Biological Control Research Articles

Entomopathogenic nematode detection and counting model developed based on A-star algorithm

Entomopathogenic nematodes are soil-dwelling living organisms widely employed in the biological control of agricultural insect pests, serving as a significant alternative to pesticides. In laboratory procedures, the counting process remains the most common, labor-intensive, time-consuming, and approximate aspect of studies related to entomopathogenic nematodes. In this context, a novel method has been proposed for the detection and quantification of Steinernema feltiae isolate using computer vision on microscope images. The proposed method involves two primary algorithmic steps: framing and isolation. Compared to YOLO-V5m, YOLO-V7m, and YOLO-V8m, the A-star-based developed network demonstrates significantly improved detection accuracy compared to other networks. The novel method is particularly effective in facilitating the detection of overlapping nematodes. The developed algorithm excludes processes that increase space and time complexity, such as the weight document, which contains the learned parameters of the deep learning model, model integration, and prediction time, resulting in more efficient operation. The results indicate the feasibility of the proposed method for detecting and counting entomopathogenic nematodes.

The hex1 gene of Trichoderma simmonsii is involved in stress responses, biocontrol potential and wheat plant growth

Woronin bodies are unique organelles in Pezizomycotina fungi that allow hyphae compartmentalization and prevent cytoplasmatic bleeding after mechanical injury. Several studies have related the peroxisomal protein HEX1, the major component of Woronin bodies with other biological processes such as hyphal growth, osmotic stress tolerance and pathogenicity. Trichoderma spp. are plant-beneficial multipurpose biological control agents, and proteomic and transcriptomic studies have shown that HEX1 and its corresponding gene are overrepresented when grown in the presence of fungal cell walls and plant polymers. To further investigate the involvement of hex1 in Trichoderma biology, we generated hex1 deletion transformants using the wheat endophytic strain T. simmonsii T137 as host. Results confirmed that hex1 gene is involved in the prevention of cytoplasmatic bleeding, and also has a role in fungal growth and biocontrol potential against phytopathogenic fungi and oomycetes. The involvement of hex1 in the fungal response to osmotic and oxidative stresses is conditioned by the type of stress and by the nutrient richness of the culture medium. The hex1 deletion also affected the interaction with wheat, but did not affect the plant protective effect of T137 against water stress. Overall, this study shows the implication of HEX1 in a wide range of biological processes necessary for T. simmonsii to deploy its abilities to be used as an agriculturally beneficial fungus.

First Complete Genome Sequence of Nigrospora osmanthi: A Fundamental Resource for Studying the Plant Pathogenic Fungus

Nigrospora osmanthi strain Z1 is a potential bioherbicide for the biological control of water lettuce, one of the most common invasive weeds. Here, the first high-quality genome assembly of N. osmanthi was obtained by a combination of PacBio and Illumina sequencing technologies. Twelve contigs representing the nuclear genome and one mitochondrial DNA were generated, with a total length of 45.94 Mb, an N50 equal to 6.99 Mb, and a GC content of 57.91%; 9 of the 12 nuclear contigs represented chromosomes from telomere to telomere characterized by telomeric-like repeats. A total of 11,051 genes were predicted using a combination of gene prediction tools, including 336 noncoding RNAs, 1,298 genes encoding secretory proteins, 1,735 genes encoding carbohydrate-active enzymes, 1,955 fungal virulence factors, and 50 putative secondary metabolite gene clusters. This complete genome sequence can serve as a valuable resource for future comparative genomic studies of the fungus Nigrospora for effective application in the biocontrol of invasive species and the discovery of fungal secondary metabolites. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

The Glucanase Enzyme Activity from Rhizospheric Streptomyces spp. in Inhibiting Growth and Damaging the Cell Walls of the Mycelium of Fusarium oxysporum

