Pineus strobi, Insect & Mite Guide

Field Guide – Prairie Pest Monitoring Network

Pineus strobi (Weymouth pine adelgid) identification, images

Pine aphid hi-res stock photography and images - Alamy

Biological control of hemlock woolly adelgid in North America

Pissodes strobi (Sitka spruce weevil)

Piezodorus guildinii - Wikipedia

Cinara strobi, Insect & Mite Guide

BSI-127: Pests Can Really Bug You

NC State Extension Publications

PDF] A manual of dangerous insects likely to be introduced in the United States through importations. Ed. by W. Dwight Pierce, entomologist, southern field crop insect investigations.

Biological control of hemlock woolly adelgid in North America