Use Of Biocontrol Agents Research Articles

Functional response and predatory potential of Neoseiulus newsami (Acari: Phytoseiidae) against Megalurothrips usitatus (Thysanoptera: Thripidae)

Megalurothrips usitatus, is an important pest of cowpeas Vigna unguiculata, that causes severe damage to cowpea crops in Southeast Asia and Hainan Province in China. Neoseiulus newsami is a natural enemy of M. usitatus that was first reported from Ledong Li Autonomous County, Hainan, China. Here, we evaluated the potential of N. newsami as a biocontrol agent for use against M. usitatus. In laboratory tests, N. newsami showed a similar rate of attack on this pest as did the better-known species Neoseiulus barkeri. The functional response curve of N. newsami fed M. usitatus showed that more 1st instar prey were consumed by N. newsami at higher prey densities, indicating a Type III functional. The maximum attack coefficient (a) was 0.063 ± 0.011 and the handling time per consumed prey (Th) was 0.58 ± 0.09. The maximum attack rate (T/Th) was 41.37. Neoseiulus newsami showed higher predation and oviposition rates than did N. barkeri or Neoseiulus cucumeris. Our results suggest that N. newsami has a higher predation capacity against M. usitatus.

Don't touch me! Mating not always preceded by courtship behavior in predatory coccinellids.

Knowledge of the ecology and behavior of biological control agents is essential for their effective use in biocontrol and Integrated Pest Management (IPM)programs. There is a lack of information regarding the courtship and mating traits that are crucial for successful mating in biocontrol population of coccinellids. To expand our current understanding in this area, 2 coccinellid species commonly used for the biocontrol of soft-bodied insects, Cryptolaemus montrouzieri (Mulsant) and Propylea quatuordecimpunctata (Linnaeus) (Coleoptera: Coccinellidae), were studied. A quantitative analysis was performed to compare their courtship and mating displays. Key behavioral traits of the precopulatory, copulatory, and postcopulatory phases were investigated. The courtship and mating sequences of C. montrouzieri and P. quatuordecimpunctata were similar to each other. During the mating phase, the key displays were the opening of the elytrae and wings followed by body shaking in C. montrouzieri and leg tapping followed by body shaking in P. quatuordecimpunctata. The mating success of both species was not correlated with any courtship display, such as antennal tapping. Only in C. montrouzieri mounting attempt showed a higher frequency from the backside without affecting male mating success. This research adds baseline knowledge about the courtship and mating behavior of the biocontrol population of coccinellids, contributing to the identification of potentiallyuseful benchmarks (e.g., body shaking, leg tapping) for monitoring prolonged mass-rearing processes, thusreducing mating failures.

Resistance Mechanisms of Plant Pathogenic Fungi to Fungicide, Environmental Impacts of Fungicides, and Sustainable Solutions

The significant reduction in agricultural output and the decline in product quality are two of the most glaring negative impacts caused by plant pathogenic fungi (PPF). Furthermore, contaminated food or transit might introduce mycotoxins produced by PPF directly into the food chain. Eating food tainted with mycotoxin is extremely dangerous for both human and animal health. Using fungicides is the first choice to control PPF or their toxins in food. Fungicide resistance and its effects on the environment and public health are becoming more and more of a concern, despite the fact that chemical fungicides are used to limit PPF toxicity and control growth in crops. Fungicides induce target site alteration and efflux pump activation, and mutations in PPF result in resistance. As a result, global trends are shifting away from chemically manufactured pesticides and toward managing fungal plant diseases using various biocontrol techniques, tactics, and approaches. However, surveillance programs to monitor fungicide resistance and their environmental impact are much fewer compared to bacterial antibiotic resistance surveillance programs. In this review, we discuss the PPF that contributes to disease development in plants, the fungicides used against them, factors causing the spread of PPF and the emergence of new strains, the antifungal resistance mechanisms of PPF, health, the environmental impacts of fungicides, and the use of biocontrol agents (BCAs), antimicrobial peptides (AMPs), and nanotechnologies to control PPF as a safe and eco-friendly alternative to fungicides.

