Pests & Diseases
Unhealthy plants are more susceptible to parasites and disease. Low humidity and poor air circulation weaken plants. Be sure to address any of these underlying problems while treating specific issues:
- Scale -- These small, immobile brown lumps on the stems, leaves, or flowers can become a persistent problem.
- Aphids - Soft-bodied, small insects can be green or black. They usually attack new leaves or flowers.
- Mealybugs -- These white parasites look like little pieces of cotton.
- Spider mites -- While these insects are too small to see, they can still cause a lot of damage. Fine webs on the undersides of leaves and a bronze or yellow color to the leaves can indicate their presence. They like dry air, so keeping the humidity high will discourage them.
- Snails & slugs -- These can eat leaves, flowers, or roots.
- Viruses -- Unfortunately viruses in orchids are difficult to identify and are usually incurable. Symptoms to watch for include deformed flowers, streaking patterns on leaves, and deformed growth. Discard infected plants.
- Pets -- Some animals do not bother plants, but others may chew them. Keep plants out of reach. Protect new flower spikes.
Always try to limit use of artificial chemicals, which can be dangerous for you and the environment. Remember that insecticides often kill beneficial insects as well as harmful ones. Using artificial chemicals inhibits Mother Nature's ability to take care of herself.
- Beneficial insects are one of the best solutions. Many garden stores sell ladybugs and praying mantises to release in your garden. Spiders eat many plant pests.
- Soapy water sprayed on the tops and bottoms of leaves can safely and effectively kill pests. You can buy insecticidal soaps at a gardening center, or make your own using a little mild, unscented soap mixed with water. Insecticidal soaps only kill insects they have direct contact with.
- Rubbing alcohol is effective for controlling Scale and Mealybugs. Use a cotton swab dipped in rubbing alcohol to wipe the bugs off. Rinse the alcohol off the plant with clean water afterwards.
- Insecticides with natural ingredients that decompose quickly, such as pyrethrins, should be used only when absolutely necessary. Always follow the instructions.
- Horticultural oils are available at garden stores and kill many pests. Always follow the instructions.
- Copper strips are effective barriers for slugs and snails, which can be very destructive for outdoor orchids.