Promising Biological Control Research Articles

Potential for the Use of the Entomopathogenic Fungus Beauveria bassiana in the Biological Control of Cryptolestes ferrugineus and Acanthoscelides obtectus

In this study, the effectiveness of different conidial suspensions of the entomopathogenic fungus Beauveria bassiana (Balsamo) on stored product pests Acanthoscelides obtectus (Bean Seed Beetle) (Coleoptera, Chrysomelidae) and Cryptolestes ferrugineus (Rusty Grain Beetle) (Coleoptera, Laemophloeidae) was aimed to be determined. For this purpose, suspensions of B. bassiana isolate at concentrations of 106, 107, and 108 conidia/ml were used, with sterile water as a negative control and a recommended Declare (EC 25 g/l) as a positive control. The application was set up in three replicates, with 10 adults in each replicate, and applied using the spraying method. To calculate the percentage of mortality, Petri dishes were regularly checked every 24 hours from the application, and the numbers of live and dead adults were recorded. According to the obtained data, it was determined that B. bassiana isolate was effective against C. ferrugineus at a rate of 80% and against A. obtectus at a rate of 56.67% after 168 hours. Among the applied suspensions, the most effective suspension was recorded at 108 conidia/ml. As a result, the entomopathogenic fungus B. bassiana (ET 10) isolate used as a biological control agent, is considered a promising biological control agent against the storage pests C. ferrugineus and A. obtectus.

Entomopathogenic Fungi: Nature's Secret Weapon Against Agricultural Pests

Insect pests pose significant challenges to agricultural productivity and crop yield worldwide. Conventional pest control methods, such as chemical pesticides, have limitations and adverse environmental effects. Therefore, there is a growing need for sustainable and eco-friendly alternatives in pest management. This review explores the potential of entomopathogenic fungi as a promising biological control agent for insect pests in agriculture. The review begins by providing an overview of entomopathogenic fungi and their significancce. These fungi possess unique mechanisms to infect and kill insect pests. The mode of action involves attachment of fungal spores to the insect's cuticle, followed by penetration, colonization, and release of toxic metabolites within the host. Various factors influence the efficacy of entomopathogenic fungi, including environmental conditions, insect host susceptibility, and formulation/application methods. The benefits of entomopathogenic fungi as biological control agents are discussed, including their compatibility with integrated pest management (IPM) strategies and minimal impact on non-target organisms. However, challenges exist in scaling up their commercial application. The review presents case studies showcasing successful field applications of entomopathogenic fungi in pest management. Future prospects and research directions are identified, emphasizing the importance of continued advancements in understanding the interactions between entomopathogenic fungi and insect pests. Regulatory frameworks and public acceptance are crucial for the widespread adoption of these fungi in agriculture. In conclusion, entomopathogenic fungi offer immense potential as sustainable and effective tools for biological control of insect pests in agriculture. Their ability to target specific pests, compatibility with IPM, and minimal environmental impact make them a viable alternative to chemical pesticides. Further research, collaboration, and implementation are necessary to fully harness the potential of entomopathogenic fungi in integrated pest management strategies.

Identification of secondary metabolites biosynthetic genes, antagonistic activity and potential mechanism of <i>Bacillus subtilis</i> NBAIR-BSWG1 in suppression of <i>Alternaria alternata</i>

Alternaria alternata wreaks havoc on fruit and vegetable production globally, threatening food security by causing black leaf spot disease. Bacillus subtilis, a natural inhabitant of soil, is a promising biological control agent for the management of A. alternata. In the present study, the antagonistic potential of B. subtilis NBAIR-BSWG1 was initially confirmed against A. alternata through a dual culture technique with 43.03% inhibition of mycelial growth. Subsequently, we extracted the cell-free extract from the NBAIR-BSWG1 pure culture and assessed its impact on A. alternata through the poison food technique and found mycelial growth inhibition of 85.82%. Identification of secondary metabolites biosynthetic genes using specific PCR markers showed the presence of surfactin genes (sfp, srf AA) with an amplicon size of 675 bp and 201 bp, respectively. Amplification of fengycin (fenB) and iturin (ituD) at 670 bp and 423 bp respectively, by using a specific PCR primer confirms the contribution of fengycin and iturin for the antagonistic potential of NBAIR-BSWG1. This study identifies NBAIR-BSWG1 as an effective bacterial biocontrol agent for control of A. alternata, unlocks the genetic basis of antifungal activity NBAIR-BSWG1, depicts molecular mechanisms involved in biological suppression of A. alternata by NBAIR-BSWG1 paving the way for the development of bioformulations for management of A. alternata.

