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Keywords:

  • Locust control;
  • Environmental effects;
  • Environmental management system;
  • Due diligence

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. DRIVERS FOR IMPROVING ENVIRONMENTAL PERFORMANCE
  5. LOCUST-CONTROL AGENTS: OPPORTUNITY OR THREAT?
  6. PATHWAYS FOR CONTINUING ENVIRONMENTAL IMPROVEMENT
  7. Acknowledgements
  8. References

The Australian Plague Locust Commission (APLC) manages locust populations across 2 million square kilometers of eastern Australia using the aerial application of chemical and biological control agents to protect agricultural production. This occurs via a preventative control strategy involving ultralow-volume spray equipment to distribute small droplets of control agent over a target area. The economic costs of, and potential gains stemming from, locust control are well documented. The application of insecticides, however, to fragile arid and semiarid ecosystems is a task that brings with it both real and perceived environmental issues. The APLC is proactive in addressing these issues through a combination of targeted environmental operational research, an ISO-14001-aligned Environmental Management System (EMS), and links with environmental regulatory and research institutions. Increasing due diligence components within Australian environmental legislation dictate that mere legislative compliance is no longer sufficient for industries to ensure that they meet their environmental obligations. The development of external research links and the formulation of an EMS for locust control have enabled the APLC to identify environmental issues and trends, quantify objective environmental targets and strategies, and facilitate continuous improvement in its environmental performance, while maintaining stakeholder support. This article outlines the environmental issues faced by the APLC, the research programs in place to address these issues, and the procedures in place to incorporate research findings into the organization's operational structure.


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. DRIVERS FOR IMPROVING ENVIRONMENTAL PERFORMANCE
  5. LOCUST-CONTROL AGENTS: OPPORTUNITY OR THREAT?
  6. PATHWAYS FOR CONTINUING ENVIRONMENTAL IMPROVEMENT
  7. Acknowledgements
  8. References

In 1974, the Australian Commonwealth Government, with the agreement of the states of New South Wales, Queensland, Victoria, and South Australia, established the Australian Plague Locust Commission (APLC) to research, monitor, and control populations of the Australian plague locust, Chortoicetes terminifera (Walker), that pose an interstate threat to the agricultural systems of eastern Australia. The APLC became operational in 1976. The Commonwealth and member states agreed in 1987 to extend the APLC's responsibility to the spur-throated locust, Austracris guttulosa (Walker), and the migratory locust, Locusta migratoria (L.).

The economic argument for locust control is significant. The APLC offers the Australian population a benefit-to-cost ratio of between 26:1 and 29:1 as calculated from the locust-control operations during the 1984 plague (Wright 1986). Such a financial benefit is made possible through a practice of proactively controlling locust populations as early as possible, preventing the aggregation of small localized populations, and minimizing the potential for migration and, therefore, minimizing crop damage in agricultural regions (Hooper 1996).

Locust control is undertaken using aerial applications of ultra low volume insecticides. Spray operations follow standard operating procedures that allow parameters to be varied for differences in individual targets such as locust life stage, weather, and vegetation type. Conservative, self-imposed buffer zones are used to reduce the risk of contamination of areas “sensitive” to the application of insecticides.

The Australian plague locust, C. terminifera, can migrate hundreds of kilometers overnight, allowing them to move between regions and states. As a result, locust control is viewed by state and Commonwealth governments as being for the public good because it is not always possible to identify the direct beneficiary of the control. In most states, locusts are declared under legislation as pest or noxious animals that must be reported and controlled. The legislation usually empowers agents of the State Minister to enter land and carry out any reasonable activity to bring the locusts under control. Within this state legislative framework, the APLC, acting on behalf of the state government, is a 3rd party undertaking the control activity but is also the proponent of that activity. This places the APLC in the position where its control operations could pose a risk to the environment, human health, and trade.

