Epinotia nanana

Distinguished from similar tortricids by the combination of small size (9–11 mm wingspan), fuscous forewings with distinctive whitish sprinkling and strigulated costa, and the obtusely angulated basal patch edge. Larval damage is diagnostic: spruce needles mined and webbed together with silk to form a cluster attached to the twig. Similar Epinotia species may occur on spruce but differ in wing pattern details and larval webbing behavior.

Adults are small moths with wingspan 9–11 mm. Head pale brownish-ochreous with whitish face. Forewings with gently arched costa; ground color lighter or darker fuscous, whitish-sprinkled; costa strigulated with dark fuscous and white; basal patch edge obtusely angulated below middle; central fascia with posterior median projection; transverse streak before apex; markings dark fuscous. Hindwings rather dark fuscous. Full-grown larvae approximately 9 mm long, brown with black head and plate of second thoracic segment.

Spruce forests and plantations; ornamental spruce plantings in urban and suburban settings. Larvae occur within the needles of host trees. In Europe, primarily associated with Norway spruce (Picea abies) in natural and planted stands.

Native to northern and central Europe, extending eastward through Russia to Mongolia. Introduced to North America: recorded from British Columbia, Ontario, and Quebec in Canada; and from Maine to Michigan and Ohio in the United States. Within its range, larvae show contagious (aggregated) distribution patterns both among trees and within shoots of individual trees.

Adults on wing from June to August. Larvae active in needles during summer and fall, overwinter in mined needles, resume feeding in early spring, and pupate in May or June.

Larvae feed internally within spruce needles, mining the mesophyll. Documented hosts include Norway spruce (Picea abies), Picea excelsa, blue spruce (Picea pungens), and Sitka spruce (Picea sitchensis). Norway spruce is preferred.

• Picea abies - primary hostpreferred host; Norway spruce
• Picea excelsa - host
• Picea pungens - hostblue spruce
• Picea sitchensis - hostSitka spruce

Univoltine (one-year life cycle). Eggs laid singly or occasionally in clusters on needles produced in previous year. Larvae hatch and feed within needles during summer and fall, mining the internal tissue. Nearly full-grown larvae (primarily fifth instar) overwinter in mined needles. In early spring, larvae resume feeding in adjacent needles, each larva mining 6–10 needles and securing them to the twig with silk. Full-grown larvae pupate in silken cocoons in soil litter or occasionally on the tree in May or June. Pupae develop into adults in approximately four weeks.

Larvae are endophagous needle miners, feeding entirely within spruce needles. Each larva constructs silk webbing to bind 6–10 mined needles together and attach the cluster to the twig. This webbing behavior is distinctive and protects the larva while feeding. Larvae show contagious spatial distribution, aggregating on certain shoots and trees rather than distributing randomly. Overwintering larvae experience substantial mortality from unfavorable climatic conditions.

Herbivore and pest of spruce trees. As a needle miner, it damages photosynthetic tissue and can cause severe defoliation of ornamental trees. Natural parasitoid control is consistently low; population regulation appears driven primarily by abiotic factors (winter mortality) rather than biotic enemies. In its introduced North American range, it functions as an invasive pest of non-native spruce plantings.

Significant pest of ornamental spruce trees in urban and suburban landscapes, particularly in Quebec where severe defoliation has been recorded. Also occurs in forest spruce plantations. Damage is most conspicuous in spring when overwintered larvae resume feeding. Management is complicated by the protected feeding habit (larvae inside needles) and low natural parasitism.

• Other Epinotia species on spruceSimilar size and host association; distinguished by wing pattern details, particularly the configuration of the basal patch and central fascia, and by larval webbing behavior
• Other spruce needle-mining tortricidsSimilar larval habits; E. nanana distinguished by the characteristic webbing of multiple needles together and the specific wing pattern of adults

• needle miner
• spruce pest
• Tortricidae
• univoltine
• introduced species
• ornamental pest
• silken webbing
• contagious distribution

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• My Publications | Beetles In The Bush
• Life History and Habits of the Green Spruce Leaf Miner, Epinotia nanana (Treitschke) (Lepidoptera: Tortricidae)
• Distribution of the Green Spruce Needle Miner Epinotia nanana Treitschke (Lepidoptera: Tortricidae) within and between Trees at Redesdale, Northumberland