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Several of our conservatory plants, particularly citrus ones, are regularly infected with a sticky white substance. It must be coming from an insect, but we can't see anything. So far, sprays bought over the counter, and warm soapy water sprays have had no affect. The only time it clears up is when we put the plants out for the summer. Any idea what it is? We'd love a lasting solution to this irritating problem. Thanks



Sounds like an infestation of some kind. I'm guessing aphids. You can use the sticky fly traps to find out exactly what is attacking your trees.

25 Nov, 2016


it could also be a form of scale insect, they are very good at looking like the bark. They also exude a sticky frass/honeydew. can you take a close up of the stems and post them with this question?

See if you can find a spray for this type of sap sucking pest. Bayer used to do one but don't know if they still do Bug Gun rings a bell.

25 Nov, 2016


Some scale insects can be killed by painting them with meths. A tedious job if there are lots but it does work.

25 Nov, 2016


It sounds like mealybugs, to me. While they are outside, natural enemies will keep the numbers down, but the greenhouse is a less friendly environment for the predators--too small--so the mealybug survivors' population explodes! Soapy water does help, but it may not help enough. Dabbing with meths does work, but, as Stera says, it can keep you busy for weeks. Commercial insectaries might have a predator suitable for release in your conservatory, but you will probably have to identify exactly which species of mealybug you have. Lots of work with a magnifying glass and internet pictures!

26 Nov, 2016


Thanks for all the help :)

26 Nov, 2016


Meths kills mealy bugs as well...cheaply and effectively. Done it many a time.

26 Nov, 2016

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