Biological insecticides have gained importance in modern society because they cause minimal environmental harm and reduce pests’ability to develop resistance.Nomuraea rileyi,a facultative entomopathogenic fungus,is s...Biological insecticides have gained importance in modern society because they cause minimal environmental harm and reduce pests’ability to develop resistance.Nomuraea rileyi,a facultative entomopathogenic fungus,is suitable for infecting lepidopteran pests,including Spodoptera litura and Helicoverpa armigera.This work aims to identify a suitable semi-solid fermentation medium to increase the conidia production of N.rileyi and enhance its biological control ability as mycoinsecticide.Research is carried out on broken rice,wheat,sorghum,and corn as substrates,both with and without nutrient addition.It also covers incubation under set conditions,colony harvesting,and conidial yield and germination determination using a haemocytometer.All the study was conducted using a completely randomized design(CRD)and a test of significance was set at p<0.05 using analysis of variance(ANOVA).This work aimed to establish the effect of various substrates on growth and conidia formation in N.rileyi.The highest conidia count of 10×10^(8)CFU/g on day 15.The result was obtained from BR+Nu followed by sorghum 7×10^(8)CFU/g,corn 7×10^(8)CFU/g and wheat 6.5×10^(8)CFU/g.Thus,post-drying,the highest corresponding viability was observed in the product containing BR+Nu–6.20×10^(8)CFU/g.Adding rice bran(BR+RB,150 g each)still increases conidial yield up to 14×10^(8) CFU/g at 15 DAI.These indings thus assert that broken rice and supplementation affect conidia yield and viability.展开更多
In this study, toxicity and control efficiency of three nicotine biopesticides against pomegranate aphids were determined via indoor toxicity test and field effica- cy test, aiming at screening the appropriate reagent...In this study, toxicity and control efficiency of three nicotine biopesticides against pomegranate aphids were determined via indoor toxicity test and field effica- cy test, aiming at screening the appropriate reagent for prevention and control of pomegranate aphids. The results of indoor toxicity test showed that LC^o of reagent 1, reagent 2 and reagent 3 reached 10 270, 12 810 and 13 040 mg/L, respectively. The results of field efficacy test showed that control efficacy of reagent 1, reagent 2 and reagent 3 reached 60.52%, 34.60% and 46.99%, respectively. Overall, reagent 1 （91% ultrafine powder of tobacco leaves, 3% silicone oil, 2% sasangua cake, 2% emulsifier, 2% ascorbic acid） exhibited the highest control efficiency against pomegranate aphids, which can be further popularized and utilized.展开更多
The green miridbug,Cyrtorhinus lividipennis,is an important predator of the rice brown planthopper,Nilaparvata lugens.In this study,the selective toxicity of seven commercial biopesticides for C.lividipennis was exami...The green miridbug,Cyrtorhinus lividipennis,is an important predator of the rice brown planthopper,Nilaparvata lugens.In this study,the selective toxicity of seven commercial biopesticides for C.lividipennis was examined under laboratory conditions; abamectin was the most selective to C.lividipennis,followed by matrine and azadirachtin.Veratridine,rotenone,Bacillus thuringiensis and Beauveria bassiana showed less selectivity for C.lividipennis.Subsequently,matrine,abamectin and azadirachtin were selected for sublethal assessments with respect to C.lividipennis due to their high toxicities to N.lugens.C.lividipennis treated with sublethal concentrations(LC10 and LC20) of the three biopesticides could distinguish volatiles released from healthy and N.lugens-infested plants indicating that the biopesticides tested did not affect the foraging ability of surviving miridbugs.Azadirachtin decreased the consumption capability of C.lividipennis when the densities of N.lugens were 20,30,40 and 50 insects per vial.Sublethal concentration treatment did not impact the pre-oviposition period or egg hatchability of C.lividipennis.However,the fecundity of C.lividipennis exposed to azadirachtin and abamectin increased by 27–41% compared to the untreated individuals.In summary,abamectin or matrine together with C.lividipennis could be considered an effective,sustainable pest management strategy for rice.展开更多
