Agroindustrial wastes are increasingly investigated for phytonematode management due to their rich phytochemical composition. However, they may also affect beneficial microorganisms used as biological control agents. This study evaluated the effects of extract fractions from Citrus sinensis (L.) Osbeck pomace, alone or combined with nematicidal agents, on the reproduction of Meloidogyne javanica (Treub, 1885) Chitwood in soybean, and assessed in vitro compatibility with biological agents and egg parasitism. A greenhouse reproduction assay used commercial products based on Purpureocillium lilacinum (Thom) Luangsa-ard, Houbraken, Hywel-Jones and Samson + Pochonia chlamydosporia (Goddard) Zare and Gams, Bacillus firmus Bredemann and Werner, and abamectin, applied with or without the ethyl acetate (EAF) and dichloromethane (DCMF) fractions of a crude methanolic extract prepared at 1.5
Sustainable agriculture urgently requires environmentally friendly pest control strategies to mitigate the risks posed by synthetic chemical pesticides. Integrated pest management (IPM) often employs combinations of control agents to enhance efficacy through synergistic interactions. Entomopathogenic nematodes (EPNs) are effective biological control agents against the potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), but their field performance can be variable. One strategy to enhance EPN efficacy is co-application with botanical adjuvants that weaken host defenses. Here, we evaluated the individual and combined effects of Marrubium vulgare L. (Lamiaceae) plant extracts (aqueous, ethyl acetate, methanol, hexane) with three EPNs species. Bioassays first determined the larvicidal activity of each extract against P. operculella. Compatibility tests showed that M. vulgare extracts caused minimal EPN mortality (≤ 9
Ecological engineering using flowering plants may counteract biodiversity loss and enhance biological control in intensified agricultural systems. In this study, we investigated the effects of flowering plants on the abundance and richness of parasitoids in maize fields and examined the relationships among these plants, parasitoids, pests, and parasitism rates. A field experiment was conducted in eight maize plots, consisting of four treatment plots with flowering plants and four control plots without flowering plants, to compare parasitoid communities, pest abundance, and parasitism rates. Pests were sampled across maize ages using up to 300 plants per field. Seventeen parasitoid families were recorded in the maize fields, with Scelionidae, Encyrtidae, and Mymaridae being the most abundant in both flowering and non-flowering plots. The results showed that flowering plants positively influenced the abundance and richness of several parasitoid families, although these benefits diminished with increasing maize age. Although flowering plants did not directly boost parasitoid populations, structural equation modeling demonstrated that increased parasitoids substantially elevated pest parasitism rates. Total pest abundance was positively associated with parasitoid abundance and richness, which was consistent with a bottom-up numerical response. Intriguingly, no significant linear relationship was found between the distance from flowering plants and pest or parasitoid communities. These findings highlight the critical, albeit complex, role of flowering plants in modulating natural enemy services for sustainable pest management.
The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a highly invasive pest causing severe economic losses in Türkiye, especially in hazelnut-producing regions. This study presents laboratory evaluations of indigenous entomopathogenic fungi against H. halys, emphasizing mortality patterns, indirect infection, and horizontal transmission. All selected isolates caused concentration-dependent reductions in survival and increases in mortality. Of 20 local fungal isolates tested, four—Beauveria bassiana KTU-24 and Pa4, Metarhizium brunneum Gg-12, and Metarhizium flavoviride As-18—consistently showed the highest virulence against both nymphs and adults. B. bassiana KTU-24 was the most effective, exhibiting the lowest median lethal concentration (LC50) for both nymphal and adult stages. Contact with fungus-contaminated surfaces and food resulted in high infection levels, reaching over 90
The green lacewing, Chrysoperla zastrowi sillemi (Esben-Petersen) (Neuroptera: Chrysopidae), commonly known as aphid lion, is an important biocontrol agent of many insect pests. The dsRNA-based biopesticides, while promising specific insect control, raise safety concerns for natural enemies and non-target organisms. For successful RNAi, a robust, systemic response mediated by the RNAi machinery genes is a prerequisite. This study aimed to provide the comprehensive characterization and expression analysis of the core siRNA machinery in the beneficial predator, C. zastrowi sillemi, including Argonaute−2 (CzsAgo-2), Dicer-2 (CzsDcr-2), Loquacious (CzsLoq) and the dsRNA transporter Sid-1 (CzsSid-1), which is critical for ensuring the presence of a functional RNAi pathway and for ecological safety assessments of dsRNA-based pesticides. We examined their expression across multiple developmental stages and key tissues in the predator to assess the RNAi pathway activity. Quantitative real-time PCR (RT-qPCR) analysis revealed that all four genes are ubiquitously expressed across developmental stages and in the tissues of larval integument and gut, which are primary barriers to environmental dsRNA. Furthermore, oral exposure to non-target dsRNA for beta-glucuronidase (dsGUS) triggered the activation of these RNAi genes, confirming the species’ susceptibility to RNAi. This is the first study to provide detailed molecular characterization, phylogenetic insights, and functional evidence of dsRNA-induced activation of the core RNAi machinery in the insect order Neuroptera. Our findings establish C. zastrowi sillemi as a suitable model predator for studying RNAi pathways and evaluating the safety of pest-specific commercial dsRNA molecules to ensure their compatibility with biocontrol agents.
