I'm slightly ashamed I even have to post about this but I wanted to pass on this helpful advice I was recently given. My poor garden had been quite neglected this past winter but we've done a lot of work recently to resurrect it.
A few weeks ago we were gardening and I was snapping photos with my camera, when I downloaded them I was shocked to realise my Meyer lemon tree was covered with little insect/fungus things...
I am very lucky as my clever dad is an entomologist and ever so handy to have to ask about random bugs, cockroaches, spiders and garden pests, so I emailed him a photo and asked for help. You know how your parents are always calling with questions about their phone and computer well this is my payback for my dad #itworksbothways. He rang me with an immediate diagnosis and remedy.
My poor Meyer lemon tree that I have worked so hard to espalier against the fence and generally is beautiful and abundant with fruit had a bad case of hard scale. It also had some sooty mould.
After many years of working in the development and registration of pest control and crop protection chemicals, I think Dad is one of the most qualified people in Australia to give advice. (He has even discovered an insect and had it named after him). He does have a love of chemicals so sorry but this is not organic gardening here today but a full on chemical emergency remedy. I usually try to keep my garden as organic as possible but my poor lemon needed major treatment a bit like a cancer patient needed chemotherapy rather than just a visit to a naturopath.
What is scale?
Scale are usually noticed in citrus trees by the yellowing of leaves followed by leaf drop. They suck the fruit trees' sap and excrete a sticky “honeydew” on the leaves that attracts ant so you may notice them on your tree also. Scale appear as waxy bumps on the trees limbs, foliage or fruit, they are an insect. While a few scale isn't too damaging, when it gets out of control like mine was, what is damaging is the ant population and sooty mould.
How to Get Rid of scale from your Citrus Tree
I bought a 5 litre agricultural sprayer with wand from the hardware shop to make the spraying easier and to ensure I could reach the whole tree and spray under each leaf.
I bought a bottle of Confidor Concentrate and a bottle of White Oil both readily available from your local nursery or hardware shop.
I filled the spray with 5 litres of water and mixed in the Confidor Concentrate as per the directions and then added White Oil as per it's directions. Use the concentration measurements for 5 litres volume for each.
I gave it a stir with a stick. Put the lid on the sprayer tighten well.
Drench the affected tree and any neighbouring fruit trees. Spray the tree until it is literally dripping wet. Ensure you wet the undersides of the leaves as well.
Wait 2 weeks. Most of the scale will fall off in this time but any remaining scale will be dead and can either be gently scraped off with your fingers or hosed off.
It's been 3 weeks since I treated my lemon tree and it's now just beautiful and so healthy again (thanks Dad!). The scale has all gone, the leaves are no longer a sickly yellow, there is lots of new growth and it's covered in blossom. I'm hoping that this means a bountiful harvest.
You can see in the photo below that there are a couple of residual scale spots but I easily removed these with my fingers.
Dad said to spray this mixture on my citrus trees every 6 months. I have 3 citrus trees that I espaliered along our side fence all in a row (a lime, a lemon and a mandarin). I love having fruit trees in our little inner suburban garden and this way they don't take up much room.
I'm hoping that none of you have had this problem with your lemon trees but if you do, this is a very effective treatment.