They have widely separated eyes, which are red in newly emerged adults,[2] on a head which is slightly wider than its length, and transparent wings with pale yellow veins.

[2] Tamarixia radiata was initially described as Tetrastichus radiatus in 1922 by the British entomologist James Waterston from specimens collected in 1921 from part of the Punjab which is now in Pakistan.

[5] The natural range of T. radiata extends from Yemen and Saudi Arabia in the west to China and Indonesia in the east.

[6] When it was reported that this species was a highly efficient parasitoid of Diaphorina citri on the French Mascarene island of Réunion,[7] it was spread around the world to control its host.

T. radiata has since been introduced or spread to Argentina, Brazil, Colombia, Guadeloupe, Mauritius, Mexico, Philippines, Taiwan, Vietnam, Puerto Rico and the United States.

[2] There are normally 1.8 females for every 3.2 males, but the sex ratio varies depending on the origin of the colony and conditions the wasps are reared under.

In the early part of the 20th century it began to be recorded in new areas in Asia and Africa and in the 1950s psyllids were shown to be vectors of the disease.

[7] In the early 1960s both T. radiata and the encyrtid Diaphorencyrtus aligarhensis, another parasitoid of D. cirti were introduced to Réunion where they successfully controlled populations of their host and reduced the impact of the disease.

This is probably due to the differences in climate from their places of origin and predation by coccinellid beetles on psyllids (consuming many that were playing host to T.

[10] The wasps have been recovered some months after the initial release suggesting that they have bred in the wild and are capable of forming self sustaining populations.

The project is run by University of California Riverside and the insects bred by them show wider genetic variability than T. radiata elsewhere, reflecting the careful sourcing and selection of the founder specimens.