Safeguarding the global fruit and vegetable supply and quality throughout storage and marketing remains a critical challenge. Post-harvest losses, caused by decay account for 20–25
This study investigates innate immune responses of economically important Phytoseiid mites to the pathogenic bacterium Acaricomes phytoseiuli, revealing stark species-specific susceptibility. Among five predatory mites tested, Phytoseiulus persimilis suffered extreme mortality (4.4
Eriopis connexa, a neotropical aphidophagous lady beetle important for various soft-bodied pest species control, requires feeding on aphids for enhanced reproductive output. To understand the physiological basis of this dependency, we investigated how the absence of the preferred prey, aphids, affects E. connexa reproductive fitness. We compared females fed only Ephestia kuehniella eggs (a factitious food) with those provided E. kuehniella eggs alongside limited access to the aphid Lipaphis pseudobrassicae (a preferred prey). Egg numbers were similar in females from both diets after 60 days. However, females on an aphid-supplemented diet cease oviposition around day 30, exhibiting egg viability around 35
The over-reliance on chemical pesticides for crop pest control has raised serious concerns about their environmental and health impacts. Biological control agents (BCAs), including entomopathogenic nematodes (EPNs), offer safer and more sustainable alternatives. Despite promising experimental results, adoption of BCAs in sub-Saharan Africa remains limited. In Nigeria, EPNs are largely unknown to farmers, and no commercial production or importation system exists. This study investigates the sociocultural and institutional factors influencing farmers’ willingness to adopt EPNs as a biological control strategy. We surveyed 740 smallholder farmers across ten study locations (two per agroecological zone; n = 74 farmers per location) representing five major agroecological zones of Nigeria. The survey was done from May to August 2022. Awareness of EPNs was virtually absent across all locations (mean < 0.5
Bacterial canker, caused by Clavibacter michiganensis subsp. michiganensis, remains one of the most devastating diseases affecting tomato production globally, necessitating sustainable biocontrol strategies. This study investigates the biocontrol potential and plant growth efficacy of indigenous lactic acid bacteria isolated from tomato tissues in the Izmir province of Türkiye. Six potent isolates, identified as Lacticaseibacillus paracasei and Lacticaseibacillus zeae, were evaluated through in vitro assays and in planta trials across two susceptible tomato cultivars, ‘SC2121’ and ‘Corvette’. While the isolates exhibited no direct antagonism against Clavibacter michiganensis subsp. michiganensis in dual culture assays, they demonstrated significant disease suppression in planta, with Lacticaseibacillus paracasei LBT2 (G1) achieving up to 45.71
Arma chinensis Fallou (Hemiptera: Pentatomidae) is a critical biocontrol agent for agricultural pests. Yet its efficacy is constrained by susceptibility to pathogens and suboptimal breeding conditions. It has been previously demonstrated that miR-8 and Toll family regulate host immunity. However, the physiological damage of miR-8 overexpression and Toll knockdown on A. chinensis is still unknown. This study reveals associations of miR‑8 and Toll receptors with tissue integrity and neural morphological development in A. chinensis. Through paraffin sectioning and RNA interference, we demonstrate that Toll receptors are critical for ovarian/testicular development, midgut barrier integrity, and fat body adhesion. Furthermore, interference with specific Toll receptors disrupted nerve cell distribution and adhesion in the brain. miR-8 over-expression was associated with reduced transcript levels of fas2 and nlg4, as well as with neuronal adhesion defects and reduced optic lobe volume, suggesting a potential transcriptional and morphological link to neural structure. These findings suggest a miR-8-Toll axis that is associated with tissue homeostasis and neural connectivity in A. chinensis, providing a foundation for understanding Hemiptera-specific developmental mechanisms and offering strategies to optimize biocontrol agent durability and reproductive output.