Biopesticides are derivatives of plants, microorganisms and insects. Substances from plants and animals have been used to manage diseases in crops, animals and humans. Reliance on nature to heal nature is a practise f...Biopesticides are derivatives of plants, microorganisms and insects. Substances from plants and animals have been used to manage diseases in crops, animals and humans. Reliance on nature to heal nature is a practise for many people around the world. Use of natural products was overtaken by synthetic chemicals due to their efficacy, reliability and quick knock down effect. However, synthetic pesticides have become a health hazards for humans and environment due to their toxicity and pollution. Biopesticides are potential alternatives to synthetic pesticides. Sources of biopesticides are readily available, easily biodegradable, exhibit various modes of action, are less expensive and have low toxicity to humans and non-target organisms. Neem, pyrethrum, cotton and tobacco are known sources of botanical pesticides and have already been commercialized. Other sources of botanical pesticides include garlic, euphorbia, citrus, pepper among others. Species of Trichoderma, Bacillus, Pseudomonas, Beauveria have been commercialized as microbial pesticides. Biopesticides are however faced with challenges of formulation, registration, commercialization, acceptance and adoption. This paper describes several aspects of biopesticide development, including but not limited to, their sources, production, formulation, commercialization, efficacy and role in sustainable agriculture.展开更多
The present research aimed at producing a biopesticide with proper formulation of invert emulsion (water-in-oil type) and effective strain of?Trichoderma harzianum?then, testing it against pathogens of postharvest mol...The present research aimed at producing a biopesticide with proper formulation of invert emulsion (water-in-oil type) and effective strain of?Trichoderma harzianum?then, testing it against pathogens of postharvest mold infections(Botrytis cinerea?&?Penicillium expansum) on fresh fruits of apple and pear. The?proper formulation of invert emulsion (IE#3) used for biopesticide production has the following ingredients (100% w/w): soybean oil (28.50%), coconut oil (19.50%), oil-soluble emulsifier: Tween 20 (2.0%), glycerine (4.25%), water-soluble emulsifier:?dehymuls k (0.75%),?sterile distilled water (22.5%) and conidial suspension of the effective strain ofT. harzianum?“TrichoPAL1” in water (22.5%, concentration 1 ×?107?conidia/ml). Testing efficacy of the produced biopesticide has indicated a significant reduction in the disease lesion diameter of mold infections on wounded apple and pear fruits stored at?20℃?± 1℃?compared to the untreated fruits or control (reduction from up to 38.75 to about 7.50 mm, respectively, according to?the type of mold infections and fruit type). Also, the treatment with the produced biopesticide has resulted in?a long protection period from mold infections on wounded and un-wounded fresh fruits of apple and pear stored under controlled and semi-commercial conditions(up to 2.5 months according to the type of mold infections and fruit type). In conclusion, the overall results have demonstrated the effectiveness of produced biopesticide on stored fruits under controlled and semi-commercial conditions therefore,?it is recommended to test this effectiveness on marketed fruits stored under variable conditions before applying it at a large scale.展开更多
[Objectives]The paper was to search for biopesticides with good control effect on grape gray mold.[Methods]A randomized field trial was carried out to compare the control effects of 100 million CFU/g Trichoderma harzi...[Objectives]The paper was to search for biopesticides with good control effect on grape gray mold.[Methods]A randomized field trial was carried out to compare the control effects of 100 million CFU/g Trichoderma harzianum WDG,200 million spores/g Trichoderma WP,24% validamycin AS,0.3% matrine AS on grape gray mold.[Results]Of the 4 biopesticides,200 million spores/g Trichoderma WP had the highest control effect on grape gray mold,with the control effect of 73.38% at 7 d post the second application,significantly higher than those of 100 million CFU/g T.harzianum WG and 0.3% matrine AS;the control effect was 75.77% at 14 d post the second application,significantly higher than those of other 3 biopesticides.[Conclusions]The 200 million spores/g Trichoderma WP shows a good control effect on grape gray mold with a long-lasting control effect,so it is more is for the control of summer black grape gray mold in Jianshui County.展开更多
