About the size of aphids, brownish-gray adult Asian Citrus Psyllids mass on the underside of a citrus leaf.


Photo credit: California Dept. of Food & Agriculture
From the California Citrus Research Board: “Adult Asian Citrus Psyllids are small (3-4 mm or 1/8-1/6 inch), brownish insects that are similar in size to an aphid. They feed with their heads down, almost touching the surface of the leaf. Because of the shape of their heads, their bodies are lifted to approximately a 45-degree angle…. The psyllids develop from an egg through five nymphal stages that look similar, but increase in size after each molt. Due to the small size – even of adult psyllids – inspection is done more easily with a magnifying glass or hand lens.