Fusarium oxysporum, a phytopathogenic fungus responsible for fusarium wilt in more than 120 plant species, is primarily managed using synthetic fungicides, which pose environmental hazards. Therefore, alternative biological control methods are urgently needed. Actinomycetes isolated from maize rhizosphere, which produce β-1.3-glucanase enzymes that degrade fungal cell wall glucans, offer promising potential as biocontrol agents. This study aimed to evaluate glucanase activity, identify genes of actinomycetes, and assess their antifungal activity against F. oxysporum. Actinomycetes demonstrating glucanase production, Streptomyces sp. ARJ 22, Streptomyces tendae ARJ 42, Streptomyces sp. ARJ 44, and Streptomyces sp. ARJ 81, were selected. Streptomyces isolates exhibited activity values ranging from 10.38 to 24.08 U/mg of protein. The presence of the bglS gene, encoding endo-β-1.3-glucanase from glycoside hydrolase family 16, supports the production of glucanase. The amino acid sequence was constructed to 3D structural model. This model exhibited high similarity to endo-β-1.3-glucanase from Nocardiopsis sp. F96. In vitro assays demonstrated that all isolates inhibited hyphal growth of F. oxysporum. Direct inhibition assays showed an average inhibition of 26.18%, whereas the filtrate culture method showed 29.38% inhibition. Enzymes from Streptomyces sp. ARJ 44 was partially purified using acetone, resulting in a specific activity of 46.34 U/mg of protein and a purity increase of up to 1.92-fold. The purified enzyme inhibited the growth of F. oxysporum mycelia by 35.80%. This inhibition was confirmed by observing damage to F. oxysporum hyphae using scanning electron microscopy. The study concluded that the four Streptomyces sp. strains producing β-1.3-glucanase enzymes have potential as biocontrol agents against F. oxysporum.

Fusarium oxysporum and soil nutrient amendments provide short-term inhibition of Cosmopolites sordidus raising questions on biopesticide and plant nutrition potentials in tissue culture banana

Endophytic Fusarium oxysporum strain V5w2 has been suggested to offer the ecosystem service of suppressing Cosmopolites sordidus and other pests that attack tissue culture banana plants in agroecosystems. The effects of endophytic F. oxysporum V5w2 and nutrient supply on C. sordidus in potted tissue culture banana plants were investigated. In the screenhouse, rhizome damage by C. sordidus larvae was lower in F. oxysporum V5w2-inoculated plants than in non-inoculated ones. Banana plants inoculated with F. oxysporum V5w2 were larger and suffered less rhizome damage but with low chlorophyll content. Weights of C. sordidus larvae were not different between those reared on F. oxysporum V5w2-inoculated banana plants and the non-inoculated ones. Larval C. sordidus from nutrient-treated plants had lower weight than those that fed on plants that did not receive nutrients. In the field, fewer adult C. sordidus were found on F. oxysporum V5w2-inoculated banana plants than on non-inoculated plants 12 h after insect release. The number of adult C. sordidus and their eggs did not vary between F. oxysporum V5w2-inoculated banana plants and controls at the end of the experiment. Adult C. sordidus did not discriminate between nutrient-treated banana plants and those without nutrient treatment. However, non-beneficial interactions between F. oxysporum V5w2 and plant-parasitic nematodes negate the chances of its application as an endophytic biological control agent. In conclusion, while F. oxysporum V5w2 is not quite viable for application as an endophytic biological control agent for C. sordidus and other banana pests, this fungus may still have some potential to offer alternative ecosystem services through the provisioning of pest-inhibitive organic compounds.

Aerial Systems for Releasing Natural Enemy Insects of Purple Loosestrife Using Drones

Lythrum salicaria (purple loosestrife) is an invasive species that displaces native wetland flora in the USA. The detection and manual release of biological control agents for L. salicaria is challenging because L. salicaria inhabits many inaccessible areas. This study was conducted to develop aerial systems for the detection of L. salicaria and the release of its natural enemy, Galerucella calmariensis (Coleoptera: Chrysomelidae). We determined the optimal sensors and flight height for the aerial detection of L. salicaria and designed an aerial deployment method for G. calmariensis. Drone-based aerial surveys were conducted at various flight heights utilizing RGB, multispectral, and thermal sensors. We also developed an insect container (i.e., bug ball) for the aerial deployment of G. calmariensis. Our findings indicated that L. salicaria flowers were detectable with an RGB sensor at flight heights ≤ 15 m above the canopy. The post-release mortality and feeding efficiency of G. calmariensis did not significantly differ from the control group (non-aerial release), indicating the feasibility of the targeted release of G. calmariensis. This innovative study establishes a critical foundation for the future development of sophisticated aerial systems designed for the automated detection of invasive plants and the precise release of biological control agents, significantly advancing ecological management and conservation efforts.

