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The Oleander Aphid (Aphis nerii) is a bright yellow, black-legged aphid that infests oleander, milkweeds, and other related ornamentals, reproducing rapidly as all-female clones (no males/eggs) and causing damage by sucking sap, leading to stunted growth, leaf curl, and sooty mold from honeydew. They sequester toxins from their hosts, making them distasteful to predators, but are controlled by natural enemies like ladybugs, parasitic wasps, and fungi.
Key Facts:
Appearance: Bright yellow body with black antennae, legs, and cornicles (tubes on abdomen). Winged forms have dark wing veins.
Hosts: Primarily Oleander (Nerium oleander) and Milkweeds (Asclepias spp.), but also Vinca, Wax Plant, and some citrus.
Reproduction: All females (viviparous, parthenogenetic), producing live nymph clones; males don't exist in the wild, allowing populations to explode quickly.
Damage: Sucks plant sap, causing stunting, deformed growth, and sooty mold from sticky honeydew. Can transmit viruses.
Defense: Sequester plant toxins (cardiac glycosides) to become toxic to predators, deterring many beneficial insects.
Control: Susceptible to natural enemies (lady beetles, lacewings, parasitic wasps, syrphid flies, fungi) and can be managed with insecticidal soaps or neem oil.
Life Cycle & Behavior:
Populations start new each year from single founding females on new growth.
Colonies form dense clusters on new shoots and leaf undersides.
Winged adults (alates) develop when plants get crowded, allowing migration.
White, shed skins (exuviae) accumulate, often mistaken for the insects themselves.
