Biological Control Research Research Articles

The benefits and potential of pre-emptive weed biological control: Three case studies in Queensland, Australia

Invasive weed species can have significant impacts on agriculture, biodiversity and livelihoods. The cost and feasibility of managing these species using conventional means can be prohibitive depending on the size of the infestations or the habitats in which they invade. Under these conditions, biological control is seen as a viable, sustainable means to manage many weeds. However, biological control can take many years and at considerable cost to achieve the desired level of control, due to the numerous steps that are involved, including native range surveys and host-specificity testing of potential agents. Pre-emptive biological control targeting particularly high-risk species prior to their arrival in a country or emerging weeds can be cost-effective, especially if the respective biological control agents have been utilized in other countries. While pre-emptive biological control of arthropods has been investigated previously, there are few examples of pre-emptive biological control of weed species. The invasive weed species, Chromolaena odorata, Mikania micrantha and Coccinia grandis have all been or are currently targets of pre-emptive biological control in Australia. Research on the gall fly Cecidochares connexa was initiated prior to its host, C. odorata being detected in Australia. Cecidochares connexa was eventually released in Australia to control C. odorata, after initial research on the agent found it to be suitably host specific and effective against the target weed. Cecidochares connexa has also been released in numerous other countries in Africa, Asia and the Pacific, where it is providing very good control. Australia funded research on the rust Puccinia spegazzinii as part of a project involving Fiji and Papua New Guinea while the target weed, M. micrantha was a target for eradication in Queensland. The rust was later approved for release in Australia to control M. micrantha following additional host-specificity testing. However, research funded by Australia overseas suggests that the rust may not be able to suppress M. micrantha populations below current levels. Consequently, while P. spegazzinii has been released in numerous countries now, it has not yet been field released in Australia. Biological control research in Australia on C. grandis is relatively new as the weed is relatively minor and not yet declared a target for biological control. Consequently, no biological control agents have yet been released in the country. Pre-emptive biological control of C. odorata and M. micrantha has been particularly cost-effective, not just for Australia, but subsequently for numerous other countries where these weeds were well-established and problematic and the respective biological control agents were later released.

Optimization of Fermentation and Biocontrol Efficacy of Bacillus atrophaeus XHG-1-3m2

Biological control plays an increasingly important role in various aspects of modern agriculture and forestry. Identifying biocontrol strains with commercial potential for effective disease management is currently a focal point in biological control research. In this study, Bacillus atrophaeus XHG-1-3m2, a strain with significant biocontrol potential against Wilsonomyces carpophilus causing shot hole disease in wild apricots, was developed. The study determined the antibacterial activity of the fermentation broth, the optimal fermentation medium composition and conditions, and explored its effectiveness in controlling Wilsonomyces carpophilus. The optimal fermentation medium for strain XHG-1-3m2 comprises 12.5 g/L yeast extract, 12.5 g/L soy peptone, 10.0 g/L sodium chloride, 1 g/L ammonium chloride, 1 g/L potassium dihydrogen phosphate, 1 g/L disodium hydrogen phosphate, and 0.5 g/L magnesium sulfate heptahydrate. With an initial pH of 7.0, a liquid volume of 40%, an inoculum volume of 3%, and shaking incubation at 28 °C for 24 h, the viable cell count reached 14 × 109 CFU/mL. In vitro and in vivo tests on leaves revealed that the fermentation broth and the biocontrol biofertilizer derived from this strain inhibited the leaf lesions caused by Wilsonomyces carpophilus on wild apricots, achieving inhibition rates of 94.62% and 82.46%, respectively.