Suppression of Thielaviopsis ethacetica wilt and root rot, the emerging pathogen on bell pepper (Capsicum annuum), and plant growth promotion properties by the safety indigenous Streptomyces SBcT04

Thielaviopsis ethacetica is an emerging pathogen responsible for wilt and root rot in bell peppers, significantly impacting crop yield. Biological control of the fungal pathogen provides significant advantages as a safe and efficient alternative to excessive chemical fungicides for managing plant diseases. Studying the screened and selected potential actinomycete strain from the indigenous collection is a quick and efficient measure to protect the yield of local bell pepper crops. The research assessed the indigenous actinomycete's ability to inhibit plant pathogens and promote plant growth both in vitro and in vivo. The Streptomyces SBcT04 was the most effective against T. ethacetica TROC-2 pathogen in vitro. The inhibition percentage reached 89.15 ± 0.46%. SBcT04 also effectively promoted plant growth properties in vitro. This strain fixed nitrogen and produced substantial amounts of indole-3-acetic acid (IAA), siderophores, and enzymes. Furthermore, the safety characteristics of SBcT04 for both the host plant (in vivo) and animals (in vitro) were confirmed. Streptomyces SBcT04 significantly processed pathogens, resulting in a reduction of approximately 40% in disease severity. Additionally, SBcT04 significantly promoted the host plant's growth, even in the presence of T. ethacetica TROC-2 infection. The indigenous Streptomyces SBcT04 efficiently inhibited T. ethacetica and significantly enhanced bell pepper plant growth. These advantageous characteristics of SBcT04 indicate its potential to foster secure and sustainable local bell pepper agricultural output.

Potential benefits of male diploidy and female triploidy for parasitoid wasps used as biological control agents: A case study in Nasonia

Potential benefits of male diploidy and female triploidy for parasitoid wasps used as biological control agents: A case study in Nasonia

Biocontrol potential of Bevibacillus brevis HK544 for fungal plant diseases

Chemical fungicides have been widely used to control plant diseases caused by fungal pathogens. Still, the overuse of these fungicides has led to concerns about the hazards to humans, animals, and the environment and an increase in fungicide resistance. Interest in biocontrol agents with strong antimicrobial activity has significantly increased to counteract the escalating risks of chemical fungicides. Our previous study found that a soil-born microbe, Brevibacillus brevis HK544, exhibited a promising antifungal activity against a plant pathogen, Fusarium graminearum, with edeine B1 identified as the active compound. Herein, we extended our study to investigate the in vitro and in vivo antifungal spectrum of B. brevis HK544, including edeine B1, against various plant pathogenic fungi and evaluated the possibility that B. brevis HK544 could be used in combination with chemical fungicides to enhance the disease control efficacy. With an in vitro broad-spectrum antifungal activity, the B. brevis HK544 culture filtrate, culture broth, and metabolite edeine B1 exhibited a promising disease control efficacy against tomato gray mold and tomato late blight among the tested fungal diseases. Based on the in vitro antifungal activity against Botrytis cinerea, when edeine B1 was combined with various chemical fungicides, the highest average synergy score among the tested combinations was observed in the edeine B1 and benomyl combination. The co-application of the B. brevis HK544 culture filtrate and benomyl improved the disease control efficacy against gray mold disease, supporting the in vitro result. Taken together, our results show that B. brevis HK544 has potential as a biological control agent for controlling plant pathogenic fungi and also that B. brevis HK544 could be combined with chemical fungicides to enhance the efficacy of antifungal agents.

Phylogenetic analysis of Syrphidae (Insecta, Diptera) based on low-coverage whole genomes

Abstract The hoverflies are one of the most abundant families in Diptera and an important category of resource insects. They can provide important ecosystem services such as pollination and beneficial biological control agents. In the four-subfamily classification system of the Syrphidae, the monophyly of the Eristalinae within Syrphidae has not been recovered. In this study, we performed new sequencing and analysis of low-coverage whole genomes for 25 species of Syrphidae. Phylogenetic reconstructions were conducted based on different datasets and analytical strategies. Across all our analyses, the monophyly of the Syrphinae is supported but we do not recover the monophyly of the Eristalinae, consistent with previous research findings. Additionally, employing fossil calibrations for divergence time estimation, our results indicate that the origin of the Syrphidae occurred between the Albian and Aptian stages, approximately between 120.5 and 109.3 million years ago, the origin of the subfamily Syrphinae was dated in the Early Eocene, about 50.8–47.8 million years ago, in accordance with the diversification of their prey. This study will help us understand the higher-level phylogenetic and evolutionary relationships within Syrphidae.