Neem extract is an alternative insecticide for organic farming and is an allowed component for commercial biopesticide in Korea. However, crop protection properties are not consistent in commercial products. In this r...Neem extract is an alternative insecticide for organic farming and is an allowed component for commercial biopesticide in Korea. However, crop protection properties are not consistent in commercial products. In this report, quantitative analysis of commercial biopesticides for the four insecticidal limonoids of neem extract-azadirachtin A, azadirachtin B, deacetylsalannin and salannin, was conducted through solid phase extraction method with lipophilic-hydrophilic balanced material. The recoveries of the four limonoids ranged from 80.5% to 105%, and their limit of quantitation ranged from 0.028 mg/L to 0.356 mg/L. On the five imported neem extracts, the total contents of the four bioactive limonoids extracted were from 321 mg/L to 5810 mg/L, but there were big variations in the relative composition of the limonoids. The total limonoidal concentrations in 23 commercial bio-pesticides made from neem showed from below LOQ to 7190 mg/L with significant differences in the relative composition. These differences determine the biopesticide’s efficacy on pests, therefore, tracking the active ingredients is necessary for the quality control of commercial bio-pesticides.展开更多
The biopesticide was prepared from locally available low cost ingredients: dried beef blood, molasses and mineral salts (ZnCl2, MgCl2, MnCl2, CaCl2CaCl2, and FeCl3) which were used as medium for the laboratory scale p...The biopesticide was prepared from locally available low cost ingredients: dried beef blood, molasses and mineral salts (ZnCl2, MgCl2, MnCl2, CaCl2CaCl2, and FeCl3) which were used as medium for the laboratory scale production of Bacillus thuringiensis (B.t.) bio-pesticide by shake flask technique. Indigenous B.t. isolate PA-Sb- 46.3 which produced two crystals—bi-pyramidal and cuboidal was found 73.6 times toxic against H. armigera than reference strain Bacillus thuringiensis var. kurstaki (HD-I-S-1980) used. Medium was fermented for 72 hours at 30℃ ± 2℃ and 160 rpm. 72 h fermented medium showed 95% - 99% sprulation, with spore yield of 3.97 × 109 spores/ml, and LC50 value to 1st instar larvae of H. armigera was 0.53 μg/ml diet. Preservatives and diluents used in the biopesticide were found to be effective to store at room temperature over a period of 30 months. These observations suggested that the biopesticide produced was effective and highly economical for the industrial scale production to manage H. armigera in Pakistan.展开更多
Successive cartridge clean-up method for the simultaneous determination of matrine and oxyma- trine in biopesticides containing Sophora flavescens extract was developed and validated by UPLC. The clean-up method was e...Successive cartridge clean-up method for the simultaneous determination of matrine and oxyma- trine in biopesticides containing Sophora flavescens extract was developed and validated by UPLC. The clean-up method was established with ENVI-Carb (0.5 g) and C18 SPE (0.5 g) cartridges for the bioactive alkaloid in biopesticides from S. flavescens, and the eluate was analyzed to quantify the matrine and oxymatrine by UPLC. The developed method was validated, and the recovery and LOQ of both materials were 105.0% and 103.6%, and 0.050 and 0.684 mg·kg-1, respectively. Of the twenty one samples, the total content of matrines were analyzed by using the developed method and the result showed the developed successive clean-up method could contribute to the manufacture and control of biopesticides including matrines, and can be ap- plied to the method development for the analysis of alkaloid materials in biopesticides.展开更多
