The oleander aphid is a bright yellow insect with black legs, and stalks known as cornicles on the back of the abdomen. Large colonies often develop over the summer and may cause injury or death of the host plant. Like other aphids the oleander aphid secretes a viscous sugary substance known as honeydew. This secretion is greedily sought after by other insects, especially ants. Some ants live in close proximity to, and tend to aphids. As honeydew accumulates on the leaves, a black sooty mold often follows and can be unsightly.
It is commonly found on oleander, butterfly weed and milkweed, appearing on buds, new shoots and foliage in the spring.