The Australian Commonwealth government's National Strategy for the Management of Agricultural and Veterinary Chemicals (ARMCANZ 1998) identifies 4 main risks in the use of agricultural chemicals:

  • Inducing resistance in the pest;

  • Damaging the environment;

  • Damaging human health; and

  • Damaging trade through detection of chemical residues in produce.

This article and case study address the 2nd of these risks and outline the research currently being conducted by the APLC to address the issue of environmental impacts arising from locust control.

To meet the challenge of environmental responsibility, the APLC has developed an environmental program focused on establishing links with external research and regulatory bodies, undertaking externally and internally funded research into the impacts of locust-control agents on Australian native fauna, and developing and implementing an Environmental Management System (EMS). The EMS enables the APLC to monitor and evaluate its environmental performance, report against performance indicators, and work continually and incrementally to reduce the impact of locust-control operations on the environment. Although there are also occupational health and safety and trade issues associated with chemicals used for locust control, they are not dealt with here.

DRIVERS FOR IMPROVING ENVIRONMENTAL PERFORMANCE

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. DRIVERS FOR IMPROVING ENVIRONMENTAL PERFORMANCE
  5. LOCUST-CONTROL AGENTS: OPPORTUNITY OR THREAT?
  6. PATHWAYS FOR CONTINUING ENVIRONMENTAL IMPROVEMENT
  7. Acknowledgements
  8. References

The nature of its core business, namely the application of insecticide for the purpose of locust control, defines the APLC as the “proponent of a threatening action” in the eyes of Australia's environmental legislation. Increasingly, such legislation is focused on the need for industry and business to demonstrate that they have due diligence processes in place for actions that could potentially have an impact on matters of environmental significance. This increase in environmental duty of care is evident in legislation at all levels of government and affects the APLC's operations.

At the Commonwealth level, the primary piece of environmental legislation governing locust control is the Environment Protection and Biodiversity Conservation Act 1999. The Act came into force on 1 July 2000. The APLC referred its locust-control activities in May 2001 to Environment Australia, the agency responsible for assessment under the Act. Environment Australia determined that controlling plague locusts would not require the Environment Minister's approval on each instance. Criteria were established, however, that required the APLC to maintain its environmental program and to report against the progress of this program annually.

At the State level, legislation such as Queensland's Environment Protection Act1994 states clearly that everyone has a “general environmental duty to take all reasonable and practicable measures to prevent or minimize environmental harm” (Queensland EPA 1994). Environmental harm has been defined in the Act as any adverse effect (whether temporary or permanent and of whatever magnitude, duration, or frequency) on an environmental value. An environmental value is defined as “a quality or physical characteristic of the environment that is conducive to ecological health or public amenity or safety” (Queensland EPA 1994). Subsequently, increasing levels of due diligence are required by environmental legislation at this level.

At the corporate level, the issue of due diligence and a duty of care for the environment is increasingly prominent. Both regulatory agencies and nongovernmental organizations are highlighting the importance of the “National Environment Agenda” within Australia and the emphasis contained within it: that industry must now go beyond mere compliance with environmental legislation to achieve appropriate environmental, social, and economic goals, maintaining the so-called “triple bottom line” (AIG 2001). Management tools available to industry that enable it to satisfy the national environmental agenda include the development of an EMS and the adoption of Public Voluntary Environmental Reporting. The APLC has adopted both of these initiatives.

LOCUST-CONTROL AGENTS: OPPORTUNITY OR THREAT?

