Risks of Microbial Biocontrol Agents and Regulation: Are They in Balance?

A wide range of biological control agents (BCAs) have been authorized and used in Hungary for the control of pests (including pathogens). BCAs are key elements of both integrated pest management and organic farming for different crops. Authorization of BCAs depends on the type of ‘active substance’. Micro-organisms can be authorized under the EU Regulation (EC) No. 1107/2009 as plant protection products (PPP), while macro-organisms are not within its scope. Plant protection tools (traps, mating disruption) are registered at a national level in Hungary, although mass traps and mating disruption pheromones are considered to be PPP. Plant extracts can be authorized as PPP, but some of them can be approved as a ‘basic substance’ and in this case they do not need further authorization. In Hungary, the vast majority of macro-organisms used as BCAs have been mainly used in greenhouses and polytunnels for the control of thrips, whiteflies, aphids, leaf mining flies, phytophagous mites and lepidopteran pests in vegetable and ornamental crops. Recently a non-indigenous chalcid wasp, Torymus sinensis, has been successfully introduced for the control of the oriental chestnut gall wasp, Dryocosmus kuriphilus, on chestnut (Castanea sativa) on different sites.

Opinions about the value of biological control are often extreme. Colloquially, biological control most often refers to classical biological control, in which one species is introduced from another region to control pests such as arthropod herbivores in agricultural systems, or weeds in managed and natural systems.1 As such, biological control has the potential to be a low-cost, chemical free, means to control pests. Numerous biological control programs have been unqualified successes (Bellows 2001), such as the control of cacti in Australia with the moth Cactoblastis cactorum (Raghu and Walton 2007), of cottony-cushion scale (Icerya purchasi) in California with the vedalia lady beetle, Rodolia cardinalis (Caltagirone and Doutt 1989), and of glassy-winged sharpshooters in French Polynesia with the egg parasitoid Gonatocerus ashmeadi (Grandgirard et al. 2009). Yet, classical biological control, as with any introduction of a species into a new area, necessarily involves the unknown and therefore carries some inherent risk (Simberloff and Stiling 1996) – what will these organisms actually do in a novel ecosystem? The most unpredictable element in biological control is the extent to which the realized niche is modified in the new environment. This effect has been responsible for some disastrous outcomes of classical biological control, many of which occurred during an era when vertebrates were being introduced around the world by Europeans for a variety of reasons (e.g., introducing the birds of Shakespeare to America, Mirsky 2008), including for biological control (Howarth 1991). The introductions as biological control agents of cane toad to Australia (Crossland et al. 2000) and mongoose to Hawaii (Hays and Conant 2007) are notorious. Introductions of generalist invertebrate agents also have had dire consequences, such as the introduction of predatory snails to French Polynesia (Murray et al. 1988; Coote 2007). In retrospect, some of the unintended consequences of biological control could have been avoided with more ecological knowledge (McEvoy and Coombs 2000) or more societal appreciation for native species (which has developed with time, Henneman and Memmott 2001), but with other introductions, it would have been impossible to know ahead of time what the risks would be (e.g., gall fly agents of knapweeds providing supplementary food to mice that harbor hantavirus, Pearson and Callaway 2006). Many of the unknown outcomes of biological control are purely ecological – what is the risk that a wasp, introduced to parasitize an agricultural pest, will also be able to feed on a native insect? Other unknowns involve evolution – will a herbivore adapt over time to be able to feed on a new nontarget host or hybridize with a closely related species? This volume explores the evolutionary aspects of biological control. Although often overlooked, evolutionary considerations are critical to all stages of classical biological control, from agent selection, to quarantine, release, establishment, and ultimately success in pest control (Ehler et al. 2004). Many questions are unresolved. For example, should agents be chosen that have a long history with the host or are ‘new associations’ more likely to succeed (Hokkanen and Pimentel 1989)? Can one improve effectiveness through artificial selection (Hopper et al. 1993)? Will postcolonization adaptation of the agent increase the likelihood of success, and/or are hosts equally likely to evolve resistance over time (Roderick 1992; Holt and Hochberg 1997; Hufbauer 2001)? Are generalist consumers more likely to survive in novel environments or are specialists more effective (Murdoch et al. 1985; Waage 1990; Brodeur 2012)? More recently, concern for the environment, as well as theory examining the reasons for success of generalist predators, prompted a shift to the release of specialized consumers typically preceded by extensive testing aimed at delimiting the host range of candidate biological control agents. While this approach has clearly made biological control more predictive ecologically, research focused on host range currently lacks measures of genetic variation in host use and responses of those hosts, and thus evolutionary uncertainties remain.

