Tiny, teardrop-shaped, bright yellow in colour, with minute black legs. There are clusters of them on only one plant in my garden, that being my milkweed. They are on the un-opened seed head pods, and they appeared at the end of the summer. I live in a wooded area (Charleswood) in Winnipeg, MB.
Comments for Tiny, bright yellow insect in clusters (Oleander aphids)
Your yellow/orange insects are the oleander aphid. They are native to the Mediterranean but are now all over North America.
This aphids feed on plants in the dogbane family which includes milkweeds, oleander, and vinca. These aphids also feed on plant in the Crassulaceae and Solanaceae families.
Aphids in this family reproduce without males giving live birth. Since they feed on milkweed, these aphids carry the toxic substance of the milkweed plant. Predators like lacewings and lady beetles that eat these aphids have problems developing properly. A braconid wasps have been seen laying eggs inside these aphids.
To control these aphids it is best to hose them off with strong spray of water. No chemicals should be used as the insecticide would kill monarch caterpillars also feeding on the milkweed. Also, the aphids tend to be on the pods not the foliage of the plants…where the monarchs need to feed.