Phytobia pruni (Grossenbacher, 1915)
Because of the lack of material this species could not be included into the IdentifyIt module. The following synopsis is based on Malloch, 1915 and Spencer and Steyskal, 1986.
IMPORTANT CHARACTERS
Adults
Wing length: 3.5 - 4 mm. Frons blackish, becoming brown in front, there similar to third antennal segment and palpus. Frons somewhat wider than eye, not projecting above eye. Third and fourth dorsocentral bristle small, anterior pair well in front of suture. Scutellum dark, prescutellar bristles half length of first dorsocentral bristle.
Wing length 3.5-4 mm, costa ending shortly after vein R 4+5, last section of M 1+2 1.5 times penultimate; inner crossvein well beyond center of discal cell, little more than own length from outer margin of the wing.
Male terminalia
Unknown.
Immature stages
Larval diagnostic characters to distinguish between different Phytobia spp. are not yet 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 under 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 are generally described in the chapter on the Genus Phytobia.
HOST PLANTS
Crataegus sp., Prunus avium, P. domestica. (Spencer and Steyskal, 1986), Prunus serotina (black cherry) (Rexrode and Baumgras, 1980; Rexrode and Baumgras, 1984). Prunus virginiana, Malus spec (apple). Lahey and Agrios, 1977.
DISTRIBUTION
USA (New York, West Virginia).
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).