Gypsonoma oppressana

Author: (Treitschke, 1835)

Poplar bud-worm

Species Overview:

Adult: 12-15 mm wingspan; forewing ground colour white, densely irrorate with grey, and with dark grey markings, coarsely irrorate and farinose, consisting of a diffuse basal patch, a poorly defined median fasciae, a subquadrate pre-tornal marking, a fasciate tornal marking, a subterminal fascia arising from near tornus and extending along termen and a diffuse apical spot; two to four blackish dashes edged with pale plumbeous present in distal area, and a variable blackish dash present in discocellular area. Hindwing fuscous-grey.
Larva: head, prothoracic plate and thoracic legs dark brown or black; abdomen greyish white to pale brown, translucent; pinacula brown, inconspicuous; anal plate small, dark brown or black.
Pupa: shining yellowish red, anal segment with 3 pairs of setae dorsally and 2 pairs of setae ventrally; spines on anal segment not or only slightly bigger than those on the 9th abdominal segment. In a flimsy cocoon in the soil, amongst leaf litter, or occasionally in a crevice in the bark of the tree [details pupa G. oppressana ].

Taxonomic Description:


Gypsonoma oppressana adult
Gypsonoma oppressana male
External characters: 12-15 mm wingspan. Forewing termen less sinuate than in other Gypsonoma species; ground colour white, densely irrorate with grey, the irroration sometimes forming dark diffuse strigulae, variably mixed with pale ochreous-yellow; markings dark grey, strigulated with fuscous and black, farinose or coarsely irrorate (tips of scales white or pale ochreous-yellow); basal and sub-basal fasciae forming a diffuse basal patch, its outer edge variably angulated below middle; median fascia poorly defined, sometimes constricted before middle, becoming obsolete dorsally before a small, subquadrate pre-tornal marking, a variable blackish discocellular dash; a fasciate tornal marking, dilated in upper part of distal area and marked with two to four blackish dashes and edged with pale plumbeous; subterminal fascia arising from near tornus and extending along termen; a diffuse apical spot; cilia grey, irrorate with white (tips of scales), with a blackish sub-basal line interrupted by two whitish subapical dashes extending onto termen. Hindwing fuscous-grey; cilia paler, with a dark sub-basal line (Bradley et al., 1979).

male genitalia G. oppressana
Genitalia: Uncus and gnathos absent; socii broad and large, curved outwards. Androconial scales on tegumen longer than valva, narrow, filiform. Valva with clasper and glabrous rim along outer margin of cucullus; cucullus with group of heavily sclerotized spinescent setae; ventral margin of valva with notch. Apex of sacculus protruding acutely or at a right angle.


Gypsonoma oppressana female
External characters: similar to male.

female genitalia G. oppressana
Genitalia: Ostium funnel-shaped; sterigma with pear-shaped lateral processes. Cingulum long, slightly swollen. Corpus bursae with 2 thorn-like signa.


Moths fly in June and July. Larvae occur from September to April and May, feeding on Populus. At first the larva feeds on the underside of a leaf in an angle of the veins, living beneath a delicate silken web and gnawing the surface of the leaf, then it overwinters in a silken hibernaculum on the bark of the tree. In the spring it feeds in the open leaf buds, moving from bud to bud. At this stage its presence is indicated by a little horn-like tube of frass and silk projecting from the bud over the entrance to the boring; later this is replaced by a larger frass-tube which lies flatly against the surface. Pupation occurs in May and June, in a flimsy cocoon in the soil, amongst leaf litter, or occasionally in a crevice in the bark of the tree (Bradley et al., 1979; Kuznetsov, 1987).

Host plants:

Populus nigra, Populus alba, Populus tremula.


Gypsonoma oppressana is considered a minor pest on poplar. Young larvae feed on the underside of a leaf in an angle of the veins, living beneath a delicate silken web and gnawing the surface of the leaf, later they feed in the buds, moving from bud to bud (Bradley et al., 1979).


Madeira; Central and Southern Europe, Trans-Caucasus to Kazakhstan and Tadzhikistan.


Pheromone unknown.

Other Gypsonoma species on Populus:
(besides Gypsonoma aceriana and Gypsonoma minutana)

1. Gypsonoma incarnana Haworth

Gypsonoma incarnana adults 1
Gypsonoma incarnana adults 2
male genitalia G. incarnana
Forewing markings variable, apex with admixture of rusty scales. Ventral margin of valva of male genitalia also with notch, but apex of sacculus not protruding; androconial scales shorter than valva. Larvae in catkins.
(Populus, Crataegus, Quercus, Corylus, Prunus, Pyrus and Salix; Northern and Central Europe to Siberia, Eastern Russia, China and Japan).

2. Gypsonoma nitidulana (Lienig & Zeller)

forewing G. nitidulana
male genitalia G. nitidulana
Median fascia distinct, dark grey, distal margin angulate; ventral margin of valve of male genitalia without large notch; spines on cucullus arranged in a row; clasper located in center of neck of valva. Larvae feed in leaves.
(Populus tremulus - Northern and Central Europe to Siberia, Eastern Russia and Mongolia; N. America).

3. Gypsonoma obraztsovi Amsel

forewing G. obraztsovi
male genitalia G. obraztsovi
Median fascia ill-defined, distal margin angulate; basal patch less angulate than in Gypsonoma oppressana; valva of male genitalia relatively short, ventral margin without large notch. Cucullus more defined, with more than 20 spines arranged in a cluster. Larvae in open leaf buds and rolled leaves.
(Populus, Salix - Southern Caucasus, Trans-Caucasus, Tadzhikistan, Romania, Asia Minor and Iran).

4. Gypsonoma euphraticana Amsel

forewing G. euphraticana
male genitalia G. euphraticana
Width of forewing less than 2 mm; valva of male genitalia covered with short and broad oar-shaped scales. Larvae between close-set leaves.
(Populus diversifolia, Populus euphratica - Kazakhstan, Turkestan, Uzbekistan, Tadzhikistan, Northern Africa, Asia Minor, Iran, Afghanistan, Pakistan).