Asian Citrus Psyllid

The vector of Huanglongbing (HLB/citrus greening), the most devastating disease threatening the global citrus industry. The Asian citrus psyllid (ACP) itself causes minor direct damage, but its role as the HLB vector makes it arguably the most economically important insect pest of citrus worldwide. ACP is present across Asia, the Americas, and parts of Africa, and HLB follows wherever ACP establishes.

Adults are tiny (3-4 mm), mottled brown psyllids that feed on new flush growth with their body tilted at a characteristic 45° angle from the leaf surface (diagnostic). Nymphs are flat, yellow-orange, and produce white waxy tubules. They are found exclusively on young developing shoots (flush).

• 1

  Look for tiny brown insects on new flush shoots feeding at a distinctive 45° body angle — this is the single most reliable field identification feature

• 2

  Yellow-orange flat nymphs with white waxy tubules on young tender shoots

• 3

  Adults jump (psyllids = jumping plant lice) when disturbed — unlike whiteflies which fly

• 4

  Tap flush shoots over a white surface — dislodged psyllids are visible as small brown specks

• 5

  Yellow sticky traps placed near flush growth catch adults for monitoring

• Tiny brown insects on new shoot growth, feeding at 45° angle

• Twisted, curled, and stunted new flush growth from heavy nymph feeding

• Waxy deposits from nymphs on young shoots

• The critical damage is INVISIBLE — acquisition and transmission of HLB bacteria

• HLB symptoms (blotchy mottling, fruit asymmetry) appearing months after psyllid transmission

Asian Citrus Psyllid can attack 5 crop species.