Use Of Biocontrol Agents Research Articles

Non‐native freshwater snails: a global synthesis of invasion status, mechanisms of introduction, and interactions with natural enemies

Abstract Non‐native freshwater snails can play important roles as consumers, hosts, and prey. Despite their potential ecological importance, global patterns in non‐native snail taxonomy, geography, and ecology have not been documented. Our objectives were to use a semi‐quantitative systematic review to describe non‐native freshwater snail global diversity, distribution, mechanisms of introduction, and interactions with natural enemies, including parasites and predators. Based on 506 relevant publications, we recorded 95 non‐native freshwater snail species from 16 families. Six taxonomic families, and pulmonate snails as a group, were over‐represented relative to the number of species expected by chance. Eight snail species represented 63% of the research records. A few snail taxa (15%) were widespread global invaders, reported from four or more continents, while most invasions were limited to a single continent. Australia and the Pacific Islands were the largest ‘sink’ for non‐native snails, with the greatest difference in the number of non‐native taxa relative to native taxa that had spread to other continents. Aquarium hobby sales were implicated as the most common mechanism of introduction (41% of species), followed by “hitchhiking” on aquatic vegetation, human consumption, use for biocontrol, transportation in canals, commercial shipping, and outdoor recreation. A search of internet sales posts indicated that four of the six over‐represented snail families were readily available for purchase online. Non‐native snails hosted parasites of wildlife, livestock, and human health importance, yet on average had 80% lower parasite richness in their non‐native compared to native range. At least 65 taxa were documented as consumers of non‐native snails, including native predators of conservation concern. These findings suggest that non‐native snails often are released from parasitism, but may commonly experience biotic resistance from predators. Our synthesis emphasizes the relatively high diversity of non‐native snails, but the disproportionate role of a few taxonomic groups in driving ecological, economic, and public health challenges. Moving forward, it will be important to limit new snail introductions through policy, education, and monitoring, particularly as the effective control of established snail invasions remains challenging in most ecosystems.

Identification of Volatile Organic Compounds in Extremophilic Bacteria and Their Effective Use in Biocontrol of Postharvest Fungal Phytopathogens.

Phytopathogenic fungal growth in postharvest fruits and vegetables is responsible for 20–25% of production losses. Volatile organic compounds (VOCs) have been gaining importance in the food industry as a safe and ecofriendly alternative to pesticides for combating these phytopathogenic fungi. In this study, we analysed the ability of some VOCs produced by strains of the genera Bacillus, Peribacillus, Pseudomonas, Psychrobacillus and Staphylococcus to inhibit the growth of Alternaria alternata, Botrytis cinerea, Fusarium oxysporum, Fusarium solani, Monilinia fructicola, Monilinia laxa and Sclerotinia sclerotiorum, in vitro and in vivo. We analysed bacterial VOCs by using GC/MS and 87 volatile compounds were identified, in particular acetoin, acetic acid, 2,3-butanediol, isopentanol, dimethyl disulphide and isopentyl isobutanoate. In vitro growth inhibition assays and in vivo experiments using cherry fruits showed that the best producers of VOCs, Bacillus atrophaeus L193, Bacillus velezensis XT1 and Psychrobacillus vulpis Z8, exhibited the highest antifungal activity against B. cinerea, M. fructicola and M. laxa, which highlights the potential of these strains to control postharvest diseases. Transmission electron microscopy micrographs of bacterial VOC-treated fungi clearly showed antifungal activity which led to an intense degeneration of cellular components of mycelium and cell death.

Complete Genome Sequence of Bacillus badius NBPM-293, a Plant Growth-Promoting Strain Isolated from Rhizosphere Soil.

ABSTRACTBacillus species have a long history of widespread use in biocontrol and crop growth-promoting fields. Here, we present the genome sequence of the rhizobacterium B. badius NBPM-293. The genome sequence will provide valuable information for a better understanding of the mechanism of plant growth promotion.

