Agromyza apfelbecki Strobl, 1902
IMPORTANT CHARACTERS
Adults
Wing length: - 4.2 mm. First presutural dorsocentral bristle of this large species is very small and thin, not much larger than acrostichals. In the key it is also accepted if one does not consider them as dorsocentral.
Frons light in the center, but the frons around the frontorbital bristles. Frontorbital setulae not extremely numerous but not situated in one row only. The setulae next to the antennae might be enlarged. Body densely pubescent, head and thorax greyish, abdomen brown.
Male terminalia
Hypandrium without apodeme but broadened a rear. "Pregonites" (attachment site of gonites at the hypandrium) very broad.
Immature stages
Posterior spiracles with three large opening slits and surrounded by spiracular hairs.
BIONOMICS
(after Ricchello, 1928 and Spencer, 1973)
The eggs are laid in the immediate vicinity of the midrib of a main lateral vein. The larva hatches after 7-8 days. In the first instar the larva forms a small blotch in the leaf-blade before entering a vein, along which it continues feeding until reaching the midrib where its main broad channels or blotches are eaten into the adjoining parenchyma. On completion of feeding the larva generally leaves the leaf by cutting an exit slit through the lower surface near its base. The larva falls on the ground, where pupation takes place.
There are several generations between September and April. During the summer the Agromyza apfelbecki aestivates as pupa.
HOST PLANTS
Cynara cardunculus L. (cardoon), Cynara scolymus L. (Globe artichoke) and the wild thistle Cynara betica L.
DISTRIBUTION
Widespread in South Europe; in South America the species was recorded from Chile and Argentina.
ECONOMIC IMPORTANCE
Agromyza apfelbecki is one of the major pests of artichokes both in South Europe and in the South America. If the species occurs in higher numbers the strength and health of the plants can be reduced considerably. Especially young plants can be affected seriously. However, Spencer, 1973 noted the damage caused by the larvae varied significantly from year to year.
Ricchello, 1928 reported that frost can cause high mortality among the larvae.