San Jose scale parasitoid - Encarsia citrina

In this photograph, the scale beneath the wasp is oleander scale.

Encarsia citrina was introduced to New Zealand accidentally. It was already known to be present in the country in 1923 when an attempt was made to supplement its effectiveness by introductions of further E. citrina from U.S.A. It is probably one of the more important natural enemies of San Jose scale, being very common and causing >90% of the parasitism in some populations, particularly from Nelson northwards. It appears to be of limited occurrence in Central Otago. E. citrina is an endoparasite, feeding within the soft body of its scale host. All the wasps are female.

The wings of E.citrina are characterised by long delicate fringes which distinguish it from its close relative E. perniciosi.