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. DRIVERS FOR IMPROVING ENVIRONMENTAL PERFORMANCE
  5. LOCUST-CONTROL AGENTS: OPPORTUNITY OR THREAT?
  6. PATHWAYS FOR CONTINUING ENVIRONMENTAL IMPROVEMENT
  7. Acknowledgements
  8. References

Historically, the APLC has relied on fenitrothion (Sumitomo Chemical, Osaka, Japan), an organophosphorus compound, as the most cost-effective pesticide to suppress locust populations. Despite fenitrothion's efficacy for locust control, concerns about its environmental impact in other countries have led to its registration being reviewed in Australia (NRA 1999). Such concerns have necessitated the APLC investigating alternative control agents for use against its target species, reviewing its criteria for control, and evaluating new approaches to monitoring for the effects of locust-control agents on the environment. Figure 1 gives the average areas sprayed and the liters of insecticide used per year by the APLC between 1977 and 2000. Fenitrothion makes up the majority of the data presented in Figure 1, however, the use of fipronil (Adonis, Rhǒne-Poulenc, now BASF, Ludwigshafen, Germany) and Metarhizium anisopliae var. acridum (see below) by the APLC has increased significantly since 1997 and 1999 respectively.

An integrated approach to locust control (Hunter 2004) has allowed the APLC to continue operating while improving its environmental performance and minimizing the impact of locust control on the environment. What follows is a brief précis of the control agents, both chemical and biological, used by the APLC and their benefits and disadvantages.

Fenitrothion and vertebrates

Fenitrothion, O,O-dimethyl O-(3-methyl-4-nitrophenol) phosphorothioate, is a broad-spectrum organophosphorus (OP) insecticide used throughout the world for the control of agricultural and forest pest and disease vectors affecting humans and animals (Bunn et al. 1993). The APLC has been using fenitrothion as its chemical of choice since it 1st began operations in 1976. During this period, there has been only 1 known incident in which birds appear to have been poisoned as a direct result of APLC operations.

During experimental spray trials in SW Queensland, in 1992, black kites (Milvus migrans Boddaert) were accidentally exposed to fenitrothion at application rates significantly higher than those currently used in APLC operations. Analysis revealed that they had been gorge feeding on C. terminifera nymphs, which had been significantly overdosed as a result of the altered spray parameters during these trials. Posttreatment checks of the site found a total of 15 dead black kites. Normal APLC spray parameters involve reduced application rates (from 381 to 267 g active ingredient [ai] • ha−1) and, therefore, a repeat of these circumstances is considered unlikely.

To quantify the pesticide doses birds are likely to be exposed to in the field, the APLC is collaborating with the University of Wollongong (New South Wales, Australia) and Texas Tech University (Lubbock, TX, USA) in a range of field- and laboratory-based research projects investigating the sublethal effects of pesticides on vertebrates. In addition to locust and vegetation residue sampling aimed at identifying the levels of bioavailability of pesticides (research that is not yet complete), birds are captured before and after spraying to measure levels of pesticide residues and OP biomarkers (cholinesterase activity) in their blood. The sublethal effects of similar low doses of fenitrothion on the metabolic (body chemistry), thermoregulatory (temperature control), and locomotory (movement) performance of a few key native species are also being studied. These performance measures provide an excellent integration of whole-animal health and can be directly related to survival in the field (Szabo et al. 2003). This research is extended across a range of vertebrate taxa.

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Figure Figure 1.. Mean amounts of insecticide and areas sprayed by the Australian Plague Locust Commission (APLC) 1977 to 2000.

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To date, results have demonstrated that the level of exposure of species feeding in sprayed areas can be quite high, even for birds not consuming locusts (e.g., zebra finches). Laboratory studies show that fenitrothion can have effects on locomotion (and, therefore, predator-escape capability) for much longer periods (days to weeks) than predicted from biomarker persistence in the blood (Szabo et al. 2003).

