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References

Laing J.E. and Heraty J.M. (1981). Establishment in Canada of the parasite Apanteles pedias Nixon on the spotted tentiform leafminer, Phyllonorycter blancardella (F.). Environmental Entomology 10: 933-935.

Lesica P. and Hanna D. (2004). Indirect effects of biological control on plant diversity vary across sites in Montana grasslands. Conservation Biology 18: 444-454.
The hypothesis that biological control agents reduce the dominance of the target weed, increasing the native plant diversity was tested. Aphthona nigriscutis was released into grassland sites infested with Euphorbia esula L. on a nature reserve in Montana (U.S.A.) and compared with herbicide treatment. After 5 years, Aphthona release caused a 33-39% decline in Euphorbia aboveground biomass compared with controls at all sites. Other effects of the biocontrol depended on the site. Results suggested that biocontrol reductions in weed dominance was not always associated with increased species diversity. Monitoring of community-level effects should accompany biocontrol introductions on nature reserves.

Lockwood J.A. (1993). Environmental issues involved in biological control of rangeland grasshoppers (Orthoptera: Acrididae) with exotic agents. Environmental Entomology 22: 504-518.
Neoclassical biological control with a parasitic wasp and an entomophagous fungus from Australia is now being applied to rangeland grasshoppers in the western USA, and it is predicted that there may be a number of possible nontarget impacts. Adverse effects include competitive suppression or extinction of both native biological control agents and nontarget acridids. Suppression of nontarget acridids may result in loss of biological diversity, existing control of weed species, release of otherwise innocuous acridid species from competitive regulation, disruption of plant community structure, suppression of essential organisms vectored by grasshoppers, and disruption of food chains and other nutrient cycling processes. Given that the value of the rangeland resource depends on the largely unknown ecological processes that underlie its sustainable productivity, there are a number of management techniques that offer a greater probability of success with a markedly lower likelihood of ecological and economic disruption than does neoclassical biological control.

Lockwood J.A. (1996). The ethics of biological control: Understanding the moral implications of our most powerful ecological technology. Agriculture and Human Values 13: 2-19.
The system of environmental ethics developed by Johnson (1991) is used to analyse the moral implications of biological control. In this formulation of ethical analysis, species and ecosystems are morally relevant because they are not simply aggregates of individuals, so their processes, properties, and well-being interests are not reducible to the sum of their individual members. Following Johnson's thesis, species and ecosystems have morally relevant interests in surviving and maintaining themselves as integrated wholes with particular self-identities. It is evident that not all biological control efforts are ethically defensible. In general terms, natural biological control is most desirable, followed by augmentative strategies, classical approaches, and finally neoclassical biological control.

Lockwood J.A. (1997). Competing values and moral imperatives: an overview of ethical issues in biological control. Agriculture and Human Values 14: 205-210.
The perception and resolution of ethical issues relating to biological control appear to emerge from a set of factors that includes one's ethical viewpoint (anthropocentric or biocentric), agricultural system (industrial or sustainable), economic context (rich or poor), and power structure (expert or public). From this set of parameters at least five major ethical questions can be formulated: (1) How we should regulate and apply biological control given uncertainty regarding environmental impacts; (2) How we balance benefits of biological control to human and ecosystem well-being against the known and anticipated risks; (3) Who should be empowered to develop policies and make decisions; (4) How we can assure a more just distribution of benefits and costs associated with biological control technologies and (5) Whether biological control can be justified as a resource substitution for pesticides or is its ethical application only possible as part of a reconceptualization of agricultural production. These central questions and possible answers are presented in a varied set of provocative analyses by some of the leading thinkers and authorities in their fields.

Lockwood J.A. (2000). Nontarget effects of biological control: what are we trying to miss? Pp. 15-30 In: Nontarget effects of biological control introductions, P.A. Follett and J.J. Duan (Ed.) Kluwer Academic Publishers, Norwell, Massachusetts, USA.

Lockwood J.A., Howarth F.G. and Purcell M. (2001). Balancing nature: Assessing the impact of importing non-target biological control agents (An international perspective). Thomas Say Publications, Lanham, Maryland, USA. 130 pp.

Longworth J.F. (1987). Biological control in New Zealand: policy and procedures. New Zealand Entomologist 10: 1-7.