Habitat quality is an important factor linked to decision-making in female parasitoids, whether related to the infestation patch quality or the availability of resources in the area. Host abundance, together with the spatial location of the infested patch, is known to be directly linked to the foraging time and parasitism efficiency of parasitoids. Within this context, this study aimed to investigate how host abundance affects patch residence time by Telenomus podisi (Hymenoptera: Scelionidae) and whether the accuracy of its spatial release in the field influences parasitism rates upon eggs of Euschistus heros (Hemiptera: Pentatomidae). Two separate experiments were conducted according to our objectives. The first, a microcosm experiment, evaluated the patch residence time in relation to host abundance. The second, a semi-field experiment, evaluated parasitism of E. heros eggs in relation to parasitoid release accuracy. The dispersal time of T. podisi females from the microcosm study was significantly lower at high densities of E. heros eggs. In addition, event probability analyses further indicated that females are less likely to disperse at high host egg abundance when compared to low abundance. In addition, the location where the parasitoids were released in the field had a significant effect on the parasitism rate. T. podisi parasitized more E. heros eggs when the females were released more accurately on the infestation spot. Given these results, host abundance and release accuracy should be considered to optimize the augmentative biological control of E. heros in soybean fields.
Arthropods were sampled in organic and conventional cherry orchards over two growing seasons using pitfall traps, yellow sticky traps, and branch shaking. The data obtained from both production systems were compared using linear mixed effects models and principal response curves (PRCs). The diversity of families and the total abundance of arthropods captured by the three sampling methods were significantly greater in the organic orchards. Phytophagous and predatory arthropods in cherry tree canopies, soil-dwelling predators and parasitoids captured in yellow sticky traps were significantly more abundant in organic orchards. Although no significant differences in the total abundance of Coccinellidae between crop managements were recorded, species richness and abundance, excluding that of Stethorus pusillus (Herbst) (Coleoptera: Coccinellidae), were significantly greater in the organic plots. According to the PRC analyses, the taxa most favoured by organic management were the predatory families Anthocoridae, Lycosidae, Staphylinidae, Gnaphosidae, Philodromidae, Hybotidae, Nabidae, Carabidae and Thomisidae; the parasitoids belonging to Pteromalidae, Mymaridae, Braconidae, Bethylidae, Platygastridae and Aphelinidae; and the phytophagous Monosteira unicostata (Mulsant Rey) (Hemiptera: Tingidae) (poplar lace bug) and aphids. The predatory coccinellid species most favoured by organic cropping were Adalia decempunctata (L.) (Coleoptera: Coccinellidae), Adalia bipunctata (L.) (Coleoptera: Coccinellidae) and Scymnus interruptus (Goeze) (Coleoptera: Coccinellidae). In contrast, some groups of arthropods were more abundant in conventionally managed orchards, among which spider mites and their predatory species S. pusillus (Herbst) stood out. Therefore, this study revealed a great benefit of organic cherry cultivation for most groups of predators and parasitoids although some phytophagous species were also favoured.
White mold, caused by Sclerotinia sclerotiorum, is one of the most important diseases affecting common bean crops. Due to its global distribution and wide host range, the persistence of S. sclerotiorum in the environment is favored by the formation of survival structures, which complicates control measures. In this context, biological control emerges as a sustainable strategy for pathogen suppression and plant growth promotion. To explore this approach, nine strains of Bacillus spp. were screened for their ability to control S. sclerotiorum strain SSF and promote growth of common bean (Phaseolus vulgaris L.) plants. All strains exhibited antagonistic activity against S. sclerotiorum strain SSF, demonstrated through in vitro antagonism assays, including dual culture and cell-free supernatant (CFS) tests, and volatile organic compounds (VOCs) exposure, indicating the involvement of multiple antagonistic mechanisms. In addition, the strains displayed key in vitro biocontrol traits, such as the production of cell wall–degrading enzymes and siderophores. Greenhouse trials confirmed the efficacy of selected strains in controlling white mold and promoting bean plant growth. Isolates EVSA, BERA II, and BEFA I stood out by enabling the survival of plants inoculated with S. sclerotiorum while not impairing seed germination. Both bacterial co-inoculation (EVSA, BERA II, and BEFA I) and the EVSA strain alone promoted shoot and root development in bean plants. EVSA demonstrated multifunctional activity, combining effective suppression of S. sclerotiorum strain SSF with plant growth promotion, positioning it as a promising candidate for bioinoculant development in the sustainable management of white mold.