Biodiversity of Trichoderma antagonist saprophytic fungi and its use for biocontrol of Fusarium wilt disease on shallots at Lombok Island, West Nusa Tenggara, Indonesia

One of the obstacles in the development of shallots in West Nusa Tenggara (NTB) is the presence of Fusarium wilt disease. The use of antagonistic saprophytic fungi Trichoderma spp. is a biological control technique. The aim of this research is to explore the biodiversity of Trichoderma spp. and its use for controlling Fusarium wilt disease. Research using exploratory methods conducted at the shallot planting center on Lombok Island included isolation of antagonistic saprophytic fungi, purification and identification of isolates. Furthermore, research was carried out in the laboratory using experimental methods including in-vitro antagonism tests by direct opposition and culture steam. The research was continued in Greenhouses in planta and in field conditions in the Highlands of Sembalun Village, Medium Plains of Santong Village and Senteluk Village Lowlands. The results concluded that: there were 6 isolates of saprophytic fungi that were antagonistic, namely T. viride, T. longibrachiatum, T. koningii, T. piluliferum, T. harzianum, and T. hamatum. The mechanism of antagonism is physically through space competition, mycoparasites and antibiosis. Three isolates, namely T. virede, T. harzianum and T. hamatum, were effective in suppressing Fusarium wilt disease and even causing immunity.

Association of L-form Bacteria with Plants and their Application in Biological Control of Phytopathogenic Fungi and Bacteria: A Review

L-form bacteria with modified or no cell walls are a special group of bacteria derived or induced from cell walled forms following suppression of their rigid cell wall. They have been used to establish non-pathogenic symbioses with a wide range of plants. These L-form-plant symbioses have been shown to confer resistance against the subsequent challenge of the associated plants by both fungal and bacterial pathogens. As the world population increases, the demand for food also increases and hence control of plant diseases is of paramount importance in producing enough agricultural crops to fulfil the food demand. Plant disease management using chemical fungicides and pesticides etc. is not an ecofriendly approach and hence researchers look for alternative options such as the use of biocontrol agents which are ecofriendly and sustainable. This review paper highlights the published information on the potential of applying L-form bacteria as a biological control agent in management of plant diseases caused by pathogenic microorganisms.

Forest Biosecurity Systems and Processes: An Indian Perspective

Biological invasions continue unabated across the globe despite all efforts to manage the problem by implementing biosecurity regulations and associated management methods. In this context, this paper reviews the plant biosecurity legislation applicable to agriculture and forestry sectors in India to prevent/manage invasions, with the objective of identifying limitations in the legislation or lapses in implementing it and propose corrective measures. The legislation can be improved by: (1) revising and updating the Destructive Insects and Pests Act (1914) and Plant Quarantine Order 2003 and (2) establishing a National Sanitary and Phytosanitary Database Center to promote exchange of information. Establishing more plant quarantine stations with state-of-the-art facilities and a Biosecurity and Trade Unit may support implementation of legislation. Some of main gaps in information and research in biosecurity are identified. The plant biosecurity legislation, though meant to be common, mainly addresses the agriculture sector; its application in the forestry context is currently scarce. Hence, it is suggested that India may enact forest biosecurity scrupulously especially in the context of introducing the REDD + strategy and a Forest Certification Scheme. It is proposed that an integrated pest management (IPM) system involving e-pest surveillance, establishment of pest-free areas and use of biocontrol may help tackle emerging pest threats. The use of new technologies for remote sensing and detection and mapping of vegetation may help bio-surveillance, forecasting, and monitoring of pests. However, successful implementation of all management options demands formation of an exclusive national policy to manage invasive alien species and an action plan governed by a single agency. To realize the plant biosecurity goals, India may also strengthen regional cooperation to: (1) harmonize regulations for sanitary/phytosanitary and plant quarantine/biosafety measures and (2) use a common pest risk analysis (PRA) for unknown pests in the region. Capacity-building of officials to identify risky goods and verify conformity with Import Health Standards is raised. Also, raising awareness on biosecurity among all stakeholders and involving them in implementing the legislation would be helpful. The proposed National Agricultural Biosecurity System and the Agricultural Biosecurity Bill currently considered by the Indian Parliament is expected to address the inadequacies.

Factors affecting the fitness of an entomopathogenic nematode (Heterorhabditis bacteriophora SUP strain) for use in biocontrol in a horticultural area of Argentina

Summary The optimum conditions for storage, infectivity and multiplication of the nematode Heterorhabditis bacteriophora SUP strain, isolated from horticultural soils in Argentina, were determined for later use in biocontrol. This strain was able to kill Tenebrio molitor larvae (over 90%) at 16 and 25°C, after 7 and 4 days, respectively, with mortality being significantly higher at 25°C. No infectivity was reported at 4 and 11°C. Higher concentrations (over 150 infective juveniles (IJ) insect−1) produced higher percentages of mortality. However, increasing inoculum density reduced offspring production and increased emergence time. Storage density between 2500 and 7500 IJ ml−1 had no effect on survival of IJ. Survival of IJ maintained at 4 and 16°C was around 80% after 4 weeks storage and 30% after 32 weeks. However, at 25°C, a 60% IJ survival was observed at 4 weeks, decreasing to around 10% after 16 weeks and with no survival at 24 weeks. An overall significant decrease in virulence was observed after 90 and 120 days of storage but this was more pronounced at a storage temperature of 4°C than at 16 and 25°C. IJ stored at 4°C had reduced virulence after 90 and 120 days, but not after 60 days. This study provides useful information about some fundamental environmental conditions influencing important nematode traits of the species H. bacteriophora.