Loomans A. and Van Lenteren J.C. (2005). Tools for environmental risk assessment of invertebrate biological control agents: a full and quick scan method. Pp. 611-619 In: Second International Symposium on Biological Control of Arthropods, Davos, Switzerland, 12-16 September, 2005, M.S. Hoddle (Ed.) United States Department of Agriculture, Forest Service, Washington.
The International Standard for Phytosanitary Measures No. 3 (ISPM3) offers a framework for risk assessment and focuses specifically on the shipment, import, export and release of biological control agents. The major challenge in developing risk assessment methodologies is to develop protocols and guidelines that will prevent serious mistakes through import and release of potentially harmful exotics, while at the same time still allowing safe forms of biological control to proceed. A risk assessment methodology for biological control agents should integrate information on the potential of an agent to establish, its abilities to disperse, its host range and its direct and indirect effects on non-targets. A comprehensive risk evaluation method (full scan) for new natural enemies is proposed and, 'quick scan' method for natural enemies already in use.

Loomans A.J.M., Van Lenteren J.C., Bigler F., Burgio G., Hokkanen H.M.T., Thomas M.B. and Editor: Enkegaard E. (2002). Evaluating environmental risks of biological control introductions: how to select safe natural enemies? Proceedings of the joint IOBC/WPRS Working Group "Integrated Control in Protected Crops, Temperate Climate" and IOBC/NRS "Greenhouse, Nursery, and Ornamental Landscape IPM Working Group" at Victoria (British Columbia), Canada, 6 9 May 2002; Bulletin OILB/SROP 25: 147-150.
Biological control of greenhouse pests has become a key component of sustainable horticulture in the world. No clear direct adverse effects have been found, but the potential nontarget effects of these releases have been little emphasized. The current situation with respect to selection procedures for importing, mass-rearing and releasing (new) exotic natural enemies is discussed.

Louda S.M. (1998). Population growth of Rhinocyllus conicus (Coleoptera: Curculionidae) on two species of native thistles in Prairie. Environmental Entomology 27: 834-841.
Rhinocyllus conicus is a flowerhead weevil deliberately introduced into the USA for the biological control of invasive exotic thistles in the genus Carduus. This study documents the course and magnitude of the weevil population expansion onto nontarget host plants Platte thistle and wavyleaf thistle, a later flowering native species. There is greater phenological synchrony of Platte thistle than wavyleaf thistle flowerhead development with R. conicus oviposition activity. The results suggest that pre-release studies should account for ecological characteristics, such as phenology.

Louda S.M. (1999). Negative ecological effects of the musk thistle biological control agent, Rhinocyllus conicus. Pp. 213-243 In: Nontarget effects of biological control introductions, P.A. Follett and J.J. Duan (Ed.) Kluwer Academic Publishers, Norwell, Massachusetts, USA.

Louda S.M. (2000). Rhinocyllus conicus - insights to improve predictability and minimize risk of biological control of weeds. Proceedings of the X International Symposium on Biological Control of Weeds: 187-193
This paper reviews information on the release of Rhinocyllus conicus to control Carduus spp. thistles in North America and suggests 8 lessons for future biological control efforts: (1) better a priori quantification of the occurrence and ecological effects of the weed; (2) improved ecological criteria to supplement the phylogenetic information used to select plants for pre-release testing; (3) increased assessment of potential direct and indirect effects when an agent looks promising but feeding tests suggest it is not strictly monophagous, (4) quantitative evaluation of the efficacy of the proposed biological agent (5) more evidence on alternative control methods; (6) expanded review, both prior to release and periodically afterward; (7) addition of post-release evaluations and redistribution control; and, finally, (8) a rethinking of the situations that qualify for the use of biological control releases.

Louda S.M. and Arnett A.E. (2000). Predicting non-target ecological effects of biological control agents: evidence from Rhinocyllus conicus. Proceedings of the X International Symposium on Biological Control of Weeds: 551-567
The significant non-target ecological effects of Rhinocyllus conicus on native species in the northcentral USA provides the opportunity to evaluate factors that might help predict direct non-target effects, and indirect effects mediated by trophic interactions. The relevance for biocontrol risk assessment of at least four important ecological relationships has emerged from these studies so far: (1) ecological and phylogenetic similarity of potential host plants; (2) synchrony of critical stages between insect and potential host plant(s), as well as acceptability; (3) population limiting processes of potential host plants; and, (4) overlap of feeding niche within the native guild of species dependent upon the host plants. In the selection of biocontrol agents, knowledge of the ecological relationships should help to quantify the risks inherent in deliberate introductions of new species.

