Phyllonorycter issikii
(lime leafminer)

Preferred Scientific Name

• Phyllonorycter issikii Kumata, 1963

Preferred Common Name

• lime leafminer

Other Scientific Names

• Lithocolletis issikii Kumata, 1963

International Common Names

• Russian: lipovaya mol-pestryanka

Local Common Names

• Czech Republic: klínenka lipová
• Finland: lehmusmiinajakoi
• Germany: Lindenminiermotte
• Hungary: hárslevél sátorosmoly
• Slovakia: ploskácik lipovy

EPPO code

• PRYCIS (Phyllonorycter issikii)

• Domain: Eukaryota
•     Kingdom: Metazoa
•         Phylum: Arthropoda
•             Subphylum: Uniramia
•                 Class: Insecta
•                     Order: Lepidoptera
•                         Family: Gracillariidae
•                             Genus: Phyllonorycter
•                                 Species: Phyllonorycter issikii

The morphology of the adult was addressed by Kumata (1963) and Kumata et al. (1983). The caterpillar chaetotaxy was described by Kumata (1993) and the morphology of the pupa was described by Gregor and Patocka (2001). The morphology of all the stages, including the larval chaetotaxy was studied by Sefrová (2002).

Egg

The egg is slightly elongated, ellipsoidal, and has a delicate pitting on the chorion surface. It is 0.32-0.37 mm by 0.23-0.27 mm. It is greenish-ochreous, which corresponds to the undersides of the leaves on the host plant.

Larva

The larval morphology corresponds to the morphology of other Phyllonorycter larvae. The larva is whitish-ochreous and is 4.0-5.6 mm long in the final instar. There are five larval instars. The first three instars are flat with reduced mouthparts and legs (sometimes called sap-feeding instars e.g. Kumata, 1978). The triangulate head capsule shows prognathy without spinneret, labial and maxillary palpi. There is a close group of stemmata on the head near the antennal base of these instars. The triangular mandibles with three curved cusps are moved horizontally between the huge flat labrum and the labium. The thoracic segments are strikingly dilated (especially in the first instar) compared with the abdominal segments. This characteristic decreases with the next instars. The final two instars (tissue-feeding instars) show the morphology of exophagous caterpillars. Their heads are more globular, semiprognathous and have complete mouthparts. The mandibles are more or less rectangular with five cusps on the frontal edge and they move vertically. The stemmata form a quadrangle. The thoracic legs, abdominal prolegs (on the third to fifth segments) and anal prolegs are normally shaped. The 23-38 claws of each proleg are positioned in multiple, usually irregular circles. The individual instars can be primarily distinguished according to the width of the head capsule: I: 0.14-0.16 mm; II: 0.18-0.21 mm; III: 0.25-0.28 mm; IV: 0.25-0.30 mm; and V: 0.31-0.40 mm.

Pupa

The pupa is light brown to brownish-black and 3.2-4.0 mm long. Its frontal process is short and broad. It is in the shape of an equilateral triangle with distinct surface sculpture. Abdominal segments two to eight bear two pairs of rigid setae and their dorsal parts are covered with coarse thorns. The male genitalia only slightly protrude. The tenth abdominal segment is long, with a broad anal field. This has an elongate cremaster, which is round in ventral view, and elongate and strongly constricted in lateral view, with one pair of small hooked thorns at the end.

Adult

The wingspan is 6.3-8.3 mm. The adult exhibits distinct seasonal dimorphism. The aestival form has a whiteish-ochreous frons and labial palpus. The hair tuft on the head is ochreous with individual white scales. The antennae are greyish-white with black circles. The thorax is golden-ochreous, with three white lines. The forewing is golden-ochreous, with a long and narrow basal streak (occasionally indistinct), lacking a dark margin, or with individual dark scales only on its fore margin. The first (basal) transversal streaks are narrow and slope outwards. The dorsal streak is distinctly longer than the costal streak. The other three costal streaks are located close to each other before the apex. The second dorsal streak, which is before the tornus, occasionally fuses with a light tornal spot. The basal margins of all the streaks are more or less bordered with black scales. A distinct line of black scales divides the yellowish-white cilia. The hind wings and their cilia are pale grey.

The winter form (differences only) has a hair tuft on the head that is greyish-black or black with individual white scales, and is entirely white. The thorax is dark brown, and occasionally has white scales and white, indistinct lines. The forewing is grey, greyish-brown or greyish-black, mixed with white and brownish-black scales or spots. The ground colour of the winter form is very variable from pale grey to brownish-black. This striking habitual seasonal difference is possibly due to the fact that the hibernating individuals easily escape the attention of their predators in overwintering shelters. No sexual dimorphism has been observed.