Enhancing Date Palm (Phoenix dactylifera L.) Resilience: Strategies Against Bayoud Spread in Moroccan Oases

Abstract “Bayoud”, a vascular disease caused by the soilborne fungal pathogen Fusarium oxysporum f. sp. albedinis (Foa), is the principal enemy of palm trees that puts at stake the future of the date palm industry in Morocco. The parasite attacks the palms through the roots and colonizes the entire vascular system, leading to wilt and ultimately palm death. Effective disease management is a major step towards the success of all sustainable development projects in the oasis. This review delineates diverse strategies for managing Bayoud disease, including prophylactic measures, chemical and cultural controls, genetic selection for resistant varieties, and exploration of biochemical and molecular markers. An integrated management approach was proposed that underscores early detection, sustainable agricultural practices, genetic resistance, biological control, community involvement, and continuous research and development. To contain the disease in already-infested areas and prevent its spread to new date palm plantations in oases.

Biological control for One Health

Biological control has been effectively exploited by mankind since 300 CE. By promoting the natural regulation of pests, weeds, and diseases, it produces societal benefits at the food-environment-health nexus. Here we scrutinize biological control endeavours and their social-ecological outcomes through a holistic ‘One-Health’ lens, recognizing that the health of humans, animals, plants, and the wider environment are linked and interdependent. Evidence shows that biological control generates desirable outcomes within all One Health dimensions, mitigating global change issues such as chemical pollution, biocide resistance, biodiversity loss, and habitat destruction. Yet, its cross-disciplinary achievements remain underappreciated. To remedy this, we advocate a systems-level, integrated approach to biological control research, policy, and practice. Framing biological control in a One Health context helps to unite medical and veterinary personnel, ecologists, conservationists and agricultural professionals in a joint quest for solutions to some of the most pressing issues in planetary health.

Phylogenomics-driven host test list selection for weed biological control

A concern in weed biological control research is the potential for candidate biocontrol agents to impact not only the target weed but also native or economically important flora. The degree of evolutionary relatedness between the target weed species and a non-target species is a key predictor of the susceptibility of the non-target to the biocontrol agent. To manage this risk, biocontrol practitioners need to understand the phylogenetic position of the host weed relative to non-target plant species. However, comprehensively sampled phylogenetic trees are often unavailable, with incomplete information scattered across multiple publications. Further, older published phylogenies based on Sanger sequence data often lack branch resolution and support, which increases uncertainty in biocontrol decision making. Decreasing sequencing cost and technological advances have led to phylogenomic approaches being more widely used to understand evolutionary relationships between species. For example, target capture sequencing methods using bait kits such as Angiosperms353 enable cost-effective and timely phylogenomic-level analysis of flowering plant groups at different scales. Here, we introduce a workflow to embed a comprehensive understanding of evolutionary relationships into the efficient development of host test lists in weed biological control. We demonstrate the effectiveness of the workflow through a case study on the major crop weed flaxleaf fleabane (Erigeron bonariensis). Phylogenomic analysis was conducted on 280 species of the tribe Astereae (family Asteraceae) occurring in Australia and New Zealand, clarifying relationships between the target species and related clades of native and non-native Astereae. We consider the phylogenetic tree in the context of a previously proposed host test list and discuss taxonomic implications, highlighting avenues of future molecular-based work to uncover the origin of Australian fleabanes. This study provides a workflow and demonstrates the practical application of target sequence capture for phylogenomic inference to support risk analysis and decision making in classical weed biological control.

Status and trends of biological control research, extension, and education in the United States

Abstract The number of public-sector biological control scientists and practitioners in the United States was determined by a survey conducted in 2019. A total of 344 personnel were identified in 49 states and Washington DC; 218 employed by universities, 86 by the federal government and 36 by state departments of agriculture. There were 10-34 personnel in eight states, 6-9 in 11, and 0-5 in 31, overall averaging less than 50% of their combined effort on biological control. Applications for biological control agents included about 30% for row crops and vegetables; 12% each for orchards, urban landscapes, outdoor ornamentals, and forests; and 22% for the remainder. The federal government provided an average of 42% of the funding for university, federal, and state biological control research and extension. The states contributed 29-35%, commodity groups supplied 19-24%, and the remaining funds were from private sources. Of 54 universities in the United States, 18 conducted in-person classroom education and training in biological control, with seven offering courses via distance. However, another 18 universities had discontinued their comprehensive courses. Biological control instruction was incorporated into courses and workshops on integrated pest management and sustainable agriculture at 50 universities. Correspondingly, during the past 24 years, biological control has gradually developed from primarily an independent discipline to increasingly being part of integrated pest management. Classical, augmentative and conservation biological control have nevertheless remained distinguishable high priority subdisciplines. Funding continues to be essential for advancing biological control, requiring societal understanding and acceptance. Advancement of biological control in the United States will require increased investment in personnel and their education and training, along with delivery of effective pest management technologies.