Combined application of the endophyte Bacillus K1 and sodium dehydroacetate alleviates postharvest gray mold in grapes

Botrytis cinerea, which causes postharvest gray mold, is a primary pathogen that limits grape shelf-life and consumption and causes substantial yield loss worldwide. The combined use of biocontrol agents and food additives has attracted increasing interest. The effects of combined treatment with the endophyte Bacillus subtilis K1 and sodium dehydroacetate (SD) on the occurrence of gray mold and maintenance of grape fruit quality were studied. Treatment with a K1 suspension (1 × 108 CFU/ml) combined with 0.32 g/L SD resulted in markedly improved control of B. cinerea on grapes. The disease incidence and severity in the groups treated with K1 alone or in combination with SD were significantly lower than those in the control groups (P < 0.05) when the mixtures were applied 2 h after pathogen inoculation. Moreover, application of the mixture could maintain the appearance, firmness, total soluble solid (TSS) content and titratable acidity (TA) of grape fruit. Furthermore, the combination triggered increases in the activities of defense-related enzymes such as peroxidase (POD), phenylalanine ammonia lyase (PAL), catalase (CAT), superoxide dismutase (SOD) and polyphenol oxidase (PPO). Additionally, it could increase the vitamin C content. Thus, appropriate combinations of biocontrol agents and chemical reagents can provide effective protection against postharvest decay.

The Use of Bio-control Agents in Mulberry Pest Management: Successful Techniques and Important Issues

Since bio-control agents target specific pests without affecting the usefulness insects or/and damaging the soil and water resources, it plays a role in conservation of ecological balance in the environment. A variety of insect and non-insect pests, as well as hosts of parasites (fungi, insect, and mite parasites), occur in silkworm sericulture. This method does not in any way influence the sustainability of environment through pest control as required by sustainable agriculture. Since bio-control agents are known to be harmless to human beings and other organisms that may be of equal importance in the ecosystem such as pollinators, wildlife etc., they also have safety advantages. This is a big step forward to eradicating pests as compared to the chemical pesticides which have been known to affect the human lives and other wildlife. In the meantime, the bio-control agents may be cost effective in the long run. Because bio-control agents could offer continuous control of pests with minimal extra cost, it is possible, even when the outlay of obtaining and developing such organisms is more expensive than straightforward chemical applications. Further, the use of bio-control agents may reduce the reliance on traditional chemical pesticides and hence cost outlay and pest control costs and also reduce the probabilities of pesticide resistance. In the farming of mulberry, bio control agents are one the most important components of integrated pest management and have proved be an effective substitute to chemical control. Bio-control agents offer long-term pest suppression in comparison to chemical control methods, whose impacts tend to weaken after several generations of treatment. The continuous use of chemicals may result in pest resistance to the pesticides used. Spraying synthetic pesticides leads to the formation of pesticide residues on mulberry foliage, which affects food products and environmental health.

Exploring the effects of entomopathogenic nematode symbiotic bacteria and their cell free filtrates on the tomato leafminer Tuta absoluta and its predator Nesidiocoris tenuis

The use of biocontrol agents, such as predators and entomopathogenic nematodes, is a promising approach for the effective control of the tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidaean), an oligophagous insect feeding mainly on Solanaceae species and a major pest of field- and greenhouse-grown tomatoes globally. In this context, the effects of two entomopathogenic nematode species Steinernema carpocapsae (Weiser) (Rhabditida: Steinernematidae) and Heterorhabditis bacteriophora (Poinar) (Rhabditida: Heterorhabditidae), as well as their respective bacterial symbionts, Xenorhabdus nematophila and Photorhabdus luminescens (Enterobacterales: Morganelaceae), which were applied as bacterial cell suspensions and as crude cell-free liquid filtrates on T. absoluta larvae, were investigated. The results showed that of all treatments, the nematodes S. carpocapsae and H. bacteriophora were the most effective, causing up to 98 % mortality of T. absoluta larvae. Regarding bacteria and their filtrates, the bacterium X. nematophila was the most effective (69 % mortality in young larvae), while P. luminescens and both bacterial filtrates showed similar potency (ca. 48–55 % mortality in young larvae). To achieve a holistic approach of controlling this important pest, the impact of these factors on the beneficial predator Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) was also studied. The results demonstrated that although nematodes and especially S. carpocapsae, caused significant mortality on N. tenuis (87 %), the bacterial cell suspensions of X. nematophila and P. luminescens and crude cell-free liquid filtrates had minimum impact on this beneficial predator (∼11–30 % mortality).

