Biological Control of the African and Asian Citrus Psyllids (Homoptera: Psylloidea), Through Eulophid and Encyrtid Parasites (Hymenoptera: Chalcidoidea) in Reunion Island

Abstract

ABSTRACT. The principal damage of the leaf sucking citrus psyllids Diaphorina citri Kuwayama and Trioza erytreae (Del Guercio), is the transmission of a bacterium- like organism which threatens seriously the citrus production of Africa and Asia. The control of the two psyllid vectors is thus a most important priority for citrus pro- duction in these areas. Two eulophid ectoparasites (super family of Chalcidoidea, 0. Hymenoptera) : Tetra- stichus dqi Waterston and Tetrastichus radiatus Waterston, were introduced, bred and released in Reunion Island. In the absence of hyperparasitism, the populations of the two psyllid vectors were reduced drastically 24 months after an original rate of release of 30 to 50 eulophid ectoparasites per square kilometer of the citrus area. A strongly limited population of the greening vectors is presently maintained. Five non citrus Rutaceae, indigenous to the Island, or imported as ornamentals, were monitored regularly. Only Murraya paniculata harboured the Asian psyllid, D. citri.