Evaluation of Different Formulations on the Viability of Phages for Use in Agriculture.

Bacteriophages have been proposed as biological controllers to protect plants against different bacterial pathogens. In this scenario, one of the main challenges is the low viability of phages in plants and under adverse environmental conditions. This work explores the use of 12 compounds and 14 different formulations to increase the viability of a phage mixture that demonstrated biocontrol capacity against Pseudomonas syringae pv. actinidiae (Psa) in kiwi plants. The results showed that the viability of the phage mixture decreases at 44 °C, at a pH lower than 4, and under UV radiation. However, using excipients such as skim milk, casein, and glutamic acid can prevent the viability loss of the phages under these conditions. Likewise, it was demonstrated that the use of these compounds prolongs the presence of phages in kiwi plants from 48 h to at least 96 h. In addition, it was observed that phages remained stable for seven weeks when stored in powder with skim milk, casein, or sucrose after lyophilization and at 4 °C. Finally, the phages with glutamic acid, sucrose, or skim milk maintained their antimicrobial activity against Psa on kiwi leaves and persisted within kiwi plants when added through roots. This study contributes to overcoming the challenges associated with the use of phages as biological controllers in agriculture.

Biocontrol mechanisms of the Antarctic yeast Debaryomyces hansenii UFT8244 against post-harvest phytopathogenic fungi of strawberries.

The use of yeasts has been explored as an efficient alternative to fungicide application in the treatment and prevention of post-harvest fruit deterioration. Here, we evaluated the biocontrol abilities of the Antarctic yeast strain Debaryomyces hansenii UFT8244 against the post-harvest phytopathogenic fungi Botrytis cinerea and Rhizopus stolonifer for the protection and preservation of strawberry fruit. The strongest inhibition of germination of B. cinerea (57%) was observed at 0 °C, followed by 40% at 25 °C. In addition, germ tubes and hyphae of B. cinerea were strongly surrounded and colonized by D. hansenii. Production of the enzymes ß-1,3-glucanase, chitinase and protease by D. hansenii was detected in the presence of phytopathogenic fungus cell walls. The activity of ß-1,3-glucanase was highest on day 12 of incubation and remained high until day 15. Chitinase and protease activities reached their highest levels on the day 15 of incubation. D. hansenii additionally demonstrated the ability to resist oxidative stress. Our data demonstrated that the main biocontrol mechanisms displayed by D. hansenii were the control of phytopathogenic fungal spore germination, production of antifungal enzymes and resistance to oxidative stress. We conclude that isolate D. hansenii UFT8422 should be further investigated for use at commercial scales at low temperatures.

Assessment of Fungal Lytic Enzymatic Extracts Produced Under Submerged Fermentation as Enhancers of Entomopathogens' Biological Activity.

The application of enzymes in agricultural fields has been little explored. One potential application of fungal lytic enzymes (chitinases, lipases, and proteases) is as an additive to current biopesticides to increase their efficacy and reduce the time of mortality. For this, a screening of lytic overproducer fungi under submerged fermentation with a chemical-defined medium was performed. Then, the enzymatic crude extract (ECE) was concentrated and partially characterized. This characterization consisted of measuring the enzymatic activity (lipase, protease and, chitinase) and determining the enzyme stability after storage at temperatures of - 80, - 20 and, 4 °C. And lastly, the application of these concentrated enzymatic crude extracts (C-ECE) as an enhancer of spores-based fungal biopesticide was proven. Beauveria were not as good producers of lytic enzymes as the strains from Trichoderma and Metarhizium. The isolate M. robertsii Mt015 was selected for the co-production of chitinases and proteases; and the isolate T. harzianum Th180 for co-production of chitinases, lipases, and proteases. The C-ECE of Mt015 had a protease activity of 18.6 ± 1.1 U ml-1, chitinase activity of 0.28 ± 0.01 U ml-1, and no lipase activity. Meanwhile, the C-ECE of Th180 reached a chitinase activity of 0.75 U ml-1, lipase activity of 0.32 U ml-1, and protease activity of 0.24 U ml-1. Finally, an enhancing effect of the enzymatic extracts of M. robertsii (66.7%) and T. harzianum (43.5%) on the efficacy of B. bassiana Bv064 against Diatraea saccharalis larvae was observed. This work demonstrates the non-species-specific enhancing effect of enzymatic extracts on the insecticidal activity of conidial-based biopesticides, which constitutes a contribution to the improvement of biological control agents' performance.