The potential of the hoverfly Allograpta exotica as a biological control agent of the strawberry aphid Chaetosiphon fragaefolii

AbstractSyrphid larvae are effective biological control agents in numerous crops due to their voracity, and they are used in both augmentative and conservation‐based strategies within horticultural systems. This study conducted laboratory trials to ascertain the predation rate of Allograpta exotica (Wiedemann) (Diptera: Syrphidae) on Chaetosiphon fragaefolii (Cockerell) (Hemiptera: Aphididae) and to compare it with the predation rate on Aphis gossypii Glover (Hemiptera: Aphididae), another significant aphid species affecting strawberries. Additionally, field trials were conducted to assess the reduction in the field population of C. fragaefolii achieved by A. exotica within strawberry crops. We observed a significant increase in the number of aphids consumed by a larva as it progressed from first‐instar larvae (L1) to third‐instar larvae (L3). Specifically, the mean aphid consumption by second‐instar larvae (L2) was nearly 11 times higher for C. fragaefolii and 10 times higher for A. gossypii compared to L1. Furthermore, the consumption rate of L3 larvae was approximately 2 times higher for both aphid species compared to L2. In laboratory conditions, A. exotica larvae significantly reduced the number of both aphid species, but the control on A. gossypii was higher than on C. fragaefolii. The results of the field experiment demonstrated that the predatory hoverfly A. exotica significantly reduced the numbers of C. fragaefolii compared to the control treatment, highlighting its potential as a promising biological control agent in strawberry crops.

Transgenerational hormesis and sublethal effects of five key insecticides for controlling Spodoptera frugiperda on its endoparasitoid Cotesia marginiventris.

The endoparasitoid Cotesia marginiventris (Cresson) is a promising biological control agent of the fall armyworm (FAW) Spodoptera frugiperda (Smith). Because the application of insecticides is one of the prime choices in pest management, we evaluated the sublethal and transgenerational effects of the five key insecticides-chlorantraniliprole, emamectin benzoate, spinetoram, Bacillus thuringiensis (Bt), and Mamestra brassicae nucleopolyhedrovirus (MbNPV)-on the parasitoid. Exposure to five insecticides at a concentration causing 10% mortality (LC10 ) caused hormetic effects in the parent generation (F0 ) by increasing the parasitism and reducing the immature duration. Interestingly, the hormetic response was also observed in the offspring generation indirectly exposed to the insecticides. Furthermore, insecticides increased the parasitism rate by 6.32-14.73% in the F1 generation, which was similar to that of the F0 generation (3.96-11.81%) compared with the control. No significant adverse effect was observed on the number of emerged parasitoids of the F1 and F2 generations. However, insecticides had a detrimental impact on body size and fecundity in the F1 and F2 generations, which showed a small body size with shorter hind tibiae and a significant reduction in the female ratio compared with the control; the exception was that chlorantraniliprole significantly improved the female ratio in the F2 generation. Five insecticides at LC10 induced transgenerational hormetic and sublethal effects on C. marginiventris. Our results provide a scientific basis for a better understanding of the long-term impacts of insecticides at sublethal doses on parasitoids, facilitating the development of improved integrated pest management programs for FAW control. © 2023 Society of Chemical Industry.

Control of two-spotted spider mite, Tetranychus urticae, on strawberry by integrating with cyetpyrafen and Phytoseiulus persimilis

