Microlepidoptera on Solanaceae

Symmetrischema tangolias

Name

Symmetrischema tangolias (Gyen, 1913)

Common names: South American potato tuber moth; Spotted or Andean potato tuber moth; tomato stem borer (in Australia)

Original combination: Trichotaphe tangolias Gyen, 1913

Synonyms:

  • Phthorimaea plaesiosema Turner, 1919
  • Phthorimaea aquilina Meyrick, 1917
  • Phthorimaea melanoplintha Meyrick, 1923 [1925]
  • Gnorimoschema tuberosella Busck, 1931

Classification: Gelechioidea: Gelechiidae: Gelechiinae: Gnorimoschemini

Adult recognition

Adults are about 6.5-8.2 mm in forewing length. They are yellowish white to light brown or brownish gray, with a large, broad, grayish black streak in the middle section of the wing that is abruptly demarcated on the basal side. The labial palpus is upturned. The hindwing is trapezoidal without hair-pencils in males. The male genitalia have an uncus with small lateral stubs, short and straight valva with falcate apex, vinculum with a projected and starkly melanized thorn-shaped process medially, and phallus with a long lateral process. Females have a large and long funnel-shaped antrum extending just past the anterior apophyses from the ostium, and a small stubby signum.

Immature stages

Larvae when fully grown are about 10-12 mm long. The prothoracic shield is uniformly brown to black or may have patches of pigmentation. The line joining setae L1 and S2 is posterior to stemma I, the outer tooth is poorly developed and SD1 on A9 is setiform (normal thickness). The L group of A9 is bisetose.

PDF - Dichotomous key to Gelechiid larvae

Similar species

This species can be distinguished by its forewing pattern: a grayish-black streak in the middle part of the wing anterior of the fold, abruptly demarcated one fifth from the base of the wing.

The poorly developed outer tooth, pale thoracic legs, bisetose L group and setiform SD1 on A9 and the western United States distribution will separate Symmetrischema tangolias from other species we have studied.

Behavior

Pupation occurs amongst the debris of host-plants.

Distribution

Native to South America, a pest worldwide. USA (Southeastern, California north to Washington), South America (Peru, Bolivia, Colombia, Ecuador, Chile), Australia, New Zealand, Indonesia.

Hosts

Capsicum annuum L. (Cayenne pepper)

Solanum aviculare G. Forst. (New zealand nightshade, kangaroo apple)

Solanum laciniatum Aiton (Kangaroo apple)

Solanum muricatum Aiton (Pepino)

Solanum nigrum L. (Black nightshade)

Solanum tuberosum L. (Irish potato)

Comments

This species is known as a pest of potato or tomato in South America and the Australian region; however, in North America, it does not attack these crops but does feed on black nightshade.

Literature

Busck, 1931.

van Gyen, 1913.

Keifer, 1937.

Meyrick, 1923 [1925].

Photo credits

Figs. 6, 7, 8: © Frans C. Griepink, Pherobank (The Netherlands)