Identification of Some Species of the Family Coccidae that Infest Fruit Orchards in Syria

Saleh, A.T. and A.M. Basheer. 2024. Identification of Some Species of the Family Coccidae that Infest Fruit Orchards in Syria. Arab Journal of Plant Protection, 42(2): 174-183. https://doi.org/10.22268/AJPP-001224 Soft scale insects are serious plant pests, are often small and highly cryptic. These pests are economically important in agriculture. Insect samples and infested plant parts were collected during the period April to June 2016 and 2017 from three locations (Al-Sanobar, Daba, and Jaba) and then brought to the Biological Control Studies and Research Center (BCSRC). The following soft scale insects of the order Coccomorpha and family Coccidae were identified: Coccus pseudomagnoliarum Kuwana, in Al-Sanobar and Dabba in Lattakia governorate in Java orange orchards, Saissetia oleae Olivier and C. pseudomagnoliarum Kuwana in Pomelo citrus tree in Daba locality, Sphaerolecanium prunastri Fonscolombe at the third site Jaba, Quneitra governorate, in almond orchards, and to our knowledge is the first record in Syria. Identification and characterization of the soft scale insects was based on microscopic characters of adult female using slide-mounted specimens. Identification of pests is essential for the implementation of biological control programs. Keywords: Coccidae, soft scale insects, Syria

Investigation the Spread of Natural Enemies Associated with The Tomato Leaf Miner, Tuta absoluta in Al-Hasakeh Governorate, Syria

Darwish, A., A. Besheer and K. Al-Asas. 2024. Investigation the Spread of Natural Enemies Associated with The Tomato Leaf Miner, Tuta absoluta in Al-Hasakeh Governorate, Syria. Arab Journal of Plant Protection, 42(3): 355-360. https://doi.org/10.22268/AJPP-001253 The tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is one of the most important pests attacking all parts of the tomato plant, especially leaves, was first recorded in Syria in 2010. Since then, it has become the most important pest affecting tomatoes and causing economic losses to tomato farmers, ranged from 50-100%. Field applied research was conducted in tomato fields at Amuda and Derbasiyah sub-district of Al-Hasake Governorate, Syria, during the seasons 2016 to 2018. Laboratory research under laboratory conditions (25±2ºС, RH 65±5%) and under long daylight (16 hrs light:8 hrs darkness) in the biological control research center, Faculty of Agriculture, University of Damascus, Syria. Five parasitoids and predators were identified on T. absoluta, namely: Hemiptera (Homoptera) predators: Nesidiocoris tenuis (Miridae), Orius sp. (Anthocoridae) and Neuroptera predator Chrysopa sp. (Chrysopidae), Hymenoptera parasitoids; Bracon (Habrobracon) sp. (Braconidae) and Ratzeburgiola sp. (Eulophidae). Keywords: Tomato leafminer, parasitoids, predators, Al-Hasake, Syria

Research Progress of Promoting Biocontrol Bacteria in Rice Rhizosphere

The irrational application of rice chemical fertilizer and the reduction of rice quality and yield caused by rice diseases have seriously affected agricultural production and the environment. To grow rice more scientifically and greenly, plant growth-promoting rhizobacteria (PGPR) has developed rapidly as a new control method for plant diseases. The discovery of PGPR is an essential process in biological control research. PGPR has many species, excellent biological traits, diverse antagonistic mechanisms, and a wide range of parasitism, which is an essential biological control method to solve the excessive application of chemical fertilizers and pesticides in rice production and has broad development prospects. In this paper, we summarize the research progress of PGPR application to rice and other plants in recent years, expound on the direct and indirect mechanisms, and look forward to the development trend of follow-up research in order to provide a theoretical reference for the in-depth study and better application of biocontrol bacteria.