The two-spotted spider mite (TSSM, Tetranychus urticae Koch) is a significant agricultural pest, particularly in strawberries. Management of TSSM has traditionally relied on synthetic acaricides, but to mitigate dependency on these chemicals, the control of TSSM on strawberry is often combined with biological control measures and chemical control strategies. The predatory mite, Phytoseiulus persimilis, is a promising biological control agent, preying on all TSSM developmental stages. In this study, we examined the toxicity of six common acaricides on TSSM and P. persimilis, and cyetpyrafen was selected due to its highest relative toxicity value. Then, we examined the compatibility of cyetpyrafen with P. persimilis for TSSM management on strawberries. The results suggested that cyetpyrafen revealed no substantial differences in prey consumption or longevity when compared to the control, though minor effects on the development durations of protonymphs and deutonymphs were noted in the subsequent generation. Additionally, cyetpyrafen's toxicity on key pollinators, such as Apis mellifera and Bombus terrestris, was found to be low. Thus, an integrated strategy combining cyetpyrafen (0.83 mg/L) with P. persimilis (predator–prey ratio of 1:30) was examined under laboratory and field conditions. Laboratory trials demonstrated a reduction in mites per leaf from 32.72 to 14.50 within 3 days, correlating to a 70.23% control efficiency. This efficacy increased to 96.04% by day 9 and was sustained until the experiment concluded on day 27. Field trials similarly showed a reduction in TSSM from 53.93 to 9.63 mites/leaf by day 6, achieving an 83.64% control efficiency, and culminated in a 98.46% reduction by day 10. These findings suggested that an integrated approach utilizing cyetpyrafen in conjunction with P. persimilis can be an effective alternative for TSSM management on strawberry plants.

Streptomyces as a promising biological control agents for plant pathogens.

Plant diseases caused by pathogenic microorganisms in agriculture present a considerable obstacle, resulting in approximately 30-40% crop damage. The use of conventional techniques to manage these microorganisms, i.e., applying chemical pesticides and antimicrobials, has been discovered to have adverse effects on human health and the environment. Furthermore, these methods have contributed to the emergence of resistance among phytopathogens. Consequently, it has become imperative to investigate natural alternatives to address this issue. The Streptomyces genus of gram-positive bacteria is a potentially viable natural alternative that has been extensively researched due to its capacity to generate diverse antimicrobial compounds, such as metabolites and organic compounds. Scientists globally use diverse approaches and methodologies to extract new bioactive compounds from these bacteria. The efficacy of bioactive compounds in mitigating various phytopathogens that pose a significant threat to crops and plants has been demonstrated. Hence, the Streptomyces genus exhibits potential as a biological control agent for combating plant pathogens. This review article aims to provide further insight into the Streptomyces genus as a source of antimicrobial compounds that can potentially be a biological control against plant pathogens. The investigation of various bioactive compounds synthesized by this genus can enhance our comprehension of their prospective utilization in agriculture.

Will climate affect the establishment and efficacy of Agnippe sp. #1 (Lepidoptera: Gelechiidae), a promising biological control agent of Mesquite in South Africa?

Several spiny leguminous tree species within the genus Neltuma Raf. (formerly Prosopis L.) (Fabaceae) occur as widespread invasive alien plants in South Africa, exerting severe negative socio-economic and ecological impacts. Given these impacts, South Africa recently released the leaf-tying moth Agnippe sp. #1 (syn. Evippe sp. #1) (Lepidoptera: Gelechiidae) as a biological control agent against invasive Neltuma species in 2021. The widespread invasion of Neltuma spp. across a vast and climatically diverse range of South Africa has led to concerns regarding the establishment and impact of the agent. Therefore, this study aimed to assess the constraints posed by climate to the potential establishment and efficacy of Agnippe sp. #1 using both climatic matching (CLIMEX) and thermal-physiology assessments. Climatic analyses revealed relatively high (71%) and moderate (66%) matches of South Africa to the native (Argentina) and introduced (Australia) ranges of Agnippe sp. #1 respectively. Thermal assessments of Agnippe sp. #1, particularly the 4th instar larvae, determined a CTmin = 0.9 ± 0.3 °C and LLT50 = −11.1 ± 0.4 °C, which suggest the moth is suited mainly to warmer regions of South Africa. Overall, these assessments propose that the establishment and performance of Agnippe sp. #1 is likely to be constrained by climate in parts of South Africa, particularly within the cold semi-arid and temperate provinces of the country. Promisingly, these climatic comparisons suggest that Agnippe sp. #1 may become more widely established in the hottest parts of the Northern Cape province, which remains a major biological control target region for Mesquite in South Africa.