Louda S.M. and O'Brien C.W. (2002). Unexpected ecological effects of distributing the exotic weevil, Larinus planus (F.), for the biological control of Canada thistle. Conservation Biology 16: 717-727.

Louda S.M., Kendall D., Connor J. and Simberloff D. (1997). Ecological effects of an insect introduced for the biological control of weeds. Science 277: 1088-1090.
The weevil Rhinocyllus conicus, introduced to control exotic thistles, has exhibited an increase in host range as well as continuing geographic expansion, in the USA and Canada. Weevils significantly reduce seed production of native thistles, and density of native tephritid flies was lower at high weevil density.

Louda S.M., Pemberton R.W., Johnson M.T. and Follett P.A. (2003). Nontarget effects - the Achilles' heel of biological control? Retrospective analyses to reduce risk associated with biocontrol introductions. Annual Review of Entomology 48: 365-396.
Ten projects with quantitative data on nontarget effects were reviewed and the patterns which emerged were discussed. The review lead to six recommendations: avoid using generalists or adventive species; expand host-specificity testing; incorporate more ecological information; consider ecological risk in target selection; prioritize agents; and pursue genetic data on adaptation.

Louda S.M., Rand T.A., Arnett A.E., McClay A.S., Shea K. and McEacherne A.K. (2005). Evaluation of ecological risk to populations of a threatened plant from an invasive biocontrol insect. Ecological Applications 15: 234-249.
The risk to the rare, Pitcher's thistle (Cirsium pitcheri) in North America from Rhinocyllus conicus, a biological control weevil now feeding on many native thistles, was evaluated. It was hypothesized that quantification of host specificity and potential phenological overlap between insect and plant would improve assessment of the magnitude of risk. In laboratory host specificity tests, we found no significant difference in R. conicus feeding or oviposition preference between the rare C. pitcheri and the targeted exotic weed (Carduus nutans) or between C. pitcheri and Platte thistle (C. canescens), a native North American species also known to be affected by R. conicus. Results of the study indicated that the weevil poses a serious risk to the threatened C. pitcheri, supporting the suggestion that ecological data can be used to improve the quantification of risk to native nontarget plant populations within the potential physiological host range of a biological control insect.

Louda S.M., Rand T.A., Russell F.L. and Arnett A.E. (2005). Assessment of ecological risks in weed biocontrol: Input from retrospective ecological analyses. Biological Control 35: 253-264.
Quantitative retrospective analyses of ongoing biocontrol projects provide a systematic strategy to evaluate and further develop ecological risk assessment. Analyses showed that host range and preference from host specificity tests are not sufficient to predict ecological impact if the introduced natural enemy is not strictly monophagous. The studies demonstrate that the environment influences and can alter host use and population growth, leading to higher than expected direct impacts on the less preferred native host species at several spatial scales, and that easily anticipated indirect effects can be both widespread and significant. It was concluded that intensive retrospective ecological studies provide some guidance for the prospective studies which are needed to assess candidate biological control agent dynamics and impacts

Louda S.M., Simberloff D., Boettner G., Connor J. and Kendall D. (1998). Insights from data on the nontarget effects of the flowerhead weevil. Biocontrol News and Information 19: 70N-71N.

Lynch L.D. and Ives A.R. (1999). The use of population models in informing non-target risk assessment in biocontrol. Aspects of Applied Biology 53: 181-188.
The use of models to illustrate risks of biological control to nontarget organisms is shown using two examples. The first model for classical biological control illustrates how the minimum density observed in the nontarget species follows a simple approximation, which is based on the carrying capacity for the target and the searching efficiency of the agent for the nontarget host. The second model looks at how augmentation methods of biocontrol may have impacts on the density of non-target.

Lynch L.D. and Thomas M.B. (2000). Nontarget effects in the biocontrol of insects with insects, nematodes and microbial agents: the evidence. Biocontrol News and Information 21: 117N-130N

Lynch L.D., Hokkanen H.M.T., Babendreier D., Bigler F., Burgio G., Gao Z.-H., Kuscke S., Loomans A., Menzler-Hokkanen I., Thomas M.B., Tommasini G., Waage J.K., Van Lenteren J.C. and Zeng Q.-Q. (2001). Insect biological control and non-target effects: a European perspective. Pp. 99-125 In: Evaluating indirect ecological effects of biological control, E. Wajnberg, J. K. Scott and P. C. Quimby (Ed.) CABI Publishing, Wallingford, Oxon., UK.

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