From our perspective as orchid cacti (Epiphyllum spp. and hybrids), we are generally resilient plants, but our succulent, segmented stems can be vulnerable to specific ailments. Understanding these issues from our point of view is key to helping us thrive.
Our juicy stems are a prime target for several pests that pierce our skin and feed on our sap. This weakens us, causes discoloration, and can introduce further disease.
Mealybugs: These appear as small, white, cottony masses in the crevices of our stems and joints. They suck our sap, leaving behind a sticky residue called honeydew, which can attract sooty mold. To treat, dab each insect with a cotton swab dipped in isopropyl alcohol. For larger infestations, a strong jet of water or an application of insecticidal soap or neem oil is effective.
Scale Insects: These pests look like small, brown, or tan bumps stuck to our stems. Like mealybugs, they feed on our sap. Scrape them off carefully with a fingernail or a soft brush. Follow up with a horticultural oil spray to smother any remaining crawlers.
Spider Mites: These tiny arachnids cause a fine, stippled yellow pattern on our stems and may leave behind delicate webbing. They thrive in hot, dry conditions. Increase humidity around us and spray our stems thoroughly with water or a miticide to dislodge and eliminate them.
Our greatest fear is rot, often caused by excessive moisture around our roots or on our stems, which creates an environment where pathogens flourish.
Stem Rot: This is often caused by fungi like Fusarium or Phytophthora. You will see soft, mushy, black or brown spots on our stems, usually starting at the base or a wound. The affected area may smell foul. Immediately cut away all the rotted tissue with a sterile knife until only healthy, green flesh remains. Allow the cut to callous over completely in a dry, airy spot before repotting us in fresh, well-draining soil.
Root Rot: This occurs when our roots are suffocated in waterlogged, poorly draining soil. You may not see it until we show signs of wilting or top-growth decline. If you suspect root rot, gently remove us from our pot. Trim away any black, mushy roots and repot us in a very airy, fast-draining cactus mix. Ensure the pot has excellent drainage.
Often, pest and disease problems are secondary symptoms of primary cultural issues that are stressing us out, compromising our natural defenses.
Overwatering: This is the most common mistake. Our roots need to breathe and will quickly rot in constantly wet soil. Water us deeply only when the top few inches of soil are dry.
Poor Air Circulation: Stagnant, humid air encourages fungal growth and pest populations. Please ensure we are in a location with good airflow.
Insufficient Light: While we dislike direct, harsh afternoon sun, too little light makes us weak and etiolated, leaving us more susceptible to attack. Bright, indirect light is ideal for keeping us strong.