Prospects for the use of endophytic and extremophilic microorganisms in the fight against phytopathogens of agricultural crops (review)

During the years with acute epiphytotic conditions, infectious diseases of plants cause significant crop losses. To ensure the productivity of agricultural crops, pesticides are used, that is, substances of chemical nature that protect plants from phytopathogens. Widespread use of pesticides leads to contamination of soil and water resources, changes in the microbiome, disruption of normal plant growth and development. In order to minimize the anthropogenic impact on the territory of the agroindustrial complex and ensure the protection of cultivated plants from biotic stresses, environmentally safe analogues of chemical pesticides have been developed – biopesticides based on bacteria and fungi (have become more widespread), as well as viruses. The review, based on the analysis of 105 scientific sources, examines the advantages of these drugs, describes promising biological control agents that can be included in their composition, namely endophytic (colonize plant tissues) and extremophilic (survive in aggressive environmental conditions) microorganisms. The use of endophytic microorganisms in the fight against infectious diseases of plants is promising due to their ability to have a direct impact on the growth of crops and their induced resistance. The positive effect associated with the use of extremophilic microorganisms is associated with the universality of their use, namely the ability to maintain efficiency in various soil and climatic conditions.

Host-specificity of biocontrol agents in the field – The significance of sampling sympatric relatives of target weeds (Acacia holosericea versus A. auriculiformis)

Acacia auriculiformis is an invasive weed that causes significant environmental damage across Florida, USA. Previous native range surveys in Australia identified a number of herbivores that are commonly associated with this plant, including several species of leaf-tying moths (Macrobathra spp.) and a chrysomelid beetle (Calomela intemerata). These herbivores are considered strong candidates as biological control agents, but the range of host species they use has not been determined. We therefore conducted a transect survey of herbivorous insects on A. holosericea, a closely-related sympatric relative of A. auriculiformis. These species share areas of sympatry and the latter was sampled simultaneously (in sympatry and allopatry). DNA barcoding approach identified an array of herbivorous insects feeding on A. holosericea, but few were found on both the Acacia species sampled. A literature survey suggested this pattern of host specificity may be consistent across Australian acacias, to the extent that each Acacia species may largely host its own suite of herbivores. These results do not negate the need for host testing procedures in biological control, but they do increase our confidence substantially that several promising potential biological control agents of A. auriculiformis (Macrobathra moths and Calomela beetles) have a restricted host species range. Our study illustrates how exploring the herbivore diversity of plant species closely related to the target weed can provide crucial information for biological control researchers.

Synergistic effects of grass competition and insect herbivory on the weed Rumex obtusifolius in an inundative biocontrol approach

Outcomes of weed biological control projects are highly variable, but a mechanistic understanding of how top-down and bottom-up factors influence the success of weed biological control is often lacking. We grew Rumex obtusifolius, the most prominent native weed in European grasslands, in the presence and absence of competition from the grass Lolium perenne and subjected it to herbivory through targeted inoculation with root-boring Pyropteron spp. To explore whether the interactive effects of competition and inundative biological control were size-dependent, R. obtusifolius was planted covering a large range of plant sizes found in managed grasslands. Overall, competition from the grass sward reduced aboveground biomass and final root mass of R. obtusifolius about 62- and 7.5-fold, respectively, and increased root decay of R. obtusifolius from 14 to 58%. Herbivory alone increased only root decay. However, grass competition significantly enhanced infestation by Pyropteron spp. and, as a consequence, enhanced the impact of herbivory on aboveground biomass and final root mass. The synergistic effect was so strong that R. obtusifolius plants grown from initially smaller roots did no longer develop. Inoculating R. obtusifolius with Pyropteron species in grasslands should be further pursued as a promising inundative biological control strategy in the weed’s native range.

A newly isolated Trichoderma Parareesei N4-3 exhibiting a biocontrol potential for banana fusarium wilt by Hyperparasitism.

