Asian Citrus Psyllid



Diaphorina Citri


The Asian citrus psyllid is a small insect with a mottled brown body. Its body is roughly 3 to 4 mm long with a pointy front end, short antennae, brown wings and red eyes. The antennae have black tips with brown spots on the middle segments. Adults often have whitish, waxy secretions on their body.


Asian citrus psyllids feed on a variety of citrus plants including oranges, grapefruit, lemons and mandarins. They acquired their name from their reputation of damaging citrus directly by feeding on the leaves. The nymphs feed on shoots and leaves by removing sap from the tissue of the plant and injecting a salivary toxin which deforms the leaves. Additionally, the psyllids may leave behind excess sap that accumulates on the surface of the leaf and promotes the growth of mold, which attracts other insects like ants.

The Asian citrus psyllids carry and transmit of the bacterium Candidatus Liberibacter asiaticus, which is associated with the citrus greening disease huanglongbing (HLB). When the psyllid feeds on a bacteria-infected plant, it absorbs the bacteria into its body. As a result, the bacteria spreads to plants when a bacteria-carrying psyllid transmits it when feeding. Once injected, the disease can cause the decline in health and eventual death of the plant. The disease originated in Asia and then spread to other parts of the world where citrus plants grow. 


After hatching, newborn Asian citrus psyllids go through five nymphal stages known as instars. At each instar, the psyllids increase in size. During the first nymphal instar, the psyllid is 0.3 mm long and 0.17 mm wide with a pink colored body and red eyes. The second instar is 0.45 mm long and 0.25 mm wide and its wing pads become more visible on the thorax. The third instar is 0.74 mm long and 0.43 mm wide with fully developed wing pads and visible evidence of antennae beginning to form. The fourth instars are around 1.01 mm in length and 0.7 mm in width with more extended wings. The fourth instar develops a second set of antenna. The fifth instars are 1.6 mm long and 1.02 mm wide with fully extended wings and a third set of antenna. 


Homeowners can inspect citrus trees to determine if an infestation has occurred. The best way to detect the presence of psyllids is by walking around citrus trees and inspecting the new leaves on a monthly basis. Typically, young trees produce new growth during warm weather. Look for signs of psyllid feeding damage, which include mold, waxy deposits, honeydew, deformed leaves and ants foraging on the plant. If you identify any of these signs, inspect more closely for small yellow eggs. 


Asian citrus psyllids can be found across the U.S., particularly in the southeast and south central states. Psyllid nymphs’ have many predators including hoverflies, lacewings, ladybirds and a few species of wasps. One wasp, Tamarixia radiata, has proven an effective psyllid control agent and has been released into regions where citrus plants grow.