OUTLOOKS ON PEST MANAGEMENT

(FORMERLY PESTICIDE OUTLOOK)

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Selected papers from Volume 21, Issue 1, February 2010

Download the press release in PDF (99kb) or Word (73kb) format. For more information on these articles, or about Outlooks on Pest Management in general, please contact the publishers, Research Information Ltd.

Impact of Anti-DDT Campaigns on Malaria – Donald R. Roberts describes the successful history of the use of DDT for the eradication of malaria and how single issue anti-DDT campaigners have compromised the success of this programme

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Abstract:

Public health insecticides have greatly improved human welfare. In the past century, insecticides were deployed strategically to control numerous human plagues, but successes in those endeavours brought new and unforeseen challenges. As insecticides rose to prominence in disease control through the mid-20th century, environmentalists and population control advocates increasingly targeted insecticides in general, and DDT in particular, for elimination. The goal of anti-insecticide advocacy was to use propaganda and emotional arguments to convince people insecticides were dangerous and their use must be stopped. Backed by richly funded environmental advocacy and supported by science writers of the popular press, the movement created a backlash against DDT and other beneficial insecticides. Successes of anti-insecticide activism, and anti-DDT activism in particular, led to public health programs being abandoned around the world - and suffering of epic proportions. Anti-insecticide activism is an even stronger force today. Indeed, it seems that anti-insecticide advocates are even more determined to deny people in developing countries protections from disease and death that only insecticides can provide. Because of their activism, the World Health Assembly (WHA) adopted a resolution (WHA 50.13) in May 1997 that calls on countries to reduce reliance on use of insecticides for disease control. Then, in 1998, the United Nations Environment Program (UNEP) began negotiations for a Persistent Organic Pollutants (POPS) treaty targeting DDT and 11 other chemicals for global elimination. The start-up of those negotiations stimulated malaria scientists and other public health professionals to mount a global campaign to defend the use of DDT in disease control programmes. The public health campaign was successful and DDT was listed on Annex B of the Stockholm Convention on Persistent Organic Pollutants, which allowed its continued use. Yet, despite the campaign's success, anti-DDT and anti-insecticide advocacy is unabated in UNEP, the US Environmental Protection Agency, the European Union, and, to lesser extent, in public agencies financing disease control programs. As a result, DDT production facilities are being closed and countries that make appropriate and effective use of DDT for disease control are pressured by anti-DDT advocacy groups and are being enticed by financial mechanisms of the Global Environment Facility (GEF) to stop. WHA resolution 50.13 and the Stockholm Convention on Persistent Organic Pollutants are only the most recent signs of anti-insecticide groups successfully eliminating disease control programmes over the past half century. This progress was achieved by unrestrained use of fear tactics and misinformation by anti-insecticide advocacy. Indeed, the use of fear was, and still is, the sine qua non of the anti-DDT movement. Anti-DDT propaganda typically claimed that insecticide caused all manner of harm to human health. Readily embraced and trumpeted by the popular press, the claims, in reality, never satisfied even the most minimal cause-effect criteria. These criteria are discussed in depth.

The Biological Control of Fallopia japonica in Great Britain: Review and Current Status - Djami Djeddour, CABI Europe-UK

Abstract:

