Dioryctria zimmermani

The zigzag pattern on the gray and red-brown forewings, combined with pale yellowish hindwings, distinguishes adults from many similar moths. Larvae may be distinguished from other Dioryctria species by host association and geographic range, though species-level identification within the D. zimmermani species group is notoriously difficult due to overlapping morphological, molecular, and behavioral traits. Molecular analysis may be required for definitive identification.

Adults have a wingspan of approximately 37 mm. Forewings are mottled gray and red-brown with zigzag light and dark markings. Hindwings are yellowish white. Full-grown larvae are 18–25 mm long.

Pine forests and plantations; larvae occur in bark recesses and cones of host trees. In Michigan studies, eggs were laid almost entirely on the main stem of host trees.

Southern Canada (Alberta, Manitoba, Saskatchewan), northeastern and Great Lakes areas of the United States, with a disjunct population in eastern Nebraska.

Adults emerge during the last three weeks of August. Eggs hatch through mid-September. Larvae overwinter in hibernacula and are active in spring and early summer.

Larvae feed on various Pinus species, with preference for Austrian pine (Pinus nigra) and Scots pine (Pinus sylvestris).

• Pinus - larval food plantVarious pine species; preference for Austrian and Scots pine

One generation per year. Adults emerge late August. Eggs laid on main stem of host trees hatch through mid-September. Newly hatched larvae enter bark recesses and spin hibernacula without feeding initially. Six larval stadia are tentatively proposed based on head capsule measurements. Larvae and pupae show fairly uniform vertical distribution over the main stem in spring and early summer, with concentration in middle whorls by late summer.

Larvae spin silk hibernacula in bark recesses immediately after hatching, entering a period of inactivity before resuming development. Vertical distribution of larvae shifts seasonally: uniform over the main stem in spring and early summer, becoming concentrated in middle whorls by late summer.

Herbivore and pest of native and ornamental pine trees. Subject to parasitism by egg parasitoids and other natural enemies. Co-occurs with related coneworm species such as Dioryctria abietivorella in some areas. Serves as host for parasitoid wasps including species in the genus Baryscapus.

Considered a serious pest of pine species in the midwestern United States. Larval boring damage affects both native forests and ornamental plantings. Management is complicated by concealed larval habit within bark and cones.

• Dioryctria abietivorellaCo-occurs in same geographic areas and shares similar conifer-feeding habits; requires careful examination for separation
• Other Dioryctria zimmermani species group membersSpecies boundaries within this group are problematic due to overlapping molecular, morphological, and behavioral traits; molecular analysis often required for definitive identification

• pest
• conifer pest
• bark borer
• cone feeder
• monophagous on Pinus
• univoltine

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Baryscapus dioryctriae Archives - Entomology Today
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• BIOLOGY AND BEHAVIOR OF ZIMMERMAN PINE MOTH, DIORYCTRIA ZIMMERMANI, IN MICHIGAN
• Complexity inDioryctria zimmermaniSpecies Group: Incongruence between Species Limits and Molecular Diversity