Orchid Infestations

Identifying Potential Pests

• Orchids suffer from a handful of pesky bugs, including aphids, fungus gnats and mites. You'll notice aphids by the yellow-tan skins they shed; if you see these, the aphid colony is probably just above. Fungus gnats are easier to spot, as these dark-winged, mosquito-like creatures flit around orchids and other plants. Mealybugs are wooly-looking creatures, while mites are miniscule, spider-like bugs that lay eggs on the undersides of leaves.

Damage to Orchids

• Aphids, mealybugs and scale insects feed on orchids, leaving flowers and leaves yellow and dehydrated. In many cases, orchid blossoms die. Mites do similar damage, though some produce interesting results. For instance, two-spotted spider mites suck chlorophyll from orchids, leaving them with pin-prick yellow dots. Fungus gnats are an exception to the feeding rule as they feed on fungus rather than orchids themselves. If you see fungus gnats around your orchid, you may have a fungal disease on your hands from overwatering or too much humidity.

Solutions

• You can get rid of flying pests using yellow stick cards specifically designed to control pest populations. When aphids, whiteflies and fungus gnats land on them, they cannot free themselves from the sticky mess and remain trapped until they die or gardeners dispose of them. Alternatively, place a carnivorous plant near the orchid, which will attract and digest flying pests. You can also introduce a predatory insect that eats or scares away the problem insects. For instance, wasps and ladybeetles attack mites and mealybugs.

Prevention

• Preventing pest infestations is the smartest way to keep orchids healthy. Insecticides and miticides keep bugs at bay, but they are costly and can kill some orchids. A less dramatic measure is lightly coating orchids with rubbing alcohol, also called isopropyl alcohol, as horticulturalist Paul J. Johnson recommends on the South Dakota State University website.

Environmental Considerations

• In most cases, insect infestations indicate an underlying problem in the orchids' environment. For instance, keeping orchids in humidity prevents two-spotted spider mites, but too much dampness causes fungus that attracts fungus gnats. Every type of orchid has slightly different needs when it comes to light, temperature, humidity and watering, so make sure you provide individualized care for your particular orchid. A carefully-maintained environment will minimize the risk of pests invading your orchids and encourage overall health and flowering.