Mealybugs on orchids and other ornamental plants can become a big problem if not cared for quickly. They can easily get out of hand and weaken orchids.
The main issue with these critters is that they create a byproduct called honeydew. It’s a sticky substance that attracts other insects and mold.
While mealybugs choose hosts indiscriminately, they seem to prefer cultivated orchids. They tend to live on orchid roots, rhizomes, and the underside of leaves.
What Is a Mealybug?
Mealybugs are oval-shaped insects that range in size between 1/20″ to 1/5″ of an inch. They are pink and covered with soft, white wax.
They generally like moist and warm locations, which attracts them to tropical orchids.
The most common mealybug found on orchids is the long-tailed mealybug or Pseudococcus longispinus. As the name implies, they have a tail that resembles a long filament.
The citrus mealybug or Planococcus citri, related to a scale, is another commonly found mealybug. Both do significant damage to orchids and other cultivated greenhouse plants.
You can identify a mealybug by the waxy filaments that look like tails extending from their rear ends. They look like wooly aphids or a cottony cushion scale.
Interestingly, mealybugs keep their legs throughout their lives, unlike scale insects.
Mealybugs are dangerous because they can lay up to 600 eggs. But, mealybugs need specific temperatures to lay these eggs.
When temperatures rise, the number of eggs drops. You can spot the eggs by the protective mass of wispy cotton covering them.
The female mealybugs die within a week of laying eggs. Yet the hundreds of eggs left behind are a concern for vulnerable orchids.
The lifespan of mealybugs has three stages, each with mobility. Mealybugs reproduce every 30 to 90 days, depending on the climate. Adult males have short lifespans but have wings and move rapidly.
If you suspect mealybugs are on your orchids, look closely at the leaf whorls. Most mealybugs look like white masses on the green whorls.
Larger masses are usually eggs, but they could be a helpful insect called a mealybug destroyer. If you see yellow or wilted leaves on your orchids, they probably have mealybug damage.
Cultivated orchids can also have mealybug masses near the planter drainage holes.
What Damage Do Mealybugs Cause?
Heavy infestations of mealybugs cause significant damage to orchids. They eat stem tips, which is where the stem and leaf meet.
Immediate damage includes wilting, stunting, and defoliation. Furthermore, mealybugs suck out the liquid in the plants, creating the sugary, wax-like substance known as honeydew.
Mealybug waste supports sooty mold fungus, which blocks light from reaching the leaves. When light cannot get to the leaves, photosynthesis stops, and the plant dies.
Honeydew on its own is not damaging, but the lack of photosynthesis is. Mealybugs that live on orchids can also inject a toxin into the stem as they eat.
How To Control Mealybugs on Orchids
Greenhouse managers struggle with mealybug infestations on orchids because they are so difficult to destroy. If your greenhouse receives infested plants, send them back to the supplier.
If you see mealybugs on orchids, hand removal with a cotton swab soaked with Isopropyl alcohol is one technique that works. Sprays of Neem oil and insecticide liquid soap are also effective.
Don’t forget to soak the potting mix as well on your orchids because mealybugs will infest wherever there is a food source.
Beneficial insects such as the Cryptolaemus montrouzierus the mealybug destroyer as also effective.