Fenitrothion generally breaks down rapidly in vertebrates and does not accumulate in body organs (Shore and Douben 1994). The indicator of exposure most widely used is cholinesterase inhibition in blood (Hamblin and Golz 1953; Rider et al. 1957; Ganlin et al. 1964; Gough et al. 1967) or brain tissue (Rider et al. 1957; Brust et al. 1971; Ludke et al. 1975; Greig-Smith 1991; Thompson 1991). Acute toxicity is generally associated with a depression in brain acetylcholinesterase activity of greater than 50 to 70%, whereas inhibitions in excess of 20%, or 2 SD below the reported norm, have been used as exposure criteria following known application of anticholinesterase pesticides (Rattner and Fairbrother 1991). Plasma cholinesterase can be inhibited to levels close to 0 without severe inhibition of brain acetylcholinesterase or overt toxic effects (Thompson 1991), and several studies have indicated that inhibition of greater than 50% in living vertebrates is not necessarily life threatening, at least in laboratory settings (e.g., Ludke et al. 1975; Evans and Batty 1986; Dell'Omo et al. 1997).

A review of the effects of OP and carbamate insecticides on vertebrate taxa found that most information on the hazard to wildlife is based on knowledge of their environmental fate, persistence, application rate, and toxicity (Story and Cox 2001). In many cases, toxicity data are gained from laboratory animals in controlled conditions. This information is often used to predict the risk to individual animals or populations in the wild. Such methods can successfully identify effects OPs have on free-living animals but have limited use when extrapolated quantitatively because differences in species sensitivity to pesticides and variation in exposure patterns between laboratory and wild animals are yet to be quantified. In addition, controlled laboratory tests can not be relied on to predict alterations in wild populations.

Organophosphorus pesticides may not only have a direct effect on individuals within a species but also populations as a whole, disrupting population dynamics and changing species composition, with the most sensitive species becoming extinct in areas of highest contamination (Story and Cox 2001). Effects of OP and carbamate pesticides can be recognized by various responses, including impaired thermoregulatory functions, changes in levels of activity and aggression, or reduced food and water intake. Hence, sublethal effects have the potential to inhibit reproduction and survival (Story and Cox 2001).

A recent pilot study to investigate the sublethal effects of fenitrothion on the metabolism and exercise performance of fat-tailed dunnarts (Sminthopsis crassicaudata [Gould]) has helped to fill an important gap in our knowledge of the effects of xenobiotics on native Australian fauna (W.A. Buttemer et al. 2005). That study also addressed the issue of inadequate linking of laboratory and field data in past studies and found that the running endurance of dunnarts (at 1 m · s−1) was reduced by up to 50% after fenitrothion (30 mg · kg−1) ingestion, although peak metabolic rate and cost of transport were unaffected during both exercise and cold exposure. Total brain cholinesterase and plasma acetylcholinesterase in these dunnarts were both reduced as a consequence of exposure to fenitrothion but had returned to approximate, predose levels by day 5 after ingestion. In addition, a consistent symptomology timeline was observed in all animals (but for varying durations) that included immobilization, excessive urination, tremors, and salivation for up to 5 h after fenitrothion ingestion (Buttemer et al. 2005).

These results indicate a potential increase in sensitivity to fenitrothion exhibited by the marsupial S. crassicaudata over that shown by similar-sized, eutherian mammals. For example, the acute, oral, fenitrothion LD50 for Mus domesticus is 240 mg · kg−1, significantly higher than the 30 mg · kg−1 dose administered to S. crassicaudata, despite being an LD50 value. It could be argued that the approach taken by Buttemer et al. (2005) gives a more precise indication of the potential effects of xenobiotics on vertebrates than do LD50 values because aerobic capacity requires the integrated function of a suite of enzymes, organelles, cells, tissues, organs, and organ systems and, as such, provides a more pertinent measure of an individual's susceptibility and reaction to any stressor. Similarly, acetylcholinesterase-reactivation techniques can remove the problem of within-population variation as each individual animal essentially acts as its own control.

