White spots and powder type coating on some juniper needles

[AndrewAustralia]

Hi All,

I have recently noticed a white powdery type crust forming on some of the lower needles and I guess probably older needles of my tree. I have noticed this on the odd occasion in the past, maybe a tiny branch here or there, but not this much ever.

To help, I will give my context on what I do...

- water every 1-3 days depending on temperature
- bonsais sit outside on the balcony. They get morning sun or afternoon sun depending on where I place them and temperature
- watering takes place at night mostly and then morning any other time
- I water the soil but occasionally mist needles when they are out of the sun
- fertilise using liquid (weekly) and balls


I've attached some images which hope help tell the story. I have attached one showing some really nice solid green growth so you can see the difference.

Any advice or solutions will be fantastic

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[shibui]

That silvering on the leaves looks like mite damage. They are pretty small and not easy to see. Try tapping the branch over a sheet of white paper and see if you can spot the tiny mites crawling on the paper.
I would spray as soon as possible with something that will control mites.
Eco Oil is a relatively safe spray that will kill mites and should be safe for the juniper but you do need so cover all parts of the plant - both sides of all leaves, etc. You may need to spray again in a few weeks to kill any that hatch after the first spray.

[AndrewAustralia]

Thanks Shibui. I'll have a look at some sprays. Once sprayed and the potential bugs are gone, will the needles return to their green self or best to prune back?

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[shibui]

I think the damaged leaves are permanently damaged but new ones will grow and soon you will not know the difference. I think it is best to leave it to recover before pruning or doing any other work.

[AndrewAustralia]

Got eco neem last night as Bunnings didn't have any eco oil. Seems to be just a concentrate of eco oil and is compatible. I shook a branch last night and about 10 little mites fell off! Disgusting....

I sprayed it last night, I'll update with any issues.

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[shibui]

Not all insecticides treat mites but Eco-neem does have mites listed so it should be fine. Remember to spray thoroughly - all sides of all branches and leaves to make contact with all of the little buggers. A follow up spray in a week or 2 should pick up any newly hatched and any you missed first time round.