Bacillus Strains as Effective Biocontrol Agents Against Phytopathogenic Bacteria and Promoters of Plant Growth.

Modern crop production relies on the application of chemical pesticides and fertilizers causing environmental and economic challenges. In response, less environmentally impactful alternatives have emerged such as the use of beneficial microorganisms. These microorganisms, particularly plant growth-promoting bacteria (PGPB), have demonstrated their ability to enhance plant growth, protect against various stresses, and reduce the need for chemical inputs. Among the PGPB, Bacillus species have garnered attention due to their adaptability and commercial potential. Recent reports have highlighted Bacillus strains as biocontrol agents against phytopathogenic bacteria while concurrently promoting plant growth. We also examined Bacillus plant growth-promoting abilities in Arabidopsis thaliana seedlings. In this study, we assessed the potential of various Bacillus strains to control diverse phytopathogenic bacteria and inhibit quorum sensing using Chromobacterium violaceum as a model system. In conclusion, our results suggest that bacteria of the genus Bacillus hold significant potential for biotechnological applications. This includes developments aimed at reducing agrochemical use, promoting sustainable agriculture, and enhancing crop yield and protection.

Evaluation of PSP1 biostimulant on Fusarium graminearum-wheat pathosystem: impact on disease parameters, grain yield, and grain quality.

BACKGROUND: Plant defense elicitors are valuable tools in sustainable agriculture, providing an environmentally friendly and effective means of enhancing plant defense and promoting plant health. Fusarium head blight (FHB) is one of the most important fungal diseases of cereal crops worldwide. The PSP1 is a novel biopesticide formulated based on an elicitor, the extracellular protein AsES, from the fungus Sarocladium strictum. The present work aimed to evaluate the effectiveness of PSP1 in controlling FHB under field conditions. Experiments were conducted during three consecutive growing seasons (2019, 2020, and 2021). Three biostimulant treatments were tested in different physiological stages (from late tillering to heading stage), and FHB inoculations were performed at anthesis. Disease parameters, seed parameters, grain yield, and grain quality parameters were evaluated. RESULTS: Depending on the year and the genotype, reductions in disease incidence (up to 11%) and disease severity (up to 5%) were reported, although these differences could not be attributed to the use of the PSP1 biostimulant. Occasional improvements in seed parameters and grain quality were observed, suggesting that early treatments could work better than late treatments, probably due to early activation/priming of defense response mechanisms. However, more studies are deemed necessary. CONCLUSION: The use of PSP1 biostimulant in commercial wheat crops could be a biological alternative or complement to traditional chemical fungicides to manage FHB. The reduced environmental impact and the potential benefits in grain yield and quality are other reasons that can generate new adherents of this technology in worldwide agriculture systems in the coming years. © 2024 Society of Chemical Industry.

Hydrogel capsules as new delivery system for Trichoderma koningiopsis Th003 to control Rhizoctonia solani in rice (Oryza sativa).

The incorporation of biological control agents (BCAs) such as Trichoderma spp. in agricultural systems favors the transition towards sustainable practices of plant nutrition and diseases control. Novel bioproducts for crop management are called to guarantee sustainable antagonism activity of BCAs and increase the acceptance of the farmers. The encapsulation in polymeric matrices play a prominent role for providing an effective carrier/protector and long-lasting bioproduct. This research aimed to study the influence of biopolymer in hydrogel capsules on survival and shelf-life of T. koningiopsis. Thus, two hydrogel capsules prototypes based on alginate (P1) and amidated pectin (P2), containing conidia of T. koningiopsis Th003 were formulated. Capsules were prepared by the ionic gelation method and calcium gluconate as crosslinker. Conidia releasing under different pH values of the medium, survival of conidia in drying capsules, storage stability, and biocontrol activity against rice sheath blight (Rhizoctonia solani) were studied. P2 prototype provided up to 98% survival to Th003 in fluid bed drying, faster conidia releasing at pH 5.8, storage stability greater than 6 months at 18 °C, and up to 67% of disease reduction. However, both biopolymers facilitate the antagonistic activity against R. solani, and therefore can be incorporated in novel hydrogel capsules-based biopreparations. This work incites to develop novel biopesticides-based formulations with potential to improve the delivery process in the target site and the protection of the active ingredient from the environmental factors.

