News Article | November 26, 2015
Researchers from West Australia are relying on genetically modified fruit flies to solve pest problems in the region. Mediterranean fruit flies (Ceratitis capitata) is causing significant dilemma among households and orchards in West Australia. Also known as Medfly, these pests feed on more than 250 kinds of fruits such as apricots, peaches, citrus, apples, nectarines, pears and mangoes. The damage occurs in fruits when the female fly "sting" on it during the process of egg-laying. The fruits then become susceptible to decomposition and subsequent infection. As per estimates, the damage in West Australian crops every year due to fruit flies is about $200 million. The Department of Agriculture and Food Western Australia (DAFWA) has been searching for a strong solution to address the problem. The agency has banned the use of an insecticide called fenthion but its quest for alternative methods has not ceased. Now, DAFWA has partnered with Oxitec, a technology firm based in the UK, to see the effectiveness of an innovative strategy that involves the use of genetically modified organisms (GMO). Neil Morrison, leader of the Oxitec group explained that a so-called "self-limiting gene" is injected into male fruit flies. Such action will halt female fruit fly offsprings from surviving through the adult life stages. When the engineered organisms are released to the natural environment, it will mate with the same species and pass the gene to its offspring, which will succumb to death prior to having the ability to damage crops. "If you reduce the number of females, that knocks down the pest population in the next generation," said Morrison. The said technique was used by his company to decrease the number of dengue-carrying Aedes aegypti in various countries such as Panama, Brazil and the Caribbean. For the Australia-UK collaboration, eggs were obtained in the UK and raised at the DAFWA, which already confirmed that it will perform an indoor evaluation of the GMOs. Dr. Nikolai Windbichler, a researcher from Imperial College concurred that multiple tests should be conducted first before arriving at a final conclusion of whether or not Medfly damage can finally be eradicated through genetic modification. In the U.S., a similar intervention was recently performed at the University of California. In the experiments, researchers reared a genetically-engineered mosquito that cannot, in any way, be infected by malaria. They specifically rearranged the DNA of a mosquito infected with malaria to fight off the parasite. After testings, the DNA was inherited by close to 100 percent of the offsprings, up until the third generation.
The WA Department of Agriculture and Food (DAFWA) and Oxford University spin-out company Oxitec are set to trial the effectiveness of a genetically modified medfly. They hope this new breed can help growers combat a pest which costs between $10-14 million annually to control and spoils up to 15 per cent of fruit crops. The technique involves researchers inserting two genes into the medfly, a self-limiting gene which prevents female offspring from surviving to reproductive age and a fluorescent track-and-trace marker (DsRed2). "This is a new approach to the Sterile Insect Technique in which radiation sterilisation of flies is replaced with a genetic method," DAFWA's David Windsor says. "It's a glimpse into the future of 21st century pest control." The Sterile Insect Technique (SIT) has been used globally since the 1950s and is considered the most environmentally-friendly form of eradication. It involves scientists sterilising male medflies through radiation and releasing them in large numbers to compete for mating opportunities. As females who couple with sterile males have no viable offspring, insect populations decrease. The new genetic approach works in a similar way but will require fewer insects, making it more cost-effective yet equally environmentally benign. "Our method only affects the target species, and because it is self-limiting, the genes and insects disappear from the environment once we stop releasing," Oxitec's Dr Neil Morrison says. "The medflies are non-toxic, non-allergenic and insecticide-free, and our studies have demonstrated that if a predator were to feed on our insects, it's just the same as eating other insects—there are no adverse effects." The project is one of a number Oxitec has under way, including breeding the mosquito Aedes aegypti, the main vector for dengue fever. Field trials of A. aegypti saw a reduction in insect populations of 93 per cent in Panama and 96 per cent in the Cayman Islands. This rate of success is good news for WA growers, who since October can no longer access broad-spectrum organophosphate insecticides such as Fenthion and Dimethoate. However, a number of challenges need to be met. "First, we need to work out whether female WA medflies want to mate with Oxitec males," Mr Windsor says. "The populations have been isolated from one another for a long time and may be slightly genetically different."
Snowball R.,DAFWA |
Snowball R.,University of Western Australia |
Mahdere A.,National Agricultural Research Institute |
Tesfay E.,National Agricultural Research Institute |
And 3 more authors.
Plant Genetic Resources: Characterisation and Utilisation | Year: 2013
This is the first report of a pasture plant collecting mission to the highlands of Eritrea and a preliminary examination of the potential of species for both Eritrea and southern Australia. In 2004, seeds from 53 legume species were collected from 58 locations in the southern highlands between Keren, Adi Quala and Senafe. Strains of Rhizobium from 18 species were also collected. Seed collections of 11 species with Rhizobium were established in germplasm nurseries at the Medina Research Station, Western Australia between 2005 and 2010. Observations on their growth, flowering and seed production were recorded. Based on a climate match analysis and observations from germplasm nurseries, it was suggested that species with most promise for parts of southern Australia include the annual legume Biserrula pelecinus ssp. leiocarpa and the perennial shrub Colutea abyssinica. The greatest potential, however, is reserved for the highlands of Eritrea where germplasm is well adapted. Species found low in the landscape including from the genera Lotus, Trifolium and Medicago appeared well utilized. Different species found higher in the landscape including from the genera Indigofera, Tephrosia, Crotalaria, Trifolium schimperi, B. pelecinus ssp. leiocarpa and C. abyssinica were much less common, appeared under-utilized and may be under threat from genetic erosion. Animal production on the non-arable dry hillsides of the highlands would benefit from better utilization of these species through replanting some areas, careful grazing management and demonstration of the benefits of increasing the native legume component of these wild pastures. Copyright © 2013 NIAB. Source
Paul K.I.,CSIRO |
Roxburgh S.H.,CSIRO |
England J.R.,CSIRO |
Ritson P.,DAFWA |
And 14 more authors.
Forest Ecology and Management | Year: 2013
To quantify the impact that planting indigenous trees and shrubs in mixed communities (environmental plantings) have on net sequestration of carbon and other environmental or commercial benefits, precise and non-biased estimates of biomass are required. Because these plantings consist of several species, estimation of their biomass through allometric relationships is a challenging task. We explored methods to accurately estimate biomass through harvesting 3139 trees and shrubs from 22 plantings, and collating similar datasets from earlier studies, in non-arid (>300mm rainfallyear-1) regions of southern and eastern Australia. Site-and-species specific allometric equations were developed, as were three types of generalised, multi-site, allometric equations based on categories of species and growth-habits: (i) species-specific, (ii) genus and growth-habit, and (iii) universal growth-habit irrespective of genus. Biomass was measured at plot level at eight contrasting sites to test the accuracy of prediction of tonnes dry matter of above-ground biomass per hectare using different classes of allometric equations. A finer-scale analysis tested performance of these at an individual-tree level across a wider range of sites. Although the percentage error in prediction could be high at a given site (up to 45%), it was relatively low (<11%) when generalised allometry-predictions of biomass was used to make regional- or estate-level estimates across a range of sites. Precision, and thus accuracy, increased slightly with the level of specificity of allometry. Inclusion of site-specific factors in generic equations increased efficiency of prediction of above-ground biomass by as much as 8%. Site-and-species-specific equations are the most accurate for site-based predictions. Generic allometric equations developed here, particularly the generic species-specific equations, can be confidently applied to provide regional- or estate-level estimates of above-ground biomass and carbon. © 2013 Elsevier B.V. Source