Wood pellets as carriers of conidia of Trichoderma atroviride SC1 for soil application

The use of biocontrol agents to control soilborne diseases is a promising alternative to chemical pesticides, however, obtaining a homogeneous distribution and incorporation of conidia of fungal biocontrol agents into the soil is often difficult. Several carriers/formulations have been proposed over time, unfortunately without offering an ultimate solution. We propose the use of wood pellets as a carrier of conidia of a saprophytic fungus that has good biodegradation and biocontrol properties (Trichoderma atroviride SC1). The coating process is based on the direct spraying of wood pellets with a conidial suspension at different rates. Beech, fir, and chestnut wood pellets were compared in terms of relevant physicochemical traits and efficacy in supporting the growth of the fungus. Beech wood pellets displayed the best characteristics in terms of water holding capacity, swelling properties, and disintegration time. T. atroviride SC1 grows best on beech and fir wood pellets and reaches a plateau after nine days of incubation, regardless of the initial coating concentrations. The addition of small quantities of a nitrogen source as tryptone or soy flour, soy proteins, and a mixture of animal proteins used as pet food to the conidial suspension can increase the growth by ten-folds on all types of wood pellets. Our results demonstrate that beech and fir wood pellets could be suitable carriers to deliver and sustain the growth of T. atroviride SC1.

Selection of bacteria and fungi for control of soilborne seedling diseases of maize

Plant-based screening experiments were conducted with the aim of identifying biocontrol bacteria and fungi for seed treatment of maize. Candidate microorganisms were evaluated for their protective effects against soilborne infections by species of Fusarium, Globisporangium (syn. Pythium) and Rhizoctonia. The microorganisms tested were bacteria and fungi from maize roots or other sources, including some active microbial components of commercial biocontrol products. Due to the method of isolation chosen, the majority of bacteria from maize roots were spore formers, most of them species of the genera Bacillus,Brevibacillus and Paenibacillus. In pot tests with the potting substrate inoculated with F. culmorum, the level of control provided by seed treatment with the most efficacious bacterial and fungal isolates was comparable or close to the chemical reference seed treatment thiram. The most effective bacteria were species of Pseudomonas, Burkholderia and Streptomyces. Among a subset of approx. 100 bacteria studied, the in vivo and in vitro activities against F.culmorum were only weakly correlated, although some strains deviated from this pattern. The most effective fungi were two strains of Clonostachys rosea and isolates of Trichoderma. The latter and a strain of Gliocladium virens provided also protection against R.solani. Activity against Globisporangium ultimum was recorded for one isolate of Trichoderma and the two strains of C. rosea. A reduction in the impact of seedborne F. culmorum was also observed after seed treatment with two strains of F. oxysporum f. sp. strigae. The results are discussed in relation to previous reports on rhizosphere bacteria of maize and their use in biocontrol of plant pathogens or for plant growth promotion.

Biocontrol: An effective tool for agricultural insect pests management

Integrated pest control systems of insect pests used worldwide; the manipulation of important species is still a significant appliance. This review summaries the effectiveness, benefits, and protection of the use of biological agents to inhibit and control insect damage caused to crops. In general, biocontrol has been shown to be effective for plants, livestock, humans, and the ecosystem. This is in stark contrast to chemical insecticides that are more commonly used, often resulting in environmental contamination that causes damage to people and the environment. Biocontrol manufacturers continue to expand new conventions for surveying operator protection, sending and estimating the achievement of treatment. Guidelines are established by government and assembly organizations to ensure the protected and correct use of biocontrol. The benefits of organic control frameworks drive the growing option of technology. Biodiversity assurance and a high-cost share advantage are clear reasons for advancing the use of biocontrol phases. This review will help the researchers for the selection of suitable biocontrol agents for different pests and crops at various stages.