Banana Fusarium wilt caused by Fusarium oxysporum f. sp. cubense tropical race4 (Foc TR4) is one of the most destructive soil-borne fungal diseases and currently threatens banana production around the world. Until now, there is lack of an effective method to control banana Fusarium wilt. Therefore, it is urgent to find an effective and eco-friendly strategy against the fungal disease. In this study, a strain of Trichoderma sp. N4-3 was isolated newly from the rhizosphere soil of banana plants. The isolate was identified as Trichoderma parareesei through analysis of TEF1 and RPB2 genes as well as morphological characterization. In vitro antagonistic assay demonstrated that strain N4-3 had a broad-spectrum antifungal activity against ten selected phytopathogenic fungi. Especially, it demonstrated a strong antifungal activity against Foc TR4. The results of the dual culture assay indicated that strain N4-3 could grow rapidly during the pre-growth period, occupy the growth space, and secrete a series of cell wall-degrading enzymes upon interaction with Foc TR4. These enzymes contributed to the mycelial and spore destruction of the pathogenic fungus by hyperparasitism. Additionally, the sequenced genome proved that strain N4-3 contained 21 genes encoding chitinase and 26 genes encoding β-1,3-glucanase. The electron microscopy results showed that theses cell wall-degrading enzymes disrupted the mycelial, spore, and cell ultrastructure of Foc TR4. A pot experiment revealed that addition of strain N4-3 significantly reduced the amount of Foc TR4 in the rhizosphere soil of bananas at 60 days post inoculation. The disease index was decreased by 45.00% and the fresh weight was increased by 63.74% in comparison to the control. Hence, Trichoderma parareesei N4-3 will be a promising biological control agents for the management of plant fungal diseases.

Field releases of the exotic parasitoid Trissolcus japonicus (Hymenoptera: Scelionidae) and survey of native parasitoids attacking Halyomorpha halys (Hemiptera: Pentatomidae) in Michigan.

An adventive population of the exotic parasitoid wasp, Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), discovered in Michigan in 2018, is a promising biological control agent of the invasive Halyomorpha halys (Stål) (Hemiptera: Pentatomidae). Following its discovery, field releases of Tr. japonicus were conducted over 2 yr in southern Michigan, to test how release size or release frequency impacts establishment. Sentinel eggs of H. halys and of the native Podisus maculiventris (Say) (Hemiptera: Pentatomidae) were used alongside yellow sticky cards to monitor parasitoids. In 2019 and 2020, 7,200 Tr. japonicus were released at 16 sites. Monitoring between 2019 and 2021 yielded only 49 individuals. The captures suggest reproductive activity and overwintering success in the field but do not allow for evaluation of best release methods. Parasitism by native parasitoids was below 7%, which is similar to other states and unlikely to provide sufficient control of H. halys. The placement of sentinel eggs or sticky traps either in the lower or middle canopy of trees did not influence parasitoid capture rates. Frozen and fresh H. halys sentinel eggs were attacked at the same rate, but more native parasitoids emerged from frozen eggs. We did not find signs of nontarget effects on P. maculiventris thus parasitism rates overall were very low. These results could indicate dispersal of Tr. japonicus from the release sites or slow population growth. The latter may be due to the relatively low densities of H. halys in Michigan or may stem from the small founding size of our laboratory colony.

Establishing Gene Expression and Knockout Methods in Esteya vermicola CBS115803.

Pine wilt disease, which is caused by the nematode Bursaphelenchus xylophilus, is one of the most destructive forest diseases worldwide. Esteya vermicola, a nematophagous fungus, has emerged as a promising biological control agent. However, the limited availability of gene function analysis techniques hinders further genetic modification of this fungus. In this study, we employed a combination of enzymes (driselase, snailase, and cellulase) to enzymatically degrade the cell wall of the fungus, resulting in a high yield of protoplasts. Furthermore, by utilizing 0.6M sucrose as an osmotic pressure stabilizer, we achieved a significant protoplast regeneration rate of approximately 31%. Subsequently, we employed the polyethylene glycol-mediated protoplast transformation method to successfully establish a genetic transformation technique for E. vermicola CBS115803. Additionally, through our investigation, we identified the Olic promoter from Aspergillus nidulans, which effectively enhanced the expression of the DsRed gene encoding a red fluorescent protein in E. vermicola CBS115803. Moreover, we successfully implemented a split-marker strategy to delete the EvIPMD gene in E. vermicola CBS115803. In summary, our findings present valuable experimental methodologies for gene function analysis in E. vermicola CBS115803.

