Blumberg, D. 1991 Seasonal variations in the encapsulation of eggs of the encyrtid parasitoid Metaphycus stanleyi by the pyriform scale, Protopulvinaria pyriformis.. Entomologia Experimentalis et Applicata 58: 231-237.

Notes: Abstract: Encapsulation rates correlate with ambient temperatures: lowest during cooler seasons and highest during hotter seasons; lower when avocado was host than when Hedera helix and Schefflera arboricola were hosts.