Evaluation and Characterization of Rhizobacteria and Endophytes for Antagonistic and Growth Promotional Traits Against Collar Rot (Sclerotium rolfsii Sacc.) of Soybean

Background: Sclerotium rolfsii Sacc. is one of the destructive soil-borne plant pathogens due to its significant loss in terms of yield and quality in several crop plants including soybean. Use of biocontrol agents in the management of disease is an ecofriendly strategy. Therefore, the study aimed to assess in vitro antagonisticactivity of rhizobacteria and endophytes against Sclerotium rolfsii following dual culture technique. Methods: A total of 75 rhizobacterial isolates, 3 endophytes along with reference cultures were evaluated for the antagonistic activity against Sclerotium rolfsii following dual culture technique. The effective rhizobacterial isolates were tested for the various plat growth promoting rhizobacteria traits viz., indole acetic acid production, siderophore production, Phosphate solubilization, production of ammonia, hydrogen cyanide production and chitinase test following the standard procedure. Result: The two promising rhizobacterial strains i.e., AUUB 209 (Streptomyces enissocaesilis) and Streptomyces racemochromogenes (AUDT 626) were found effective with 76.79 and 64.75 percent mycelial inhibition of Sclerotium rolfsii under in vitro. The antagonistic activity of these two rhizobacteria is mainly attributed to the positive confirmation of various PGPR activities viz., production of Indole acetic acid, siderophore, phosphate solubilization and chitinase production.

Biocontrol Agents: Risks and Opportunities from Farm to Fork

AbstractOne of the less popular and less investigated topics of law is the use of biocontrol agents (BCAs). Despite the general growing attention to the use of BCAs in primary production, a comprehensive regulatory framework is still lacking. When shifting to possible uses of BCAs in the following phases of the food chain, legislation is even more incomplete (and inadequate) despite the challenging opportunities they offer both for pest control and for pathogen control. The paper will provide an overview of the uses of BCAs taking into consideration all the food chain stages, the relevant partial EU regulatory scheme and its critical issues.

Fungal Diseases in Yerba Mate: Status and Management Strategies.

Yerba mate (Ilex paraguariensis St. Hil.), with its health benefits and socioeconomic significance, plays a crucial role in Argentina and other South American countries like Brazil and Paraguay. Its cultivation in the Province of Misiones (Argentina) supports various sectors, contributes to regional development, and provides employment opportunities. However, the transition from extractive practices to monoculture, accompanied with increased demand, has led to phytosanitary challenges. Imbalanced native microbiota, disease development, and pathogen dispersion have become prevalent issues. Understanding the known pathogens associated with yerba mate plants is crucial for developing effective agricultural strategies. The primary objective of this study is to synthesise current knowledge on prevalent fungal diseases in yerba mate cultivation, as well as to provide agricultural management recommendations for effective disease control. Fungal diseases can cause significant damage to different parts of the plant, resulting in economic losses. The proximity of neighbouring plantations to yerba mate crops may contribute to the cross-contamination of pathogens, emphasizing the need for comprehensive epidemiology and accurate diagnosis. Multiple fungal genera have been reported to cause pathologies in yerba mate. Among the fungi causing foliar diseases are Ceratobasidium niltonsouzanum, Cylindrocladium spathulatum, Pseudocercospora mate, Asterina sphaerelloides, Colletotrichum gloeosporioides aff var. yerbae, and Phyllosticta sp. Caulinary diseases are caused by Alternaria sp., Phoma sp., Colletotrichum sp., and Ceratocystis fimbriata. Regarding root rot, the genera Rhizoctonia sp., Pythium sp., Fusarium sp., and Rosellinia sp. have been reported. Proper crop management practices and monitoring are essential for effective disease control. To reduce reliance on chemical compounds, the use of biocontrol agents like Trichoderma sp. has shown promise in regulating phytopathogenic fungi populations. Continued research is vital to preserve the yerba mate industry and ensure its long-term viability while minimizing environmental impact.