Buğday biti Sitophilus granarius (L., 1758) (Coleoptera: Curculionidae) üzerinde bazı entomopatojen fungusların patojenisitesi

In the present study, the toxicities of seven entomopathogenic fungal isolates, Beauveria bassiana (ARSEF-4984), Isaria farinosa (ARSEF-3580), Isaria fumosorosea (ARSEF-4501), Lecanicillium muscarium (ARSEF-5128), L. muscarium (ARSEF-972), Lecanicillium lecanii (TR38/11) and L. muscarium (Ve6), were tested against the adults of granary weevil, Sitophilus granarius (L., 1758) (Coleoptera: Curculionidae), under laboratory conditions (25±1°C, 75±5% RH and 14h light:10h dark). Studies were conducted in Atatürk University (Erzurum, Türkiye), in 2018. Fungal isolates were sprayed to adults at two different conidial concentrations (1×105 and 1×107 ml-1). Mortality percentages were observed on the 2nd, 4th, 6th, 8th, and 10th days of treatment. A commercial isolate of L. muscarium were used as positive control and sterile water+0.25% Tween 20 used as negative control. The results demonstrated that the mortality rates of S. granarius adults treated with entomopathogenic fungi ranged from 1.01% to 98.9% across 10-day period. Higher concentration and longer exposure periods resulted in increasing virulence on the adult individuals. Among the strains tested, at 1×107 ml-1 concentration, I. fumosorosea, L. muscarium (ARFES-5128) and L. lecanii isolates displayed 97.85%, 94.62% and 93.58% cumulative mortalities respectively, on S. granarius adults by the 10th day of the experiment. These three isolates are regarded as highly promising biological control agents.

Parasitism by Gryon aetherium (Hymenoptera: Scelionidae) on Bagrada hilaris (Hemiptera: Pentatomidae) eggs in northcentral California.

Bagrada bug, Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae), is an invasive pest of cruciferous crops. The parasitoid Gryon aetherium Talamas (Hymenoptera: Scelionidae) is a promising biological control agent for B. hilaris because it can forage in the soil where B. hilaris deposits most of its eggs. In this study, we assessed parasitism by G. aetherium on B. hilaris eggs in situ in northcentral California, including the Salinas Valley where most cruciferous crops in the United States are grown. Parasitism was documented by leaving soil-filled trays under infested plants for 7-14 days, then removing eggs and holding them for emergence of parasitoids. Gryon aetherium accounted for over 99% of emerged parasitoids, and occurred at 11 of the 12 sampled sites. Of the 17,729 and 31,759 B. hilaris eggs collected in 2021 and 2022, 1,518 (8.84%) and 2,654 (8.36%) were parasitized by G. aetherium, respectively. Parasitism rates were generally higher inland and ranged from 3.64% to 44.93% in 2021 and from 1.01% to 23.04% in 2022, and never exceeded 15% on any sample dates at several coastal sites in the Salinas Valley. Discovery efficiency (a measure of the ability of parasitoids to locate egg patches) reached 80% or higher at all but 1 site, but exploitation efficiency (a measure of the ability of parasitoids to exploit the egg patch after it has been discovered) was generally <20%, suggesting that G. aetherium can locate egg patches efficiently but is less efficient at finding eggs within patches.

Field Efficacy of Antagonistic Fungi against Black Spot Disease of Chinese Kale

Background: Alternaria brassicicola (Schw.) causes black spot disease, which is one of the major diseases limiting the production of vegetable crops, especially Chinese kale in Southeast Asia and Thailand. Previous pathogen management based on synthetic fungicides is expensive, toxic for humans, and harmful to the environment. The current study investigated the efficiency of Talaromyces flavus (Klöcker) Stolk and Samson Bodhi001, Talaromyces trachyspermus (Shear) Stolk and Samson Bodhi002, Talaromyces flavus (Klöcker) Stolk and Samson Bodhi003, Neosartorya fischeri (Wehmer) Malloch and Cain Bodhi004, and Neosartorya fischeri (Wehmer) Malloch and Cain in controlling Chinese kale black spot disease caused by A. brassicicola under field conditions. Methods: A. brassicicola and four antagonistic fungus strains were cultured separately on a PDA plate and incubated at room temperature for 14 days. Ten mL of sterile water was poured into a culture plate, and the spores were gently scraped from the mycelium with a sterile loop to obtain a spore suspension and afterward adjusted to a final concentration of 106 spores mL−1. Result: The results showed that spore suspensions of 106 spores mL−1 of T. flavus Bodhi001, T. trachyspermus Bodhi002, T. flavus Bodhi003, N. fischeri Bodhi004, and N. fischeri effectively controlled black spot disease in field trials and resulted in a significant reduction in black spot incidence compared with the unprotected control. Meanwhile, the spore suspension of T. flavus Bodhi001 revealed the greatest suppression of black spot incidence, causing 10.23% and 42.93% disease reduction, compared with the negative control, indicating promising preventive activity against A. brassicicola. Based on our results, T. favus Bodhi001 is a promising biological control agent (BCA) in controlling A. brassicicola causing Chinese kale black spot disease.

