Current status of Saissetia oleae biological control in Sardinia (Italy)

During 1993 and 2008 the parasitoid complex of black scale, Saissetia oleae (Oliv.), was studied in olive groves of Sardinia after the encyrtids Metaphycus helvolus (Comp.) and M. lounsburyi (How.) were introduced in the period 1981-1982. The parasitism rate on nymphs was 6.7% in 1981, before the introduction of the two encyrtids, and 8.0% and 5.3% in 1993 and 2008, whereas the parasitism rate on females was 21.0%, 23.7% and 7.7%, respectively. The pteromalids S. caerulea (Fonsc.) and Moranila californica (How.) were the dominant parasitoid species in 1981, whereas the introduced M. helvolus and M. lounsburyi were the most abundant species in 1993. M. helvolus and M. lounsburyi, introduced for the first time 30 years ago, are well established and provide biological control of black scale in combination with other natural enemies.