Pandemis pyrusana

Kearfott, 1907

apple pandemis, pandemis leafroller moth

Pandemis pyrusana is a to western North America, commonly known as the apple pandemis or pandemis moth. It is a significant pest of deciduous fruit trees and ornamental plants, with feeding on leaves by rolling and tying them together. The has one or two per year depending on location, with active in late spring and again in autumn in coastal California.

Pronunciation

How to pronounce Pandemis pyrusana: //pænˈdeː.mɪs ˌpaɪ.rəˈsɑː.nə//

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Identification

Distinguished from similar by size and pattern, geographic range, and associations. Males identified by presence of . examination may be required for definitive separation from . Distinguished from by -specific blend composition and .

Appearance

8–12.5 mm in males, 9.5–14 mm in females. have mottled forewings with variable darker markings. pattern includes a distinct in males. Resting posture characteristic of , with wings held roof-like over body.

Habitat

Forests with deciduous trees and shrubs. Found in riparian corridors, orchards, and wooded areas where plants occur.

Distribution

Western North America: Alberta and British Columbia south through Idaho, Utah, Colorado, and California. Also present in Washington State apple-growing regions.

Seasonality

active May to July, with second September to November in coastal California. One or two generations per year depending on latitude and elevation.

Diet

feed on leaves of deciduous , rolling and tying leaves together to form shelters.

Host Associations

Alnus - larval multiple
Betula occidentalis - larval
Lonicera - larval multiple
Cornus sericea - larval
Ribes - larval multiple
Ceanothus cuneatus - larval
Malus - larval including Malus pumila (apple)
Prunus - larval including Prunus avium and Prunus virginiana
Pyrus - larval multiple
Rosa - larval multiple
Populus tremuloides - larval
Salix - larval including Salix lasiolepis and Salix sessilifolia

Life Cycle

with , , , and stages. One or two per year. stage not specified in available sources.

Behavior

are , constructing shelters by rolling and tying leaves with . Males initiate courtship by approaching females, with stereotyped sequence including fanning and antennal contact. -mediated communication guides mate location. Males show reduced source contact and attraction when exposed to specific pheromone inhibitor blends, possibly functioning in reproductive isolation from .

Ecological Role

on deciduous . Larval feeding damage can defoliate plants. Susceptible to (PapyGV) , which increases mortality and alters feeding .

Human Relevance

Pest of apple (Malus pumila), pear, cherry (Prunus avium), and other deciduous fruit . Leaf rolling and feeding damage reduce fruit quality and tree vigor. Target of -based and in programs. Pheromone inhibitor research has been conducted to improve -specific control.

Similar Taxa

Choristoneura rosaceana and synchronic pest in Washington apple orchards; distinguished by different blend composition and -specific courtship behaviors including distinct male fanning patterns.
Other Pandemis species may overlap in range; identification requires examination of or analysis.

More Details

Pheromone Biology

Males respond to a 5-component blend of cis-11-tetradecenyl-acetate (Z11-14Ac), trans-11-tetradecenyl-acetate, cis-11-tetradecenyl-1-ol, cis-11-tetradecanal, and cis-9-tetradecenyl-acetate (Z9-14Ac) in a 90.05:1.89:1.42:0.95:5.69 ratio. The 5-blend at higher concentrations causes significant reduction in male attraction compared to simpler blends, representing the first reported inhibitor for this . This inhibitory effect may function in nature to prevent interspecific matings with C. rosaceana, but complicates development of attracticide targeting multiple species simultaneously.

Viral Pathogen Susceptibility

Susceptible to PapyGV, a that increases larval mortality and modifies feeding . This has been investigated as a potential agent.