In biological control programs, multiple natural enemies may be used against a single pest. However, when different species target the same host, they can engage in antagonistic interactions, such as intraguild predation, during which parasitoids are particularly vulnerable while developing inside their hosts. This vulnerability may reduce parasitoid effectiveness, especially when predators preferentially attack parasitized prey. Traditional assessments of parasitoid-predator interactions often overlook how prey density influences predator selection behavior. We investigated intraguild predation using an integrated approach combining functional response and prey-selection models, focusing on the parasitoids Anagyrus cachamai Triapitsyn, Logarzo Aguirre and A. lapachosus Triapitsyn, Aguirre Logarzo (Hymenoptera: Encyrtidae) and the predator Hyperaspis conclusa Weise (Coleoptera: Coccinellidae), candidate biological control agents of the Puerto Rican cactus pest Hypogeococcus sp. (Hemiptera: Pseudococcidae). Using a Bayesian approach, we selected the best-supported models and estimated parameters. The interaction between the predator and the parasitoids was antagonistic, with coccinellid females preferring to feed on parasitized prey. Their feeding behavior differed depending on whether prey had been exposed to A. cachamai or A. lapachosus. When acting sequentially, parasitoids and predators caused higher total mortality than single‐enemy treatments, while exhibiting subadditive multiple‐enemy effects relative to random expectations. Our findings indicate that predator preference and prey density must be considered when evaluating combinations of natural enemies, and show that parasitoid-predator interactions, although antagonistic and subadditive, do not necessarily eliminate overall pest suppression under laboratory conditions.
Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) is a destructive lepidopteran pest commonly managed using microbial biopesticides such as Bacillus thuringiensis (Bt), entomopathogenic fungi, and nucleopolyhedroviruses (NPVs). However, the relatively slow speed of action and variable efficacy of these agents can limit their broader application. Vip3Aa35, a vegetative insecticidal protein secreted by Bt strain M190, exhibits strong toxicity against lepidopteran larvae. This study evaluated the potential of Vip3Aa35 to enhance the efficacy of three microbial control agents, Xentari® (Bt-based), Beauveria bassiana BCC 48145, and Spodoptera exigua nucleopolyhedrovirus (SeNPV), under laboratory and greenhouse conditions. When combined with Xentari®, Vip3Aa35 increased overall insecticidal performance and reduced larval killing time. In combination with B. bassiana at sub-lethal concentrations (62.5–125 ng cm–2), Vip3Aa35 markedly enhanced fungal virulence and accelerated larval mortality. Co-application with SeNPV substantially reduced the LC50 and shortened LT50 values, indicating faster viral infection and killing. Greenhouse experiments further demonstrated that Vip3Aa35, even at low application rates (17.78 µg pot–1), improved plant protection when combined with B. bassiana or SeNPV, resulting in reduced leaf damage and more rapid larval death. Early visual symptoms, including fungal outgrowth and virus-induced larval cadavers, were observed sooner in combined treatments than in single-agent applications. Overall, these findings demonstrate that Vip3Aa35 can enhance the performance of fungal, bacterial, and viral biocontrol agents against S. exigua, supporting its potential use as a synergistic component in integrated pest management strategies.