Simple SummaryThe whitefly, Bemisia tabaci, is considered one of the most destructive insect pests of vegetables and ornamental crops globally. Synthetic chemical pesticides are mainly used to control B. tabaci, however, their extensive usage has led to a series of detrimental concerns to human health and environmental contamination. It is therefore of significant interest to develop a safer and eco-friendly alternative for controlling B. tabaci. Here, we review the use of entomopathogenic fungi as a proven, biologically sustainable method to effectively control B. tabaci. The development of entomopathogenic fungi in an integrated pest management strategy against B. tabaci can reduce our reliance on chemical pesticides, and help us to secure food safety while preserving nature.Whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), consists of genetically diverse species known to cause significant destruction in several crops around the world. Nymphs and adults of B. tabaci cause damage to plants during feeding, and they can act as a virus vector, thus causing significant yield loss to crops in the tropical and subtropical regions. Chemical pesticides are widely used to control B. tabaci due to their immediate action, but this approach has several drawbacks including food safety issues, insecticide resistance, environmental pollution, and the effect on non-target organisms. A biological control agent using entomopathogenic fungi (EPF) has therefore been developed as an alternative against the conventional use of chemical pesticides in an integrated pest management (IPM) system to effectively control B. tabaci. It is apparent from this review that species of hyphomycetes fungi are the most common EPF used to effectively control B. tabaci, with the second instar being the most susceptible stage of infection. Therefore, this review article focuses specifically on the control of B. tabaci with special emphasis on the use of EPF as biological control agents and their integration in IPM.

The use of microorganisms for biological pest control as biological control agents (BCAs) and biopesticides was developed worldwide in the 1960s. Despite the abundance of reviews published on this topic, no meta-analysis using bibliometric tools has been published. The objective of this study was to determine patterns of research on microorganisms for the biological control of pests, based on publications available in the SCOPUS® database. The data were obtained from the Elsevier® Scopus meta-database using the search terms “biological pest control” and “microorganism” (title, abstract, and keywords). The main publications were identified, along with the journals, countries, and institutions that have published on the subject. The data were analyzed with VOSviewer to determine the co-occurrence of terms, and four maps were generated. The results show two phases in the scientific research on the subject: The first is the characterization of biological control agents, and the second is focused on the commercial development of biopesticides and biological control agents. The most recent research emphasizes the discovery of new species and strains that have commercial potential, with an emphasis on genetic engineering and biotechnology.

Nesidiocoris tenuis is a zoophytophagous insect widely used commercially as a biological control agent against different pests and crops under greenhouse conditions. For a successful Integrated Pest Management (IPM) strategy, it is crucial to know the compatibility of available and new crop protection products with biological control agents. The aim of this study was to evaluate and classify the lethal and sublethal effects of different crop protection products on the biological control agent N. tenuis, including the novel insecticides dimpropyridaz and Beauveria bassiana strain PPRI 5339, in accordance with the International Organisation for Biological and Integrated Control (IOBC) directives. Dimpropyridaz, B. bassiana PPRI 5339, the adjuvant fatty acid esters and the combination of B. bassiana PPRI 5339 with the adjuvant have been classified as harmless (IOBC 1 < 25% of mortality and beneficial capacity). The evaluation of reproduction and capacity for increase (rc) showed no significant sublethal effects between the previous compounds and the untreated control. Flupyradifurone, sulfoxaflor, and dimethoate were classified as harmful (IOBC 4 > 75% of mortality and beneficial capacity). The compatibility of these two new products (dimpropyridaz and B. bassiana PPRI 5339) with Nesidiocoris tenuis is of great importance because it adds new tools to be used in IPM programmes in which chemical and biological control strategies are used together.