Genetic differences among Ailanthus altissima collections across and outside Italy by a Citizen science approach and their susceptibility to the candidate mycoherbicide Verticillium dahliae Kleb.

Ailanthus altissima (Mill.) Swingle is considered one of the worst invasive alien plant species (IAPS) in Europe, able to cause several disturbances to ecosystems and economic issues. To date, the control methods applied are often ineffective, restricted or under assessment by the scientific community, as in the case of Verticillium dahliae (a promising biological control agent to counteract this species). Citizen science initiatives aim to involve the public in the research process to generate genuine outcomes and, in the case of invasive species, represent a valuable additional tool in their earlier detection, monitoring and management. Here, seventy-two citizens were recruited to recognize and record A. altissima across and outside Italy, as well as to collect leaf and seed samples to allow professional scientists to perform the molecular characterization of the Italian (and more) gene pool and, subsequently, test the susceptibility of these provenances to V. dahliae. The collected material matched the identification for the 97% of the cases, and included 129 accessions divided in four genetic groups (with a high percentage of variability, as typically observed for other IAPS subjected to frequent movements and the constant supply of new propagules). Verticillium dahliae inoculation of plants from different provenances selected for each genetic group, revealed a very high mortality (≥93%) independently to the origin area. These outcomes confirm the high susceptibility of A. altissima to the fungal pathogen, and lead to speculate that V. dahliae seems to have no limits in counteracting Ailanthus populations, at least at the Italian level.

Overexpression of PPtase in Streptomyces sp. NAUS: Increasing biocontrol potential against postharvest tomato fruit decay and isolation of a novel antifungal compound

Streptomyces species are considered promising biological control strains since they produce various antimicrobial substances to control diseases in fruit and vegetables. Many Streptomyces species' biosynthetic gene clusters (BGCs) are silent when subjected to conventional laboratory conditions. Therefore, activating these BGCs is crucial for developing effective strategies for controlling postharvest phytopathogens. In the present study, phosphopantetheinyl transferase (PPtase) genes were overexpressed in 20 actinomycetes isolated from the soil rhizosphere of Osmanthus fragrans to trigger cryptic BGCs. The genomic comparison between the highly proficient actinomycete (strain NAUS) and Streptomyces albiflaviniger DSM 42598T yielded an average nucleotide identity (ANI) exceeding 95%, indicating that the strain belongs to the same species. The NAUS - PPtase-overexpressed strain exhibited 4.7 times higher antifungal activity than the wildtype strain against Penicillium citrinum. Its fermented extracts remarkably reduced postharvest tomato fruit decay by 89.71%. A novel ionophore compound with outstanding antimicrobial activity was identified based on spectroscopic and chemical methods. The enhanced antifungal activities and biocontrol efficacy can be attributed to activated secondary metabolites in the PPtase-overexpressed S. albiflaviniger strain, highlighting the usefulness of this pipeline for biocontrol of pathogenic fungi and bacteria.

Application of a novel phage LPCS28 for biological control of Cronobacter sakazakii in milk and reconstituted powdered infant formula

Contamination of infant formula with Cronobacter sakazakii (C. sakazakii) can cause fatal infections in neonates. Phages have emerged as promising antibacterial agents for food safety, but their effectiveness may be limited by thermal processing. In this study, we isolated 27 C. sakazakii phages from environmental water samples and selected LPCS28 due to its broad lysis spectrum. The titer of LPCS28 will not be significantly affected by heating at a temperature of 60 °C for one hour. In both reconstituted powdered infant formula (RPIF) and liquid milk, the pre-added LPCS28, after the thermal processing at 63 °C for 30 min, significantly inhibited the post-contaminated C. sakazakii (103 CFU/mL) and eventually reduced the number of C. sakazakii to below the limit of detection (<10 CFU/mL) within 9 h at 37 °C and significantly delayed the increase of bacterial concentration in the samples at 23 °C. The phylogenetic analysis revealed that LPCS28 belonged to a new genus, we proposed as Nanhuvirus, under the family Straboviridae. These findings suggest that phage LPCS28 is a promising biological control agent for pathogenic C. sakazakii in the dairy industry.