Argyresthia (Blastotere) trifasciata Staudinger, 1871

Ruseva, Stoyka & Zlatkov, Boyan, 2018, First record of Argyresthia trifasciata Staudinger, 1871 in Bulgaria (Insecta: Lepidoptera: Argyresthiidae), ZooNotes 2018 (132), pp. 1-4 : 2-3

Argyresthia (Blastotere) trifasciata Staudinger, 1871

The moth can be easily recognised by its characteristic wing pattern ( Fig. 1A ). In the pinned specimen, the head is covered with white scales, the antennae are filiform reaching the third fascia of the forewing, the labial palps are porrect, tapering. The forewing length is 4.08 mm (male), 4.20 mm, 4.44 mm (females). Like the other members of the family, the wings are elongated, narrow, with long fringes especially on the hindwings. The forewings are golden-brown with three complete white transverse fasciae. The hindwings are grey-brown. The male genitalia in the genus Argyresthia are relatively conservative, the most distinguishing characters are found in the phallus ( Fig. 1B ) and the shape of the sclerotised fork of segment 8. The damage caused by the larval feeding ( Fig. 2 ) is found on the terminal shoots which stem tissues are mined; the leaves die and become brown. Small circular openings made by the larva are visible.

The species is univoltine (with a single generation per year). According to Konečná & Šefrová (2014) the moth overwinters in pupal stage while in other publications ( Agassiz 2004, Gomboc 2003) it is mentioned that it overwinters as larva. Our observations showed that overwintering stage is larva. The flight period is from early May to early June ( Gál & Szeöke 2000, Gomboc 2003, Soika & Łabanowski 2014). In our study (in laboratory conditions) two adult specimens emerged from the shoots sample earlier, at the beginning of April. Five adult specimens emerged from the 4-6 cm cuttings on 16.iv.2018, and another four moths from the 2-4 cm cuttings on 18.iv.2018. According to some studies ( Agassiz 2004, Konečná & Šefrová 2014) the larvae pupate in the ground while in our study adults emerged from cocoons spun on the bark.

The larvae of A. trifasciata feed on Cupressaceae species, mainly on the genus Juniperus , and other not spiked species ( Lopez-Vaamonde et al. 2010): J. scopulorum “Skyrocket ”, J. scopulorum “Grey Owl ”, J. chinensis L., J. sabina L., J. horizontalis Moench , J. virginiana L. ( Soika & Łabanowski 2014), Thuja sp. (Essl & Rabitsch 2002, Gomboc 2003), Chamaecyparis sp. (Essl & Rabitsch 2002, Gomboc 2003, Lopez-Vaamonde et al. 2010) and × Cupressocyparis leylandii (A.B.Jacks. & Dallim.) Dallim. ( Gomboc 2003, Kollár & Hrubík 2009, Lopez- Vaamonde et al. 2010). The affected plants lose their aesthetical value – their terminal shoots became hollow, dry and grey-brown due to the larval feeding. In case of a heavy infestation the whole plant appeared physiologically weakened and more prone to diseases. In the course of our study the species was found only in Sofia on J. scopulorum “Skyrocket ”. It is difficult to predict the possible invasion of this pest in Bulgaria, therefore areas with this plant species should be monitored.

Figures

Fig. 1. Adult of Argyresthia trifasciata: A - female, Sofia, e. l. 16.iv.2018, scale bar 2 mm. B - male genitalia of a specimen from the same locality with a fork of segment 8 at left (left arm broken off during preparation) and phallus below, scale bar 250 μm.

Fig. 2. Damage on shoots of Juniperus scopulorum “Skyrocket” caused by mining larvae of Argyresthia trifasciata. A - general view of shoots. B - detail of a damaged shoot. The white arrows show circular openings made by larvae. Scale bars 5 mm.