Here's the recipe:

GARLIC SPRAY:
Soak 1/2 cup crushed garlic cloves in 1/2 cup vegetable oil for one week. Add a little liquid soap and dilute the mixture - 1 part mixture to 10 parts water. Garlic spay will kill and repel aphids, woolly aphids, bean fly, stink bugs, crickets, grasshoppers, red spider mite, sawfly larvae, scale, snails, slugs, thrips and caterpillars, mosquitoes and ticks, the adult moths of leaf-miners and mealy bugs. It is an effective fungicide when used 3-4 times a week against potato blight and damping off.
OR
Crush 100g garlic, 2 chillies and 2 onions and cover with water for 24 hours. Strain and add enough water to make up 2 litres.

You can use any garlic you like, even garlic chives if you want (though this won't be as potent as true garlic). You can even use dried or bottled mushed garlic if you can't be bothered growing your own. Just make sure to strain it well so you don't get a clogged-up nozzle.

Thanks for the information.

Peaches