Phytobia cambii (Hendel, 1931)
IMPORTANT CHARACTERS
Adults
Wing length: 3.7 - 4.1 mm. Mesonotum with prescutellar bristles variable in number (1-4). Squamal fringe normally darkened with long and numerous hairs.
Male terminalia
Genitalia distinct within European Phytobia species (Phb cambii aedeagus.pct, Phb cambii2 aedeagus front.pct).
Immature stages
Although the larva of the present species is well studied (see pictures in the multimedia part of this species card), the diagnostic value of the observed characters is unknown. 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. The life histories of the Phytobia species are apparently rather uniform and are generally described 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. 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. Apparently this species does not leave the stem far above ground level (Ylioja et al., 1998). The life histories of the Phytobia species are apparently rather uniform and treated on the higher taxa card of Genus Phytobia.
HOST PLANTS
Spencer, 1973: Salix alba L. (Cricket Bat Willow), S. purpurea L., S. triandra L., S. viminalis L. (Basket Willow), perhaps also S. fragilis L.
After synonymizing betulae, von Tschirnhaus, 1992 published several additional host plants, partly the former hosts of betulae but also new records from the author and M. J. L. Martinez.
Populus spp., Corylus avellana, Carpinus betulus, Alnus spp., Betula pubescens, Betula pendula, Betula platyphylla and probably other Betula spp.
DISTRIBUTION
Widespread in Europe, known from Austria, Finland, Sweden, Denmark, Germany, Great Britain, France, Netherlands, Poland, Romania.
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).