Black Sigatoka disease (BSD) is a foliar disease caused by <em>Mycosphaerella fijiensis</em>, responsible of reduction of the photosynthetic area of banana plant and yield at harvest since it has an influe...Black Sigatoka disease (BSD) is a foliar disease caused by <em>Mycosphaerella fijiensis</em>, responsible of reduction of the photosynthetic area of banana plant and yield at harvest since it has an influence on fruit physiology. The control of BSD relies on the use of chemicals which are not affordable for the small holder farmers and increase the cost of production. Moreover, this chemical control is ineffective, negatively impacting the environment and human health, and is at the origin of strain resistance. <em>Tithonia diversifolia</em> is known as rich in many compounds such as mineral elements, defense metabolites, some phytochemicals;and it is increasingly used in agriculture. Recently, the protective effect of <em>Tithonia diversifolia</em> liquid extract against BSD development on plantain vivoplants in the nursery was highlighted. The aim of our study was to evaluate the efficacy of a biopesticide base on <em>Tithonia diversifolia</em> on the BSD development in a plantain field under high disease pressure. The effect of<em> Tithonia diversifolia</em> biopesticide on <em>Mycosphaerella fijiensis</em> mycelial growth<em> in vitro</em> was evaluated. An experimental field at the flowering stage was selected and treated with the biopesticide base on <em>Tithonia diversifolia</em> at three different concentrations: undiluted (100%), diluted at 1/2 (50%) and diluted at 1/4 (25%) for 17 weeks. The disease severity, the number of functional leaves, the youngest spotted leaf (YSL) and the youngest necrotic leaf (YNL) were evaluated in course of time. The biopesticide treatments significantly (P < 0.001) reduce the BSD severity in course of time, but it is more effective for the most diluted concentration (25%). The number of leaves increases in course of time as well as the rank of the YSL and the YNL confirming the efficiency of BSD control. The efficacy of this biopesticide base on <em>Tithonia diversifolia</em> could be a hopeful ecoresponsible solution for the plantain sector in general and in particular for poor small farmers.展开更多
Cowpea, Vigna unguiculata L. Walp, is an important food grain legume in Niger facing production losses due to insect pests. This study aims to determine the efficiency of non-chemical methods for managing these pests....Cowpea, Vigna unguiculata L. Walp, is an important food grain legume in Niger facing production losses due to insect pests. This study aims to determine the efficiency of non-chemical methods for managing these pests. A trial was conducted during the 2020 and 2022 cropping seasons at the INRAN station in the Maradi region. A Fischer experimental design with 6 repetitions was used to compare 4 treatments: synthetic chemical pesticide;the entomopathogenic fungus Beauveria bassiana;aqueous extracts of neem seeds, and control. Observations were carried out every three days. The cowpea pod-sucking bug, pod borer, and thrips were the main insect pests recorded. In terms of effectiveness, the synthetic pesticide was the best treatment. It reduced insect pest densities by 71.35% to 90.40% in 2020 and by 35.11% to 42.13% in 2022. Grain yields varied between treatments. Neem seed extract followed the synthetic pesticide and significantly reduced insect infestations in both years. The synthetic pesticide and neem seed extract resulted in yields 3 to 5 times higher than the control treatment in 2020. By contrast, B. bassiana 115 and neem seed extract produced similar yields in 2022. Therefore, the results of this study showed that B. bassiana 115 and neem seed extract have insecticidal potential and could be used as an ecological alternative for managing cowpea insect pests in the Sahel.展开更多
Introduction Unconventional alternatives such as aerobic and anaerobic effluent from starch industry contain essential nutrients for Btk active ingredient synthesis.Effluent from starch industry is rich in carbon and ...Introduction Unconventional alternatives such as aerobic and anaerobic effluent from starch industry contain essential nutrients for Btk active ingredient synthesis.Effluent from starch industry is rich in carbon and nitrogen and can replace expensive feedstock used during the fermentation process.Objectives The main objective of this study was to achieve a biopesticide formulation from starch industry wastewater(SIW)with high entomotoxicity(UI/ml)of larvae comparable to Foray 76B,which is a commercial biopesticide.Methods Bacillus thuringiensis var kurstaki HD1(Btk)strain was cultivated and sub-cultured to aerobic,anaerobic digested effluent and SIW.Pre-treatment was carried on these different substrates to enhance the residual carbon required for Btk growth and delta endotoxin synthesis.After 48 hours of fermentation,cells count and delta-endotoxin