What pests does rubbing alcohol kill?

Soft-bodied pests with a waxy coating, including mealybugs, aphids, spider mites and scale. See the full directions for use below for dilution rates and application.

Is rubbing alcohol the same as isopropyl alcohol?

Yes and no. Rubbing alcohol contains isopropyl alcohol, but at a lower concentration. Rubbing alcohol varies between brands but for use to kill pests on indoor plants, the general advice is to avoid going over 70% alcohol. Isocol Rubbing Alcohol is 64% isopropyl alcohol. 

Precautions: Is rubbing alcohol safe on all plants?

On the whole, yes, however some plants are more sensitive than others. Unless you're confident your plant is not sensitive to rubbing alcohol or dish soap, dilute as per the directions below, and do a test patch first on a leaf or two (avoid getting rubbing alcohol on roots). 

How to do a patch test: Apply to one or two leaves and wait at least 2 days / 48 hours. Look for signs such as leaf scorch. If you do see a reaction, either do not treat the rest of the plant, or dilute more than usual and patch-test again before treating the rest of the plant.

When to apply: The same as all insect treatments, best to apply early morning or early evening, and apply on a day not expected to reach over 30 degrees. Plants being treated should be isolated. Avoid direct sun on leaves during treatment.

Treating pests comes with risks: There is always some risk involved in treating any plant with any insecticide or non-insecticidal treatment (including soap). Some leaf browning, wilting or leaf drop are common. This should come right relatively quickly, once the pests are eradicated, and your plant can put out healthy growth again, without pests damaging foliage or stunting growth. When using dish soap, plain and without additives is best, such as pure castile liquid soap.

Directions for using rubbing alcohol to treat mealybugs, aphids, scale and spider mites

READ BEFORE FIRST USE: Check precautions above as some plants are more sensitive to alcohol than others. Following are shortened directions for use by pest, however these are a guide only because rubbing alcohol is a 'DIY treatment / home remedy' for plant pests, so you won't find this on the label. You can also search 'rubbing alcohol + [pest name]' online for more advice. For best results use a super fine spray mister for better coverage and better contact with the leaf surface and pests.

MEALYBUGS: Isolate the plant. Dip a cotton bud, cotton pad or similar in rubbing alcohol (undiluted). Press on-to then wipe off visible adults for instant kill. Then treat the entire plant with a mix of 1 part rubbing alcohol with 1 part water and a couple of drops of liquid dish soap. Stir then spray foliage thoroughly, including stems and (lightly), the top of the soil (do not pour mixture on to roots or drench the soil). Wait 5 to 10 minutes. Spray off and rinse thoroughly with plain water. Repot if needed. Repeat fortnightly until gone (check detailed mealybugs treatment directions here).

SCALE: Isolate the plant. For a light infestation, dip a cotton pad or cotton bud in rubbing alcohol (undiluted), and dab then wipe off visible scale. For a more serious infestation, spot treat (undiluted), and also spray the rest of the plant with diluted rubbing alcohol. Mix 1 cup rubbing alcohol with a tablespoon of liquid dish soap and 1 litre of water and spray foliage and stems. Repeat every 3 days for at least 2 weeks. 

SPIDER MITES: Isolate the plant. Use undiluted rubbing alcohol for best results, or for sensitive plants (test first), mix 1 part rubbing alcohol to 3 parts water, and wipe leaves (top and bottom), with mixture. For best results follow-up with the diluted mixture in a spray bottle, applied to foliage, top and bottom. Leave for 1 to 3 hours and rinse off dead mites with plain water. Another popular combination against spider mites is 1 tablespoon of liquid dish soap, 1 litre of water and 1 cup of rubbing alcohol. Mix and apply as both a wipe and a spray, rinse off 1 hour later. Repeat every 3 days for at least 2 weeks.  

APHIDS: Isolate the plant. Make an insecticidal soap and alcohol solution, using 2 parts rubbing alcohol, 5 parts water and 1 tablespoon of liquid dish soap. Spray foliage and stems liberally. Although time-consuming and fiddly with how small aphids are, you can also spot treat aphids directly using undiluted rubbing alcohol on a cotton bud or similar. Rubbing alcohol kills aphids almost instantly on contact but a spray treatment is usually needed for anything except a very light infestation caught early. Spray or spot treat (or both), every 2 to 3 days, for at least 2 weeks.

PS: I'll send you a copy of these directions by email after you purchase, and you can also find them later here under Product Guides.