Top 20 environmental weeds for classical biological control in Europe: a review of opportunities, regulations and other barriers to adoption

Classical biological control remains the only tool available for permanent ecological and economic management of invasive alien species that flourish through absence of their co‐evolved natural enemies. As such, this approach is recognized as a key tool for alien species management by the Convention on Biological Diversity (CBD), the European and Mediterranean Plant Protection Organization (EPPO) and the European Strategy on Invasive Alien Species (ESIAS). Successful classical biological control programmes abound around the world, despite disproportionate attention being given to occasional and predictable non‐target impacts. Despite more than 130 case histories in Europe against insect pests, no exotic classical biological control agent has been released in the EU against an alien invasive weed. This dearth has occurred in the face of increasing numbers of exotic invasive plants being imported and taking over National Parks, forests and amenity areas in this region, as well as a global increase in the use of classical biological control around the world. This paper reviews potential European weed targets for classical biological control from ecological and socioeconomic perspectives using the criteria of historical biological control success, taxonomic isolation from European native flora, likely availability of biological control agents, invasiveness outside Europe and value to primary industry and horticulture (potential for conflicts of interest). We also review why classical biological control of European exotic plants remains untested, considering problems of funding and public perception. Finally, we consider the regulatory framework that surrounds such biological control activities within constituent countries of the EU to suggest how this approach may be adopted in the future for managing invasive exotic weeds in Europe.     

IMAGING DIAGNOSIS—USE OF MULTIPHASIC CONTRAST‐ENHANCED COMPUTED TOMOGRAPHY FOR DIAGNOSIS OF MESENTERIC VOLVULUS IN A DOG

A 4‐year‐old German shorthaired pointer presented with collapse and hematochezia. Radiographs showed gas and fluid‐distended small intestines and loss of serosal detail. Ultrasound examination showed hypomotile, fluid‐distended small intestines, and thrombosed jejunal veins. Multiphasic contrast‐enhanced computed tomography was performed and showed a CT “whirl sign,” an important but nonspecific sign of intestinal volvulus in human patients. At surgery, the majority of the small intestine was entangled in the volvulus and showed black discoloration. The patient was euthanized. Postmortem evaluation yielded a diagnosis of jejunoileal mesenteric volvulus secondary to a congenital omphalomesenteric duct remnant.     

Conception rates in European fallow does (Dama dama dama) following intrauterine insemination with frozen-thawed semen from Mesopotamian fallow (Dama dama mesopotamica) and crossbred (Dama dama dama x Dama dama mesopotamica) bucks

Ninety eight parous fallow does received laparoscopic intrauterine insemination of frozen-thawed semen at one of 2 fixed intervals following oestrus synchronisation treatment. Semen was collected from a Mesopotamian (Dama dama mesopotamica) and a crossbred (F1) (Dama dama dama x Dama dama mesopotamica) fallow buck. Does were inseminated at either 56 or 66 hours after the removal of an intravaginal controlled internal drug releasing device. Eighty eight does received a single straw of frozen-thawed semen containing a total of 50 x 10(6) spermatozoa, while the remaining 10 received split straws containing 25 x 10(6) spermatozoa. Overall, the use of F1 semen containing 50 x 10(6) spermatozoa resulted in a 68% (17/25) conception rate compared with the Mesopotamian semen, which resulted in a 41% (26/63) conception rate. Conceptions were also achieved using 25 x 10(6) spermatozoa of either Mesopotamian or F1 semen (3/8 versus 2/2, respectively). Overall, the conception rate was higher for F1 than Mesopotamian semen (P less than 0.025) and there was a significant interaction with time of insemination (P less than 0.05); for F1 semen there was no difference in conception rate at the 2 insemination times, but for Mesopotamian semen conception was significantly higher (P less than 0.005) following insemination at 66 hours than at 56 hours.     

Histological survey for oxalate nephrosis in Victorian koalas (Phascolarctos cinereus)

The Mount Lofty Ranges koala (Phascolarctos cinereus) population in South Australia has a high prevalence of the renal disease oxalate nephrosis, for which an underlying genetic cause is suspected. South Australian koalas primarily originate from those in French Island, Victoria; however, oxalate nephrosis has not previously been reported in Victorian koalas. Examination of kidney tissue sections from 63 koalas across Victoria found that nine koalas were affected by oxalate nephrosis (14.3%). These included 2/5 koalas from French Island (40%), 4/14 koalas from the western regions (29%), 2/11 Raymond Island koalas (18%), and 1/13 Cape Otway koalas (8%). There were no cases of oxalate nephrosis identified in the Strzelecki koalas (n = 12). These findings suggest that oxalate nephrosis occurs in koalas from French Island and populations that have received significant influx of koalas from French Island, but not in the Strzelecki region, which has little to no French Island input. This lends support to the theory that an inherited abnormality of oxalate metabolism could underlie the high prevalence of oxalate nephrosis in the Mount Lofty Ranges koala population, and molecular investigations are currently underway to investigate a genetic cause.