Limosilactobacillus reuteri as sustainable biological control agent against toxigenic Fusarium verticillioides.

Corn contamination with Fusarium verticillioides (Sacc.) Nirenberg is a worldwide problem that affects yield and grain quality resulting in severe economic losses and implications for food safety. Control of F. verticillioides is a challenge, but lactic acid bacteria (LAB) has high potential as a biological control agent. In this study, the antifungal effect of Limosilactobacillus reuteri (formerly Lactobacillus reuteri) LR-92 against F. verticillioides 97L was investigated. Cell-free supernatant (CFS) from L. reuteri showed concentration-dependent fungicidal and fungistatic activity against F. verticillioides 97L. The antifungal compounds from CFS showed heat stability and pH dependence, and antifungal activity was not affected by treatment with proteolytic enzymes. High-performance liquid chromatography analysis indicated that L. reuteri LR-92 produces lactic and acetic acids. After liquid-liquid extraction, electrospray ionization mass spectrometry analysis of the active ethyl acetate fraction containing antifungal compounds revealed the production of 3-phenyllactic acid, cyclo-(L-Pro-L-Leu), cyclo-(L-Pro-L-Phe), and cyclo-(L-Phe-trans-4-OH-L-Pro). L. reuteri LR-92 has potential as a biocontrol agent for F. verticillioides and contributes to food safety.

Hormone released by the microalgae Neochlorisaquatica and alkalinization influence growth of terrestrial and floating aquatic plants.

The microalgae Neochloris aquatica were previously evaluated as a potential biological control agent and source of bioactive compounds against immature stages of Culex quinquefasciatus. Larvae reared on microalgae suspension showed mortality or drastic effects with morphological alterations and damage in the midgut. N. aquatica have nutritional and toxic effects, resulting in delayed life cycle and incomplete adult development. Given the possibility of its use as a biological control agent, in this work we evaluate the effect of microalgae on other organisms of the environment, such as plants. Arabidopsis thaliana, a terrestrial plant, and Lemna sp., a floating aquatic plant, were selected as examples. Interaction assays and compound evaluations showed that the microalgae release auxins causing root inhibition, smaller epidermal cells and hairy root development. In Lemna sp., a slight decrease in growth rate was observed, with no deleterious effects on the fronds. On the other hand, we detected a detrimental effect on plants when interactions were performed in a closed environment, in a medium containing soluble carbonate, in which microalgae culture rapidly modifies the pH. The experiments showed that alkalinization of the medium inhibits plant growth, causing bleaching of leaves or fronds. This negative effect in plants was not observed when plants and microalgae were cultured in carbonate-free media. In conclusion, the results showed that N. aquatica can modify plant growth without being harmful, but the rapid alkalinization produced by carbon metabolism of microalgae under CO2-limiting conditions, could regulate the number of plants.

Lactic acid bacteria and Bacillus spp. as fungal biological control agents.

Fungal pathogens are one of the most important agents affecting crop production and food safety, and agrochemical application is one of the main approaches to reduce phytopathogenic fungi contamination in agricultural products. However, excessive and inadequate use can cause environmental damage, human and animal hazard, and increased phytopathogen resistance to fungicides. Biological control using lactic acid bacteria (LAB) and Bacillus spp. is an environmentally friendly strategy for phytopathogenic fungi management. Several molecules produced by these bacteria indeed affect fungal growth and viability in different plant crops. In this article, the activity spectra are reviewed along with the antifungal effect and antifungal compounds produced by LAB (e.g. organic acids, peptides, cyclic dipeptides, fatty acids, and volatile compounds) and Bacillus spp. (e.g. peptides, enzymes, and volatile compounds).

