Paropsis charybdis, the most serious pest of Eucalyptus in New Zealand, was controlled with the introduced Australian egg parasitoid Enoggera nassaui in the late 1980s. Using frass traps to monitor P. charybdis populations, we report that pest outbreaks still occur, resulting in heavy defoliation of susceptible Eucalyptus species. The results suggest that the presence of large larval populations and commensurate defoliation result from poor spring parasitism by the parasitoid. A second wave of P. charybdis oviposition is effectively attacked, preventing late season defoliation by larvae. A climatic mismatch of E. nassaui is suspected to be the cause of this poor performance.

The first instances of egg parasitism of Chrysophtharta agricola, a pest of eucalypt plantations, are recorded. Enoggera nassaui was found parasitising C. agricola egg batches in Tasmania, the Australian Capital Territory (ACT), New South Wales and Victoria: this is the first record of this parasitoid species from Victoria. One instance of Neopolycystus sp. parasitising C. agricola eggs in Victoria was also recorded. Parasitism of egg batches by E. nassaui ranged from 0 to 55% between five geographical populations collected in mainland Australia (n = 45), and from 0 to 2% between two populations collected in Tasmania (n = 300). For mainland sites at which parasitism was recorded, parasitism rates within sites differed significantly from either population in Tasmania. Reciprocal exposure experiments using one Tasmanian (Florentine Valley) and one parasitised mainland (Picadilly Circus, ACT) population were conducted in the laboratory to examine whether these different parasitism rates were attributable to egg or parasitoid origin. Parasitoids from the ACT parasitised C. agricola eggs of both origins more successfully than parasitoids from Tasmania, with up to 65% wasp emergence compared with 33% from Tasmania. Parasitoid origin significantly affected the number of wasps that emerged from exposed batches, but not the total loss from parasitism.

Paropsis charybdis (Coleoptera: Chrysomelidae)

No abstract

Intriguingly, Connie Birdsall and Brendán Murphy have discovered that as communications go digital, the outcome has been greater similarity—rather than greater diversity—among media. Addressing this phenomenon, they discuss the evolution of this cross‐channel pollination and outline principles to guide the development of effective communications in this Digital Age.