Addressing the Concern of Orange-Yellow Fungus Growth on Palm Kernel Cake: Safeguarding Dairy Cattle Diets for Mycotoxin-Producing Fungi.

Palm kernel cake (PKC), a byproduct of palm oil extraction, serves an important role in Ecuador's animal feed industry. The emergence of yellow-orange fungal growth in PKC on some cattle farms in Ecuador sparked concerns within the cattle industry regarding a potential mycotoxin-producing fungus on this substrate. Due to the limited availability of analytical chemistry techniques in Ecuador for mycotoxin detection, we chose to isolate and identify the fungus to determine its association with mycotoxin-producing genera. Through molecular identification via ITS region sequencing, we identified the yellow-orange fungus as the yeast Candida ethanolica. Furthermore, we isolated two other fungi-the yeast Pichia kudriavzevii, and the fungus Geotrichum candidum. Molecular identification confirmed that all three species are not classified as mycotoxin-producing fungi but in contrast, the literature indicates that all three have demonstrated antifungal activity against Aspergillus and Penicillium species, genera associated with mycotoxin production. This suggests their potential use in biocontrol to counter the colonization of harmful fungi. We discuss preventive measures against the fungal invasion of PKC and emphasize the importance of promptly identifying fungi on this substrate. Rapid recognition of mycotoxin-producing and pathogenic genera holds the promise of mitigating cattle intoxication and the dissemination of mycotoxins throughout the food chain.

Antibiotic Resistance in Plant Pathogenic Bacteria: Recent Data and Environmental Impact of Unchecked Use and the Potential of Biocontrol Agents as an Eco-Friendly Alternative.

The economic impact of phytopathogenic bacteria on agriculture is staggering, costing billions of US dollars globally. Pseudomonas syringae is the top most phytopathogenic bacteria, having more than 60 pathovars, which cause bacteria speck in tomatoes, halo blight in beans, and so on. Although antibiotics or a combination of antibiotics are used to manage infectious diseases in plants, they are employed far less in agriculture compared to human and animal populations. Moreover, the majority of antibiotics used in plants are immediately washed away, leading to environmental damage to ecosystems and food chains. Due to the serious risk of antibiotic resistance (AR) and the potential for environmental contamination with antibiotic residues and resistance genes, the use of unchecked antibiotics against phytopathogenic bacteria is not advisable. Despite the significant concern regarding AR in the world today, there are inadequate and outdated data on the AR of phytopathogenic bacteria. This review presents recent AR data on plant pathogenic bacteria (PPB), along with their environmental impact. In light of these findings, we suggest the use of biocontrol agents as a sustainable, eco-friendly, and effective alternative to controlling phytopathogenic bacteria.

Harnessing nature's arsenal: Ochrobactrum bacteria metabolites in the battle against root- knot nematode – Insights from in vitro and molecular docking studies

Agricultural Productivity and plant health are threatened by the root-knot nematode. The use of biocontrol agents reduces the need for chemical nematicides and improves the general health of agricultural ecosystems by offering a more environmentally friendly and sustainable method of managing nematode infestations. Plant-parasitic nematodes can be efficiently managed with the use of entomopathogenic nematodes (EPNs), which are widely used biocontrol agents. This study focused on the nematicidal activity of the secondary metabolites present in the bacteria Ochrobactrum sp. identified in the EPN, Heterorhabditisindica against Root-Knot Nematode (Meloidogyne incognita). Its effect on egg hatching and survival of juveniles of root- knot nematode (RKN) was examined. The ethyl acetate component of the cell-free culture (CFC) filtrate of the Ochrobactrum sp. bacteria was tested at four different concentrations (25 %, 50 %, 75 % and 100 %) along with broth and distilled water as control. The bioactive compounds of Ochrobactrum sp. bacteria showed the highest suppression of M. incognita egg hatching (100 %) and juvenile mortality (100 %) at 100 % concentration within 24 h of incubation. In this study, unique metabolite compounds were identified through the Gas Chromatography- Mass Spectrometry (GC–MS) analysis, which were found to have anti- nematicidal activity. In light of this, molecular docking studies were conducted to determine the impact of biomolecules from Ochrobactrum sp. using significant proteins of M. incognita, such as calreticulin, sterol carrier protein 2, flavin-containing monooxygenase, pectate lyase, candidate secreted effector, oesophageal gland cell secretory protein and venom allergen-like protein. The results also showed that the biomolecules from Ochrobactrum sp. had a significant inhibitory effect on the different protein targets of M. incognita. 3-Epimacronine and Heraclenin were found to inhibit most of the chosen target protein. Among the targets, the docking analysis revealed that Heraclenin exhibited the highest binding affinity of −8.6 Kcal/mol with the target flavin- containing monooxygenase. Further, the in vitro evaluation of 3- Epimacronine confirmed their nematicidal activity against M. incognita at different concentrations. In light of this, the present study has raised awareness of the unique biomolecules of the bacterial symbiont Ochrobactrum sp. isolated from H. indica that have nematicidal properties.

