Advantages and Disadvantages of Biological Control

Advantages and Disadvantages of Biological bidSummary by-line numerous pr each(prenominal)ings of the risks associated with biologic mold, (see Howarth, 1991 Simberloff Stiling 1996 Thomas Willis 1998) lit was reviewed in straddle to investigate whether biologic t bothy was an environmentally friendly or a tough business. Although a lack of impregnable demo suggests that risks whitethorn be perceived rather than real, the become of the biologic tick off performer Harmonia axyridis by countries lacking in ordination has severely priced biologic visualizes reputation and eco remainss all everywhere europium. Biological reckon is the most sustain fitted, embody cost- cost-efficient and immanent method of pest management and thitherfore it should be procedured to its full dominance. Harmonized regulation is geted to improve biological falsifys reputation by preventing the push of risky agents in the future. principle should further rather than restrict the utilize of biological attend below its potential. Regulation should be specialally designed for biological bidding and should enforce the use of an environmental risk estimate ( date of reference). Scientifically ground methodologies ar required to ensure an efficient era is conducted for potential biological control agents. An efficient ERA should identify unsuitable agents as early as attainable to skip cost and while requirements. This will endure the continued increment of the biological control industry. Biological control should be apply as part of Integrated Pest Management to ensure the most efficient control of each pest.Introduction and objectivesInsects argon the foundations of ecosystems, transmitters of disease and bucolic pests close to the world (Gassmann et al. 2009). dodge 1 shows that as agricultural pests, worms cause sparing losses of billions every grade.The economic damage ca utilize by insect pests (see gameboard 1) and the join ond consumer demand for blemish free produce has take to the practice session of different approaches to pest management (Castle et al. 2009). For example, modern pesticides mother been used since their cultivation in the 1940s and it has recently been estimated that 8000 metric tons of insecticide (FAO, 2009) are used around the world at an approximate cost of $40 billion every year (Akhabuhaya et al. 2003).The advantages of pesticide use intromit the short clock among c everyplace and force, the eradication of the pest in the region of application and the predictability of success (Bale et al. 2008). The speed and assumed efficiency of pesticides led to their great popularity up to the seventies when concerns arose about their personal personal effects on health and the environmental (see Table 2).The rise in public concern and incrementd conclusion of the blackball effects of pesticides (see Table 2) led to the decrement of their use in the 1970s (Chiu Blair, 2009). Pesticides associated with the more salutary risks were made illegal, such as DDT in 1984 (Attaran Maharaj, 2000). The great decline in pesticide use over the last 50 years has allowed other pest management techniques, such as biological control, to be further developed and apply (Suckling Brockerhoff, 2010).Biological control has real great support due to its innate mechanisms. For example, van Lenteren (2005) estimates that 95% of immanent insects are already controlled through inbred biological control. In addition, a continuous increase in international trade and travel has led to increased insect dispersal mingled with countries (Waage Mumford, 2008). For example, 62,000 pests were reported pursuance an fleshly and Plant Health Inspection Service (APHIS) studycarried out on carpenters plane and boat passengers in the USA (Dunn, 1999). Also, there has been a recent increase in the number of crops stand upn in glasshouses crosswise atomic number 63. Glasshouse co nditions are much more suited to trespassing(a) insects, so this has allowed increased brass (Hunt et al. 2008). The movement to reduce pesticide use, popularity of innate control, increased levels of insect encroachments and the use of glasshouses to grow crops greatly increased the demand for biological control in the eighties (Sheppard et al. 2003).Biological control is the use of living organisms to actively reduce the state density of a pest species. A biological control evasion is deemed a success if the pest tribe densities are tear downed to the fulfilment that they are no longer conceiveed an economic or environmental menace (van Klinken Raghu, 2006).Biological control can be further classified as innocent, enhancive (inundative) or conservation. Classical biological control is the permanent decrease in the population of an st arena pest species through introduction of its exotic natural enemy. The introduced control agent is required to ready as it is meant f or ego sustaining control of the pest (Eilenberg et al. 2001). A classical biological control system that has reached great success is the use of Rodolia cardinalis against the invasive scale insect Icerya purchasi. Following its accidental introduction into California, I. purchasi was threatening to ruin the Californian citrus industry. R. cardinalis was selected as a monophagous natural enemy and 128 individuals were