Mealybugs

Pseudococcidae (Family), Mealies, Woolly bugs, Cottony bugs

These are soft-bodied, wingless insects that look like tiny white, waxy oval spots. They are often mistaken for tufts of cotton or white fungus. You will typically find them tucked into the "axils" (where the leaf meets the stem), under leaves, or hidden in the crevices of new growth.

Mealybugs are piercing-sucking insects. They insert their straw-like mouthparts into the plant tissue to suck out the sap, and as they drain the plant’s energy, growth slows or stops. Mealies excrete a sticky substance called "honeydew," which attracts ants and encourages the growth of black sooty mold. Infested leaves often turn yellow, curl, and eventually drop off.

Variants

While these are closely related, where they live on the plant significantly changes how you spot and treat them.

Foliar Mealybugs

  • Location: Found on stems, leaves, and flowers.
  • Impact: Causes visible scarring, distorted new leaves, and the classic "cottony" buildup.
  • Detection: Easy to see with the naked eye during regular inspections.

Root Mealybugs (Rhizoecus)

  • Location: Found entirely underground, attached to the root system and the inside of the pot.
  • Impact: These are more dangerous because they are "invisible." The plant will look like it is suffering from underwatering or nutrient deficiency (wilting and yellowing) even if the soil is moist.
  • Detection: You usually only find these when repotting. You will see white, waxy deposits on the roots or the interior walls of the pot that look like mineral buildup or salt.

Rehabilitation Instructions

Foliar (Surface) Mealybugs

  • Manual Removal: Dip a cotton swab in 70% Isopropyl alcohol and dab it directly onto the white pests. The alcohol dissolves their protective waxy coating and kills them instantly.
  • Systemic Rinse: For heavy infestations, wash the plant with a steady stream of water to physically knock the insects off.
  • Horticultural Oil/Neem: Apply Neem oil or insecticidal soap, ensuring you spray the undersides of leaves and deep into the stem joints.
  • Isolate: Move the plant away from others immediately, as the crawlers (nymphs) can move between pots.

Root Mealybugs:

  • The "Hot Water" Dip: If the plant is hardy enough, some growers submerge the root ball in water heated to 115°F (46°C) for 10 minutes. This kills the bugs without killing the plant (use a thermometer to be precise!).
  • Total Repot: Remove the plant from the pot, discard all old soil in the trash (not compost), and wash the roots thoroughly with a mild soap solution.
  • Pot Sterilization: Scrub the old pot with bleach or high-strength alcohol before reusing.
  • Systemic Insecticide: Because root mealies are so hard to reach, a systemic soil drench (containing Imidacloprid or similar) is often the most effective way to ensure the entire colony is eradicated as the plant absorbs the pesticide through its roots.

Note: Root mealybugs are notorious for surviving in the dry crevices of terracotta pots or on the bottom of saucers. Always treat the surrounding area, not just the plant!

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