- Subfamily: Glaphyriinae
- Wingspan: 15-19 mm
- Flight period:Aug - Sep
- Spread: Common
- Host plants: Brassicaceae
The Hellula undalis is a moth of the Crambidae family, subfamily Glaphyriinae, with a wingspan of 15-19 mm.
It is a cosmopolitan moth, in Europe it is visible in Portugal, Spain, United Kingdom, France, Holland, Germany, Denmark, Switzerland, Austria, Croatia, Bosnia Herzegovina, Hungary, Romania and Greece. *
In Italy it is also present in the islands. *
The front wings range from gray to yellow-brown, and three transverse white wavy lines, surrounded by a light brown line, respectively in the basal, discal and post discal region, a fourth line, usually narrower, is visible parallel and close to the edge. A pale subterminal band is visible between the third and fourth lines. A brown, kidney-like spot is visible one third of the length of the wing from the apex. The hind wings are white, silky, with brown shades, sometimes intense, to color the entire wing, the length of the body is 15-18 mm.
Adults are short-lived and can complete 7-8 generations per year depending on latitude. The females, which are active in the evening and at night, place their eggs (about 75-250 eggs / female) individually or in groups of 2-3 on the internal tissues of the host plants. **
The larvae burrow into the stems of growing shoots, weaving silk cocoons in which they live, subsequently undermine the leaves and leaf stems. The development of a generation takes about 4-5 weeks at 27 ° C. **
They pupate in the soil within cocoons which include soil particles, approximately 8 mm long, bright light brown with a dark stripe on the back. **
The larvae (caterpillars) are yellow / brown, with dark pink longitudinal lines; black head, and can reach a length of about 15 mm. It is an important pest of cruciferous crops especially in the tropics and subtropics, affecting in particular cabbages and radishes.
Food plants are Brassicaceae and include broccoli, head cabbage, Chinese cabbage, daikon radish, horseradish, mustard, radish and turnip.
* Lepidoptera mundi https://lepidoptera.eu/ - Fauna Europea https://fauna-eu.org/
** The Hebrew University of Jerusalem, The Robert H Smith Faculty of Agriculture, Food and Environment - http://www.agri.huji.ac.il/mepests/pest/Hellula_undalis/