Fenitrothion and invertebrates

The effect of the ultralow-volume formulation of fenitrothion on nontarget invertebrates was studied in detail by the APLC between 1990 and 1993 (Carruthers et al. 1993; Hooper et al. 2000). Field trials were conducted to assess the short- and long-term impact of fenitrothion applied aerially at the rate of 381 g ai · ha−1 on the epigeal invertebrate fauna of arid grasslands at 5 locations in eastern Australia. More than 331,000 arthropods were caught in the traps during the life of the study. The Collembola constituted the most numerous and most sensitive invertebrate group, but ants (Formicidae), Coleoptera, and Hemiptera were also trapped in adequate numbers to permit statistical analysis. A significant reduction in the total number of arthropods caught was detected at most sites immediately after spraying, but most of the fauna had fully recovered by 28 days posttreatment. Longer-term effects on the abundance of Collembola were seen on a small number of occasions throughout the 5 trial sites, but no differences in species diversity or community structure was detected at 2 sites studied in detail. It was concluded that the application of fenitrothion at 381 g ai · ha−1 would only have a short-term effects on the epigeal invertebrate fauna of arid grasslands of eastern Australia. The dose of fenitrothion now used by the APLC for most of its control of the Australian plague locust is 267 g ai · ha−1. This dose reduction was attained through the APLC's objective of finding the lowest possible dose for each of the control agents it uses, while maintaining optimum and economical population suppression. Reduced pesticide-dose levels also have the potential to furher minimize any adverse impacts on grassland invertebrates.

Fipronil

Fipronil, 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylsulfinylpyrazole, a phenyl pyrazole compound, is a broad-spectrum, low-dose insecticide that works via direct contact and stomach action. It is highly effective against both the nymph and adult stages of locusts and grasshoppers. Although not as fast acting as some other insecticides currently used for locust control, it does work at very low doses and has longer residual activity. Fipronil is an extremely active molecule and is a potent disrupter of the insect central nervous system via interference with the passage of chlorine ions through the chlorine channel regulated by γ-aminobutyric acid.

Fipronil can be applied to target areas as either a blanket or barrier treatment. Blanket treatments are used to treat small blocks of 1 to 5 km2 with doses of < 1 g ai · ha, whereas barrier treatments are used mainly against larger areas infested with mobile bands of nymphs. This method exploits the residual activity of fipronil with individual spray runs spaced widely across target areas (usually 500 m apart) leaving strips of treated vegetation (the barriers) containing approximately 0.25 to 0.5 g ai · ha−1. Bands of nymphs encountering these barriers in the 10 d following spraying come into contact with the treated vegetation and die. The advantages of this method include reduced insecticide use and aircraft costs as well as lower overall doses in target areas.

The APLC began operational use of the ultralow-volume formulation of fipronil in spring 2000. Aerial application of fipronil to control migratory locusts (L. migratoria) in Madagascar, applied at a rate of 3.2 to 4.0 g ai · ha−1, has been shown to have a long-term effect on populations of mound-building termites and their specialized vertebrate predators (Peveling et al. 2003). The APLC uses much lower application rates of fipronil (0.25–1 g ai · ha−1) to control locusts in Australia and few, if any, mound-building termites occur in sprayed areas. To determine the effect of fipronil on invertebrates and vertebrates in Australian grasslands, the APLC initiated the first of an intended series of impact studies in February 2002. In this trial, fipronil (1.25 g ai · ha−1) was aerially applied to bands of C. terminifera nymphs infesting an open, Mitchell grass (Astrebla spp.) plain in far-western Queensland. The fipronil was compared with a nearby area sprayed with fenitrothion (267 g ai · ha−1) and an untreated control. Invertebrates were monitored immediately before and after spraying using pitfall traps, yellow-pan traps, and malaise traps. Sampling is still ongoing and has been conducted at irregular intervals for more than a year.

Preliminary analysis of the results shows that both insecticides had a similar short-term impact on the number of invertebrates caught, with most groups showing recovery when sampled about 11 weeks after spraying. Full recovery of populations from perturbation by insecticides, however, has been affected by a prolonged drought. No substantial rain fell on the trial site until February 2003, 12 months after spraying. A sample taken in late March 2003 indicated that partial recovery of invertebrate populations had occurred in sprayed and unsprayed areas but not to the levels before spraying. As in previous studies, Collembola and ants were found to be the most useful indicator groups because they were caught in high enough numbers for statistical analysis and showed sensitivity to the insecticide treatments. Both groups are currently being identified to morphospecies to determine whether the insecticides have had an effect on species diversity and community structure.

