Homemade garlic spray is effective against sucking insects such as mealybugs and aphids. Determine where the pests are congregating -- the undersides of foliage is a common hiding place. Then spray the garlic solution directly on them, covering them completely. Allow the spray to sit on the plant for one hour, and then rinse it off. Sometimes you will need to repeat the treatment once a week until the pests are controlled.
Use a sharp knife to mince the garlic cloves.
Place the minced garlic in a large bowl and cover it with the mineral oil. Allow the solution to sit for 24 hours.
Strain the mixture into a clean pitcher or other spouted container.
Add liquid soap. Pour the solution into a spray bottle.
Liquid Castile soap helps the spray stick to the leaves and is biodegradable. It can be purchased at most chemists and is sold under brand names including Dr. Bronner's and Desert Essence. Add 3/4 tsp of rubbing alcohol to the solution to kill ants in the garden. Test the solution on an inconspicuous part of the plant to make sure the plant can tolerate the alcohol.