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Oystershell scale - overseas biological control |
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Oystershell scale originates from Europe where it is reported to be only occasionally of economic importance. This is in part due to a wide range of natural enemies which includes those in the table. Those already present in New Zealand are highlighted:
| Natural enemy/Family | Species |
| Parasitoid wasp/Aphelinidae | Aphytis mytilaspidis (Le Baron), Aphytis bovelli, Aphytis testaceus, Archenomus longiclava (= longicornis)(Girault), Archenomus bicolor, Archenomus caucasicus, Archenomus maritimus, Azotus atamon (Walker), Azotus celsus, Azotus marchali, Azotus matritensis, Azotus pinifoliae, Azotus pulcherrimus, Coccophagoides similis, Encarsia aurantii (Howard), Hispaniella lauri, Pteroptrix dimidiata Westwood, |
| Parasitoid wasp/ Encyrtidae | Zaomma lambinus (Walker) |
| Parasitoid wasp/Signiphoridae | Thysanus ater Walker |
| Predatory ladybird, Coccinellidae | Chilocorus renipustulatus |
| Predatory beetle, Nitidulidae | Cybocephalus politus |
| Predatory mite, Hemisarcoptidae | Hemisarcoptes malus (Shimer) (introduced to New Zealand but failed to establish) |
Aphytis spp. are often found to be the most efficient of the scale natural enemies because (i) their life cycle is shorter than their host, (ii) they cause high mortality by both parasitism and predation, (iii) they are rather host-specific, (iv) they have few hyperparasites, and (v) they have excellent searching ability.