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Parkville, Australia

Umina P.A.,University of Melbourne | Edwards O.,CSIRO | Carson P.,Cesar | Rooyen A.V.,Cesar | Anderson A.,Cesar
Journal of Economic Entomology | Year: 2014

The green peach aphid, Myzus persicae (Sulzer), is a serious pest throughout the world, attacking a broad range of crop plants across numerous agricultural industries. This species has a high propensity to develop chemical resistance, and has the unenviable title of having resistance to more insecticides than any other insect species. An extensive survey of field populations was undertaken across Australia, and showed widespread and high levels of resistance to carbamates and synthetic Pyrethroids in M. persicae. Moderate levels of resistance to organophosphates were also observed in many populations, while there is new evidence of resistance developing to neonicotinoids. Isofemale (clonal) lines of M. persicae were generated and subsequently tested across a range of insecticides; individual genetic clones were found to contain resistance to multiple chemical classes. Resistance genotyping of these aphids were consistent with published literature of known resistant mechanisms. The high and widespread levels of resistance identified within Australia are concerning. Resistance in M. persicae has spread quickly across Australia, and thus farmers are likely to have fewer chemical control options in the future. There is a need to develop resistance management strategies that rotate insecticides, spray insecticides only when economically necessary, and incorporate nonchemical control options. © 2014 Entomological Society of America. Source

Griffiths J.,Cesar | Kelly T.,Cesar | Weeks A.,Cesar | Weeks A.,University of Melbourne
Australian Mammalogy | Year: 2013

It has been suggested that platypuses (Ornithorhynchus anatinus) may avoid nets following capture, compromising abundance estimates using mark-recapture models. Here, we present the first direct evidence of net avoidance behaviour by the platypus. Using acoustic telemetry, we record a platypus bypassing several nets following capture. Understanding variation in capture probabilities will lead to better estimation of platypus abundance, which is currently lacking. © 2013 Australian Mammal Society. Source

Roberts J.M.K.,University of Melbourne | Roberts J.M.K.,CSIRO | Weeks A.R.,University of Melbourne | Hoffmann A.A.,University of Melbourne | And 2 more authors.
Biological Control | Year: 2011

Throughout southern Australia, the lucerne flea, Sminthurus viridis (Collembola: Sminthuridae), is an important pest of a variety of winter grain crops and pastures. The predatory mite, Bdellodes lapidaria (Acari: Bdellidae), co-occurs with S. viridis and is reported to be a biological control agent of this pest. Using laboratory bioassays and field experiments, we assessed the susceptibility of B. lapidaria to several pesticides and investigated its impact in controlling S. viridis. In the laboratory, B. lapidaria was found to be susceptible to the synthetic pyrethroids, α-cypermethrin and bifenthrin, but relatively tolerant to the avermectin, abamectin, and organophosphorous chemicals, omethoate and chlorpyrifos. In field experiments, B. lapidaria was not adversely affected by applications of either bifenthrin or omethoate. Despite strong intraspecific interactions, we found no detectable impact of B. lapidaria on S. viridis numbers in the field. These results indicate that B. lapidaria has a relatively high tolerance to several pesticides, perhaps partly through behavioural avoidance, but little impact as a biological control agent on S. viridis in south-eastern Australia. © 2011 Elsevier Inc. Source

Jenkins S.,University of Melbourne | Hoffmann A.A.,University of Melbourne | McColl S.,Cesar | Tsitsilas A.,University of Melbourne | Umina P.A.,University of Melbourne
Journal of Economic Entomology | Year: 2013

Broad-spectrum pesticides used to protect field crops and pastures from invertebrate pests are frequently reported to reduce populations of nontarget fauna, but there is often little relevant field data. Nonetheless, this notion is used to promote the adoption of more selective pesticides with less impact on nontarget invertebrates, including beneficial insects. Selective pesticides are not widely available for broad-acre grain crops and pastures in southern Australia; however, several options available in other industries could be compatible with these agricultural systems. In this study, the impact of broad-spectrum pesticides and several selective pesticides on nontarget invertebrate fauna was assessed in five field trials in wheat and canola fields. Despite extensive sampling over short and medium timeframes, few treatment effects on nontarget groups were detected. In cases where broad-spectrum pesticides were detrimental, patterns were often inconsistent among nontarget groups and between field trials. In contrast, the pest species, Hatotydeus destructor Tucker and Penthateus spp., were effectively controlled by the broad-spectrum treatments and less effectively by the selective pesticides. The inconsistent and relatively small impact of broad-spectrum pesticides on some nontarget invertebrates demonstrates that caution is required when extrapolating from laboratory-based assessments routinely used to assess the impacts of pesticides to field conditions in agriculture. © 2013 Entomological Society of America. Source

Furlan E.M.,University of Melbourne | Griffiths J.,Cesar | Griffiths J.,Australian Department of Primary Industries and Fisheries | Gust N.,Biofouling Solutions | And 4 more authors.
Conservation Genetics | Year: 2013

Dispersal patterns can have a major impact on the dynamics and viability of populations, and understanding these patterns is crucial to the conservation and management of a species. In this study, patterns of sex-biased dispersal and waterway/overland dispersal are investigated in the endemic Australian platypus, Ornithorhynchus anatinus, a semi-aquatic monotreme. Analyses of over 750 individuals from south-eastern Australia at 13 microsatellite loci and two mitochondrial genes, cytochrome b and cytochrome oxidase subunit II, provide genetic insight into dispersal patterns. For the first time, platypuses of western Victoria are shown to be genetically distinct from other populations of the mainland. Despite distinct morphological differentiation either side of the Great Dividing Range, populations remain genetically similar between coastal and inland areas suggesting gene flow is likely to occur across these ranges. Landscape genetic analyses indicate variability in dispersal patterns between Victorian and Tasmanian platypuses with a greater avoidance of overland travel indicated in Victoria compared to Tasmania. Females appear to remain within their natal area or return to breed, maintaining greater genetic structure in maternally inherited mitochondrial DNA in comparison to nuclear DNA and sharing genetic similarity within a short river distance (i.e. ≤1.4 km). The results of this study provide a valuable spatial framework for the management of wild platypus populations within south-eastern Australia and a baseline for future monitoring of populations that are likely to be impacted by environmental and anthropogenic change. © 2013 Springer Science+Business Media Dordrecht. Source

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