Khapra beetle, Trogoderma granarium interceptions and eradications in Australia and around the world

Research output: Working paper


The number of recorded intercepts and eradications of khapra beetle (Trogoderma granarium) have increased in Australia and the United States in recent years. Khapra beetle is one of the most destructive stored grain pests,and infestations can destroy the quality of grain and other commodities rendering the product unfit for human consumption. This pest can be easily transported from khapra beetle countries undetected as live beetles, eggs and larvae or in a state of diapause, with the transfer of people and goods around the world. Historically, discovery of khapra beetle post-border has generally resulted in costly eradication programs including methyl bromide fumigation and years of surveillance. Misidentification, failed detection or lack of preparedness has led to slow responses and at times the wide distribution of the pest prior to action. The United States spent over thirteen years (1953 -1966) eradicating a large scale khapra beetle outbreak that involved fumigation of over 600 sites of infestation and undertaking approximately 97,000 property inspections at a cost of USD $96 –130 million (2016 dollars).In a first, the United States demonstrated khapra beetle was eradicable,when all infestations are detected, progressively eliminated and reinfestation’s controlled.Later other infestations were detected and eradicated between 1978 and 1997, and the occasional domestic eradication program since. In this paper past khapra beetle incursions, intercepts and eradications in Australia and other countries have also been reviewed. In 2007, a post-border detection in Western Australia was eradicated. Factors contributing to the successful response strategy included the small scale infestation, limited distribution and technical feasibility of the fumigation. Prior preparedness and agreement and cooperation across government, industry and community also led to the rapid response to the incursion. The eradication programs described in this paper were found to be economically justified, although actual losses from pest damage were not that significant.For any exporting country where khapra beetle is endemic costly phytosanitary measures and trade implications come into effect. Therefore, eradication programs are worthwhile and likely to be the optimal response when costs are compared with expected damages avoided. Inidentifying the optimal response program an understanding of pest biology and behaviour is critical. In this paper we also compare response strategies to khapra beetle infestations with the Australian outbreak of the warehouse beetle (Trogoderma variabile) in 1977 –1993. We explore the differences in pest characteristics that led to the successful eradication of one and not the other. Finally we consider the problems that are currently of most concern, which are the ability to eradicate khapra beetle in the absence of methyl bromide and the development of resistance to phosphine. Given the inevitability of future khapra beetle incursions, resolving these issues will be essential to maintaining global market access for grain exporting countries such as Australia, the United States and Canada.
Original languageEnglish
Publication statusPublished - 30 Oct 2016


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