introduced to California. Populations of I. purchasi were controlled within a year (Frank McCoy, 2007). Classical biological control schemes that and reached partial success, i.e. pest population densities were reduced just the agent did non fully establish, led to the growing and use of augmentative biological control.Augmentative biological control is the rout of natural enemies in an inundative or seasonal inoculative manner (van Lenteren, 2005). Inundative biological control is the mass release of biological control agents to quickly reduce a pest populat ion density (Eilenberg et al. 2001). Inundative control agents are non meant to establish so agents may require reintroduction. An example of this is the mass release of the parasitoid Trichogramma brassicae to control the European corn borer (Ostrinia nubilalis) (Bigler, 1986). Seasonal inoculative biological control is the release of a natural enemy species with the aim that they will reproduce, belong and control pests end-to-end a crops growing season (van Lenteren Woets, 1988).Conservation biological control is the alteration of the environment towards one more suited to the pests natural enemy. For example, the readying of extra innkeeper plants (Anethum graveolens and Coriandrum sativum) for the natural enemies (Edovum puttleri and Pediobius foveolatus) of the Colorado potato hammer (Lepti nonarsa decemlineata) (Patt et al. 1997). The aim is a long term increase in natural enemy populations issuinging in increased control of pests (Landis et al. 2000).Until the mid 1980s, the introduction of over 2000 natural enemy species and the successful control of over 165 invasive pest species, led to the belief that biological control was an environmentally fail-safe and cost hard-hitting ersatz to pesticides and GM organisms (van Lenteren et al. 2006a). However, Howarths (1991) argument that there were serious risks associated with biological control was followed by a flood of storys discussing essay of similar risks (for example, Simberloff Stiling, 1996 Louda et al. 2003). It was recognised that an unsuitable biological control agent may cause the problems associated with an invasive insect.The potential risks of biological control include the hazard that the exotic agent could be poisonous, allergenic or the vector of a disease that is dangerous to humans (Howarth, 1991). Introduced species could become immanent crops pests or they could indirectly cause an increase in other crop pest populations (Howarth, 1991). For example, the reduction in come in pest species may allow oldly outcompeted insects to increase population size to pest densities (Kenis et al. 2009). Biological control agents may pour down a plant that other insects rely on for food or shelter (Simberloff Stiling, 1996). For example, the destruction of ash by the Chinese buprestid Agrilus planipennis has menace the only Frazinus genus of leptidoptera (Kenis et al. 2009). Further-more, biological control agents may predate or outcompete insects elusive in plant in tri-trophic interactions or they may kill plant essential pollinators (Simberloff Stiling, 1996).The greatest risks of biological control are those that impact on the environment. These risks include non betoken effects (Hokkanen, 2003). For example, the generalist biological control agent Compsilura concinnata has threatened the extinction of six non buttocks Lepidoptera species in North America (Boettner et al. 2000). The effect of a biological control agent on non chump organisms m ay be direct, such as the parasitisation of a non target host when the target is unavailable, or the preference of exotic prey over the target (Simberloff Stiling, 1996 Kriticos et al. 2009). For example, Cotesia glomerata parasitised the non target butterfly Pieris oleracea which is now at risk of extinction (Van Driesche et al. 2003). A reduction in non target population size may reduce their genetic diversity and therefore ability to adapt to future environmental changes (Kenis et al. 2009). Introduced agents may hybridise with native species or be a vector of a disease to which native invertebrates strike no resistance (NRC, 2002).The thinkable indirect effects of biological control include resource opposition (Delfosse, 2005). For example, the introduced parasitoid C. concinnata appears to make outcompeted the native silk moth parasitoid (Lespesia frenchii) in reinvigorated England (Parry, 2009). Biological control agents may share predators with a native herbivore. This may burden in the falling out of natural biological control reduced predation of the native herbivore may allow its population to increase to pest densities. Severe alterations to the ecosystem may go by if the introduced species affects an ecosystems lynchpinstone species or becomes a give awaystone species (Wagner Van Driesche, 2010). This would alter natural co-evolved relationships (Strong Pemberton, 2000) inducing evolutionary changes (Kenis et al. 2009). Finally, biological control agents may disperse from their area of introduction. This means the risks described are pertinent to any(prenominal) neighbouring habitats and countries (Howarth, 1991).The increased discussion of these risks has led to demand for regulation work throughing a thorough risk assessment to ensure that only safe biological control agents are released (Delfosse, 2005). numerous publications accommodate been released by organisations and countries (such as IPPC, 1997 EPPO, 1999 EPPO, 2001 EPP O, 2002 EU-funded ERBIC, 1998-2002 OECD, 2004 IOBC/WPRS, 2003 IPPC, 2005 REBECA, 2007). These publications declare oneself useful regulatory guidelines but they are non legally binding, they are similarly too dull as they do not state appropriate Environmental pretend Assessment (ERA) methods (Kuhlmann et al. 2006). Many countries moderate not produced regulations or do not actively utilise them and this has resulted in extremely patchy regulation crossways the globe.Advocates of biological control argue that the discussions of the potential risks do not provide fitting certify that sight effects were due to biological control (Lynch et al. 2001). Also, insect invasions occur accidently all the time with little evidence of any harm and therefore, an increase in regulation is not required.To answer the nous posed (is biological control an environmentally friendly or risky business?) this review will address the following querys Are the perceived risks of biological contro l founded on relevant evidence? What and where are the real biological control regulatory systems? Are ERA methods described and if so are they efficient ortoo strict, expensiveor vague? Do they acknowledge the differences between classical and inundative biological control and are they applicable to both? What should an efficient ERA comprise of? Is biological control compatible with other pestmanagement schemes?MethodsThe initial literature search was conducted to identify the scope of the topic Web of Knowledge was used because this search engine has a database holding a wide range of journals. The use of Web of Knowledge alike has the advantage of being able to read the abstract ahead downloading the paper and the search can be restricted to Science Citation Index Expanded to increase the relevance of results. In order of battle to study the full history of biological control, there was no restriction markd on the year of publishing and a range of broad key words were used including insect biological control AND history.Following the initial search and study of primary papers, key areas of interest were identified where further research was required in order to answer the question posed. Papers of interest were found using oblige reference lists and topic peculiar(prenominal) searches. These searches were conducted using key words for each area that required more detailed research. For example, papers on the problems associated with pesticide use were searched for using PubMed. PubMed is a biomedical database so was a more relevant search engine for this particular topic. Key words used include pesticide limit* AND human health. Once found, citation searches were used on key papers to help establish their importance and accuracy.Boolean operators were used to blend in keywords in the Topic search. An asterisk (*) was typed at the end of words that could soak up various endings. This allowed a wider search including titles with singular and plural word forms. The OR operator was used between likely key words to allow for variation in terminology. When a search found too many another(prenominal) results (over atomic number 6), AND or NOT were used between words and more specific key words were identified to help make the results more relevant. more specific keywords were identified using terminology that was common in the titles of elicit papers. When a search resulted in less than 100 papers all abstracts were read. If the abstract suggested the paper might provide evidence towards answering the question posed, the full paper was read. This search strategy allowed the efficient search of specific papers relevant to each area of interest.Key Papers effect of a Biological Control Introduction on Three Non-target domestic Species of Saturniid MothsBoettner et al. (2000) Conservation Biology, 14, 1798- clxxx6.To answer the question posed, (is biological control an environmentally friendly or risky business?) this review ne eds to consider whether or not the risks discussed for biological control are founded on relevant evidence. Examples used to demonstrate non target effects are often criticized because they do not account for native predation causing non target death rate (Lynch et al. 2001). This study is pioneering as it is the first to directly assess the non target effects of the classical biological control agent Compsilura concinnata and compares these effects to native predators.The effects of C. concinnata on the non targets Hyalophora cecropia, Callosamia promethean and the state endangered Hemileuca maia maia were studied. This prove was conducted following observations that these non target species populations had declined since the introduction of C. concinnata. Cohorts of 100 H. cecropia larvae, densities of 1 100 C. promethean larvae and wild H. maia maia eggs were observed in the field. The voice mortality of each species that was due to C. concinnata was calculated.Boettner et a l. (2000) found that 81% of H. cecropia mortality was due to C. concinnata (see Table 5). 