DIY White Oil

I’ve been having a little problem with Mites in our Community hydroponics setup. It’s interesting that there are very few in the open aquaponics system or rest of the garden where predatory insects can reach but not in this section which is fed on artificial nutrient mixes and well netted, preventing access to many bugs, including predators. The second observation is that they started on the stumps of Pak Choy and Lettuce which I have regenerating leaves.

By the looks of them (brown with orange legs) they are probably Bryobia mites, which are known to swarm after heavy rains. They’re not usually a pest on leafy greens like this but the damaged plant tissue must have been too much for them to resist.

I’ve left it all for a week or so, hoping that predator wasps might find them but no luck. As they’re doing visible damage to seedlings, it’s time to act.

Bring on the White Oil!

What is White Oil?

White Oil is one of the safest pesticides that you can make at home. It’s a blend of vegetable oil and liquid soap – that’s all.

Insects and arthropods don’t have lungs, they breathe through tubes in their exoskeleton ( called ‘spiracle’) that allow air to enter their trachea and from there spread directly to the relevant tissues. The oil suffocates the pest insects and arthropods by blocking these spiracles as well as physically immobilising the critter . The soap helps the oil spread and also breaks down the exoskeleton. Simple and fatal.

How to make your own White Oil

There’s 2 kinds of White Oil, one is just another name for mineral oil, the other you can make at home using this recipe –

1 part dishwashing soap : 4 parts vegetable oil.

Put it in a blender and go nuts mixing it until it’s white. That’s it!

Put the resulting thick, white liquid in a labelled bottle for storage. Make up a spray bottle to use by mixing the oil with water at the rate of 1 tbsp oil :  1 litre water.

Using your White Oil

Spray the diluted solution onto the affected plant, making sure that you get both sides of the leaves and the area immediately around the plant. You don’t have to drench the plant tough, just a light spray will do the job

You may have to spray again after 2 – 2 days. You will kill any adults that the White Oil comes into contact with on the first spray but there are often a few tucked away in nooks and crannies that you don’t reach. For most varieties of pests, there are always eggs to think of too. They usually take 2 – 3 days to hatch and repeat the insect’s lifecycle so a second or even a third spray will be needed to ensure that you eliminate the whole population.

I lie to leave a small break as well, so that the plant doesn’t get drenched in oil for too long otherwise, the stomata (pores) through which the plant exchanges gasses may get clogged for too long, to the detriment of the plant.

Deadly stuff if you’re a pest. Free to you. If you make enough, you might not be able to wash your dishes…hooray!