Because of the limited number of products available for control of fire blight, the search for alternative methods of control has been a dynamic and productive field of scientific research. Today, only a few biological control agents are registered for control of this disease, representing a relatively small part of the market for products to control fire blight. This is in spite of fire blight being an economically important bacterial disease whose impact could be significantly lowered by simply protecting the flowers from the pathogen, a task that many biological control agents seem able to do. The number of new biological control agents being commercialised might be restricted by problems linked to the registration process. This is especially true for biological control agents that belong to species containing poorly characterised strains of medical or environmental interest. Furthermore, the biological control agents available in the USA were reported to exhibit a much lower and more variable efficacy than streptomycin. This may contribute to the choice by growers to use antibiotics more often than they use biological control agents. The future of biological control agents for the control of fire blight might rest in the ability to incorporate such products in new strategies of control. These strategies might include the use of several biological control agents, but may also include antibiotics or some elicitors.

The presence of mycotoxin-producing Aspergillus species in vineyards is a problem for food safety and the economy. In addition, rising temperatures due to climate change are modifying microbial communities, causing the replacement of some fungal species and the rise of mycotoxins such as aflatoxins. The use of microorganisms as biological control agents (BCAs) is one of the most promising strategies to prevent fungal growth and toxin production. In this study, 513 microorganisms were isolated from organic vineyard soils in different regions of Spain. The 480 bacteria and 33 yeasts isolated were sequentially screened to select those with the most suitable characteristics to be used as BCAs. After identifying 16 isolates meeting all requirements, six bacterial isolates were selected to test their potential to control three relevant toxigenic grape fungi in vitro: A. carbonarius, A. niger and A. flavus. Isolates of Arthrobacter sp., Rhodococcus sp. and Bacillus mycoides showed an excellent ability to reduce the growth and mycotoxin concentration of the above-mentioned fungi and represent potential candidates for further study regarding their possible industrial application as a BCA.

Normal 0 14 false false false IT ZH-TW X-NONE MicrosoftInternetExplorer4 Grapes were treated post harvest with a variety of biological agents to determine their effcacy in reducing yield loss. The agents Pseudomonas , Bacillus , Trichoderma and yeast isolates were individually screened against a number of postharvest pathogens including Aspergillus carbonarius , Penicillum expansum , and Fusarium moniliforme . B. subtilis strains EPC-8 and EPCO-16 showed high mycelial growth suppression of A. carbonarius and P. expansum in vitro . The fungal antagonist Trichoderma viride strain (Tv Tvm) was the most effective, inhibiting mycelial growth by 88.8 per cent. The biological control agents were tested in pre, post and combined inoculation studies against postharvest pathogens of grapes. In the pre inoculation, B. subtilis (EPC-8) reduced the disease incidence of A. carbonarius causing rot, T. harzianum (Th Co) was effective against P. expansum , and T. viride (Tv Tvm) was effective against F. moniliforme . The same trend of effectiveness was also found in the post-inoculation and combined inoculation tests.