Interactive effect of biocontrol agents in the management of Fusarium rot in cardamom and its impact on plant defense mechanism

Cardamom plantations are subjected to constant threat due to the Fusarium rot disease caused by Fusarium oxysporum Schlecht which is pronounced during summer months. The current study deals with the identification of an effective and ecofriendly management practice for the disease through the use of biocontrol agents. Survey conducted between February and May 2019 revealed maximum disease severity and incidence in Pampadumpara panchayat of Nedumkandam block (84.40% and 100%) and minimum in Erattaar panchayat of Kattappanablock (50.40% and 60.00%). A pot culture experiment was conducted to study the effect of three bioagents (Glomus fasciculatum, Trichoderma asperellum and Pseudomonas fluorescens) individually as well as in combinations. Root inoculation of G. fasciculatum with basal application and spray with P. fluorescens as well as root inoculation of G. fasciculatum along with basal application of T. asperellum and P. fluorescens spray were identifiedto be effective against the disease. Disease suppression by the above bioagents was facilitated by reduced pathogen antagonist ratio in the soil, high level of mycorrhizal colonization in the roots and enhanced biochemical activity of defense enzymes like peroxidase, poly phenol oxidase and phenylalanine ammonia lyase in the plants.

Genome editing for resistance against plant pests and pathogens.

The conventional breeding of crops struggles to keep up with increasing food needs and ever-adapting pests and pathogens. Global climate changes have imposed another layer of complexity to biological systems, increasing the challenge to obtain improved crop cultivars. These dictate the development and application of novel technologies, like genome editing (GE), that assist targeted and fast breeding programs in crops, with enhanced resistance to pests and pathogens. GE does not require crossings, hence avoiding the introduction of undesirable traits through linkage in elite varieties, speeding up the whole breeding process. Additionally, GE technologies can improve plant protection by directly targeting plant susceptibility (S) genes or virulence factors of pests and pathogens, either through the direct edition of the pest genome or by adding the GE machinery to the plant genome or to microorganisms functioning as biocontrol agents (BCAs). Over the years, GE technology has been continuously evolving and more so with the development of CRISPR/Cas. Here we review the latest advancements of GE to improve plant protection, focusing on CRISPR/Cas-based genome edition of crops and pests and pathogens. We discuss how other technologies, such as host-induced gene silencing (HIGS) and the use of BCAs could benefit from CRISPR/Cas to accelerate the development of green strategies to promote a sustainable agriculture in the future.

Biocontrol Agents: Toolbox for the Screening of Weapons against Mycotoxigenic Fusarium.

The aim of this study was to develop a set of experiments to screen and decipher the mechanisms of biocontrol agents (BCAs), isolated from commercial formulation, against two major mycotoxigenic fungi in cereals, Fusarium graminearum and Fusarium verticillioides. These two phytopathogens produce mycotoxins harmful to human and animal health and are responsible for the massive use of pesticides, for the protection of cereals. It is therefore essential to better understand the mechanisms of action of alternative control strategies such as the use of BCAs in order to optimize their applications. The early and late stages of interaction between BCAs and pathogens were investigated from germination of spores to the effects on perithecia (survival form of pathogen). The analysis of antagonist activities of BCAs revealed different strategies of biocontrol where chronological, process combination and specialization aspects of interactions are discussed. Streptomyces griseoviridis main strategy is based on antibiosis with the secretion of several compounds with anti-fungal and anti-germination activity, but also a mixture of hydrolytic enzymes to attack pathogens, which compensates for an important deficit in terms of spatial colonization capacity. It has good abilities in terms of nutritional competition. Trichoderma asperellum is capable of activating a very wide range of defenses and attacks combining the synthesis of various antifungal compounds (metabolite, enzymes, VOCs), with different targets (spores, mycelium, mycotoxins), and direct action by mycoparasitism and mycophagy. Concerning Pythium oligandrum, its efficiency is mainly due to its strong capacity to colonize the environment, with a direct action via microbial predation, stimulation of its reproduction at the contact of pathogens and the reduction of perithecia formation.