Morphology of the Mouthparts of Ladybeetle Vibidia duodecimguttata (Coleoptera: Coccinellidae), with Emphasis on Their Sensilla

Mouthparts are the feeding organs of insects, which play vital roles in the feeding process. The morphology of insect mouthparts has greatly evolved according to different foods and feeding habits. Therefore, studying the structure of the mouthparts is the key to understanding their feeding mechanisms. Vibidia duodecimguttata is an important biological control agent for powdery fungus. In this study, the fine morphology of the mouthpart of V. duodecimguttata was studied by scanning electron microscopy. The basic components of mouthpart of V. duodecimguttata are similar to those of other ladybeetles, while the specific morphology of each part is different. In total, six kinds of sensilla were identified on mouthpart, and twelve types of sensilla were divided according to their morphology, length and distribution. In addition, two kinds of glandular structures were also found, namely perforated plates and cuticular pores. Finally, the morphological differences between mycetophagous and other feeding habits ladybeetles were compared, and the function of each kind of sensilla was discussed, which may establish a solid foundation for further understanding of the feeding mechanism of ladybirds.

Forecasting Western Corn Rootworm (Diabrotica virgifera virgifera LeConte) Density and Non-Chemical Control of Larvae: A Practical Review

The western corn rootworm (WCR) (Diabrotica virgifera virgifera LeConte; Chrysomelidae) is one of the most significant maize pests in Europe, with farmers spending a substantial amount (approximately 140 EUR) on its control. In the context of climate change, WCRs could pose an even greater threat to EU maize production, particularly as the European Union continues to withdraw an increasing number of effective yet environmentally harmful active agents. Biological control methods have now emerged to the forefront in creating sustainable agriculture. In this review, we carried out an extensive literature analysis on methods for forecasting WCRs and evaluated the practical applicability of the latest non-chemical control methods targeting its larvae. Effective forecasting is essential for successful pest management, enabling informed planning and the selection of the most suitable control methods. Several traditional predicting techniques remain in use today, but recent advancements have introduced modern electronic forecasting units combined with sensor-equipped pheromone and colour traps, as well as thermal sum calculations. Research has demonstrated that crop rotation is one of the most effective methods for controlling WCR larvae. Biological agents, such as entomopathogenic fungi (Beauveria bossiana and Mettarrhyzum anasoplia), entomopathogenic nematodes (Heterorhabditis bacteriophora), and botanical insecticides such as azadirachtin can significantly reduce larval populations and root damage, thereby maintaining infestation levels below the economic threshold. Genetically modified maize plants that produce specific toxins, along with conventional breeding efforts to increase root system regeneration, are also promising tools for the sustainable management of this pest. This review summarizes the solutions for prediction of western corn rootworm infestations and non-chemical control of its larvae. Accurate forecasting methods provide a clear picture of infestation levels in a given area, enabling precisely targeted control measures. In all cases, the control should be directed primarily against the larvae, thereby reducing root damage and reducing the size of the emerging imago population. This review demonstrates that biological control methods targeting larvae can be as effective as pesticides, supporting sustainable pest management.

High Prevalence of Sarcocystis in a Collapsed Black Rat (Rattus rattus) Population from the Florida Keys.

We collected and screened black rats (Rattus rattus) in Key Largo, Florida, USA, to determine the potential role of disease or parasites in the collapse of the local population. Rats appeared healthy, but 94% (n=15/16) tested positive for Sarcocystis sp. The partial 18S rRNA gene sequence was 98.7-99.7% similar to a strain of Sarcocystis zuoi that is now considered a strain of the newly described Sarcocystis kani within the larger S. zuoi species complex that contains numerous new species. These Sarcocystis spp. use Asian snakes as definitive hosts and rodents, shrews, or tree shrews as intermediate hosts. Pythons are the definitive host for several Sarcocystis spp. in Asia, including a related parasite (Sarcocystis singaporensis) that has been used as a biologic control agent for Rattus spp. in southeast Asia. It is probable that increasing numbers of invasive Burmese pythons (Python bivittatus) in the Florida Keys are contributing to the spread of this parasite in addition to imposing predation pressure on both rodents and native snakes. As such, further surveillance and molecular and morphologic characterization of parasites from rodents and snakes in south Florida should be prioritized.

