Phytobia cerasiferae (Kangas, 1955)
IMPORTANT CHARACTERS
Adults
Wing length: 2.9 - 3.5 mm. R1 subapically hardly thickened.
r-m located at anterior third of discal cell.
Male terminalia
Distiphallus long with long terminal tubules, which are apically thickened (Phb cerasiferae aedeagus.pct). Basiphallus about as broad as distiphallus with side arms without visible bridge. Hypandrium short, 'u'-shaped with broad frame without hypandrial apodeme. Ejaculatory apodeme not seen. Surstyli articulated.
Immature stages
Larval diagnostic characters to distinguish between different Phytobia spp. are not yet exactly known. In general the larvae are extremely long and slender (up to 3 cm long and 0.5 cm broad) and rather strong mouth hooks with the right mandible being distinctly larger than the left one. Usually the posterior spiracles have three bulbs, which are of nearly equal size.
The puparia are not as slender as the larvae but somewhat longer than those of other Agromyzidae. They have prothoracic horns. More detailed information can be found in the chapter on the Genus Phytobia.
BIONOMICS
The larva mines near the cambium of twigs and stems. The eggs are deposited into smaller twigs and the emerging larvae mine towards the base of the tree. Depending on the size of the tree the fully grown larvae escape from the tree near the root or above it. Pupation takes place in the soil, the puparia usually can be collected near the base of the stems, in hollowed stems or sometimes in birds' nests on the trees. The life histories of the Phytobia species are apparently rather uniform and treated on the higher taxa card of the Genus Phytobia.
Oviposition of the present species takes place from the end of June into early July. Females oviposit in one year old twigs. After hatching, the larva enters the older wood and feeds mainly in two- to four-year wood. The larva feeds during the summer and autumn and apparently in the spring of the following year. From mid may onwards the larvae leave the tree for pupation in the soil. The pupal period lasts about 30 days (Pitcher, 1956, cited after Spencer, 1973.
HOST PLANTS
Prunus cerasifera Ehrh., P. domestica L. (plum), P. insititia L. (damson), Prunus spec. (Cherry).
DISTRIBUTION
Known from Germany, Great Britain, Italy (Corsica).
ECONOMIC IMPORTANCE
Larval feeding causes the so-called pith flecks in the wood of the respective host trees (fig. Tschirnhaus), which can affect stability and reduce the aesthetical and commercial value of the wood. Sometimes it is also reported that the vigor of infested young trees can be reduced in nurseries (see Genus Phytobia).