Mound-building termites were not present on the trial site, but subterranean nesting species were commonly found infesting cattle dung. No effect on the percentage of cattle dung infested by these termites was detected 7 weeks after spraying, but further work on this group is needed and is planned in future trials. Trials to assess the impact of fipronil in contrasting locust habitats, such as central New South Wales rangelands, are planned when suitable conditions arise.

Recent concern has been expressed over the use of fipronil in Madagascar because of its impacts on termites and subsequent effects on specialist termite predators (Peveling et al. 2003). Results from ongoing APLC research has detected fipronil and its metabolites in caudally stored fat of S. maacroura (Gould) and S. crassicaudata up to 6 months after application in arid-zone Australian rangelands. Although the amounts discovered are minute (0.8–4 ppb fiproles), the fat stored in the tails of these insectivorous, native marsupials is used throughout traditionally dry winters as an energy source. Therefore, any compromise of this valuable resource at key points in the life cycle of either S. macroura or S. crassicaudata could prove critical for the population dynamics of the species. Subsequently, a comparison of the sublethal effects of fenitrothion and fipronil has been incorporated into our research program as a high priority.

Table Table 1.. Comparison of locust-control agents currently available to the Australian Plague Locust Commission (APLC)
 FenitrothionFipronil (blanket treatment)Fipronil (barrier treatment)aMetarhiziumbIGRs
  1. a The risk of barrier treatments is extrapolated from blanket treatments but is expected to be considerably lower if at least 50% of the area remains uncontaminated (FAO UN 1999).

  2. b As detailed in FAO UN (1999); risk when applied at the product formulation and dose approved by National Registration Authority (NRA); risk assessed primarily on overseas data.

  3. c Classification based on large-scale field trials and operational data from locust areas (mainly African locust control) (FAO UN 1999).

  4. d Classification based on laboratory data or small-scale field trials with indigenous species from locust areas (FAO UN 1999).

  5. e Classification based on laboratory and registration data with species that do not occur in locust areas (FAO UN 1999).

  6. f World Health Organization (WHO) toxicity class for active ingredients.

  7. g GABA = γ-aminobutyric acid; ESL = export slaughter interval; ND = not detected.

  8. h Period that must elapse for stock grazing on sprayed pasture, also applies to kangaroo and feral animal harvesting for human consumption (APLC, www.daff.gov.au/aplc).

  9. i Period that must elapse between application and harvesting (APLC, www.daff.gov.au/aplc).

Risk to wildlife     
  FishLowcLowdLowLowLow
  MammalsLowcLoweLowLowLow
  BirdsModeratecLoweLowLowLow
  Reptiles/amphibiansUnknownUnknownUnknownUnknownUnknown
  BeesHigheHigheHighLowLow
  Aquatic arthropodsModeratecLowdLowLowHigh
Risk to human healthfModerately hazardousUnlikelyUnlikelyUnlikelyUnlikely
WHO toxicity classfIIUnknownUnknown  
Mode of actionAChE inhibitionBlocks GABA receptorsgBlocks GABA receptorsFungal diseaseInhibits molting
Speed of actionFast, 2–3 dModerate, 2–7 dModerate, 2–7 dSlow, 7–14 dSlow, 4–10 d
PersistenceLowModerateModerateLow–moderateModerate
Withholding periods     
  Livestockh14 d21 d ESLg21 d ESLNDg21 d ESL
  Harvestingi14 d14 d14 dNDND