were determined.A biopesticide formulation containing fermented broth and adjuvants was fed to larvae to determine larvae mortality.Results Btk cell growth and sporulation profile in SIW media displayed a high total cell count and viable spores compared to btk growth in anaerobic or aerobic media after 48h fermentation.The maximum endotoxin concentration in the SIW medium was 435μg/mL,whereas,in anaerobic and aerobic effluent,the maximum concentrations were at 161μg/mL and 136μg/mL,respectively.When acidic treatment was performed at pH 2 for these substrates,entomotoxicity obtained from aerobic and anaerobic biopesticide formulations displayed significantly higher entomoxicity than the untreated ones.The entomotoxicity of SIW treated at pH 2 was equivalent to the standard Foray 76B which is 20,000 IU/μL.Conclusion Anaerobic and aerobic effluent did not contain enough total organic carbon to augment Btk growth and entomo-toxicity.Substrates pre-treated at pH 2 provided significant organic matter for Btk growth and resulted in larval mortality equivalent to the com ercial biopesticide Foray 76B.展开更多
Biopesticides are attracting interest as alternatives to conventional pesticides but without many of the non-target effects, promising a better record of safety and sustainability in pest control practices. In this ar...Biopesticides are attracting interest as alternatives to conventional pesticides but without many of the non-target effects, promising a better record of safety and sustainability in pest control practices. In this article we summarize and discuss the current status and future promise of biopesticides, including how biopesticides use may increase the quality and safety of the food supply.展开更多
Excessive application of mineral fertilizers and synthetic pesticides poses a substantial threat to the soil and water environment and food security.Organic fertilizer and biopesticides have gradually become essential...Excessive application of mineral fertilizers and synthetic pesticides poses a substantial threat to the soil and water environment and food security.Organic fertilizer and biopesticides have gradually become essential technology for reducing mineral fertilizer and pesticide inputs.In the process,the technical environment is critical for promoting farmer behavior related to the adoption of organic fertilizer and biopesticides.This paper analyzes the influence of the technical environment on farmer behavior related to the adoption of organic fertilizer and biopesticides based on a survey of 1282 farmers in Heilongjiang Province,China,using the bivariate probit model.The results indicate that(1)farmer behavior related to the adoption applying organic fertilizer and biopesticides were positively correlated;(2)the technical environment had a significant positive impact on farmer behavior related to the adoption of organic fertilizer and biopesticides;and(3)the technical environment had a heterogeneous effect across different groups of farmers.This research provides insights useful for promoting organic fertilizer and biopesticides to farmers.It can be helpful to bundle relevant environmental technologies,conduct technology training for farmers and strengthen the construction of rural information networks.展开更多
Plants with bioactive properties are greatly useful in preventing and controlling blood-sucking and disease-vector invertebrates, particularly in developing countries and low-income communities. Their application is a...Plants with bioactive properties are greatly useful in preventing and controlling blood-sucking and disease-vector invertebrates, particularly in developing countries and low-income communities. Their application is a promising alternative to synthetic compounds whose use remains a health, environmental, and economic challenge. However, many are still unknown and unvalued, while others are becoming ignored and threatened. The main objective of this ethnobotanical study is to identify and characterize indigenous and locally grown plants against blood-sucking and disease-vector insects. Salient opportunities and challenges of using these plants are documented and discussed. Semi-structured interviews, using a prepared questionnaire, were conducted with 228 informants. The consensus index (CI) was calculated to analyze the reliability of the collected information. The identified 31 anti-insect plant species belong to 20 botanical families, four morphological