by Wizzie Brown
Oleander aphids are also known as milkweed aphids, and in Central Texas can often be seen on tropical milkweed. The wingless adult and nymph aphids are bright yellow in color with black appendages, while winged adults are black and yellow with dark wings.
The females of the oleander aphid are parthenogenetic and viviparous which means that they do not require to mate before producing offspring and that they give birth to live young instead of laying eggs. Both adult and nymphs cluster together along stems and on the underside of the foliage while they feed. Winged aphids are produced when there is overcrowding on the plant or if the plant is in decline. The winged aphids allow a new population to move to different host plants.
Oleander aphids have piercing-sucking mouthparts which they use to suck up phloem from the host plant. Aphids are honeydew producers and excrete the sticky, sweet substance that can lead to secondary problems such as sooty mold, stickiness on areas or objects under or surrounding infested plants, and can attract ants that protect aphids from predators and parasites.
Non-chemical methods to reduce populations of oleander aphids include pruning off heavily infested parts of the plant or removing aphids with a strong stream of water. Various biological control methods that occur naturally can be observed if you know what to look for. Both ladybug and hover fly larvae feed on aphids. There are also small, parasitic wasps that lay their eggs inside of aphids. When the wasp larva hatches from the egg, it consumes the aphid from the inside. Aphids that have been parasitized appear as puffed up, dark colored aphids, called aphid mummies. When looking at pesticide options, you can try insecticidal soaps or horticultural oils.
For more information or help with identification, contact Wizzie Brown, Texas A&M AgriLife Extension Service Program Specialist at 512.854.9600. Check out my blog at www.urban-ipm.blogspot.com
This work is supported by Crops Protection and Pest Management Competitive Grants Program [grant no. 2017-70006-27188 /project accession no. 1013905] from the USDA National Institute of Food and Agriculture
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