Integrated Pest Management Precision: Harnessing the Joint Influence of Entomopathogenic Fungi, Nematodes, and Chlorantraniliprole for Targeted Control of Fall Armyworm (Spodoptera Frugiperda)

Background: The Spodoptera frugiperda, commonly known as the fall armyworm (FAW), is a significant pest impacting agricultural productivity worldwide. Originating from tropical and subtropical regions, FAW has shown a high capacity for migration and destruction across a wide variety of crops. Integrated Pest Management (IPM) strategies offer sustainable approaches to managing pest populations, minimizing environmental impact, and reducing reliance on chemical insecticides. Objective: This study aimed to evaluate the efficacy of combining biological control agents, specifically Heterorhabditis bacteriophora (Hb) and Beauveria bassiana (Bb), with the chemical insecticide chlorantraniliprole (Ch) against third and fifth instar larvae of S. frugiperda. The study sought to determine the potential synergistic effects of these combinations on larval mortality and developmental disruption. Methods: The research encompassed laboratory bioassays, greenhouse, and field trials to assess the impact of the biocontrol agents and chlorantraniliprole, both individually and in combination, on FAW larval mortality and development. Larval populations of S. frugiperda were collected and reared under controlled conditions. Treatments applied included Hb, Bb, Ch, Hb+Bb, Hb+Ch, Bb+Ch, and Hb+Bb+Ch. Mortality rates were recorded at 3, 5, and 7 days post-treatment, while developmental parameters were assessed through pupation rates, adult emergence, and egg eclosion percentages. Results: The combined application of Hb, Bb, and Ch significantly increased mortality rates in both the third and fifth instar larvae compared to individual treatments, with the highest mortality observed in the Hb+Bb+Ch group (100% by day 7). Developmental disruptions were also noted, including reduced pupation rates, adult emergence, and egg eclosion, particularly in treatments involving the combined use of biocontrol agents and chlorantraniliprole. Statistical analysis confirmed the significance of these findings (P&lt;0.01). Conclusion: The integration of Hb, Bb, and Ch presents a viable IPM strategy for effectively managing S. frugiperda populations. This combination not only enhances larval mortality but also disrupts developmental stages, offering a potential reduction in FAW infestation levels and associated crop damages. These results underscore the importance of adopting sustainable pest management practices that leverage synergistic effects between biological and chemical agents.

Post-harvest Biotechnology or Genetic Engineering Solutions: Extending Shelf Life and Reducing Food Waste

Post-harvest losses and food waste have become critical challenges in the global food supply chain, contributing to economic losses, environmental degradation, and food insecurity. This article explores the innovative applications of post-harvest biotechnology and genetic engineering as promising solutions to address these issues by extending the shelf life of perishable products and minimizing food waste. Advancements in genetic engineering techniques have paved the way for the development of crops with enhanced resistance to pests, diseases, and environmental stresses. Additionally, the manipulation of genes associated with ripening and senescence has allowed scientists to engineer fruits and vegetables with extended shelf life. These genetically modified organisms (GMOs) exhibit improved post-harvest characteristics, providing a longer window for transportation, storage, and consumption. Biotechnological interventions also include the use of biocontrol agents and beneficial microorganisms to suppress post-harvest pathogens, thereby reducing spoilage and decay. The development of bio-preservatives, such as antimicrobial peptides and natural compounds, offers an eco-friendly alternative to traditional chemical preservatives, contributing to both food safety and sustainability. Furthermore, the integration of smart packaging technologies with genetic modifications enhances the monitoring and control of environmental conditions during storage and transportation. Intelligent packaging materials equipped with sensors can detect changes in temperature, humidity, and gas composition, enabling real-time adjustments to prolong the freshness of perishable goods.

