The successful introduction to Australia of Diversinervus sp. near stramineus Compere (Hymenoptera: Encyrtidae), Kenyan parasitoid of green coffee scale

Abstract

The Encyrtid parasitoid Diversinervus sp. near stramineus Compere was introduced from coastal Kenya to Australia for the biological control of green coffee scale Coccus viridis (Green) infesting citrus, coffee and ornamentals. After quarantine testing against 16 other native and introduced insect scales and mealybugs, D. sp.nr stramineus was found to be specific to C. viridis and releases were made throughout Queensland and northern New South Wales. The parasitoid’s effectiveness was assessed in three citrus blocks in southeast Queensland and in a coffee block in north Queensland over three to four years. The parasitoid established readily, becoming the dominant natural enemy within 12 months of release with parasitism levels of up to 80%. D. sp.nr stramineus has established throughout Queensland and northern New South Wales and together with the existing aphelinid parasitoids Coccophagus ceroplastae (Howard) and Eurischomyia flavithorax (Girault and Dodd) and the fungal pathogen Verticillium lecanii (Zimmerman), has reduced C. viridis to minor pest status. Three other parasitoids Metaphycus baruensis (Noyes), Metaphycus stanleyi Compere and Coccophagus bogorensis (Koningsberger) were introduced to quarantine but not successfully reared on C. viridis.