What's Eating Your Amaryllis?

Inspect every bulb at planting and reject suspects

Grow potted indoors instead of in the ground

Adult flies are active outdoors from April through June and only lay eggs on bulbs they can reach in soil. Amaryllis grown in a pot indoors, on a windowsill or shelf, are out of the egg-laying window entirely. This is the simplest and most effective prevention for hardiness zones 8 to 10 where the fly is established.

Floating row cover during fly emergence outdoors

If you summer the pot outside or grow amaryllis in a southern garden, drape lightweight row cover (Agribon AG-15, ~$15) over the soil from April through June. The cover blocks adult flies from reaching the bulb neck to lay eggs. Remove once flowering begins or once you bring the pot back indoors.

Cotton swab dipped in 70% isopropyl alcohol

Dab every visible mealybug between the leaf bases at the bulb neck. The alcohol melts the waxy coating and kills on contact. Pull the strap leaves apart gently, since amaryllis bases overlap tightly. Repeat every 3 days for 3 weeks to catch newly hatched crawlers hiding deeper in the joint.

Insecticidal soap into the leaf bases, weekly for 4 weeks

Spray ready-to-use insecticidal soap directly into the joint where leaves meet the bulb neck. Tilt the plant so the soap runs down between the layers. Repeat every 7 days for 4 weeks because eggs hatch in protected pockets at the bulb top over time.

Inspect during dormancy and dust the dry bulb

When the bulb goes dormant and you remove the leaves, peel back the dry papery outer scales and check for hidden colonies. Wipe any cottony patches off with a paper towel. Dust the bulb lightly with horticultural sulfur (Bonide, ~$10) before storing for the rest period.

Blue sticky traps at flower-stalk height

Hang blue sticky cards (Stikem or Trappify, ~$10 per pack) right beside the rising flower stalk before the buds open. Thrips are attracted to blue and stick on contact. Replace every 2 weeks. Won't eliminate alone but knocks down the population during the critical bud window.

Spinosad spray on buds before they open

Spinosad (Captain Jack's or Monterey Garden Insect Spray, ~$12 to $15) is the most effective home treatment. Spray the rising stalk and the unopened buds at lights-out, twice a week from when the stalk emerges until the first flower opens. Stop spraying once flowers open so the petals stay clean.

Cut the affected stalk if scarring is heavy

If the buds are already badly scarred, cut the entire flower stalk near the bulb neck with a clean blade. The bulb often pushes a second stalk in the same season, and removing the infested one breaks the local thrips population before it reaches new growth.

Shower the strap leaves weekly for 3 weeks

Move the pot to the shower or sink. Spray cool water along the underside of every strap leaf for 30 seconds. Mites can't reattach quickly when knocked off. Keep water out of the bulb neck so it doesn't sit wet and rot. Repeat weekly for 3 weeks.

Neem oil at lights-out, every 5 days for 3 rounds

Raise humidity above 50% during winter heat

Run a humidifier near the plant to hold 50 to 60% relative humidity. Hot dry indoor heating is the climate mites need to breed fast, and amaryllis foliage tolerates the humidity well during the active growth phase.