WARM MONTHS · ALL YEAR IN SOUTH FLORIDA
Oleander caterpillar
Orange caterpillars with black hair tufts feed in groups on new shoots, which turn light brown. UF/IFAS says they can strip a plant in as little as a week; Clemson says a few days.
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Oleander
The worst oleander pest is the oleander caterpillar (Syntomeida epilais), which Clemson HGIC and UF/IFAS both call the most damaging pest of oleanders. The caterpillars are orange with tufts of black hairs and grow to about 2 inches (Clemson). Females lay clusters of pale eggs under the young leaves; the young caterpillars feed in groups and turn new shoots light brown, and UF/IFAS says that, left unchecked, they can defoliate a plant in as little as a week. The adult is the polka-dot wasp moth: blue-black with white spots and a red-tipped abdomen, it looks like a wasp. It thrives in warm weather and lives year-round in south Florida and the Keys, but cold winters usually kill it in north and north-central Florida.
The crowds of bright yellow, black-legged aphids on the new shoots are oleander aphid. Oleander is its principal host (UF/IFAS). The damage is honeydew, sooty mould and sometimes deformed tips. Oleander scale (Aspidiotus nerii) shows up as small, round, whitish armoured scales, 1–2 mm across, on either side of the leaves. UF/IFAS also names false oleander scale. UC IPM calls oleander scale generally not damaging, and lists mealybugs, black scale and other scales on oleander as well, without naming the mealybug species. Clemson says aphids, mealybugs and scales are occasional problems.
Every part of oleander is poisonous to people, pets and livestock. The sap irritates skin and eyes, and UF/IFAS warns not to burn the prunings, because the smoke is toxic. Most control on oleander means cutting out infested shoots, so wear gloves and bag the cuttings.
crop context · oleander shoot with caterpillar feeding
The pests on oleander
SPRING PEAK · ALL SEASON
Oleander aphid
Bright yellow colonies with black legs on the tender shoots; honeydew, sooty mould and deformed tips. Mostly cosmetic.
ALL YEAR
Oleander scale
Small (1–2 mm), round, whitish armoured scales on either side of the leaves. UC IPM calls it generally not damaging; heavy infestations wilt and malform shoots.
ReleaseWild lady beetles and parasitic waspsWild — conserve; scrape or scrub off small patches
OCCASIONAL · ALL YEAR
Mealybugs
White, waxy clusters in leaf joints and on stems. Extension sources list mealybugs on oleander as occasional pests without naming the species, so check which one you have.
OCCASIONAL · ALL YEAR
Black scale and other soft scales
Brown or black bumps on stems and leaf midribs that do not move, with sticky leaves and sooty mould below. UC IPM lists black scale on oleander and says it gets worse where ants tend it.
ReleaseWild parasitic wasps and lady beetlesWild — conserve; keep ants off
SOUTHERN US · CALIFORNIA
Sharpshooters (oleander leaf scorch)
Large leafhoppers that carry the bacterium behind oleander leaf scorch: yellowing, browning leaf edges and dieback. UF/IFAS says infected plants die within about 2 years; UC IPM says 3–5.
ReleaseNone — no release or spray stops the diseaseRemove infected plants early
Season calendar
WARM-CLIMATE GARDENS · ACTIVE ALL YEAR IN SOUTH FLORIDA · QUALITATIVE| J | F | M | A | M | J | J | A | S | O | N | D | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Oleander caterpillar | Jan: Quiet | Feb: Quiet | Mar: Quiet | Apr: Building | May: Building | Jun: Pest pressure high | Jul: Pest pressure high | Aug: Pest pressure high | Sep: Pest pressure high | Oct: Building | Nov: Building | Dec: Quiet |
| Oleander aphid | Jan: Quiet | Feb: Building | Mar: Pest pressure high | Apr: Pest pressure high | May: Pest pressure high | Jun: Building | Jul: Building | Aug: Building | Sep: Building | Oct: Building | Nov: Quiet | Dec: Quiet |
| Scales & mealybugs (check all year) | Jan: Building | Feb: Building | Mar: Building | Apr: Building | May: Building | Jun: Building | Jul: Building | Aug: Building | Sep: Building | Oct: Building | Nov: Building | Dec: Building |
- Pest pressure high
- Building
- Release window
- Quiet
- Oleander caterpillar · high pressure Jun–Sep
- Oleander aphid · high pressure Mar–May
- Scales & mealybugs (check all year) · high pressure
Starter program
Most oleander problems are handled with pruners and a hose. Bt is for small caterpillars. A beetle release only makes sense on a potted oleander under glass, where the insects cannot fly away.
- WARM MONTHSCheck the new shootsLook for light-brown, skeletonised shoot tips and clusters of pale eggs under the young leaves (caterpillars), yellow aphid colonies, and white or brown bumps on the stems.
- FIRST CATERPILLARSCut out infested shootsUF/IFAS calls this the most environmentally friendly control. Bag the shoots and freeze them for 24 hours. Wear gloves.
- SMALL CATERPILLARSBt kurstakiUF/IFAS lists Bt while the caterpillars are small and treats insecticides as a last resort, since the damage is unsightly but does not kill oleander. Use a product whose label covers ornamentals and caterpillars.
- APHIDSHose and hold backHose colonies off and water, fertilise and prune less. Leave the papery tan mummies, which contain parasitoid wasps. Use soap or oil only if colonies stay heavy.
- MEALYBUGS, UNDER GLASSCryptolaemus montrouzieri5 beetles per infested plant, on a potted oleander in a greenhouse or conservatory.
- LEAF SCORCH SIGNSPrune hard or removeUF/IFAS: prune infected limbs 2–3 feet below the symptoms and sterilise tools between plants. UC IPM: pruning will not save the plant, so remove infected plants early.
Setting up the garden
The setup on oleander is mostly about what you feed it and how you handle it.
Wear gloves; never burn the prunings
All parts of the plant are toxic if eaten, the sap irritates skin and eyes, and UF/IFAS warns that burning cuttings puts the toxins into the smoke.
Go easy on water, fertiliser and pruning
UF/IFAS says all three push out the tender shoots that oleander aphid feeds on. Oleander is very drought tolerant once established.
Keep ants off
UC IPM says ants tend aphids for their honeydew and protect them from natural enemies. UC also says black scale is worse where ants tend it.
Do not spray for leaf scorch
UC IPM says available insecticides do not stop the spread of oleander leaf scorch, because sharpshooters are around all year.