Óleos essenciais e extratos vegetais como ferramentas alternativas ao controle químico de larvas de Aedes spp, Anopheles spp e Culex spp / Essential oils and plant extracts as alternative tools for chemical control of Aedes spp, Anopheles spp, and Culex spp

Objetivos: Realizar um levantamento das contribuições científicas produzidas entre 2017 e 2021 acerca do efeito larvicida de óleos essenciais e extratos vegetais no controle de Aedes spp, Anopheles spp e Culex spp. Métodos: de setembro a outubro de 2022, foi realizado um levantamento de artigos científicos publicados entre os anos de 2017 e 2021, nas bases de dados Portal Periódicos Capes, Scielo, Science Direct e Scopus. Foram utilizados os descritores "larvicide", "essential oil" e "plant extracts" com a interposição do operador boleano "AND". Resultados: inicialmente, foram obtidos 246 artigos, dos quais 110 foram excluídos (68 não estavam disponíveis na íntegra e 42 apareceram em mais de uma base de dados). Dos 136 artigos restantes, 36 foram excluídos por não terem realizado ensaio larvicida. Dos 100 artigos remanescentes, 63 foram excluídos por não mencionarem valores de CL50, enquanto 3 não especificaram a estrutura vegetal de obtenção dos produtos naturais, restando, portanto, 34 artigos para análise. Foram utilizadas 57 espécies vegetais para a obtenção dos produtos vegetais utilizados contra larvas de Aedes spp; 11 espécies nos ensaios contra Anopheles spp, e 36 espécies nos ensaios contra Culex spp. Os óleos essenciais predominaram nos ensaios contra Aedes spp, enquanto os extratos, contra Anopheles spp. A maior parte dos produtos testados exibiu CL50 < 100 ppm. Conclusão: a atividade larvicida demonstrada por uma grande variedade de extratos vegetais e óleos essenciais representa uma alternativa promissora ao tradicional controle químico feito à base de inseticidas sintéticos em programas de manejo integrado de vetores.

Objectives: Conduct a survey of the scientific contributions produced between 2017 and 2021 on the larvicidal effect of essential oils and plant extracts in the control of Aedes spp, Anopheles spp, and Culex spp. Methods: from September to October 2022, a survey was carried out of scientific articles published between 2017 and 2021 in the Portal Periódicos Capes, Scielo, Science Direct, and Scopus databases. The descriptors "larvicide", "essential oil" and "plant extracts" were used with the Boolean operator "AND". Results: initially, 246 articles were obtained, of which 110 were excluded (68 were not available, and 42 appeared in more than one database). Of the remaining 136 articles, 36 were excluded because they did not perform a larvicide assay. Of the 100 remaining articles, 63 were excluded for not mentioning LC50 values, while three did not specify the plant structure for obtaining natural products, thus leaving 34 articles for analysis. A total of 57 plant species were used to obtain plant products used against Aedes spp larvae; 11 species in the tests against Anopheles spp, and 36 species in the tests against Culex spp. Essential oils predominated in the tests against Aedes spp, while extracts against Anopheles spp. Most of the products tested exhibited an LC50 < 100 ppm. Conclusion: the larvicidal activity demonstrated by a wide variety of plant extracts and essential oils represents a promising alternative to traditional chemical control based on synthetic insecticides in integrated vector management programs.

Antifungal activity and genomic characterization of the biocontrol agent Bacillus velezensis CMRP 4489.

The development of bio-based products has increased in recent years, and species of the Bacillus genus have been widely used for product development due to their elevated production of antimicrobial molecules and resistance to extreme environmental conditions through endospore formation. In this context, the antifungal potential of Bacillus velezensis CMRP 4489 was investigated using in silico predictions of secondary metabolites in its genome and in vitro tests against the following phytopathogenic fungi: Sclerotinia sclerotiorum, Macrophomina phaseolina, and Botrytis cinerea. The in-silico predictions indicated that CMRP 4489 possesses several Biosynthetic Gene Clusters (BGCs) capable of producing molecules with antifungal properties and other non-identified BGCs. The in vitro assay results evidenced strong antifungal activity, inhibiting more than 60% of the tested fungi, and the isolate's molecules were stable under diverse physicochemical conditions. The in vitro assay evidenced significant antifungal activity, deformation of the hyphal structure in SS, biofilm formation capacity, and swarming motility. In the colonization assay, we observed attachment, colonization, and net-shaped biofilm formation, with the strain transitioning from the seeds to nearby structures. Therefore, CMRP 4489 showed to be a potential biocontrol agent against various diseases with agronomic importance and can be used under adverse environmental conditions.

