Encarsia Förster is a relatively large genus of Aphelinidae, currently containing about 400 described species. Encarsia species are, like most other aphelinids, mostly primary parasitoids or hyperparasitoids of Hemiptera, mainly whiteflies (Aleyrodidae) and armoured scale insects (Diaspididae), with four species known from aphids (Hormaphididae).
Males are commonly hyperparasitoids of females (or males) of their own or other species, and the males of certain species have been recorded as (probably facultative) hyperparasitoids of Psyllidae, and obligate parasitoids of lepidopteran eggs.
Species of Encarsia have been considered as the most efficacious group of biocontrol agents of whitefly pests on a broad range of agricultural crops. Recently their economic importance has been recognized worldwide and more attention has been given to their taxonomy. This is especially true of the Encarsia species parasitic on whiteflies.