Cerodontha (Cerodontha) australis (Malloch, 1925)
In Australia the species can be confused with the somewhat smaller species Cerodontha (Cerodontha) milleri Spencer, 1973 Cer milleri aedeagus Sp.pct. However, the genitalia are distinct (Spencer, 1973).
IMPORTANT CHARACTERS
Adults
Wing length: 1.9 - 2.6 mm. Only 2-4 acrostichal hairs if any. Both notopleural bristles present. Second antennal segment light brown or yellow, distinctly lighter than third segment. The few frontorbital setulae are restricted to the anterior part of the frons. One of this setulae is inwards directed and may be interpreted as a reduced bristle. Cuticle surrounding the vertical bristles can vary in color.
BIONOMICS
The larvae live in the leaf sheath of grasses and pupate inside the mine. Morrison, 1938 reported that the larva can enter the space between leaf sheath and stem.
HOST PLANTS
Hordeum vulgare L., Triticum aestivum L. (summarized by Spencer, 1973); Dactylis, Poa anceps (Spencer, 1990).
Barker, 1994: also Lolium perenne L. (ryegrass), Phalaris aquatica L., Festuca arundinacea Schreb. (tall fescue), Bromus willdenowii Kunth (prairie grass).
All known host plants are recorded in New Zealand. The species was found on both introduced and native host grasses.
DISTRIBUTION
Australia: New South Wales; New Zealand; Moko Hinan Is.; Little Barrier Is.; Mayor Is. (Spencer, 1973).
ECONOMIC IMPORTANCE
Cerodontha australis is an abundant leaf miner on pastures in New Zealand similar to denticornis in Europe. The infestation rate is rather low, Barker et al., 1984 and Barker, 1994 reported that the proportion of infested tillers are usually below 20% (infestation does not necessarily mean destruction). Yet australis contributes to the overall damage of pasture grasses and should not be neglected.
On cereals damage caused by australis is not known.