Bovine pancreatic trypsin inhibitor and soybean Kunitz trypsin inhibitor: Differential effects on proteases and larval development of the soybean pest Anticarsia gemmatalis (Lepidoptera: Noctuidae).

Pest management is challenged with resistant herbivores and problems regarding human health and environmental issues. Indeed, the greatest challenge to modern agriculture is to protect crops from pests and still maintain environmental quality. This study aimed to analyze by in silico, in vitro, and in vivo approaches to the feasibility of using the inhibitory protein extracted from mammals - Bovine Pancreatic Trypsin Inhibitor (BPTI) as a potential inhibitor of digestive trypsins from the pest Anticarsia gemmatalis and comparing the results with the host-plant inhibitor - Soybean Kunitz Trypsin Inhibitor (SKTI). BPTI and SKTI interacts with A. gemmatalis trypsin-like enzyme competitively, through hydrogen and hydrophobic bonds. A. gemmatalis larvae exposed to BPTI did not show two common adaptative mechanisms i.e., proteolytic degradation and overproduction of proteases, presenting highly reduced trypsin-like activity. On the other hand, SKTI-fed larvae did not show reduced trypsin-like activity, presenting overproduction of proteases and SKTI digestion. In addition, the larval survival was reduced by BPTI similarly to SKTI, and additionally caused a decrease in pupal weight. The non-plant protease inhibitor BPTI presents intriguing element to compose biopesticide formulations to help decrease the use of conventional refractory pesticides into integrated pest management programs.

Mushroom extract of Lactarius deliciosus (L.) Sf. Gray as biopesticide: Antifungal activity and toxicological analysis.

Monilinia fructicola (Wint.) Honey is a plant pathogenic fungus that infects stone fruits such as peach, nectarine and plum, which are high demand cultivars found in Brazil. This pathogen may remain latent in the host, showing no apparent signs of disease, and consequently may spread to different countries. The aim of this study was to evaluate the activity of hydroalcoholic extract (HydE) obtained from Lactarius deliciosus (L.) Sf. Gray a mushroom, against M. fructicola phytopathogenic-induced mycelial growth. In addition, the purpose of this study was to examine phytotoxicity attributed to HydE using Brassica oleracea seeds, as well as cytotoxic analysis of this extract on cells of mouse BALB/c monocyte macrophage cell line (J774A.1 cell line) (ATCC TIB-67). The L. deliciosus HydE inhibited fungal growth and reduced phytopathogen mycelial development at a concentration of 1.25 mg/ml. Our results demonstrated that the extract exhibited phytotoxicity as evidenced by (1) interference on germination percentage and rate index, (2) decreased root and initial growth measures, and (3) lower fresh weight of seedlings but no cytotoxicity in Vero cell lines. Data suggest that the use of the L. deliciosus extracts may be beneficial for fungal control without any apparent adverse actions on mouse BALB/c monocyte macrophage cell line (J774A.1 cell line) viability.

Formulation of the biological control yeast Meyerozyma caribbica by electrospraying process: effect on postharvest control of anthracnose in mango (Mangifera indica L.) and papaya (Carica papaya L.).