Biological control programmes have varied in the extent of ecological studies carried out on potential agents and target organisms. At one extreme, studies were limited to surveys for potential biological control agents, which were then shipped to the target country. The biological control programme against Scotch broom (Cytisus scoparius) is at the other extreme: we list 29 significant studies on the ecology of broom in its native and introduced ranges, probably representing at least 100 years of work by scientific personnel. These studies have proved useful for predicting the success and safety of the biological control programme against broom as an alien weed. Three studies highlight the significance of insect herbivores reducing broom longevity and seed production: an 11-year insecticide exclusion experiment in the UK; replicated experiments examining recruitment of broom as a native plant in the UK/France and as an alien weed in New Zealand/Australia; and simulation modelling of broom abundance. However, predicting the contribution of each biological control agent to broom suppression is difficult, and may be required for risk-benefit analyses under new regulations. The safety of broom agents to non-target plant species has been addressed using normal host range testing procedures, and extensive field surveys of broom and related plants in Europe. There are concerns over adverse, indirect effects that released biological control agents may have on non-target organisms. For insect herbivores released against weeds, adverse indirect effects could occur because the agent acts as a new food source, competitor or disease vector in existing food webs; or because there are adverse effects on existing biota via a reduction in the abundance of the target weed (or non-target plant). Ecological studies of broom enable us to identify some of these potential effects, but predicting their magnitude prior to release of an agent is a major ecological challenge. Equally important to emphasize are the potential benefits to indigenous species from suppression of alien weeds. A balance is needed, because the time and resources required to make accurate ecological predictions of potential adverse effects from released agents could impede biological control of key environmental weeds, resulting in worse net impacts on indigenous species.

Greenhouse tomato production holds strong economic importance in the Western Balkan (WB) countries, driven by escalating market demands. To align with global food safety trends, systematic advancements in cultivation practices and pest management strategies are essential for the WB region. Conventional reliance on chemical pesticides as the primary pest control method has led to various adverse outcomes, impacting pest management effectiveness and reducing product quality. The impact of climate change on agricultural productivity further emphasizes the need for environmentally friendly solutions in pest protection. To address these challenges and mitigate the detrimental effects of chemical pesticides, this review explores sustainable, alternative solutions, like biological control agents (BCAs), for tomato pest control in the WB region. With biological control gaining recognition as an effective approach, yet remaining underutilized in the WB, this review provides a thorough analysis of the most effective, commercially available BCAs, critically evaluating their advantages and limitations. Widespread BCA application could support the expansion of the tomato production sector while fostering sustainable agricultural practices. Furthermore, the review explores the role of BCAs within Integrated Pest Management (IPM) frameworks in tomato production, emphasizing their alignment with Sustainable Development Goals (SDGs), particularly for countries aiming for EU integration.

Non-native invasive arthropod species threaten biodiversity and food security worldwide, resulting in substantial economic, environmental, social and cultural costs. Classical biological control (CBC) is regarded as a cost-effective component of integrated pest management programmes to manage invasive arthropod pests sustainably. However, CBC programmes are traditionally conducted once a pest has established in a new environment, and invariably all research needed to achieve approval to release a biological control agent can take several years. During that time, adverse impacts of the pest accelerate. A pre-emptive biocontrol approach will provide the opportunity to develop CBC for invasive pests before they arrive in the country at risk of introduction and therefore enhance preparedness. A critical aspect of this approach is that risk assessment is carried out in advance of the arrival of the pest. Implementing pre-emptive biocontrol risk assessment means that natural enemies can be selected, screened in containment or abroad and potentially pre-approved prior to a pest establishing in the country at risk, thus improving CBC effectiveness. However, such an approach may not always be feasible. This contribution defines the fundamental prerequisites, principles, and objectives of pre-emptive biocontrol risk assessment. A set of guidelines and a decision framework were developed, which can be used to assess the feasibility of conducting a pre-emptive risk assessment for candidate biological control agents against high-risk arthropod pests.

