About Epiphyllum Diseases
Eepiphyllums, also known as Christmas or orchid cacti, are a common decorative plant found in garden stores and are noted for their bright colored flowers. They are easy to grow and relatively disease and pest free. Any infections should be treated early to prevent damage and halt the spread of the infection to other plants.
Epiphyllums are susceptible to common plant pests like mealybugs, hard scale, aphids and spider mites. They are also a prized meal for slugs and snails when left near the ground outdoors and in greenhouses. In cooler climates, root weevils have been a problem when unsterilized potting medium is used.
For minor infestations, dip a cotton swab in a mixture of half rubbing alcohol and half water or apply the alcohol water with a spray bottle and wipe the infected areas off with a paper towel. Avoid using harsh chemicals that might damage the waxy coating on the outer layer of the leaves. Mild insecticidal soaps are available that will eliminate aphids, mealy bugs, and scale but will not treat spider mites. Horticultural oil will kill spider mites with repeated treatments. For really bad infestations, a systemic chemical may be needed. Caution should be taken to follow the directions carefully and only use ones recommended for tropical plants.
Bacteria and Fungus
Not much is known about fungal and bacterial infections in Epiphyllums. They usually show up as a creeping black rot that slowly kills the plant and are difficult, if not impossible, to control with commercial products. Infected plants should be quarantined and destroyed before the infections are allowed to spread to nearby healthy plants. These types of infections are best prevented instead of treating.
The growing environment is the greatest contributing factor in what type of diseases infect an Epiphyllum. Plants grown outdoors in the summer should be kept away from trees and other plants that might spread infections. Carefully check the plants when bringing them inside for any pests they might have picked up outside. When growing indoors or in a greenhouse, keep humidity levels stable and use a small fan to make sure there is good airflow.
Poor Plant Care
Failing to care for an Epiphyllum can lead to problems that look like a disease or weaken the plant, making it subject to infection. Some irregularities like spots on leaves may be normal consequences of growing the plant outdoors in the summer or in a greenhouse but are not unhealthy. Withering of leaves can be due to over watering, and burn spots are often caused by exposure to direct sun. Outdoor plants can also be damaged by unexpected frost, leading to brown dead spots over night.