Survey of brown soft scale Coccus hesperidum L. parasitoids in southern California citrus

Taxon-specific multiplex-PCR for quick, easy, and accurate identification of encyrtid and aphelinid parasitoid species attacking soft scale insects in California citrus groves

“…However, the re-emergence of citricola scale as a pest in the San Joaquin Valley coincided with the evolution of resistance by the economically important armored scales Aonidiella aurantii Maskell and A. citrina Coquillet to broad-spectrum organophosphate and carbamate insecticides (Grafton-Cardwell 1994), and a subsequent shift to biological control methods to suppress armored scale (Luck et al 1997;UCIPM 2009a). In contrast, citricola scale remains extremely rare in southern California citrus groves (Morse et al 2006;Kapranas et al 2007;UCIPM 2009b), following its fortuitous demise in the 1930s, when several parasitoids were introduced to combat black scale, Saissetia oleae Olivier (Bartlett 1953(Bartlett , 1978.…”

“…The stark difference in the occurrence of citricola scale between the two regions has been largely credited to a relative paucity in the diversity and abundance of encyrtid species (Hymenoptera: Encyrtidae) in the San Joaquin Valley, particularly those in the genus Metaphycus Mercet (Lampson and Morse 1992;Bernal et al 2001;Kapranas et al 2007). As primary endoparasitoids, mainly of soft or armored scales, species of Metaphycus play a crucial role in the natural regulation of their hosts (Guerrieri and Noyes 2000).…”

“…However, together they account for \14% of total scale parasitism and the overwhelming majority of scale parasitism in that region (83.9%) is attributed to the aphelinid autoparasitoid Coccophagus lycimnia (Walker) (Bernal et al 2001). In contrast, in southern California, a recent survey of the parasitoid complex associated with brown soft scale, Coccus hesperidum L. (an alternative host for parasitoids of citricola scale), identified four Metaphycus species, M. helvolus, M. luteolus, M. stanleyi (Compere), and M. angustifrons (Compere), which together accounted for 75% of scale parasitism (Kapranas et al 2007). Another encyrtid, Microterys nietneri (Motschulsky), accounted for a further 7% of scale parasitism, but Coccophagus spp.…”

“…Another encyrtid, Microterys nietneri (Motschulsky), accounted for a further 7% of scale parasitism, but Coccophagus spp. (abundance of individual species was not determined) accounted for only 11% of total scale parasitism (Kapranas et al 2007). It is thought that the complex of Metaphycus spp.…”

“…Interestingly, although M. angustifrons was found to be by far the most abundant parasitoid of brown soft scale in southern California, this was actually a new record of establishment in California for this species. However, M. angustifrons and M. stanleyi are morphologically very similar (indeed males of the two species are acknowledged as inseparable; Kapranas et al 2007) and it seems highly likely that M. angustifrons has previously been misidentified.…”