Host-specificity of biocontrol agents in the field – The significance of sampling sympatric relatives of target weeds (Acacia holosericea versus A. auriculiformis)

Acacia auriculiformis is an invasive weed that causes significant environmental damage across Florida, USA. Previous native range surveys in Australia identified a number of herbivores that are commonly associated with this plant, including several species of leaf-tying moths (Macrobathra spp.) and a chrysomelid beetle (Calomela intemerata). These herbivores are considered strong candidates as biological control agents, but the range of host species they use has not been determined. We therefore conducted a transect survey of herbivorous insects on A. holosericea, a closely-related sympatric relative of A. auriculiformis. These species share areas of sympatry and the latter was sampled simultaneously (in sympatry and allopatry). DNA barcoding approach identified an array of herbivorous insects feeding on A. holosericea, but few were found on both the Acacia species sampled. A literature survey suggested this pattern of host specificity may be consistent across Australian acacias, to the extent that each Acacia species may largely host its own suite of herbivores. These results do not negate the need for host testing procedures in biological control, but they do increase our confidence substantially that several promising potential biological control agents of A. auriculiformis (Macrobathra moths and Calomela beetles) have a restricted host species range. Our study illustrates how exploring the herbivore diversity of plant species closely related to the target weed can provide crucial information for biological control researchers.

Evolution of knockdown resistance (kdr) mutations of Aedes aegypti and Aedes albopictus in Hainan Island and Leizhou Peninsula, China.

Aedes aegypti and Aedes albopictus are important vectors of human arboviruses, transmitting arboviral diseases such as yellow fever, dengue, chikungunya and Zika. These two mosquitoes coexist on Hainan Island and the Leizhou Peninsula in China. Over the past 40 years, the distribution of Ae. albopictus has gradually expanded in these areas, while the distribution of Ae. aegypti has declined dramatically mainly due to the ecological changes and some other factors such as heavy use of insecticide indoor based on endophagic bloodfeeding of the species. This study focused on the knockdown resistance (kdr) genes of both mosquitoes, investigated their mutations, and analyzed their haplotype and evolutionary diversity combined with population genetic features based on the ND4/ND5 genes to further elucidate the molecular mechanisms underlying the development of insecticide resistance in both mosquitoes. Three mutations, S989P, V1016G and F1534C, were found to be present in Ae. aegypti populations, and the three mutations occurred synergistically. Multiple mutation types (F1534C/S/L/W) of the F1534 locus are found in Ae. albopictus populations, with the three common mutations F1534C, F1534S and F1534L all having multiple independent origins. The F1534W (TTC/TGG) mutation is thought to have evolved from the F1534L (TTC/TTG) mutation. The F1534S (TTC/TCG) mutation has evolved from the F1534S (TTC/TCC) mutation. The most common form of mutation at the F1534 locus found in this study was S1534C, accounting for 20.97%, which may have evolved from the F1534C mutation. In addition, a new non-synonymous mutation M1524I and 28 synonymous mutations were identified in Ae. albopictus populations. Correlation analysis showed that the genetic diversity of Ae. aegypti and Ae. albopictus populations did not correlate with their kdr haplotype diversity (P>0.05), but strong gene flow between populations may have contributed to the evolution of the kdr gene. The study of kdr gene evolution in the two mosquito species may help to identify the evolutionary trend of insecticide resistance at an early stage and provide a theoretical basis for improving the efficiency of biological vector control and subsequent research into new insecticides.

