Napomyza cichorii Spencer, 1966
IMPORTANT CHARACTERS
Wing length: 2.7 - 3.5 mm.
Diagnosis after Zlobin, 1994 a:
- broad orbits bearing numerous orbital hairs.
- third antennal segment large, distinctly cut away below, appearing bare.
- basal part of distiphallus (mesophallus) narrow.
- (?) neck of distiphallus with characteristic angle (instead of the curve) Nap cichorii aed lat exp1.pct.
- spermathecae small, higher than broad.
Immature stages
Larval mouthparts similar to that of Napomyza lateralis with conspicuous lateral sclerites next to the mandibles (see fig. lateralis). Puparium light brown Nap cichorii puparium.pct.
BIONOMICS
The eggs are invariably laid into the midribs, near the base of the leaves. The larvae can feed either in the thicker parts of the leaves, the stems or within the roots Nap cichorii mines.pct. Pupation generally takes place in the leaf mines or the roots of the host plant. Puparia can survive in discarded chicory heads and decaying plant matter in the field or on compost heaps.
There are several successive generation per year, van 't Sant et al., 1975 found three generation in the Netherlands, of these the last adults emerging in September. The offspring of this third generation imagines feed from autumn onwards throughout the winter. That is crucial since the final processing (forcing) of the chicory heads takes place in the winter. Larvae mining through the chicory heads and leaving their brownish traces can reduce the market price of the product considerably. However, the first generation may reduce the vigor of the chicory plants and may contribute to yield reduction.
HOST PLANTS
Cichorium endivia L. (endive), C. intybus L. (chicory, witloof), Lactuca sativa (lettuce) also Sonchus sp.
DISTRIBUTION
Widespread in the palaearctic region, known from Armenia, Belgium, Estonia, Finland, France, Germany, Hungary, Italy, Netherlands, Russia (European part, East Siberia, Far East), Ukraine.
ECONOMIC IMPORTANCE
Napomyza cichorii often occurs together with Ophiomyia pinguis, the other agromyzid fly feeding on Cichorium. Both species can cause considerable damage. Napomyza cichorii, however, can be regarded as more severe because it mines not only within the leaves but also penetrates the pith of the roots. Van 't Sant et al., 1975 considered cichorii as the most significant pest species among the Napomyza species of economic importance.
Various authors furthermore gave hints for possible control measures. Apart from insecticidal treatments it is recommended before forcing to cut as close to the head as possible to prevent larvae from penetrating the heads. The leaves should be removed from the field, where they have been grown.