BACKGROUND: Microorganism for biological control of fruit diseases is an eco-friendly alternative to the use of chemical fungicides. RESULTS: This is the first study evaluating the electrospraying process to encapsulate the biocontrol yeast Meyerozyma caribbica. The effect of encapsulating material [Wey protein concentrate (WPC), Fibersol® and Trehalose], its concentration and storage temperature on the cell viability of M. caribbica, and in vitro and in vivo control of Colletotrichum gloeosporioides was evaluated. The processing with commercial resistant maltodextrin (Fibersol®) 30% (w/v) as encapsulating material showed the highest initial cell viability (95.97 ± 1.01%). The storage at 4 ± 1 °C showed lower losses of viability compared to 25 ± 1 °C. Finally, the encapsulated yeast with Fibersol 30% w/v showed inhibitory activity against anthracnose in the in vitro and in vivo tests, similar to yeast fresh cells. CONCLUSION: Electrospraying was a highly efficient process due to the high cell viability, and consequently, a low quantity of capsules is required for the postharvest treatment of fruits. Additionally, the yeast retained its antagonistic power during storage. © 2021 Society of Chemical Industry.

Non-Chemical Treatments for the Pre- and Post-Harvest Elicitation of Defense Mechanisms in the Fungi-Avocado Pathosystem.

The greatest challenge for the avocado (Persea americana Miller) industry is to maintain the quality of the fruit to meet consumer requirements. Anthracnose is considered the most important disease in this industry, and it is caused by different species of the genus Colletotrichum, although other pathogens can be equally important. The defense mechanisms that fruit naturally uses can be triggered in response to the attack of pathogenic microorganisms and also by the application of exogenous elicitors in the form of GRAS compounds. The elicitors are recognized by receptors called PRRs, which are proteins located on the avocado fruit cell surface that have high affinity and specificity for PAMPs, MAMPs, and DAMPs. The activation of defense-signaling pathways depends on ethylene, salicylic, and jasmonic acids, and it occurs hours or days after PTI activation. These defense mechanisms aim to drive the pathogen to death. The application of essential oils, antagonists, volatile compounds, chitosan and silicon has been documented in vitro and on avocado fruit, showing some of them to have elicitor and fungicidal effects that are reflected in the postharvest quality of the fruit and a lower incidence of diseases. The main focus of these studies has been on anthracnose diseases. This review presents the most relevant advances in the use of natural compounds with antifungal and elicitor effects in plant tissues.

Essential oils of Bursera morelensis and Lippia graveolens for the development of a new biopesticides in postharvest control.

Fruit and vegetable crops that are not consumed immediately, unlike other agricultural products, require economic and time investments until they reach the final consumers. Synthetic agrochemicals are used to maintain and prolong the storage life of crops and avoid losses caused by phytopathogenic microorganisms. However, the excessive use of synthetic agrochemicals creates health problems and contributes to environmental pollution. To avoid these problems, less toxic and environment-friendly alternatives are sought. One of these alternatives is the application of biopesticides. However, few biopesticides are currently used. In this study, the biopesticide activity of Bursera morelensis and Lippia graveolens essential oils was evaluated. Their antifungal activity has been verified in an in vitro model, and chemical composition has been determined using gas chromatography-mass spectrometry. Their antifungal activity was corroborated in vitro, and their activity as biopesticides was subsequently evaluated in a plant model. In addition, the persistence of these essential oils on the surface of the plant model was determined. Results suggest that both essential oils are promising candidates for producing biopesticides. This is the first study showing that B. morelensis and L. graveolens essential oils work by inhibiting mycelial growth and spore germination and are environment-friendly biopesticides.

Characterization of extracellular secondary metabolites in Oudemansiella canarii BRM-044600 displaying antifungal activity against the phytopathogen Sclerotinia sclerotiorum.

White mold disease, caused by the phytopathogen Sclerotinia sclerotiorum, provokes severe productivity losses in several economically important crops. Biocontrol agents, especially antagonist filamentous fungi, are environmentally friendly alternatives to the chemical fungicides used in white mold management. The objective of this study was to screen for basidiomycete fungi capable of inhibiting S. sclerotiorum and investigate their bioactive metabolites responsible for antifungal activities. Two out of 17 tested basidiomycete isolates inhibited the mycelial growth of S. sclerotiorum in pair culture experiments on agar plates, namely Oudemansiella canarii BRM-044600 and Laetisaria arvalis ATCC52088. O. canarii BRM-044600 liquid culture filtrate exhibited the greatest antifungal activity and was selected for further investigation. UHPLC-MS analysis suggests that six putative strobilurins, including strobilurin A and/or stereoisomers of this compound (m/z 259.1299, [M + H]+) and three putative strobilurins with m/z 257.1184 ([M + H]+) are likely responsible for the antifungal activity observed in the culture filtrate. For the first time, this work demonstrated the potential of O. canarii for white mold biocontrol and strobilurin production.