A Taxonomic Study of Some Species of Hyperparasitoids Attacking the Primary Parasitoid Microterys nietneri of the Citricola Scale Insect, Coccus pseudomagnoliarum in Syria

Saleh, A.T. and A.M. Basheer. 2023. A Taxonomic Study of Some Species of Hyperparasitoids Attacking the Primary Parasitoid Microterys nietneri of the Citricola Scale Insect, Coccus pseudomagnoliarum in Syria. Arab Journal of Plant Protection, 41(3): 292-305. https://doi.org/10.22268/AJPP-41.3.292305 The citricola scale insect, Coccus pseudomagnoliarum, (Kuwana) (Hemiptera: Coccomorpha: Coccidae) is an economically important pest that occurs on citrus trees along the Syrian coast. The samples of host insects and infested plant parts were collected from April to June during 2016 and 2017 from two locations (Al-Sanobar, Dabba) in Lattakia Province and brought to the Biological Control Studies and Research Center (BCSRC), Faculty of Agriculture, Damascus University. Based on the information gathered, Microterys nietneri (Motschulsky) (Hymenoptera: Encyrtidae) may play an important role as a biological control agent of citricola scale insect, but high hyperparasitoids levels reduced M. nietneri efficiency as a citricola scale parasitoid. The objective of this study was to describe and identify naturally occurring hyperparasitoids. The following parasitoids were identified and reported for the first time in Syria: Cheiloneurus claviger (Thomson), Pachyneuron muscarum (Linnaeus), and Marietta leopardine (Motschulsky). Microscopic images were provided to illustrate the morphological and morphometric characteristics of these species. Keywords: Hyperparasitoids, Citricola scale, Microterys, Syria

Partial refuges from biological control due to intraspecific variation in protective host traits.

Predicting how much of a host or prey population may be attacked by their natural enemies is fundamental to several subfields of applied ecology, particularly biological control of pest organisms. Hosts or prey can occupy refuges that prevent them from being killed by natural enemies, but habitat or ecological refuges are challenging or impossible to predict in a laboratory setting-which is often where efficacy and specificity testing of candidate biological control agents is done. Here we explore how intraspecific variation in continuous traits of individuals or groups that confer some protection from natural enemy attack-even after the natural enemy has encountered the prey-could provide partial refuges. The size of these trait-based refuges (i.e., the proportion of prey that survive natural enemy encounters due to protective traits) should depend on the relationship between trait values and host/prey susceptibility to natural enemy attack and on how common different trait values are within a host/prey population. These can be readily estimated in laboratory testing of natural enemy impact on target or nontarget prey or hosts as long as sufficient host material is available. We provide a general framework for how intraspecific variation in protective host traits could be integrated into biological control research, specifically with reference to nontarget testing as part of classical biological control programs. As a case study, we exposed different host clutch sizes of target (pest) and nontarget (native species) stink bug (Hemiptera: Pentatomidae) species to a well-studied exotic biocontrol agent, the egg parasitoid Trissolcus japonicus (Hymenoptera: Scelionidae). We predicted that the smallest and largest clutches would occupy trait-based refuges from parasitism. Although we observed several behavioral and reproductive responses to variation in host egg mass size by T. japonicus, they did not translate to increases in host survival large enough to change the conclusions of nontarget testing. We encourage researchers to investigate intraspecific variation in a wider variety of protective host and prey traits and their consequences for refuge size.

Biological Disease Control by Beneficial (Micro)Organisms: Selected Breakthroughs in the Past 50 Years.

