Giant bark aphid

The giant bark aphid (Longistigma caryae) is a member of the Lachnidae family and is recognized as the largest aphid species in North America and several other regions. Adults are conspicuous, typically measuring up to 8 mm in length, often found in clusters on the bark of host trees.

This pest primarily infests deciduous hardwood trees, showing a strong preference for pecan, oak, maple, walnut, and linden species. Unlike many other aphids, they feed directly on the branches and trunks, utilizing their long proboscis to penetrate the tree's vascular tissues.

The life cycle begins with eggs overwintering in crevices on the bark. As temperatures rise in spring, nymphs emerge and initiate feeding. The population grows rapidly through parthenogenetic reproduction, leading to dense aggregations that are often attended by ants attracted to the sugary honeydew secretions.

Damage is characterized by heavy sap loss, which leads to twig dieback, reduced vigor, and increased susceptibility to drought or pathogens. Furthermore, the massive amount of honeydew promotes the growth of sooty mold, which coats the bark and foliage, potentially interfering with gas exchange.

• Regular inspection of trunks and branches during the dormant and early growth stages.
• Targeted application of horticultural oils during the egg stage to reduce initial populations.
• Use of systemic insecticides for severe infestations in urban or ornamental settings.
• Encouraging natural predators such as lady beetles, lacewings, and parasitic wasps.