67.5% of C. promethean larvae and 36% of H. maia maia mortality were overly found to be due to C. concinnata.Boettner et al. (2000) found that C. concinnata was responsible for the majority of non target deaths and that the numbers of individuals surviving may be less than the minimum workable population size for each species. Biological control should neer result in a loss of biodiversity (Kuris, 2003).Methods utilised were supported by previous studies and were conducted in realistic conditions. This is important because host selection is effected by physiological conditions including the availability of hosts (van Lenteren et al. 2006b). However, the species were reared in a laboratory before and afterwards exposure to parasitoids. This is undesirable as larvae were reared in unnatural conditions which could alter the parasitoids host selection (van Lenteren et al. 2006b). In addition, re peats should have been conducted for each taste to allow for natural variation in host selection (Bigler et al. 2005).Although this paper accounts for mortality due to native predators, it is still limited by the assumption that the observed reduction in saturniid moth populations was due to increased levels of predation. Other possible reasons for non target population declines and the parasitisation rate prior to the introduction of C. concinnata require consideration. Van Lenteren et al. (2006b) states that firm evidence non target population declines are due to biological control is often lacking. Therefore, it may be argued that this study does not provide secure evidence that C. concinnata has caused the observed decline in non target populations.Overall, Boettner et al. (2000) provide evidence that C. concinnata parasitises non target species. Since its initial release in 1906, C. concinnata has been observed parasitizing over 180 native North American species. In combinati on with other evidence of non target effects and with the knowledge that non target studies are rarely conducted following introductions, this study assists in the argument that non target effects are a reality (Louda Stiling, 2004). Therefore, biological control has the potential to be environmentally risky.Changes in a lady beetle community following the establishment of common chord alien speciesAlyokhin Sewell (2004) Biological Invasions, 6, 463-471.The successful introduction of Rodolia cardinalis was followed by the introductions of numerous coccinellids without a thorough risk assessment (van Lenteren, 2005). As a result, many indirect effects have been enter. However, numerous experiments that appear to provide evidence for indirect effects have been criticized because they took place over such a short time scale. This means that limited conclusions can be raddled because they do not allow for natural variation in species abundances (Alyokhin Sewell, 2004). colossal t erm research is required in order to provide adequate evidence for the indirect effects of biological control. This is particularly relevant to coccinellids as they are known for population fluctuations (Alyokhin Sewell, 2004).This paper provides evidence of the biological control agents Harmonia axyridis, Coccinella septempunctata and Propylea quatordecimpunctata competitively displacing native coccinellids. This paper is pioneering as the change in coccinellid populations was observed over a 31 year period so it allows for natural variation.Alyokhin Sewell (2004) found that prior to 1980 the majority of coccinellid species recorded were native. Following the establishment of C. septempunctata in 1980, native species were outcompeted the abundance of C. septempunctata increased from 6.1% in 1980 to 100% in 1994 (see cipher 1). In 1993 and 1995 P. quatordecimpunctata and H. axyridis established respectively (see Figure 1). Alyokhin Sewell (2004) concluded that the increase in ex otic coccinellid establishment was strongly correlated with a statistically pregnant decline in native coccinellid populations.This study provides evidence for the indirect effects of biological control. The methodology allows for natural population fluctuations and both methods and results were supported by previous studies (such as Brown Miller 1998 Elliott et al. 1996). However, controls were obtained from an archive, this is undesirable as it does not ensure the use of the said(prenominal) protocol. Experiments should always include appropriate validatory and negative controls to enable the drawing of accurate conclusions (van Lenteren et al. 2006b). In addition, this study does not consider other factors that might have affected native species populations such as temperature and other native species.The establishment of exotic coccinellids did not result in the total displacement of native species native species were present throughout the study in reduced abundance. This may indicate that although competition took place, it was not substantial enough to place the native coccinellids at risk of extinction. Therefore, it may be argued that the benefits of aphid control are worth a reduction in native coccinellid populations (Pearson Callaway, 2005).In addition, this study is further limited as it took place on a potato field and potato is exotic to the area. Therefore, this experiment may not reflect the effects of an introduction exotic insect to a naturally evolved ecosystem. For example, potato and native coccinellids did not evolve unneurotic and this may have provided exotic species with a competitive advantage (Strong Pemberton, 2000). in spite of the limitations discussed, this study provides evidence of habitat displacement in biological control. Alyokhin Sewell (2004) utilised appropriate statistical tests to provide valuable insight into the change in native species populations following biological control agent establishment. The regula tions and assessments under which biological control agents such as H. axyridis and C. septempunctata were released needs to be reassessed to ensure biological control is environmentally safe.Harmonia axyridis in Great Britain analysis of the revolve and distribution of a non-native coccinellidBrown et al. (2008) BioControl, 53, 55-67.Harmonia axyridis has been released to control aphids and coccids crosswise Europe (for example, Ukraine in 1964, Belarus in 1968, France in 1982, Portugal in 1984, Italy in 1990s, Greece in 1994, Spain in 1995, Netherlands in 1996, Belgium in 1997, Germany in 1997, Switzerland for a short period in the 1990s before it was deemed too risky and finally, Czech republic in 2003). Since its introduction into these countries, H. axyridis has also been observed in Austria, Denmark, the UK, Liechtenstein, Luxembourg, Norway and Sweden (Brown et al. 2007). This paper provides evidence of H. axyridis dispersal into Great Britain, where it has never advisedly been released. This paper was selected as unlike other countries, Great Britain has monitored the spread of H. axyridis since its initial arrival in 2004 (Majerus et al. 2006).Brown et al. (2008) utilised a net ground survey to follow the dispersal of H. axyridis across Great Britain. mingled with 2004 and 2006, the analysis of 4117 H. axyridis recordings indicated that H. axyridis dispersed an average of 58 km north, 144.5 km westmost and 94.3 km north-west per year. The increased western dispersal rate is suggested to be due to multiple invasions from the European mainland. H. axyridis recordings increased by an average of 2.9 tidy sum each year and the mean number of adults per recording increased from 2.9 in 2004 to 6.2 in 2006.The results from this study indicate that H. axyridis has invaded Great Britain on multiple cause and through multiple methods. For example, a single blue population of H. axyridis was recorded in Derby. This indicates that this population must ha ve arisen from a separate invasion than those populations spreading across the UK from the East.Public recordings were verified before inclusion in the analysis. Although this would have increased the accuracy of results, 4316 recordings were not verified so were not included. Some of the non verified recordings were likely to be H. axyridis but verification was not possible. Therefore, the analysis in this paper could be a huge lowball of the actual dispersal and abundance of H. axyridis across the Great Britain. This data primed(p) is also limited due to the uneven spread of human populations across Great Britain. This would have resulted in a variation in the frequence of recordings in different areas. Therefore, these results may not accurately represent the species abundance.This paper demonstrates that the currently inconsistent regulation for biological control across Europe is not adequate. The release of a biological control agent in one country will inevitably affect ne ighbouring countries. For example, H. axyridis has never been intentionally released in the UK but it has been estimated that since its invasion, H. axyridis could negatively affect 1, 000 of Great Britains native species (Majerus et al. 2006). The release of H. axyridis provides evidence that patchy regulation is a risk of biological control in itself.Review of invertebrate biological control agent regulation in Australia, newfangled Zealand, Canada and the USA preachations for a harmonized European systemHunt et al. (2008) Journal of Applied Entomology, 132, 89-123.Whilst the potential risks of biological control have only recently been acknowledged in Europe, they have been recognised and regulations have been implemented to avoid them for over forty years in Australia, radical Zealand, Canada and the USA. Following a thorough and pioneering review of current regulation, Hunt et al. (2008) have discussed the adaptation of some concepts for Europe.Hunt et al. (2008) found that although most European countries have regulation in place, only eight countries utilise them. Therefore, like Australia, unsanded Zealand, Canada and the USA, Europe requires the passing of legislations to enforce the safe use of biological control. Australia is the only country to have a governing body specifically for biological control. Regulations in New Zealand, Canada and the USA fall under plant, conservational, environmental or endangered species Acts (Hoddle, 2004). Europe requires an EU level body and regulation specifically for insect biological control. This body should cover both environmental and agricultural issues and should be composed of experts representing each country. The EU body should implement regulations across Europe and should make decisions for the release of biological control agents. Like Canada, the USA, Australia and New Zealand a group of scientific experts should be utilised to review applications and recommend decisions to the EU body. This will ensure the decision for each introduction is based on the