Biological control of plant disease by beneficial (micro)organisms is one of the main tools available to preserve plant health within the wider context of One Health and in line with the goals of the Agenda 2030 for Sustainable Development. The commercial development of biocontrol agents, together with a new perspective on the resident microbial community, all supported by innovative "omics" technologies, continues to gain in prominence in plant pathology, addressing the need to feed the increasing world population and to assure safe and secure access to food. The present review considers selected advances within the last 50 years, highlighting those that can be considered as breakthroughs for the biological control research field. Selected examples of successful biocontrol agents and strategies are reported, including the history of the progress in researching Trichoderma isolates as commercial biocontrol agents, the exploitation of mycoviruses to confer hypovirulence to plant pathogenic fungi, the role of microbial communities in the suppressiveness of soils, and evolving approaches including the establishment of synthetic microbial communities.

Recent Advances in Life History Transition with Nematode-Trapping Fungus Arthrobotrys oligospora and Its Application in Sustainable Agriculture.

Parasitic nematodes cause great annual loss in the agricultural industry globally. Arthrobotrys oligospora is the most prevalent and common nematode-trapping fungus (NTF) in the environment and the candidate for the control of plant- and animal-parasitic nematodes. A. oligospora is also the first recognized and intensively studied NTF species. This review highlights the recent research advances of A. oligospora as a model to study the biological signals of the switch from saprophytism to predation and their sophisticated mechanisms for interacting with their invertebrate hosts, which is of vital importance for improving the engineering of this species as an effective biocontrol fungus. The application of A. oligospora in industry and agriculture, especially as biological control agents for sustainable purposes, was summarized, and we discussed the increasing role of A. oligospora in studying its sexual morph and genetic transformation in complementing biological control research.

Insect and weed biological control in Hawaii: Recent case studies and trends

Hawaii has a long history of classical biological control research and implementation. Many successes have been achieved in suppressing invasive insect species and plants though the introduction of insect and plant pathogenic natural enemies. This review paper details selected recent introductions and discusses selected cases highlighting successes with highly impactful invasive species control in diverse environments. The current state of biological control in Hawaii is discussed, including recent trends in numbers of species released, concerns about non-target impacts, and how these are addressed. Research on the biological aspects is thorough, but the ability to expand research to address continuing invasive species issues is constrained largely by infrastructure limitations. Urgent research needs for continued biological control research are identified.

Mapping biological control research: A systematic review of 20 years of research in Indonesia

Biological control research in Indonesia has a long history since it was started by Dutch scientists more than 100 years ago. Currently, the number of research has arisen, but there has been no systematic analysis of how this research produces technology that can be practiced in the field. This analysis is essential since it provides baseline information about biocontrol research and provides future research direction. This study aims to conduct a systematic review of biocontrol research conducted in Indonesia over the past 20 years. All articles were obtained from various databases using keywords related to biocontrol. A total of 437 articles were analyzed. We focussed our research on predators and parasitoids and found 269 articles related to parasitoids and predators. We found that biocontrol research in Indonesia was dominated by research on insect pathogens. Further analyses showed that research on identification and biology dominated most of the studies on predators and parasitoids. Almost all the research that was conducted addressed the basic biology of different types of natural enemies for different crops’ pests but has not addressed the full-scale host-parasitoid research that is needed to develop natural enemies that are ready to be released on a large scale. Four natural enemies have been reported in large-scale applications: Anagyrus lopezi, Lanius schach, Trichogramma spp., and Tetrastichus brontispae. There is limited research on the mass release of parasitoids or predators in the field. Most of the research on releases was focussed on the short-term establishment without long-term evaluation and measure of success. It leads to a knowledge gap in biological control research and should become one of the future research directions.