Green Guard®

The native fungus, M. anisopliae var. acridum (Driver and Milner) (isolate FI-985), marketed as Green Guard (Becker Underwood Pty Ltd., Somersby, New South Wales, Australia), can be applied using aerial or ground equipment for locust control. It was originally isolated from a dead spur-throated locust, A. guttulosa, in 1979 but has also been isolated from acridid grasshoppers in Africa, Asia, South America, and North America (Mexico). The APLC applies M. anisopliae at a rate of 25 spores suspended in a 500-ml mixture of mineral and corn oil per ha. Spores can either land on locusts directly during application or can be picked up as they move through vegetation (Scanlan et al. 2001). Live spores germinate when they contact the cuticle of the locust or grasshopper and then grow into the body. Once inside the target host, the fungus is usually undetectable for several days, after which, it can be found as hyphal fragments initially in the gut and later spreading to fat deposits. In the field, the host is usually killed within 1 to 2 weeks, although mortality can take 3 to 5 weeks when temperatures for fungal development are unfavorable.

Locust control in Australia is an increasingly difficult task to undertake. Constraints facing the APLC include an expanding organic agricultural industry (particularly organic beef enterprises) and raised awareness of the locations and status of rare and threatened species and ecosystems, as well as the need to maintain 1,500-m spray buffers around waterways. Green Guard provides the APLC with an opportunity to manage these situations and continue operations where, previously, the only option was total avoidance. For example, during spring 2000, with the approval of the New South Wales Parks and Wildlife Service, locust control using Green Guard was permitted in habitat considered critical to the survival of the endangered plains-wanderer (Pedionomus torquatus Gould). The plains-wanderer is currently listed as endangered in New South Wales under the Threatened Species Conservation Act (1995), and chemical locust-control agents have been identified as a threatening process for this species. Therefore, the use of Green Guard, in this instance, is the only method by which locust control can be undertaken in areas considered to be critical habitat for the plains-wanderer.

Table 1 documents the issues associated with the use of M. anisopliae var. acridum (LUBILOSA isolate IMI 330189), relative to other control agents as determined by the Food and Agriculture Organization's Pesticide Referees Group (FAO UN 1999). This group assesses locust-control agents based on available data and use patterns and makes recommendations for locust-control operations worldwide.

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Figure Figure 2.. Framework for the Australian Plague Locust Commission's (APLC) Environmental Management System (EMS).

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Although for some regions within the APLC's area of responsibility, there remains an acute need for the fast knockdown capabilities of insecticides, specifically, to reduce the potential for locusts to migrate to cropping zones, the use of biological control agents, such as Green Guard, is critical to maintaining the organization's effectiveness. An integrated pest management approach to locust control has been put forward by previous authors (Lomer et al. 1999; Hunter 2004), and its implementation is essential for locust-control agencies, such as the APLC, to successfully balance their core business of locust-population suppression while maintaining environmental due diligence processes, and therefore, in the case of Australia, their legislated environmental responsibilities.

Insect growth regulators

Insect growth regulators, generally the benzoylureas, are used in a number of countries to control locusts and grasshoppers. Following ingestion, insect growth regulators disrupt chitin synthesis in arthropods and prevent the insect from successfully molting to the next life stage. Typically, the old exoskeleton is shed and mortality occurs when a new exoskeleton cannot be formed. Sublethal doses can result in mortality from other causes, such as predation, when wing or limb formation in the locust is impaired. Mortality, although not immediately apparent, normally occurs between 4 and 10 d after treatment, reflecting the typical duration of a nymphal instar.

IGRs have a significant advantage over fenitrothion and fipronil in that they have very low vertebrate toxicity. They also have little direct effect on adult arthropods as these do not need to molt, thereby, allowing natural enemies to have full effect. This advantage in reduced impact on natural enemies also causes the limitation in operational use to targeting only nymphal stages of the locust. Insect growth regulators are toxic to immature stages of aquatic arthropods, and downwind buffers must be strictly imposed. Risks to trade are probably the greatest obstacle to operational use by the APLC. Their extended half-life and high lipid solubility could impact on market access for beef and lamb or mutton fed on treated pasture.

