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The Asian citrus psyllid (Diaphorina citri Kuwayama (Psyllidae)) and the African citrus psyllid (Trioza erytreae (Del Guercio) (Triozidae)) are two of the most serious pests of citrus in the world (Hoy and Nguyen 1998). The Asian citrus psyllid is usually found crowded on the lower sides of leaves, with the head almost touching the surface and the body raised almost to a 30 degree angle. The greatest activity of this psyllid occurs simultaneous with new citrus growth (Frank 1998). The Asian psyllid causes leaf distortion and curling in young tender growth due to direct feeding damage and toxic saliva (Hoy and Nguyen 1998); and a chlorosis resembling zinc deficiency, twig dieback and reduced fruit size and quality, caused by the pathogenic phloem limited bacterium, Liberobacter asiaticum, which it transmits. This disease is called “citrus greening” or “Huanglongbing”, which means “yellow dragon disease” (Halbert 1998). This bacterium occurs in many countries of tropical and subtropical Asia and Africa (CABI and EPPO).