- Unknown distribution. Recorded only from Fiji on two weeds: crowsfoot and barnyard grasses. The Oulema species unknown. Another species, Oulema melanopus, is recorded from Asia, Africa (north), North America, Europe, as a major pest of cereals.
- Eggs laid on leaf mid-vein; larvae hump-backed, covering themselves in faecal matter. Pupate on soil. Adults with red heads and thorax and black wing cases; often seen 'mate-guarding'.
- Larvae feed on the surface of leaves setting back plant growth so that the grasses are overgrown by other weed species. Damage greatest on crowsfoot grass.
- No control measure required. Whether or not the beetles will move to other grasses, i.e., those of the grasslands of western Viti Levu, Fiji, is unknown.
- Alternatively, the Fiji Oulema species may have potential as a biocontrol organism attacking particular weed grasses.
Pacific Pests, Pathogens, Weeds & Pesticides
Grass leaf beetle (354)
Leaf beetle, grass leaf beetle (not an accepted common name).
Oulema species. The Oulema species recorded from Fiji has not been identified. However, the cereal leaf beetle (oat leaf beetle), Oulema melanopus, is a major pest of wheat, barley, oat, and millet, worldwide. In countries where it is not yet present, it is considered a pest of quarantine importance. For these reasons, the Fiji species is described here.
AUTHOR Grahame Jackson
Information from CABI Oulema melanopus (oat leaf beetle) (2017) Crop Protection Compendium. (https://www.cabi.org/cpc/datasheet/30249); and Cereal leaf beetle. Wikipedia. (https://en.wikipedia.org/wiki/Cereal_leaf_beetle); and from BugGuide (2020) Oulema melanopus - Cereal leaf beetle. Department of Entomology, Iowa State University. (https://bugguide.net/node/view/89610). Photos 1-4 Mani Mua, SPC, Sigatoka Research Station, Fiji.
Produced with support from the Australian Centre for International Agricultural Research under project HORT/2016/185: Responding to emerging pest and disease threats to horticulture in the Pacific islands, implemented by the University of Queensland and the Secretariat of the Pacific Community.