Phytobia betulivora Spencer, 1969
This species could not be included into the IdentifyIt module.
IMPORTANT CHARACTERS (Spencer and Steyskal, 1986)
Adults
Wing length: about 4.3 mm. Palpus, frons and antennae reddish orange; humeri dark; costa extending to M1+2.
Male terminalia
Distiphallus with long and thin terminal tubules.
Immature stages
Larval diagnostic characters to distinguish between different Phytobia spp. are not 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. 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 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 history of the Phytobia species is apparently rather uniform and treated on the higher taxa card of Genus Phytobia.
HOST PLANTS
Betula nigra L. (river birch).
DISTRIBUTION
USA and Canada.
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).