Blumberg, D., & Blumberg, O. 1991 [The pyriform scale, Protopulvinaria pyriformis, and its common parasitoid, Metaphycus stanleyi, on avocado and Hedera helix.]. Alon Hanotea 45: 265-269.

Notes: Abstract: Phenology of this scale and its most common parasitoid studied on avocado and Hedera helix; encapsulation rates were low during winter and high during summer. Keywords: biological control.