Microlepidoptera on Solanaceae

Leucinodes orbonalis

Name

Leucinodes orbonalis Guenée, 1854

Common name: Brinjal borer, Fruit and shoot borer (FSB), Eggplant borer

Original combination: Leucinodes orbonalis Guenée, 1854

Synonyms: none.

Alternative combinations: none.

Classification: Pyraloidea, Crambidae, Spilomelinae, Leucinodes group

Adult recognition

Forewing length: 8.5 - 12.0 mm, broad. The frons is more or less swollen into a rounded or bluntly conical projection. In the female, the apical palp segment is nearly as long as the second segment. In the male genitalia, the juxta is broad and rectangular at the base and a projecting triangle at the apex. The two fibulae are stout, curved horns in the distal half of the valve. In the female genitalia, the corners of the 8th sternite are extended as ostial sclerites. The antrum is not sclerotized and hardly thickened. The ductus bursae is as long as the round corpus bursae.

Immature stages

Larvae grow to 2 cm in length. The body is pink in life, the pinacula are pigmented pale brown, and each D1 pinaculum has a brown spot anterior of the seta. The T1 L group has two setae, and the A1 SV group has one. The A8 SD1 seta is anterior of the spiracle. Diagnostic characters that separate L. orbonalis larvae from related species in the complex have not been discovered.

Similar species

The populations of “L. orbonalis” in Africa are not conspecific: they comprise at least three cryptic species. Externally nearly identical, they differ primarily in genitalic characters, such as the shape of the juxta (which may be truncate or narrowly extended) and fibulae.

Neotropical genera that have a bulging frons are species in the Neotropical genera Euleucinodes Capps and Proleucinodes Capps. They are generally larger in body size, and the females do not have elongate palps. They have no reported economic importance.

Whittle and Ferguson (1987) comment on the use of the D1 spots to distinguish L. orbonalis from Neoleucinodes. Although these spots seem to be consistently present in Asian L. orbonalis, they may be absent in African populations and present in some Neoleucinodes species, such as N. torvis.

Behavior

Eggs are laid singly (rarely 2 or 3) on any part of the plant, preferably on growing parts. Larvae hatch in 3 to 6 days and bore into fruit under the calyx, or less often into shoots or mining leaves. Entry holes are small and packed with excreta, often hidden under the calyx. Larvae pass through 5 or 6 instars and are full-grown after one to three weeks. They prefer fruit or, secondarily, the soft growing parts of the plant. They emerge from the fruit through larger exit holes and spin a tough, brownish, leathery cocoon on the ground near the plant, sometimes 3 cm into the soil, or on other parts of the plant itself. Adults emerge after 7 to 12 days. The total life cycle lasts 23 to 35 days; in India, there can be 5 to 9 generations per year. Infested fruit rots, and other affected tissues (leaves, stems) wither.

Distribution

Aside from trade interceptions, the natural populations are restricted to South Asia, including China, Nepal, India, Japan, Pakistan, Sri Lanka, and much of Southeast Asia including Indonesia and the Philippines. In Africa, it is represented by at least one cryptic sibling species. In Europe, L. orbonalis is often intercepted with Solanum fruits imported from Asia.

Hosts

Preferred: Solanum melongena L. (eggplant, brinjal)

Secondary:

  • Physalis minima L.
  • P. peruviana L. (cape gooseberry)
  • Solanum aculeatissimum Jacq. (Sodom apple)
  • S. aethiopicum L. (Ethiopian nightshade)
  • S. erianthum D. Don. (potatotree)
  • S. anguivi Lam. (as S. indicum L.)
  • S. integrifolium Poir.
  • S. lycopersicum L. (tomato)
  • S. macrocarpon L. (nightshade)
  • S. melongena L. (eggplant, brinjal)
  • S. mammosum L. (nipplefruit)
  • S. nigrum L. (black nightshade)
  • S. torvum Sw. (turkey berry)
  • S. tuberosum L. (potato)
  • S. viarum Dunal (tropical soda apple)
  • S. xanthocarpum Schrad.

Comments

The preferred host is eggplant (S. melongena). Although L. orbonalis will feed on other hosts, such as tomatoes and potato shoots, its economic importance on these crops is lesser. For even less important cultivated plants, such as S. torvum, the frequency of damage may or may not be underreported. In any case, alternative hosts should nevertheless be considered as pathways for dispersal.

Literature

EPPO, 2013. http://www.eppo.int/QUARANTINE/Alert_List/insects/leucinodes_orbonalis.htm

Mahmood, Alam, and Hussain, 1987.

van der Gaag et al., 2005.

Whittle and Ferguson, 1987.