categories, and six habitat types. They can be categorized as insecticidal plants (42% of the total), insect repellent (42% of the total), and both insecticidal and insect repellent (16% of the total). More than 54% of these are still abundant in the study area, while about 35.5% have become rare and difficultly accessible. Based on the numerical importance of related anti-insect plant species, the seven targeted blood-sucking insects range in the following decreasing order: Jiggers (16 species) > Fire Ants (9 species) > Flies (8 plants) > Mosquitoes (4 species) > Fleas (2 species) > Bedbugs (1 species) > lice (0 species). The three most commonly used plants, with the highest confirmation indices, are Tetradenia riparia (ICs = 0.712), Eucalyptus globulus subsp. maidenii (ICs = 0.302), and Solanum aculeastrum (ICs = 0.288). The antimicrobial role of many locally grown anti-insect plants and the multiple other associated valorization possibilities are ignored by most informants. Domesticating, propagating, protecting, and promoting the sustainable use of these plants would be an appropriate route for their conservation and continued availability.展开更多
Aromatic plant distillation produces residues rich in phenolic compounds known to be bioactive. In this context, residues from the hydrodistillation of Mentha piperita L., Cymbopogon citratus Stapf, and Eucalyptus cam...Aromatic plant distillation produces residues rich in phenolic compounds known to be bioactive. In this context, residues from the hydrodistillation of Mentha piperita L., Cymbopogon citratus Stapf, and Eucalyptus camaldulensis Dehnh were chemically and biologically analyzed. The ethanol percentages (70%, 50%, and 30%) were evaluated by determining antioxidant activity using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging, total phenolic content, and total flavonoid content. Antifungal activity was evaluated “in vitro” against Fusarium oxysporum, Alternaria alternata, Trametes versicolor, and Coniophora puteana using the diffusion method in malt-agar medium. Antitermite activity was also assessed against Reticulitermes flavipes using the most active extract with low ethanol concentrations (50% and 30%). The optimum ethanol concentration to extract phenolic compounds is 70% for TFC and 30% for TPC, and the antioxidant activity was 0.45 ± 0.01 mg/mL (IC50). The most active extracts were the ethanolic ones, particularly for Eucalyptus camaldulensis, presenting 100% inhibition against the mycelial growth of Coniophora puteana and Alternaria alternata at 1 mg/mL and 0.5 mg/mL, respectively. For antitermite activity, EE50 was the most effective, with a 24% termite survival rate and a degraded food supply surface of 28%. These data suggest the potential use of hydrodistillation residues for biopesticide development.展开更多
In order to mitigate the occurrence and damage of cowpea anthracnose and reduce the chemical pesticide consumption, residue and environmental pollution, the methods of forecasting, randomized block design and statisti...In order to mitigate the occurrence and damage of cowpea anthracnose and reduce the chemical pesticide consumption, residue and environmental pollution, the methods of forecasting, randomized block design and statistical analysis were conducted to study the control effect of biopesticide chitosan, biochemical compound Prochloraz-Chitosan and chemical pesticides difenoconazole and thifluzamide by field efficacy trials. The results showed that under serious occurrence of anthracnose in autumn greenhouse cowpea, when the 2% chJtosan AS （2 250 g/hm^2）, 46% Prochloraz-Chitosan EW （450 g/hm^2）, 10% difenoconazole WG （900 g/hm^2, CK） or 24% thifluzamide SC （360 ml/hm^2） were applied three times with an interval of 5-8 d, the control efficiency on day 7, 14 and 20 reached 83%, 78% and 73%, respectively. No significant difference was found in control efficiency among the four kinds of agents. These four kinds of agents, especially chitosan and Prochloraz-Chitosan, could be used as ideal agents for controlling anthracnose, as well as for modern agricultural demonstration zones, pollution-free agricultural products, green agricultural products and organic agricultural products,thereby meeting the develop- ment needs of ＇modern agriculture, green agriculture, organic agriculture and ecological agriculture.展开更多
