Natural products for biocontrol: review of their fate in the environment and impacts on biodiversity

Cyto- and Genotoxicity of Selected Plant Extracts and Microbial Metabolites with Confirmed Activity Against Phytopathogens of Potato Seed (Solanum tuberosum L.)

The aim of this study was to evaluate the cytotoxicity and genotoxicity of potential biocontrol agents for use against phytopathogens of potato seed (Solanum tuberosum L.). Plant extracts from Allium sativum L., Syzygium aromaticum L. Merr. & Perry, Salvia officinalis L., and Curcuma longa L., as well as metabolites of bacteria Lactiplantibacillus plantarum KB2 LAB 03 and yeast Metschnikowia pulcherrima TK1, were investigated. The chemical characteristics of the plant extracts and the metabolic profiles of the tested microorganisms were evaluated by GC-MS. An insect cell line from Spodoptera frugiperda (Sf-9) and human cervix adenocarcinoma cells (HeLa) were used to evaluate cytotoxicity in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The single-cell electrophoresis assay was used to estimate DNA damage. The cytotoxicity and genotoxicity of the microbial metabolites depended on their chemical profiles and pH. The plant extracts induced stronger DNA damage in the Sf-9 cell line than in HeLa cells. The garlic (Allium sativum L.) extract showed the highest cytotoxicity against Sf-9 insect cells (IC50 41.6 mg/mL). The sage (Salvia officinalis L.) extract showed the highest cytotoxicity against HeLa cells (IC50 49.6 mg/mL). This study is the first to investigate not only the potential of these novel biocontrol agents for plant disease control, but also their safety for humans and biodiversity within the context of sustainable agriculture.

Effects of plant protection products on ecosystem functions provided by terrestrial invertebrates

Plant protection products (PPP) are extensively used to protect plants against harmful organisms, but they also have unintended effects on non-target organisms, especially terrestrial invertebrates. The impact of PPP on ecosystem functions provided by these non-target invertebrates remains, however, unclear. The objectives of this article were to review PPP impacts on the ecosystem functions provided by pollinators, predators and parasitoids, and soil organisms, and to identify the factors that aggravate or mitigate PPP effects. The literature highlights that PPP alter several ecosystem functions: provision and maintenance of biodiversity, pollination, biotic interactions and habitat completeness in terrestrial ecosystems, and organic matter and soil structure dynamics. However, there are still a few studies dealing with ecosystem functions, with sometimes contradictory results, and consequences on agricultural provisioning services remain unclear. The model organisms used to assess PPP ecotoxicological effects are still limited, and should be expanded to better cover the wide functional diversity of terrestrial invertebrates. Data are lacking on PPP sublethal, transgenerational, and "cocktail" effects, and on their multitrophic consequences. In empirical assessments, studies on PPP unintended effects should consider agricultural-pedoclimatic contexts because they influence the responses of non-target organisms and associated ecosystem functions to PPP. Modeling might be a promising way to account for the complex interactions among PPP mixtures, biodiversity, and ecosystem functioning.

Prevention and management of plant protection product transfers within the environment: A review

The intensification of agriculture has promoted the simplification and specialization of agroecosystems, resulting in negative impacts such as decreasing landscape heterogeneity and increasing use of plant protection products (PPP), with the acceleration of PPP transfers to environmental compartments and loss in biodiversity. In this context, the present work reviews the various levers for action promoting the prevention and management of these transfers in the environment and the available modelling tools. Two main categories of levers were identified: (1) better control of the application, including the reduction of doses and of PPP dispersion during application thanks to appropriate equipment and settings, PPP formulations and consideration of meteorological conditions; (2) reduction of post-application transfers at plot scales (soil cover, low tillage, organic matter management, remediation etc. and at landscape scales using either dry (grassed strips, forest, hedgerows and ditches) or wet (ponds, mangroves and stormwater basins) buffer zones. The management of PPP residues leftover in the spray tanks (biobeds) also represents a lever for limiting point-source PPP pollution. Numerous models have been developed to simulate the transfers of PPPs at plot scales. They are scarce for landscape scales. A few are used for regulatory risk assessment. These models could still be improved, for example, if current agricultural practices (e.g. agro-ecological practices and biopesticides), and their effect on PPP transfers were better described. If operated alone, none of the levers guarantee a zero risk of PPP transfer. However, if levers are applied in a combined manner, PPP transfers could be more easily limited (agricultural practices, landscape organization etc.).

trans-2-Octenal controls Fusarium oxysporum f. sp. lycopersici, the causal agent of tomato wilt in vitro, in soil and in the field

BACKGROUND

Fungal plant diseases cause major crop losses. Phytopathogenic fungi's ability to evolve resistance to fungicides, alongside ongoing prohibition of such agents by the European Commission because of their pronounced adverse effects on human health and the environment, make their control a challenge. Moreover, the development of less perilous fungicides is a complex task. Here we describe the process and challenges involved in the development of a novel fungicide, from in-vitro studies to field experiments.

RESULTS

In-vitro experiments with trans-2-octenal, a bioactive compound secreted by the endophytic fungus Daldinia cf. concentrica, revealed its ability to fully inhibit and kill phytopathogenic microorganisms. A formulated version of trans-2-octenal was then used against the soil-borne pathogen Fusarium oxysporum f. sp. lycopersici (Forl), the causal agent of tomato vascular wilt disease, in pot experiments with different soil types. We found the highest fungicidal activity in sandy and loam soils, whereas heavy soil impaired activity. Lastly, we investigated the activity of the formulated trans-2-octenal against Forl in semi-field experiments. We achieved complete elimination of Forl, provided the soil is rotavated after trans-2-octenal application.

CONCLUSION

trans-2-Octenal has the potential to control Forl in vitro, in pots and in the field. © 2025 Society of Chemical Industry.

Biocontrol agents and their potential use as nano biopesticides to control the tea red spider mite (Oligonychus coffeae): A comprehensive review

Tea red spider mite (TRSM), Oligonychus coffeae Nietner, is one of the major pests that cause considerable crop losses in all tea-growing countries. TRSM management often involves the use of multiple chemical pesticides that are linked to human health risks and environmental pollution. Considering these critical issues, employing biocontrol agents is a potential green approach that may replace synthetic pesticides. This review study aims to discuss the efficacy of plant extracts, entomopathogenic microorganisms, and predators in controlling TRSM. This study includes 44 botanical extracts, 14 microbial species, and 8 potential predators used to control TRSM, along with their respective modes of action. Most of the botanical extracts have ovicidal, adulticidal, and larvicidal activity, ranging from 80 to 100 %, attributed to bioactive compounds such as phenols, alcohols, alkaloids, tannins, and other secondary metabolites. Among microbial pesticides, Purpureocillium lilacinum, Metarhizium robertsii, Aspergillus niger, Pseudomonas fluorescens, and Pseudomonas putida are highly effective against TRSM without causing any harm to the nontarget beneficial insects. Besides, some predators, including green lacewings, ladybirds, and phytoseiid mites have the potential to control TRSM. Employing these biocontrol agents simultaneously in tea plantations could be more effective in preventing TRSM. Nevertheless, their high biodegradability rate, uneven distribution, and uncontrolled release pose challenges for large-scale field applications. This study also explores how nanotechnology can enhance sustainability by addressing the limitations of biopesticides in field conditions. This review study could contribute to the search for potential biocontrol agents and the development of commercial nano biopesticides to control TRSM.