CHARACTERIZATION OF SUPERNATANT EXTRACT AND VIABILITY OF BACILLUS SUBTILIS KM16 AND PSEUDOMONAS SPP. IN FISH FEED AS BIOCONTROL AGENTS AGAINST AQUACULTURE PATHOGENS

The use of biocontrol agent in aquaculture is being adapted as an effective alternative to antibiotics which can lead to the elaboration of antibiotic-resistant bacteria and confer unpleasant impacts to aquatic organisms. Aquatic bacteria have been discovered as biocontrol agents and potential probiotic candidates to improve the health of aquatic organisms, feed efficiency, and disease resistance to aquaculture pathogens. However, local isolate has not intensively been explored and used to increase aquaculture sector productivity. Therefore, this research aimed to determine minimum inhibitory concentrations of their antibacterial compounds against aquaculture pathogens and to characterize aquatic bacteria by their viability in the feed. Four isolates from several aquatic environments in Indonesia (Pseudomonas sp. S1.1, Pseudomonas sp. S1.2, Pseudomonas sp. SL1.1, and Bacillus subtilis KM16) were used to characterize of antibacterial compound and to determine the viability in feed. Ethyl acetate extracts from all isolates showed better antibacaterial activity against Aeromonas hydrophila and Vibrio vulnificus than chloroform and dichloromethane extracts, in which ethyl acetate extract from Bacillus subtilis KM16 showed the strongest antibacterial activity. Pseudomonas spp. were more effective against V. vulnificus (40 mg/mL) and Bacillus subtilis KM16 was more effective against A. hydrophila (20 mg/mL), as proved by the minimum inhibitory concentrations of their ethyl acetate extracts. In this research, Bacillus subtilis KM16 had stable viability in feed than Pseudomonas sp. isolates.

Quantification of the Aflatoxin Biocontrol Strain Aspergillus flavus AF36 in Soil and in Nuts and Leaves of Pistachio by Real-Time PCR.

The species Aspergillus flavus and A. parasiticus are commonly found in the soils of nut-growing areas in California. Several isolates can produce aflatoxins that occasionally contaminate nut kernels, conditioning their sale. Strain AF36 of A. flavus, which does not produce aflatoxins, is registered as a biocontrol agent for use in almond, pistachio, and fig crops in California. After application in orchards, AF36 displaces aflatoxin-producing Aspergillus spp. and thus reduces aflatoxin contamination. Vegetative compatibility assays (VCAs) have traditionally been used to track AF36 in soils and crops where it has been applied. However, VCAs are labor intensive and time consuming. Here, we developed a quantitative real-time PCR (qPCR) protocol to quantify proportions of AF36 accurately and efficiently in different substrates. Specific primers to target AF36 and toxigenic strains of A. flavus and A. parasiticus were designed based on the sequence of aflC, a gene essential for aflatoxin biosynthesis. Standard curves were generated to calculate proportions of AF36 based on threshold cycle values. Verification assays using pure DNA and conidial suspension mixtures demonstrated a significant relationship by regression analysis between known and qPCR-measured AF36 proportions in DNA (R2 = 0.974; P < 0.001) and conidia mixtures (R2 = 0.950; P < 0.001). Tests conducted by qPCR in pistachio leaves, nuts, and soil samples demonstrated the usefulness of the qPCR method to precisely quantify proportions of AF36 in diverse substrates, ensuring important time and cost savings. The outputs of this study will serve to design better aflatoxin management strategies for pistachio and other crops.

The bacterial biocontrol agent Paenibacillus alvei K165 confers inherited resistance to Verticillium dahliae.

The biocontrol agent Paenibacillus alvei K165 was previously shown to protect Arabidopsis thaliana plants against Verticillium dahliae. Here we show that K165 also confers inherited immune resistance to V. dahliae. By performing a histone acetyltransferases mutant screen, ChIP assays, and transcriptomic experiments, we were able to show that histone acetylation significantly contributes to the K165 biocontrol activity and establishment of inheritable resistance to V. dahliae. K165 treatment primed the expression of immune-related marker genes and the cinnamyl alcohol dehydrogenase gene CAD3 through the function of histone acetyltransferases. Our results reveal that offspring of plants treated with K165 have primed immunity and enhanced lignification, both contributing towards the K165-mediated inherited immune resistance. Thus, our study paves the way for the use of biocontrol agents for the establishment of inheritable resistance to agronomically important pathogens.

Plant Associated Rhizobacteria for Biocontrol and Plant Growth Enhancement.

Crop disease remains a major problem to global food production. Excess use of pesticides through chemical disease control measures is a serious problem for sustainable agriculture as we struggle for higher crop productivity. The use of plant growth promoting rhizobacteria (PGPR) is a proven environment friendly way of controlling plant disease and increasing crop yield. PGPR suppress diseases by directly synthesizing pathogen-antagonizing compounds, as well as by triggering plant immune responses. It is possible to identify and develop PGPR that both suppress plant disease and more directly stimulate plant growth, bringing dual benefit. A number of PGPR have been registered for commercial use under greenhouse and field conditions and a large number of strains have been identified and proved as effective biocontrol agents (BCAs) under environmentally controlled conditions. However, there are still a number of challenges before registration, large-scale application, and adoption of PGPR for the pest and disease management. Successful BCAs provide strong theoretical and practical support for application of PGPR in greenhouse production, which ensures the feasibility and efficacy of PGPR for commercial horticulture production. This could be pave the way for widespread use of BCAs in agriculture, including under field conditions, to assist with both disease management and climate change conditions.