opinion of experts covering a broad range of expertise.Following the establishment of an EU wide body and the passing of legislation, scientifically based ERA procedures need to be developed. In both Australia and the USA, approval is seek for the non target list prior to host specificity testing, however, this may restrict the ideally flexible spirit of host specificity testing where species should be added or withdraw when appropriate (Kuhlmann et al. 2005). Hunt et al. (2008) suggest European regulation should follow New Zealand by involving discussions with experts. This will ensure the consideration of all risks, be, benefits and the use of a scientifically based ERA. Discussion with experts will also reduce costs and time wasted on projects that do not have potential or are not being completed in an efficient manner.This paper uses examples from the USA and Canada to demonstrate that a regulatory body over the whole of Europe is possible. It also emphasises the importance of utilising previous experiences of regulated countries to implement effective regulation in Europe. However, Messing (2005) argues that the USA has unresolved legislative problems between their federal and state governing boards. For example, Hawaii has such strict ERA regulations that the use of biological control is hindered and the federal ERA regulations are meager as they do not involve adequate application review. In addition, Cameron et al. (1993) argues that only 24% of biological control projects in New Zealand have been a success. Goldson et al. (2010) adds that Australian and New Zealand legislations are too strict. For example, in order to receive approval for release, evidence is required to prove agents do not pose any risks but this is often impossible due to time and cost constraints.Care is required when reviewing the regulation of biological control in other countries. The presence of regulation does not necessarily mean it is enforce and information from government employees may be susceptible to political issues. Europe wide legislation is required but time and cost constraints need to be taken into account. In conclusion, regulation is needed to enforce the environmental safety of biological control but it should not restrict its effective use.Establishment potential of the predatory mirid Dicyphus hesperus in northern EuropeHatherly et al. (2008) BioControl, 53, 589-601.Many guidelines have been released for an ERA (such as EPPO, 2001 NAPPO, 2001 IPPC, 2005) but no(prenominal) state a clear and effective methodology to test for establishment. As a result of this, climate matching has been widely accepted as an efficient predictor of establishment (for example, Messenger van den Bosch, 1971 Stiling, 1993). However, the augmentative biological control agent, Neoseiulus caliginosus has proved its inadequacy as individuals with diapause ability were released by chance (Jolly, 200 0). McClay Hughes (1995) use of a degree-day model to predict establishment potential has also been criticized due to its labour intensive nature (McClay, 1996). In addition, the numerous methods utilised to delay developmental thresholds have led to differing conclusions for the establishment potential of the same insect (Hart et al. 2002). Hatherly et al. (2008) utilise a clear and scientifically based methodology for a test for establishment that should be used as an alternative to climate matching and day degree models.Each experiment involved treatments of fed and unfed first instar nymphs, adults and diapause induced adults. Supercooling points (SCP), Lower lethal times (see Figure 2) and temperatures were determined. Field experiments were completed to study the effects of naturally move temperatures and a control experiment was conducted to ensure experimental conditions did not damage the mirids.Statistical tests (one way ANOVA and Tukeys HSD test) found no significant differences between the SCP (-20oC) for different life cycles and Ltemp90 was found to be -20.4oC for diapausing insects. After 140 long time in the field, 5% of fed nymphs and 50% of fed diapausing adults were alive. After 148 days, 15% of fed non diapausing adults were alive. Following transfer to the lab, the survivor adults were observed laying executable eggs.Overall, it was concluded that D. hersperus were able to diapause and individuals from each life cycle were able to survive outdoors in the UK. Feeding increased survival times and the polyphagous nature of D. hersperus meant it was likely to find food.Laboratory methods to test the establishment potential of possible biological control agents need to be environmentally relevant (Hoelmer Kirk, 2005). To determine SCP, the rate of temperature decrease was 0.5oCmin-1, this could be reduced to make it more realistic. Mortalities for lower lethal temperatures were recorded after 24 and 48 hours, however, winter lasts for 4 to six months. In this case, this was appropriate as 90% mortality was reached at each temperature exposure within the timescale. To make this study more realistic, it was ensured that D. hersperus was experimented on in the condition received by commercial buyers. To ensure that the results did not occur by chance, lower lethal temperatures and time were determined in addition to SCPs (Bale, 2005).To determine establishment potential, both b