How do you control Scale insects organically?
Pests are a natural part of gardening, whether we like it or not! Depending on the season and the weather, your garden can suffer from caterpillars, scale insects, mealy-bug, grasshoppers and a myriad of other insect invasions.
In my garden I have an annual invasion of scale insects. They don’t limit themselves to any one plant species. It seems that they are happy to attack all manner of plants including gardenias, eggplant, ferns, citrus trees and fig trees.
It may have something to do with the fact that I seem to be living atop an ant farm! Ants and scale have a particularly nasty co-dependent relationship.
If left unchecked, a scale infestation can result in the death of your plants from loss of vital nutrients. Also, the black sooty mould, which also accompanies such an invasion, can get in the way of the plant photosynthesising.
So, what can cause a scale invasion?
Scale and others pests mostly attack plants that are under stress or already weakened. I have found that it is beneficial to check that the plant is getting enough nutrients. This isn’t just adding more fertiliser. What you may need to do is check the pH of the soil! If the pH is wrong the plant may not be able to access nutrients. Even if they are present!
I don’t like using pesticides to control scale
I don’t like using pesticides, so each summer I used to go through vast quantities of organic pest oil! Each winter I would spray my citrus plants with lime sulphur to try and kill off the scale as it over-winters.
This year has been particularly bad due to the hot, dry conditions we have experienced in south-east Queensland. The scale have been in abundance, as have the ants! What has been missing is the “mild” weather days when it is safe to apply pest oil.
If you apply pest oil on a hot day you can cause almost as much stress to your plants as the scale is causing!
Until one day! I was soo exasperated by ongoing scale attack on my grapefruit tree, I sprayed the leaves with Neem oil. Now, I am a big fan of Neem oil, but everything I had read for scale treatment suggested either scraping off the scale with your fingernail (get serious), dabbing with alcohol or spraying with pest oil. No-one had even suggested Neem oil!!
The result was almost immediate! By the next morning the scale were still there, but the tree was looking like it had a new lease on life. And it has continued to flourish! So, I did a bit a of research!
It seems that the Neem oil penetrates the leaves to poison the scale from within, while at the same time the oil covers the outside of the scale and suffocates it!
I also add a few drops of whatever vegetable oil I have in the cupboard to my Neem oil to help it settle on the plant and not be washed off immediately. My favourite oil at present is sesame oil because I bought a 700ml bottle and there is no way I am going to eat all this before it goes rancid! It also leaves a really pleasant smell in the garden, like you’ve been cooking!
So, if your garden is suffering from an attack of scale, why not try spraying with Neem oil. See also beneficial insects Good Bugs in your garden #1
If my experience is anything to go by, your scale problem will be resolved! I will be only using Neem oil from now on for all future infestations. Let me know how you get on by leaving a comment.
Happy gardening 🙂
Rohanne, your Edible Gardening Expert