Cacti can sometimes become infested with mealybugs. "Mealies," as they are often referred to, are tiny insects about 0.1 inches (3mm) in length, which shroud themselves in a oval-shaped, cottony covering.  Mealybugs are peircing insects and live their entire adult lives within their cottony fortresses, dining on your plant. A plant infested with mealybugs will stop growing, weaken, and often eventually succumb to rot.

Mealybugs' cottony coverings protect them from predators and contact pesticides. Minor infestations can be handled by dabbing with a cotton swab that has been dipped in rubbing alcohol. The alcohol dissolves the covering, leaving them defenseless. You can also simply wipe away smaller infestations. For more severe problems you will have to treat a several times over a few weeks. Consistency and thoroughness are important and will eventually defeat this pest.

For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service