Biocontrol Agents of Fusarium Head Blight in Wheat: A Meta-Analytic Approach to Elucidate Their Strengths and Weaknesses.

The use of biocontrol agents (BCAs) coping with fungal pathogens causing Fusarium head blight (FHB) is a compelling strategy for disease management, but a better elucidation of their effectiveness is crucial. Meta-analysis is the analysis of the results of multiple studies, which is typically performed to synthesize evidence from many possible sources in a formal probabilistic manner. This meta-analytic study, including 30 pathometric, biometric, physiochemical, genetic, and mycotoxin response variables reported in 56 studies, evidences the BCA effects on FHB in wheat. The effectiveness of BCAs of FHB in wheat in terms of pathogen abundance and disease reductions, biomass and yield conservation, and mycotoxin prevention/control was confirmed. BCAs showed higher efficacy (i) in studies published more recently; (ii) under controlled conditions; (iii) in high susceptible wheat cultivars; (iv) when Fusarium inoculation and BCA treatment did not occur directly on the plant (i.e., at the seed and kernel levels) in terms of disease development and mycotoxin control, and vice versa in terms of biomass conservation; (v) if Fusarium inoculation and BCA treatment occurred by spraying spikes in terms of yield; (vi) at 15 to 21 days post Fusarium inoculation or BCA treatment; and (vii) if they were filamentous fungi. However, BCAs overall were less efficacious than conventional agrochemicals, especially in terms of pathogen abundance and FHB reductions, as well as of mycotoxin prevention/control, although inconsistencies were reported among the investigated moderator variables. This study also highlights the complexity of reaching a good balance among BCA effects, and the need for further research.

In vitro Inhibition of Rhizoctonia solani Radial Growth by Native Mycoflora: Implications for Root Rot Disease in Chili

In the course of the study, native bioagents isolated from the rhizosphere of the chili crop were used to manage the soil-borne pathogens Rhizoctonia solani. The study was conducted in the laboratory of the Department of Plant Pathology and Nematology, RPCAU, Pusa, Bihar in the year 2020-23. The soil microflora (fungal and bacterial) was isolated from the rhizosphere of Chili and screened in vitro by evaluating their antagonistic potential against Rhizoctonia solani, and resultantly two fungal and two bacterial isolates were found most effective in inhibiting the mycelial growth of the pathogen over control. The maximum percent inhibition was recorded in the case of Trichoderma harzianum (71.98%) followed by Trichoderma viride (62.54%) and among the bacterial isolates maximum inhibition was recorded in the case of RB1 that inhibit (69.38%), followed by RB6 (66.42%). Overall, these findings suggest that the combination of Trichoderma and Bacteria could be an effective and sustainable method for reducing the radial growth of Rhizoctonia solani causing Root rot disease in chilli. Rhizoctonia solani was established as a causal organism of chili. The use of Bio-control agents is an eco-friendly approach and a good option to manage soil borne phyto-pathogens. These biological control agents either use the mechanism of antibiosis or mycoparasitism against the fungal pathogen. Evaluation of Trichoderma spp. and Bacterial isolates against Rhizoctonia solani showed that significantly reduced the mycelial growth of Rhizoctonia solani in vitro.

Bacillus strain BX77: a potential biocontrol agent for use against foodborne pathogens in alfalfa sprouts.