Efficacy of Some Local Isolates of the Fungus Beauveria bassiana (Bals.-Criv.) Vuill Towards the Immature Stages of the Fall Armyworm, Spodoptera frugiperda (J. E. Smith)

Alshadidi, B., J. Faddoul and A. Basheer. 2023. Efficacy of Some Local Isolates of the Fungus Beauveria bassiana (Bals.-Criv.) Vuill Towards the Immature Stages of the Fall Armyworm, Spodoptera frugiperda (J. E. Smith). Arab Journal of Plant Protection, 41(4): 384-390. https://doi.org/10.22268/AJPP-41.4.384390 The fall armyworm, Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) is one of the major pests that attack the maize crop. The use of entomopathogenic fungi is considered one of the most important strategies in managing this invasive pest as opposed to synthetic pesticides that are hazardous to human, environment and biodiversity. The experiments were conducted at the Biological Control Studies and Research Center (BCSRC), Faculty of Agricultural Engineering, University of Damascus during the period 2020-2022. The efficiency of seven Beauveria bassiana isolates was evaluated on the immature stages of armyworm. Isolates KA.1 and BS.5 caused the highest eggs mortality rate, 88.17 and 83.40%, respectively, when applied at a concentration of 1 x 108 spores/ml7 days after treatment. Isolate BS.5 caused the highest mortality rate of 54.77% at the same spore concentration and there was no significant effect on second instar larvae and pupae. However, when the isolate KA.1 was used, the highest mortality rate was in the pupa and reached 21.27 % two weeks after treatment. Thus, B. bassiana fungus can be applied with high efficiency in controlling the armyworm community, especially in the early larval stages. Keywords: Entomopathogenic fungi, larval stages, Spodoptera frugiperda.

DNA High-Throughput Sequencing for Arthropod Gut Content Analysis to Evaluate Effectiveness and Safety of Biological Control Agents.

The search for effective biological control agents without harmful non-target effects has been constrained by the use of impractical (field direct observation) or imprecise (cage experiments) methods. While advances in the DNA sequencing methods, more specifically the development of high-throughput sequencing (HTS), have been quickly incorporated in biodiversity surveys, they have been slow to be adopted to determine arthropod prey range, predation rate and food web structure, and critical information to evaluate the effectiveness and safety of a biological control agent candidate. The lack of knowledge on how HTS methods could be applied by ecological entomologists constitutes part of the problem, although the lack of expertise and the high cost of the analysis also are important limiting factors. In this review, we describe how the latest HTS methods of metabarcoding and Lazaro, a method to identify prey by mapping unassembled shotgun reads, can serve biological control research, showing both their power and limitations. We explain how they work to determine prey range and also how their data can be used to estimate predation rates and subsequently be translated into food webs of natural enemy and prey populations helping to elucidate their role in the community. We present a brief history of prey detection through molecular gut content analysis and also the attempts to develop a more precise formula to estimate predation rates, a problem that still remains. We focused on arthropods in agricultural ecosystems, but most of what is covered here can be applied to natural systems and non-arthropod biological control candidates as well.

Metabarcoding and applied ecology with hyperdiverse organisms: Recommendations for biological control research.

Metabarcoding is revolutionizing fundamental research in ecology by enabling large-scale detection of species and producing data that are rich with community context. However, the benefits of metabarcoding have yet to be fully realized in fields of applied ecology, especially those such as classical biological control (CBC) research that involve hyperdiverse taxa. Here, we discuss some of the opportunities that metabarcoding provides CBC and solutions to the main methodological challenges that have limited the integration of metabarcoding in existing CBC workflows. We focus on insect parasitoids, which are popular and effective biological control agents (BCAs) of invasive species and agricultural pests. Accurately identifying native, invasive and BCA species is paramount, since misidentification can undermine control efforts and lead to large negative socio-economic impacts. Unfortunately, most existing publicly accessible genetic databases cannot be used to reliably identify parasitoid species, thereby limiting the accuracy of metabarcoding in CBC research. To address this issue, we argue for the establishment of authoritative genetic databases that link metabarcoding data to taxonomically identified specimens. We further suggest using multiple genetic markers to reduce primer bias and increase taxonomic resolution. We also provide suggestions for biological control-specific metabarcoding workflows intended to track the long-term effectiveness of introduced BCAs. Finally, we use the example of an invasive pest, Drosophila suzukii, in a reflective "what if" thought experiment to explore the potential power of community metabarcoding in CBC.