Orchid Soil Pests

Scales

• Scales are small and pale gray insects that infest all parts of orchids, from their roots up through to their buds. Many novice gardeners mistake scales for mealybugs at first. Gardeners may not notice them until many of them surface in the soil and resemble a solid covering on the soil and parts of the plant. When scales infest orchids, they attach their small, strawlike mouth to the plant and suck out all the plant's fluids; they leave behind honeydew, a sticky, sweet substance, on the orchids they infect.

Orchid Mealybugs

• Orchid mealybugs are grayish-pink insects with waxy filaments surrounding the body. Not a lot is known about mealybugs, except they like warm climates and live in the soil and roots of orchids and other similar plants. They feed off the plants by inserting their tubelike mouths into orchids and sucking out the juices. This causes affected plants to become stunted and even die as a result. When orchid mealybugs feed, they leave behind a honeydew substance, similar to scales.

Gnats

• Fungus gnats are known for infesting damp soil and decaying vegetable matter. They can get into the soil of either indoor or outdoor plants. The female gnats lay their eggs in the soil, which will hatch in only five to seven days. The larvae are white and appear similar to maggots, and the adults have black heads. Adult gnats feed on the soil and roots of orchids and other plants, causing the plant to appear unhealthy and damaging the root system.

Control

• When controlling scales on orchids, separate the affected plants to limit the possibility of the scales spreading, and then wash the orchids in a soapy solution. Dissolve soap shavings, or soap flakes, in warm water and then pour the mixture into a squirt bottle. Spray down the orchids every other day for a month. Keep a diligent watch over the orchids to quickly catch any signs of an infestation.

  For mealybugs, dispose of any orchids that are heavily affected, and then saturate a cotton swab with rubbing alcohol and apply to those orchids with a less severe infestation. Spray down the orchids with a mixture of liquid dish detergent and warm water.

  Control gnats by replanting your orchids every other month and using a sterile potting soil. Avoid overwatering your orchids, as gnats prefer more saturated soil.