Olfactory response to HIPVs and biological aspects of Chrysoperla externa intended for the biological control of Aleurodicus cocois in cashew

ABSTRACT This study evaluates the olfactory response of Chrysoperla externa to the volatiles of the Embrapa 51 genotype of the cashew induced by the herbivory of Aleurodicus cocois, identifies the chemical profile of these compounds and evaluates the development of C. externa fed on A. cocois. The volatiles emitted by the leaves of the cashew genotype, both infested and not infested with A. cocois, were analysed by solid-phase microextraction with GC-MS. In the olfactometry tests, C. externa was attracted to and spent more time in the olfactometer arm containing cashew plant volatiles induced by A. cocois. From the analysis of the volatile profiles, α-phellandrene, α-terpinene, ρ-mentha-2,4(8)-diene, β-caryophyllene and germacrene D were released in large amounts by the Embrapa 51 genotype only after infestation by A. cocois; these compounds may therefore be involved in attracting the predator. Under laboratory conditions, although the development time and survival of some immature stages of C. externa may vary with the type of prey, when fed on A. cocois, the predator is able to complete the egg-adult development cycle. Based on the behavioural and biological assays, C. externa is an effective biocontrol agent for A. cocois in the cashew.

Pathogenic diversity of Puccinia kuehnii strains, causal agent of sugarcane leaf rust and biological control approach using biopesticides under semi-controlled conditions

Context: In Côte d'Ivoire, sugarcane plays an important role in the economy. However, its production is constrained by biotic factors, particularly orange rust caused by Puccinia kuehnii. Pathogenic diversity of strains is not widely understood. Existing control methods are ineffective and limited. The aim of this study was to determine the pathogenicity of Puccinia kuehnii strains, and to evaluate anti-fungal activity of essential oil-based formulations against this disease. Materials and methods: Strains 51bB and 381Z were evaluated for infectivity by foliar spraying plants of variety SP711406 under semi-controlled conditions at the Université Félix Houphouët-Boigny in Abidjan (Côte d'Ivoire). Curative control was carried out by foliar spraying plants with formulations based on natural substances of Ocimum gratissimum L, Zingiber officinale and Cymbopogon citratus, at 1000 and 2000ppm. The synthetic product copper oxide was used at a single dose of 5000 ppm. Results: Strains 51bB and 381Z showed infection rates of 62.26 and 67.36% respectively after a four-month incubation period. Severities of 30.64% (51bB) and 30.23% (381Z) were observed. ZinC1 and ZinC2 treatments had an estimated incidence reduction rate of 64.28%. Treatments based on natural substances achieved a reduction in severity of over 50%. The CymC2 treatment was the most effective, with a reduction rate of 86.04% followed by ZinC1 with rates of over than 50% reduction rate of incidence and severity due to the synthetic product was 50 and 48.83% respectively. Conclusion: Puccinia kuehnii strains induced orange rust disease in sugarcane. The effect of essential oil-based formulations has been proven on the disease under semi-controlled conditions.

Control of Helminth Infections in Captive Herbivores: An Overview of Experience

There are numerous challenges associated with helminth control in captive animals. The aim of the present paper is to provide an overview of the research on deworming of captive herbivorous mammals, the associated problems and the solutions sought, in order to derive recommendations for practice in the relevant institutions. The research was conducted by searching electronic internet databases and following the bibliographies in the published articles. The articles found are presented in summarized form. Most of the results relate to herbivores of the family Bovidae, followed by the families Cervidae, Equidae, Elephantidae, Camelidae and Giraffidae. Systematic data are presented on the types of anthelmintics used, dosages and application regimens for different animal species. Anthelmintics were administered at doses similar to or even higher than those used in farm animals, with no evidence of side effects. Treatment results often depended on the animal and parasite species. Incomplete cure, reinfection, and resistance to anthelmintics were the most common problems in the field. Based on the literature reviewed, the optimal prevention measures include the following: quarantine of newly arrived animals; daily or as intensive as possible cleaning of droppings; regular change of substrate in the enclosures; and monitoring of possible infections and their qualitative and quantitative composition (monthly or at least every two months). For treatments and monitoring effectiveness, recommendations include the following: individual assessment of the need for treatment; selective choice of anthelmintics; post-treatment examination between the 10th and 14th day after deworming; carrying out a group treatment after a preliminary drug effect test; conducting mass deworming only in case of a significant increase in fecal egg counts, highly pathogenic helminth species and a deterioration in the condition of the animals. In the future, more attention should be paid to new approaches such as biological control by saprophytic fungi or natural compounds as an alternative to anthelmintics. This would help minimize the use of anthelmintics, protect refugia and allow animals to remain healthy by maintaining a balance with the low levels of parasites present.

