Bulletin of Entomological Research (1995) 85, 531-539
P.A. Pedata, M.S. Hunter, H.C.J. Godfray and G. Viggiani (1995)
The population dynamics of the white peach scale and its parasitoids in a mulberry orchard in Campania, Italy
Bulletin of Entomological Research 85 (4), 531-539
Abstract: White peach scale, Pseudaulacaspis pentagona (Targioni-Tozzetti) (Homiptera: Diaspididae), was a serious pest of mulberry until it was the subject of a successful biological control programme in Italy at the turn of the century. Since the 1950s it has returned as a sporadic pest of commercial peach and, more recently, kiwi fruit orchards. We sampled white peach scale in an unmanaged mulberry orchard in coastal Campania over a 17 month period to measure the impact, relative abundance, and interactions of the parasitoids in the absence of pesticides. Sampled scales were dissected, and the immature stages of the parasitoids identified. Mean densities of white peach scale varied with month from 3-15/9 cm2 on primary (interior) branches and 15 -100/1.5 -2 m secondary (exterior) branch. The generalist ectoparasitoid Aphytis proclia (Walker) was most abundant, followed by two specialist endoparasitoids, Encarsia berlesei (Howard) and Pteroptrix orientalis (Silvestri) (all Hymenoptera: Aphelinidae). Primary parasitism also varied with month from 25-85% on primary branches and 20-90% on secondary branches. Parasitism on primary branches was inversely density-dependent, but was density-independent on secondary branches. Low levels of superparasitism were generally observed in E. berlesei and P. orientalis (0-6%), but were higher in A. proclia (0-21%). Multiple parasitism of hosts by E. berlesei and A. proclia was fairly common (up to 24% of E. berlesei immatures were found sharing a host with A. proclia), and A. proclia was the probable winner of within-host competitions. The hyperparasitoid Azotus perspeciosus (Girault) (Hymenoptera: Aphelinidae) parasitized late pre-imaginal instars of all three primary parasitoid species. There was no significant difference in hyperparasitism of the three primary parasitoid species, but the rate of hyperparasitism was inversely related to the total density of primary parasitoids.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Gennaro Viggiani, Paolo Alfonso Pedata, Martha S. Hunter
Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
surveys/distribution/isolation
environment/habitat manipulation
