Agromyza rondensis Strobl, 1900
The species is related to A. conjuncta Spencer, 1966 known from Spain, Italy and the former Yugoslavia.
IMPORTANT CHARACTERS
Adults
Wing length: 1.75 - 3 mm. Frons yellowish or brown but not black; mesonotum mat greyish; third antennal segment elongated (Spencer, 1973).
Immature stages
The puparia and third instar larva was described by Beri, 1984. Anterior spiracles with 6-7 bulbs. Each posterior spiracle with three bulbs, apparently without spiracular hairs. Larval mouthparts with two mouth hooks on each mandible with the upper one larger. According to Beri, 1984 the mouth hooks are alternating. Mandibular sclerite present. Locomotion welts with prominent denticles.
BIONOMICS
Hering, 1951 b found only a single generation in the spring with larval feeding from April till May. Spencer, 1973 disagreed, because in England he observed larvae producing adults in the same year as larval feeding had taken place.
The eggs are laid towards the upper half of the leaf, after hatching the young larva usually first feeds upwards in a narrow linear mine than turns downwards. As in other Agromyza species the fully grown larvae produce large full-depth blotch mines. Beri, 1984 reported the pupation occurs within the mines. This behaviour would be an exception within the genus Agromyza.
HOST PLANTS
Hordeum vulgare L. (barley), Secale cereale L. (rye), Triticum aestivum L. (winter wheat); also some wild grasses.
DISTRIBUTION
Apparently widespread throughout the Palaearctic and Oriental region, Spencer, 1973 reported Germany, Austria, England and Spain; India (Beri, 1984), Korea.
ECONOMIC IMPORTANCE
In high population densities the species may be harmful for young plants in spring because the species emerges remarkably early (Hering, 1951 b). Actual damage has nevertheless never been observed since Hering's article, although the species was sometimes found on cereals (e.g. Beri, 1984). This means that Agromyza rondensis can be regarded as potential pest only.