Molecular Assay Development to Monitor the Kinetics of Viable Populations of Two Biocontrol Agents, Bacillus subtilis QST 713 and Gliocladium catenulatum J1446, in the Phyllosphere of Lettuce Leaves.

Simple SummaryThere is a need to be able to track the viable populations of biocontrol agents when applied on the foliar surfaces of plants. We have developed a molecular-based method for the quantification of viable cells of two commercial biocontrol agents—a bacterium (Bacillus subtilis) and a fungus (Gliocladium catenulatum). The method has been tested on the leaf surfaces of lettuce plants to examine the changes in viable population over 10–12 days for the first time.Optimising the use of biocontrol agents (BCAs) requires the temporal tracking of viable populations in the crop phyllosphere to ensure that effective control can be achieved. No sensitive systems for quantifying viable populations of commercially available BCAs, such as Bacillus subtilis and Gliocladium catenulatum, in the phyllosphere of crop plants are available. The objective of this study was to develop a method to quantify viable populations of these two BCAs in the crop phyllosphere. A molecular tool based on propidium monoazide (PMA) (PMAxx™-qPCR) capable of quantifying viable populations of these two BCAs was developed. Samples were treated with PMAxx™ (12.5–100 μM), followed by 15 min incubation, exposure to a 800 W halogen light for 30 min, DNA extraction, and quantification using qPCR. This provided a platform for using the PMAxx™-qPCR technique for both BCAs to differentiate viable from dead cells. The maximum number of dead cells blocked, based on the DNA, was 3.44 log10 for B. subtilis and 5.75 log10 for G. catenulatum. Validation studies showed that this allowed accurate quantification of viable cells. This method provided effective quantification of the temporal changes in viable populations of the BCAs in commercial formulations on lettuce leaves in polytunnel and glasshouse production systems.

Impact of integrated pest management programs on knowledge of tribal farmers of Karnataka

ICAR-National Research centre on Integrated Pest Management, New Delhi and University of Agricultural and Horticultural Sciences, Shivamogga, Karnataka, India were organising various training programs to cater felt needs of the remote tribal farmers. The training programs focus on integrated pest management technologies which make use of locally available material for managing pests. The present study was conducted during the year 2020 and a total of 85 tribal farmers and women were selected from Sirsi district of Karnataka. The ex-post facto evaluation of training programmes revealed that there was an overall increase of 45.9 per cent in knowledge level of respondents regarding various plant protection activities. However, 23.0 per cent gaps indicated that tribal men farmers and women were not well conversant of IPM activities. More technical gaps were recorded on identification of pest and natural enemies, use of bio control agents. Socio-economic attributes of tribal farmers had not much influence in improving their knowledge on plant protection strategies and hence, a number of training programmes were organised need-based training IPM training programmes to enhance their knowledge and skill of these farmers to modify their plant protection strategies for enhancing the crop yield and income for their lively-hood.

Micromycetes antagonistic potential in vitro against Alternaria sp., a pathogenic strain associated with grapes

Fungi from the genus Alternaria Nees are new harmful grapes mycopathogens; they are a part of the necrotic leaf spot pathocomplex. The disease intensive development leads to more than 50% necrotisation of the leaf surface, leaving no leaf on the plant by the end of the growing season. An alternative to chemical protection against the disease is the use of biocontrol agents. For this purpose, the screening of fungal antagonist strains from the collection of the laboratory of the biological method of the Federal scientific center «V.S. Pustovoit All-Russian Research Institute of Oil crops» (FSBSI «FSC «ARRIOC») was carried out in relation to the causative agent of necrotic leaf spot of grapes Alternaria sp. by the dual cultures method on two nutrient media – potato-sucrose agar and Rudakov’s agar. Of the 27 fungal strains that were screened for the antagonistic activity to 425-3 Alternaria sp. 17 strains showed the activity. Of these, 12 strains competed for feeding area and exhibited hyperparasitism. Strains A-1 and I-3 Basidiomycota, Tr-1 Trichothecium sp. and all strains of Trichoderma sp. showed the greatest antagonistic activity on both media.