Kosakonia radicincitans and Cryptococcus laurentii controlled Penicillium expansum rot and decreased patulin production at 4 and 25 °C.

In the present work, we evaluated the effects of a mixture of biocontrol agents against two toxigenic strains of Penicillium expansum isolated in Argentine Patagonia from pome fruits. The two strains, INTA-5 and INTA-10, were previusly selected among ten strains coming from the Alto Valle (Rio Negro-Argentina) for their high production of patulin. For the biocontrol, Kosakonia radicincitans, Cryptococcus laurentii, and Rhodosporidium fluviale were tested in vitro experiments on Potato Dextrose Agar (PDA) dishes against the INTA-5 and INTA-10 strains. The bacterium K. radicincitans and the yeast C. laurentii were selected to be used in a mixture due to their capacity to control the fungus and reduce the mycotoxin severely. In vitro assays with the mixture showed a high antagonism against P. expansum INTA-5 and INTA-10, at 21 d of incubation at 25 °C and a patulin reduction of 98%. The mixture of microorganisms was also effective in apples stored at 25 °C for 10 d and 4 °C for 30 d. At cold storage, the mixture controlled moderately the development of rot and decreased patulin concentration. At 25 °C, the pathogen's optimal growth temperature, the mixture of Biological Control Agent (BCAs) assured both the control of rot and decrease of patulin concentration. The combination of two microorganisms, with different requirements and abilities, resulted in a mix with a strong antagonism against P. expansum with the capability to decrease the patulin concentration. Treatment with the selected mixture could be a good option for controlling strains with different behaviours and in different environmental conditions.

Trichoderma as biological control agent: scope and prospects to improve efficacy.

A major current challenge is to increase the food production while preserving natural resources. Agricultural practices that enhance the productivity and progressively improve the soil quality are relevant to face this challenge. Trichoderma species are widely used in agriculture to stimulate the plant growth and to control different pathogens affecting crops, representing useful tools for sustainable food production. This mini-review summarizes applications of Trichoderma strains in agriculture to control fungal pathogens, nematodes and insects, the involved biocontrol mechanisms, efficacy and inoculation forms in greenhouse, field and post-harvest conditions. Aspects of Trichoderma handling that influence on biocontrol efficacy such as preventive treatments, frequency of applications and delivery methods are discussed. Strategies useful to improve the antagonistic performance such as the use of native strains, protoplast fusion, formulation, growth on pathogen cell wall medium and combination with other antagonists in integrated treatments are discussed. This mini-review provides practical knowledge to design safe and optimal biocontrol strategies based on Trichoderma and pose challenges to expand its antagonist performance.

Compatibility of Bt biopesticides and adjuvants for Spodoptera frugiperda control.

Spodoptera frugiperda is a pest of economic importance for several crops with resistance reports to Bt crops and pesticides. Eco-friendly Bt biopesticides may be an alternative to chemical insecticides due to their selectivity and specificity. However, the efficacy of Bt biopesticides may be influenced by the association with other chemicals, such as adjuvants. This study evaluated the compatibility and toxicity of Bt biopesticides mixed with adjuvants for the control of S. frugiperda. The treatments included the association of Dipel SC and Dipel PM with adjuvants. Compatibility tests were used to evaluate the Bt mixture. Bt suspensions obtained from mixtures of Bt and adjuvants at 106 and 3 × 108 spores/mL-1 were used to evaluate S. frugiperda mortality and distilled water was used as the control. The addition of the adjuvant LI increased growth and sporulation, indicating compatibility with Bt biopesticides. The other adjuvants were toxic to reducing Bt growth and sporulation. Only the mixture of Bt with LI and Bt alone was effective to S. frugiperda. The addition of adjuvants to Bt biopesticide affect the Bt sporulation, growth and mortality.