Japanese knotweed, Fallopia japonica var. japonica (Polygonaceae) is one of the most pernicious invasive weeds in Europe. A vigorous, herbaceous perennial, it was introduced from Japan to the nursery of Philipp von Siebold in the Netherlands in 1849 and was subsequently made widely available to the European public, soon becoming a much-prized ornamental. In the UK, its history has been well documented and shows an invasion pattern which is typical of many Victorian introductions; becoming naturalised by the late 1880s, it was first recorded in the wild in Maesteg, South Wales, in 1886. It has subsequently increased its range to include most regions of the UK, with a further northward spread anticipated due to climate change. Its status as a weed was soon recognised, and today it is one of only two terrestrial plants which are “illegal to cause to grow in the wild” under the UK 1981 Wildlife and Countryside Act, as well as being classed as a 'controlled waste', meaning that a licence is required for its disposal. The success of Japanese knotweed as a weed is all the more impressive when one considers that its expansion, at least in GB has been achieved without the advantage of sexual reproduction, which normally contributes to long-distance dispersal. It is believed that only a male-sterile clone of F. japonica was introduced into Europe and its spread is the result of disturbance, such as flood events, which move rhizome fragments along river systems, as well as human activity, in particular the illegal dumping of garden waste and the use of top soil contaminated with rhizome fragments. The plant's extensive and resilient rhizome system makes control very challenging and official knotweed management guidance has been issued in the UK to provide best practice advice to landowners and contractors. Nonetheless, the long term efficacy of traditional control attempts is often found wanting. The costs of Japanese knotweed can be considered as both economic and environmental. Its reputation as a “concrete cracking superweed” is justified and it causes many costly problems in the built environment both structurally and aesthetically. Though harder to quantify, the impacts the weed has on ecosystem function and biodiversity are also considerable, shading out native vegetation and prohibiting - regeneration, reducing invertebrate species richness and consequently impacting the higher food chain. Dense stands can also exacerbate flooding, damage riverbank protection works and impede flow, whilst dead stems can cause blockages downstream when swept away. Knotweed's influence on riparian systems is particularly pertinent in the light of the EU Water Framework Directive, which demands that member nation's waterways achieve “good ecological status” by 2015. With national control costs estimated to be in excess of £1.5 billion if such a task were to be attempted, and the limited arsenal of chemicals permitted for use in its preferred riparian habitats, the only sustainable and viable long-term control option is classical biological control. This article describes the search for a Japanese knotweed specific biological control agent (a psyllid - Aphalara itadori), its evaluation and the request for its use in the UK from 2010.

Insect Odorant-binding Proteins: Do they Offer an Alternative Pest Control Strategy? - Jing-Jiang Zhou, Centre for Sustainable Pest and Disease Management, Rothamsted Research, UK

Abstract:

Effective control of insect pests often depends on several complementary approaches that combine to form an integrated pest management strategy. Recent efforts to find new pesticides have not been able to prevent the evolution of resistance to insecticide treatment. The most successful insecticidal control method used to date has been the development of crops transformed with toxin genes of Bacillus thuringiensis (Bt). However, Bt toxins mostly target lepidopteran pests and have only been licensed in certain countries to control insect pests of corn and cotton. It is imperative that other non-insecticidal strategies be developed to alleviate the current reliance on chemical pesticides. One potential approach to this is to interfere with the ability of pest insects to find suitable mates and hosts which they do through volatile chemical signals (semiochemicals). Such olfaction-based approaches have been applied successfully in 'push-pull' pest control strategies using plants which are capable of producing attractants and repellents. Recently an aphid alarm pheromone synthase gene was successfully transformed into Arabidopsis thaliana, resulting in plants that both repelled aphids and attracted beneficial insects. Efforts to introduce such genes into crops are currently ongoing. There is also a need for efficient eco-friendly control strategies for the insect vectors of human and animal diseases, such as mosquitoes, tsetse flies and horn flies. For example, despite concerted efforts to develop vaccines, and attempts to interfere with parasite development in the arthropod vector through mosquito transgenesis, to date, malaria control relies mainly on repressing the insect vector-human target interaction allied with insecticide treatments. Insects use their sense of smell to find mates for reproduction and to locate hosts for nutrition by detecting semiochemicals. These enter the antennae by diffusion through pores on the cuticle and are transported to the olfactory neurons across the sensillum lymph. Several functional components of the insect olfaction system, which are involved in olfactory signal recognition and transduction in insects, are currently under investigation at the molecular level. These include odorant-binding proteins (OBPs), sensory neuron membrane proteins (SNMPs) and olfactory receptors (ORs). Insect OBPs are thought to provide the first filtering mechanism for semiochemicals and to mediate the activation of the ORs. Recent studies at Rothamsted now provide a starting point for the potential use of OBPs as targets to interfere with insect host location and mating behaviour. Such non-insecticidal approaches could play an important role as part of integrated pest management strategies and broaden the arsenal of available tools for insect pest control.