PATHWAYS FOR CONTINUING ENVIRONMENTAL IMPROVEMENT

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. DRIVERS FOR IMPROVING ENVIRONMENTAL PERFORMANCE
  5. LOCUST-CONTROL AGENTS: OPPORTUNITY OR THREAT?
  6. PATHWAYS FOR CONTINUING ENVIRONMENTAL IMPROVEMENT
  7. Acknowledgements
  8. References

It is inevitable that the APLC's operations will have some impact on the environment. Australian organizations in the public and private sector are becoming increasingly aware of the financial and ecological gains achievable through minimizing their environmental impacts, and an increasingly popular and effective tool for accomplishing this is the EMS. An EMS is a structured system designed to help an organization measure and reduce environmental effects of their operations through a series of targeted and continuous improvements. It allows the APLC to integrate its environmental policy into its core business and helps the organization meet its regulatory requirements. The APLC's EMS also comprises those elements of its overall management system that ensure environmental issues are identified and managed through ongoing risk assessment and performance monitoring.

The APLC's EMS complements ongoing environmental research including comparative projects investigating the effects of fenitrothion and fipronil on vertebrates and invertebrates, investigations into establishing the lowest effective doses for locust-control agents, trials of less environmentally hazardous control agents such as M. anisopliae var. acridum, and assessments of improved pesticide spray technology.

Additionally, compliance with Commonwealth and state environmental legislation is made easier, as is the mitigation of environmental impacts, through efficient resource use, reduced pollution and, therefore, an increased level of environmental duty of care and due diligence.

Some of the operational improvements initiated under the EMS are identified in Figure 2 and include the following:

  • The move from a mostly paper-based control operation in the field to a laptop-based electronic system that incorporates geographic information system mapping software, aircraft differential global positioning system log files, a comprehensive property contacts database, spray control records that meet legislative requirements, before- and after-spray risk assessments, and record management and reporting;

  • An improved chemical-drum management system;

  • Development of a “sensitive areas” geographic information system database to include regular updates on organic properties, national parks, on-farm wildlife areas, and sites of national and international conservation significance; and

  • Incorporation of environmental research into the APLC's core business strategy.

The APLC, like other organizations worldwide, is increasingly aware of its environmental obligations and the need to be proactive in meeting them. Within the context of Australian environmental legislation, emphasis is being placed on encouraging the proponents of threatening actions to provide adequate due diligence in addressing the potential environmental impacts of their activities at both the state and Commonwealth levels. What remains unclear is the level of due diligence considered by regulatory authorities to be sufficient to satisfy this legislation.

The APLC is employing a combination of targeted operational and research-based strategies to ensure it applies a level of environmental due diligence sufficient to satisfy its legislative obligations and to identify and avoid potential environmental issues while setting quantifiable milestones to ensure demonstrated improvement in its environmental performance.

Acknowledgements

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. DRIVERS FOR IMPROVING ENVIRONMENTAL PERFORMANCE
  5. LOCUST-CONTROL AGENTS: OPPORTUNITY OR THREAT?
  6. PATHWAYS FOR CONTINUING ENVIRONMENTAL IMPROVEMENT
  7. Acknowledgements
  8. References

All vertebrate research outlined in this paper was undertaken in collaboration with the University of Wollongong (Wollongong, New South Wales, Australia) and Texas Tech University (Lubbock, Texas, USA) and funded through the Australian Research Council's Linkage program. Invertebrate research and the development of the APLC's Environmental Management System was funded by the APLC.

References

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. DRIVERS FOR IMPROVING ENVIRONMENTAL PERFORMANCE
  5. LOCUST-CONTROL AGENTS: OPPORTUNITY OR THREAT?
  6. PATHWAYS FOR CONTINUING ENVIRONMENTAL IMPROVEMENT
  7. Acknowledgements
  8. References
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