one plant.

It is making a right mess and is going to the tip if we can't resolve the issue.

Any help would be most appreciated.
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applestar
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Location: Zone 6, NJ (3/M)4/E ~ 10/M(11/B)

Look at branches and leaves above this one for sucking insect infestation. Likely culprit — Scale insects are very difficult to spot until you know what you are looking for and your eyes adjust. They look like bumps of same color as the plants. Look along the central leaf veins and leaf nodes, and OTHER side of the branches — I Don’t know how, but they seem to always manage to be in the blind spot.

Ah! I zoomed in — there ARE scale insects on these branches. Look for the olive colored waxy blobs. Start with cotton swabs dipped in rubbing alcohol to wipe them off as you see them.
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BTW, crush and smell the leaves — lemon Leaves should smell lemony. I believe these are lemon in any case since the leaf stems don’t have wings.

pepperhead212
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Scale insects get on the undersides of the leaves of my kaffir lime plants and curry tree (also a citrus), and they do get sticky, like that. And look for ants - they feed on that sticky "honeydew", and are known to farm scale insects and aphids, for that sticky food. That could be how they got there.

When I have had a severe infestation, I trim the plants way back, then spray with some pyrethrins, soaking the soil, as well, as this is where they come from (my lime and curry trees are in pots). Then, a dilute solution of isopropyl alcohol can be used to remove the sticky substances and the dead scale. This is one of the few things that I have had to use insecticide on.

Last summer, when I re-potted those plants, I put a generous amount of diatomaceous earth in the potting mix - about 2 c in a 12 gal bucket - to see if that would keep the scale and ants off the plants. I also scratched even more into the surface 2" of the pots, and so far, this seems to have kept them bug free, KOW.

Another thing that I did, once I trimmed them back and re-potted them, was to brush tanglefoot on the 3" or so of the trunks, just above the soil line. Anything trying to crawl up on the plant is immediately stopped by this, so an insect needs wings, or another route, to get onto it.

imafan26
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You should also put out ant bait. Usually where there are aphids and scale on citrus, ants are nearby.

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rainbowgardener
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The sticky stuff is known as "honeydew." Sucking insects like scale insects, aphids, leaf hoppers accumulate so much sugars from their diet that they have to have a way to get rid of some, so they excrete it as this sweet, sticky honeydew stuff. Trouble is, not only are the insects sucking the life out of your plant, but the honeydew attracts other things like ants and sooty mold.

So you need to wash it off the leaves as well as trying to manage the insect problem.

caveman
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Many thanks folks, I'll have a closer look and go to it!

Most helpful!

Close up shows a little bug(ger) :shock:
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rainbowgardener
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Closer up shows seven or so of the scale insects plus probably a bunch of aphids....

pepperhead212
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Be sure to check the undersides of the leaves. Mine would look fine on the tops, but as soon as I'd see the honeydew starting to show on the tops, the bugs would be all over the bottoms of the leaves. Same outside, with aphids.



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