Orchids are colorful tropical flowers suited for home growing or in warmer outdoor gardens. Although they are vulnerable to temperature changes, orchids are largely healthy. They are prone to some diseases and pests that should be taken into account when growing orchids in your home or garden.
Aphids attach to orchid leaves and stems and they suck sap from the plant. They also exude honeydew, a sticky sweet substance that attracts ants and sooty mold. The sooty mold, in turn, covers the leaves and the stem, preventing the orchid from receiving the nutrition it needs. Use a stream of water to remove the aphids or a mild insecticide to kill them.
Scale insects are small, hard-bodied insects that attach to the underside of the leaves and the orchid bulbs. They are easily visible and look like very small bumps. According to Houston Orchid Society, dispose of heavily infested plants, as they wither the plants in time. Because they are visible, scrape them off the orchid whenever you see them.
Leaf rot is a disease causing a slight coloration on the leaf. Initially, it causes a discolored spot on the leaf that is slightly darker or lighter than the surrounding leaf. In time, the spot gets bigger and develops irregular borders. Remove any leaves showing signs of leaf rot using clean scissors or knives. Place the orchid in a place with good air circulation to mitigate this disease.
Bacterial Root Rot
While orchids are water-loving plants, too much watering makes them susceptible to bacterial root rot. The first sign of root rot involves the shriveling of the lower leaves. To solve this issue, remove the orchid from its pot, remove the soggy soil and any dark, soft roots. Repot the orchid in a smaller pot and avoid watering it for several days. Reduce watering overall if you have continual problems with root rot.