Bemisia tabaci (Gennadius) is a major pest in soybean, causing both direct feeding damage and acting as a vector for several plant viruses. The emergence of resistant B. tabaci biotypes to synthetic insecticides underscores the need for effective and sustainable alternatives. This study evaluated the efficacy of an indigenous isolate of the entomopathogenic fungus (EPF) Aschersonia aleyrodis (TMP-Dc3) for managing B. tabaci populations under laboratory and field conditions between February and October 2024. Treatments included varying conidial concentrations of A. aleyrodis (105, 106, 107, and 108 conidia ml−1) and a synthetic insecticide (thiamethoxam) as a chemical control. The 107 conidia ml−1 treatment significantly suppressed B. tabaci populations in the field compared to other fungal densities and thiamethoxam. Notably, B. tabaci densities were higher in the thiamethoxam treatment, likely due to reduction in natural enemy abundance. Although thiamethoxam-treated plants produced slightly higher seed yields (14.26 g plant−1), plants treated with 107 conidia ml−1 of A. aleyrodis achieved a comparable yield (14.03 g plant−1). A significant negative correlation was observed between the number of empty pods and total seed weight (r = –0.697), while a positive correlation existed between whitefly populations at 56 days after planting and empty pods (r = 0.476). The TMP-Dc3 isolate exhibited strong chitinase and protease activities, highlighting its potential as a promising biopesticide and sustainable alternative to chemical insecticides for managing B. tabaci in soybeans crops.
Following the international trade and use of bamboo as exotic ornamentals, several species of bamboo spider mites (Stigmaeopsis spp.) have invaded the Americas and Europe, and their distribution is expanding, particularly across Europe. These mites construct dense silk nests that serve as effective defences against natural enemies, posing challenges for biological control. We evaluated the predatory performance of two commercially available phytoseiid mites native to the Americas and Europe, Phytoseiulus persimilis and Neoseiulus cucumeris, in comparison with Typhlodromus bambusae, a natural enemy of Stigmaeopsis spp. in their native Asian range. Stigmaeopsis spp. show nest size variation among species. For instance, S. longus typically builds larger nests than S. celarius. To consider this difference, we conducted experiments with both species, using nests aged 0, 24, or 72 h to reflect differences in silk density. T. bambusae consistently exhibited high predation on both adult females and eggs across all nest ages. In contrast, P. persimilis showed limited predation, particularly when more elaborate woven nests were present, suggesting difficulty penetrating or entering these structures. N. cucumeris exhibited moderate but variable predation: some individuals preyed on adult females at rates comparable to T. bambusae, and a few also successfully attacked eggs, even in well-developed nests. These findings suggest that nest architecture and silk density strongly influence predator access, and behavioural variation may allow some N. cucumeris individuals to overcome such barriers. Evaluating predator efficacy under varying nest structures offers a useful framework for assessing their potential in managing exotic spider mite invasions.
Climate change is increasing constraints on crop production and reinforcing the need for sustainable alternatives to chemical disease control. Sorghum is a drought-tolerant crop of increasing importance. However, anthracnose caused by Colletotrichum sublineola remains its most destructive disease, and no biological control products are currently registered for its management. This study evaluated bacterial isolates as potential biological control agents against sorghum anthracnose. Bacteria isolated from honey were identified as Bacillus spp. based on 16S rDNA sequencing and screened for antifungal activity in vitro. Four isolates inhibited mycelial growth of C. sublineola by more than 67
In recent years, biocontrol agents (BCAs) have gained attention as sustainable alternatives or complements to synthetic chemicals for managing phytopathogens and enhancing plant growth. In this study, six bacterial strains were evaluated as BCAs against Rhizoctonia solani (RS), a soil-borne pathogen affecting economically important crops. Two strains (Bacillus sp. B04A33 and Psychrobacillus sp. B04A42) were isolated from maize embryos, while Lactiplantibacillus plantarum strains (ITEM 17215, ITEM 17218, ITEM 18335 and S61) originated from food or animal sources. A commercial Trichoderma-based product (REMEDIER®, Gowan Italia) served as the control. Biocontrol effectiveness was assessed both in vitro and in vivo on lettuce using an automated imaging system for plant growth monitoring. In soils infected by R. solani, the inoculum of strains B04A33, B04A42, and S61 enhanced germination and seedling vigor, and increased dry weight of shoots and roots. Root system development, analyzed via image processing in Matlab, confirmed improved growth. The qPCR analysis of soil samples showed that microbial abundance increased in non-treated (NT) and S61 + RS treatments, while R. solani levels decreased in B04A33 + RS and B04A42 + RS. Oxford Nanopore MinION sequencing of soil samples revealed dominance of Pseudomonadota, Actinomycetota, and Bacillota, with enrichment of Bacillaceae and Lactobacillaceae in B04A42 and S61 treatments, confirming the successful establishment of the inoculated strains within the soil microbiome. These results support both the potential of selected bacterial strains as effective BCAs against RS and the use of automated imaging in BCAs screening procedures, promoting sustainable and technology-assisted crop management.