Despite regulatory and technological measures, edible sprouts are still often involved in foodborne illness and are considered a high-risk food. The present study explored the potential of spore-forming Bacillus isolates to mitigate Salmonella and Escherichia coli contamination of alfalfa sprouts. Food-derived Bacillus strains were screened for antagonistic activity against S. enterica serovar Typhimurium SL1344 (STm) and enteropathogenic E. coli O55:H7. Over 4 days of sprouting, levels of STm and E. coli on contaminated seeds increased from 2.0 log CFU/g to 8.0 and 3.9 log CFU/g, respectively. Treatment of the contaminated seeds with the most active Bacillus isolate, strain BX77, at 7 log CFU/g seeds resulted in substantial reductions in the levels of STm (5.8 CFU/g) and E. coli (3.9 log CFU/g) in the sprouted seeds, compared to the control. Similarly, co-culturing STm and BX77 in sterilized sprout extract at the same ratio resulted in growth inhibition and killed the Salmonella. Confocal-microscopy experiments using seeds supplemented with mCherry-tagged Salmonella revealed massive colonization of the seed coat and the root tip of 4-day-old sprouted seeds. In contrast, very few Salmonella cells were observed in sprouted seeds grown with BX77. Ca-hypochlorite disinfection of seeds contaminated with a relatively high concentration of Salmonella (5.0 log CFU/g) or treated with BX77 revealed a mild inhibitory effect. However, disinfection followed by the addition of BX77 had a synergistic effect, with a substantial reduction in Salmonella counts (7.8 log CFU/g) as compared to untreated seeds. These results suggest that a combination of chemical and biological treatments warrants further study, toward its potential application as a multi-hurdle strategy to mitigate Salmonella contamination of sprouted alfalfa seeds.

Two insecticidal neurotoxins from parasitoid wasp Habrobracon hebetor venom and their potential use in biocontrol

Two insecticidal neurotoxins from parasitoid wasp Habrobracon hebetor venom and their potential use in biocontrol

Effects of biocontrol Bacillus sp. strain D5 on the pathogenic Fusarium oxysporum R1 at the microscopic and molecular level in Crocus sativus L. (saffron) corm.

Corm rot of saffron caused by Fusarium oxysporum is a major threat to saffron cultivation the world over. To minimize the ill effects of chemical fungicides, attention has been shifted to the use of biocontrol agents for disease management in a sustainable way. In saffron, various biocontrol agents against corm rot disease have been reported and characterized but no study has been done so far to understand their interaction at the molecular level. The present study was conducted to unravel the mechanism of action of an already characterized native biocontrol agent i.e. Bacillus sp. strain D5 (Bar D5) against F. oxsporum R1 (Fox R1) in the saffron corm. The growth inhibition of Fox R1 was observed in vitro and in planta (saffron corm) by real time imaging. Bacillus sp. strain D5 reduced Fox R1 load in infected corms by 50% as quantified by q-PCR and the colony-forming unit method. Comparative transcriptome analysis revealed upregulation and downregulation of various Fox R1 genes in presence of Bar D5. The genes related to carbon metabolism, cell wall and membrane synthesis, and growth of Fox R1 were significantly downregulated in Bar D5-primed and Fox R1-inoculated corms as compared to only Fox R1-inoculated corms.

Laboratory Evaluation of the Efficiency of The Entomopathogenic Fungus Beauvaria bassiana as a Biological Control Factor Against the Cucurbit Fly, Dacus ciliates

Al-Shweily, B.M., J.B. El-Zidawi and M.J. Hinnawi. 2024. Laboratory Evaluation of the Efficiency of The Entomopathogenic Fungus Beauvaria bassiana as a Biological Control Factor Against the Cucurbit Fly, Dacus ciliates. Arab Journal of Plant Protection, 42(3): 335-339. https://doi.org/10.22268/AJPP-001260 The cucurbit fly, Dacus ciliatus is a major pest which attack a wide range of crops and causes significant losses in agricultural production. Due to the high toxicity of chemical pesticides on human health and the environment, scientists focused on developing alternative safe methods to control this insect, including the use of biocontrol agents. Beauveria bassiana is one of the common fungi used as a bio-control agent. This entomopathogenic fungus was cultivated on Petri dishes containing PDA. The spore suspension of this fungus was prepared using sterilized distilled water, and three concentrations were used: 20×106 , 10×106 and 5×106 spores/ml. The effectiveness of these three concentrations was tested on larvae and pupae of the studied insect. The larval mortality rate ranged from 73.33% at the highest concentration to 33.33% at the lowest concentration used. Pupal mortality reached 66.66% at the highest concentration and 16.66% at the lowest concentration of spore suspension. Mortality rate was directly proportional to the spore suspension concentration of the entomopathogenic fungus. Keywords: Cucurbit fly, agricultural pest, biological control, Dacus ciliates, Beauveria bassiana, entomopathogenic fungi.