Phytopathogens pose a major threat to ecosystem stability and food production, indicating the need for developing methods to control the severe losses caused by these pathogens. To control these pathogens, the use of various chemical pesticides is majorly practiced. These pesticides are associated with environmental and health hazards and also pose a risk of resistance development in phytopathogens against them forcing the researcher towards the development of alternative and innovative methods by which sustainable management of plant diseases can be achieved. To control plant diseases and have pesticide-free food worldwide, the use of natural antagonistic microorganisms known as biocontrol agents or biological control agents (BCA) is employed. BCA can act on these pathogens through a number of mechanisms such as antibiosis, hyperparasitism, enzyme production, induction of plant resistance mechanisms and competition for essential nutrients and space and through plant growth promotion. Apart from controlling phytopathogens, these microbial agents also promote plant growth and stress tolerance. BCA can be used as bioinsecticides, bionematicides and biopesticides. They are also used for the management of post-harvest diseases. Recently, recombinant microbes have been developed with enhanced biocontrol capabilities. Several commercially available BCA are currently being used for the efficient control of plant disease with improved productivity of many crops. These majorly include GB34, Kodiak, Serenade and Companion containing Bacillus as the active ingredient, Biosave 10LP and Bio-jet containing Pseudomonas as the active ingredient and Soilguard, Trichodex and Trichojet containing Trichoderma as the active ingredient. Thus, use of microbes such as fungi, bacteria, yeast and viruses holds an enormous potential as biocontrol agents to replace conventional chemical-based pesticides and provide food security in a safe and eco-friendly manner.

Maydis leaf blight caused by Bipolaris maydis is one of the limiting factors in increasing maize production. The application of biological control agents (BCAs) as a biopesticide to control pests and plant diseases expected to decrease synthetic fungicide usage and its impacts. Several researches showed that the formula of Bacillus subtilis biopesticide suppress the development of several plant diseases including maydis leaf blight in maize. Nevertheless, biological control agents cannot completely replace the need for chemical fungicides in the agro-ecosystem. Therefore, this study was carried out to evaluate the effect and compatibility of several synthetic fungicides with antagonistic bacterial formulas in controlling B. maydis on maize. Five types of synthetic active ingredients used were difenoconazole, propinep, fluopicolide, metalaxyl, and dimethomorph. From the results of laboratory tests, 3 types of active ingredients with the highest inhibitory effectiveness be selected for the field test. Field treatments were arranged using a Randomized Block Design with 2 factors, factor I was biological control agents with 2 levels (T0 = without biological control agents, T1 = with biological control agents) and factor II was synthetic fungicide with different active ingredients with 4 levels (S0 = no synthetic fungicide, S1=diphenoconazole, S2=propinep, S3 = fluopicolide). Each treatment combination was repeated 4 times. The result showed that all the synthetic fungicides tested were compatible with the biological control agent. Fungicide with active ingredient of diphenoconazole was the most compatible with the BCAs showing the lowest disease severity value of 27%, while control treatment conditions without BCAs was 72%.

Aim The use of host‐specific biological control agents is widely considered an effective option for the management of invasive alien plant species. However, the formation of novel associations between released biological control agents and indigenous species poses risks. Here, we investigate whether native food webs associated with two galling biological control agents on Acacia longifolia and A. saligna are similar to those found in their introduced range.Location Gall inhabitants recorded from South Africa and Australia.Methods Non‐targeted insects were collected from galls in introduced ranges for comparisons to that of the agents’ native ranges.Results We find that two host plant‐specific galling biological control agents accumulate food web links with higher trophic levels in their introduced range that are similar in number, taxonomic/phylogenetic pattern and guild composition to those in their native range. Bray‐Curtis percentage similarity between native (Australia) and novel (South Africa) food webs was 30–50% and 50–75% at the family and superfamily taxonomic level, respectively, and 45–50% if considering shared phylogenetic diversity.Main conclusions Trichilogaster acaciaelongifoliae and Uromycladium tepperianum accumulated food webs in South Africa that are strikingly similar in complexity and structure to those that occur in their native ranges. This indicates that the structure of food webs in the introduced range could be predicted by studying food webs in the native range of a biological control agent, potentially paving the way for more effective risk assessment of weed biological control.

Questioning the effectiveness of seed-reducing agents on invasive Acacia: Pod production relative to gall abundance of classical biological control agents