Bacillus thuringiensis strains with high insecticidal activity against insect larvae of the orders Coleoptera and Lepidoptera

Abstract The concept of sustainable agricultural development is aimed at reducing the use of chemical pest control agents. Since the use of chemical pesticides poses a significant environmental threat, one of the possible solutions to overcome this problem is the study of biological approaches, in particular, the use of entomopathogenic microorganisms as biological pest control agents. Insecticidal activity of over 220 strains of Bacillus thuringiensis (Bt) and Lysinibacillus sphaericus from the collection of the Laboratory of Spore-Forming Microorganisms of the Microbial Depository Center of the Scientific and Production Center “Armbiotechnology” and 15 strains isolated from samples of dead insects (imago) of representatives of various genera of the Coleoptera order was studied. The pathogenic effect of the strains was assessed in relation to the insect species Tenebrio molitor, Zophobas morio, Leptinotarsa decemlineata Say and Pieris brassicae, belonging to the Coleoptera and Lepidoptera orders. Among the test objects, the representative of Lepidoptera Pieris brassicae demonstrated the highest degree of sensitivity to B. thuringiensis strains up to 100%, with some Bt strains causing 60–100% mortality of Tenebrio molitor and Zophobas morio larvae of different ages. The larvae of the beetle Leptinotarsa decemlineata Say were also partially susceptible, presenting mortality levels of between 31 and 60%. The article is devoted to the study of Bt bacterial strains that have pronounced insecticidal activity against insect larvae of the orders Coleoptera and Lepidoptera.

Assessing the status of soil seed bank in Parthenium hysterophorus invaded land use types and its social aspects in Lower Hare Watershed, Southern Ethiopia

In Ethiopia, Parthenium hysterophorus (P. hystrophorus) is an invasive alien plant affecting various ecosystems. P. hysterophorus displaced native plant species and caused a serious threat to biodiversity. This study aimed to assess soil seed bank of P. hysterophorus under major land use types and assess community perception towards the effects of P. hysterophorus on social aspects in lower Hare watershed. For this study, 210 soil samples were collected from fifteen transect lines in grassland, cropland, and forest land use types. Statistical analysis using three ways factorial ANOVA was used to analyze the difference in density of P. hysterophorus among various land uses soil depths, and sites (P < 0.05). For the perception of local communities regarding the effects of P. hysterophorus, a total of 117 respondents were used and semi-structured and close-ended questionnaires for data collection. It found that all factors: land use, site, and soil depth significantly affected the soil seed bank density in the lower Hare watershed (P < 0.05). Results indicated that mean density of seeds were the highest in croplands of other land use types. Meanwhile, the highest mean density of seeds was identified in 0-10 cm soil depth, but the lowest mean density of seeds was identified in 10-15 cm soil depth. The highest seeds were identified at Chano Cheliba, but the density of seeds the lowest in density at Kola Shera. 38.5% of households in Kola Shera, and 21.4% in Kola Cheliba, but 8.5% in Kola Doriga said that it had effects on ecosystem services such as crop yield and livestock production. There should be a need for increased awareness about the density of P. hysterophorus in various land uses and its impacts on native plant species. Seeking possible solutions such as biological and mechanical control methods are among the local people, researchers, and extension workers can use for the management of its invasion, and appropriate control measures can be designed to combat its further invasion and impacts on different land uses of the region.

Natural Occurrence of Metarhizium rileyi on Darna diducta as a Biological Control for Oil Palm Pests in Poso, Central Sulawesi

Natural Occurrence of Metarhizium rileyi on Darna diducta as a Biological Control for Oil Palm Pests in Poso, Central Sulawesi

Tomato Root Exudates Infected by Meloidogyne incognita Impact the Colonization of Nematicidal Proteus vulgaris

Root exudates play a pivotal role in shaping the microbial community in the rhizosphere and can impact the efficacy of bacteria in controlling nematode populations. This study identified Proteus vulgaris BX-1 as significantly effective in controlling Meloidogyne incognita. The infection of tomato plants with this nematode induced noticeable alterations in the composition of tomato root exudates and led to an increased colonization rate of strain BX-1. Further investigation into how strain BX-1 responded to changes in tomato root exudates revealed that specific metabolites, such as caffeic acid, coumarin, salicylic acid, sebacic acid, and butyric acid, strongly attracted strain BX-1. This attraction potentially contributed to its enhanced colonization and improved efficiency in controlling nematodes. Understanding the correlation between specific metabolites in root exudates and the response of antagonistic bacteria provides valuable insights for enhancing their effectiveness as biological control agents against plant-parasitic nematodes.