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Acer- what are these black bugs?

soeg44soeg44 Posts: 10
in Problem solving
I inherited an acer from my mum last year and both years i've had an issue with these small black bugs all over the new growth leaves. There's small silver balls on the underside of the leaves which seem to be the eggs. There's hundreds - ive tried to get a good photo. I've tried some general bug spray but it hasnt seemed to help. Last year I lost one of the main branches which i think was due to these bugs so I'm hoping to stop this before it gets too out of control!

The acer is in a pot and is about 4 feet tall and healthy for the rest of the year. It's in a mostly sheltered spot with some sunlight in the morning. 

Any help is much appreciated!

Posts

  • Cambridgerose12Cambridgerose12 Posts: 1,134
    Hmmm--to me they look like some sort of sawfly larva. But I can't find any information about them. The RHS offers an identification service: https://www.rhs.org.uk/membership/rhs-gardening-advice/sending-in-samples
  • Jenny_AsterJenny_Aster Posts: 945
    Have you tried blasting them off with the jet on a hosepipe. Hosing does work very well to rid the greenfly on my roses. Using bug spray might kill off their predators so you'll always be trying to get rid of them. I don't know what they are, but if pushed I'd say they were blackfly. 
    Trying to be the person my dog thinks I am! 

    Cambridgeshire/Norfolk border.
  • barry islandbarry island Posts: 1,847
    I have two acers in pots a few feet apart and one in particular gets attacked each spring by sap suckers although they are so small as not to be seen clearly with the naked eye, I have to start as early as February washing them off with a mild soapy spray or when the leaves emerge they will suck them until they wither and die, I would suggest a spray bottle with a mild soap shaken well to create a foam and keep it up each day until they have gone.
  • soeg44soeg44 Posts: 10
    Thanks for your suggestions. I might give them a blast with the hose to see if i can get rid of them, and then start on the soapy water spray. When my mum had the acer she never had a problem, but since i've had it in my garden it's had issues which is so disappointing as i love acers!

    @barry island - does the soap spray damage the plant at all? Is it ok if the soap spray dries on the leaves?
  • barry islandbarry island Posts: 1,847
    I got rid of my bugs before the leaves opened but it was a weak soap water mixture anyway and it doesn't cause my acer any harm, I will say that you will need to check the plant every day as the bugs are persistent and multiply unless you are vigilant.
  • barry islandbarry island Posts: 1,847
    Just checked the acer and there were a few leaves with clumps of aphids so had to spray them off and give the whole bush underside of leaves a general soapy spray.
  • soeg44soeg44 Posts: 10
    I sprayed mine this afternoon so I'm hoping to see results in the next few days. It's a bit rainy so I may have to keep up with the spray for a while. Fingers crossed it works for us both! 
  • barry islandbarry island Posts: 1,847
    I think that we can beat a few aphids, don't forget to spray the underside of the leaves as that is where the little blighters hide. The problem that I have found is that if the aphids go unchecked and feast on the leaf sap the leaves dry out curl up and the bush is ruined for the season, it's hard enough keeping the acer looking good through the summer as it is what with wind and sun damage.
  • soeg44soeg44 Posts: 10
    That's exactly when I noticed the issue last year - the new leaves were curling up and then I saw the thousands of aphids! Some are so tiny they just look like black pinprick dots.

    I've been spraying with the soapy water and it's made a massive difference. There's only a few tiny bugs now, so thank you for the advice. Totally worked and didn't damage the acer! 
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