Currently, plant diseases and insect infestations are mainly controlled by the extraneous application of pesticides. Unfortunately, the indiscriminate use of such agrochemicals can cause ecological and environmental p...Currently, plant diseases and insect infestations are mainly controlled by the extraneous application of pesticides. Unfortunately, the indiscriminate use of such agrochemicals can cause ecological and environmental problems, as well as human health hazards. To obviate the potential pollution arising from the application of agrochemicals, biological control of soilborne pathogens or insect pests using antagonistic microorganisms may be employed. Certain soil bacteria, algae, fungi, plants and insects possess the unique ability to produce hydrogen cyanide(HCN), which plays an important role in the biotic interactions of those organisms. In particular, cyanogenic bacteria have been found to inhibit the growth of various pathogenic fungi, weeds, insects, termites and nematodes. Thus, the use of HCN-producing bacteria as biopesticides offers an ecofriendly approach for sustainable agriculture. The enzyme, HCN synthase,involved in the synthesis of HCN, is encoded by the hcnABC gene cluster. The biosynthetic regulation of HCN, antibiotics and fluorescent insecticidal toxins through the conserved global regulatory GacS/GacA system is elaborated in this review, including approaches that may optimize cyanogenesis for enhanced pest control. In addition, the effects of bacterially synthesized HCN on the production of indole acetic acid, antibiotics and fluorescent insecticidal toxins, 1-aminocyclopropane-1-carboxylate deaminase utilization and phosphate solubilization may result in the stimulation of plant growth. A more detailed understanding of HCN biosynthesis and regulation may help to elaborate the precise role of this compound in biotic interactions and sustainable agriculture.展开更多
Chromium(Cr) may cause losses in the yield of field plant, which is one of the favorite habitats of Bacillus thuringiensis(Bt). The purposes of our study were to assess the Cr(VI)-resistance and Cr(VI)-reducing abilit...Chromium(Cr) may cause losses in the yield of field plant, which is one of the favorite habitats of Bacillus thuringiensis(Bt). The purposes of our study were to assess the Cr(VI)-resistance and Cr(VI)-reducing abilities of an indigenous soil isolate of Bt and to determine the factors governing Cr(VI) reduction. Towards this end a novel dichromate-reducing Bt BRC-ZYR2, characterized with insecticidal crystal proteins(ICPs), was isolated from a uranium deposit. Minimum inhibitory concentrations(MICs) of Cr(VI) were determined by broth dilution method and the concentrations of Cr(VI) and total Cr in the supernatant were quantified colorimetrically using 1,5-diphenylcarbazide(DPC) reagent and a mixture of sulfuric-nitric acids, respectively. The isolate contained five ICP genes(cry1Ba, cry1 Bb, cry1Be/cry1 Bf, cry9 Ca and cry9Da) and exhibited a high level of Cr(VI) resistance with MICs of 150 mg L-1at pH 7.0 and 30?C, and 500 mg L-1under optimal conditions(pH 9.0 and 40?C). The total Cr concentration was similar to initial concentration of Cr(VI) under the optimal condition, suggesting that the essential removal of the Cr(VI) was dependent on Bt reduction. Under optimal conditions, the initial Cr(VI) concentrations from 25 to 75 mg L-1significantly decreased in 24 h after incubation. Addition of Mn2+, Co2+, Mo2+and Cu2+activated Bt-mediated Cr(VI) reduction, while Zn2+, Ni2+and glucose were found to inhibit the reduction. Our results indicated that this isolate could be a promising biopesticide with the potential for both insect biocontrol and Cr bioremediation in the field.展开更多
Thirty-six strains of marine actinomycetes were isolated from a sample of marine sediment collected from the Yellow Sea and evaluated in terms of their inhibitory activity on the growth of Aspergillus parasiticus and ...Thirty-six strains of marine actinomycetes were isolated from a sample of marine sediment collected from the Yellow Sea and evaluated in terms of their inhibitory activity on the growth of Aspergillus parasiticus and the production of norsolorinic acid using dual culture plate assay and agar diffusion methods.Among them,three strains showed strong antifungal activity and were subsequently identified as Streptomyces sp.by 16 S rRNA gene sequencing analysis.The supernatant from the fermentation of the MA01 strain was extracted sequentially with chloroform and ethyl acetate,and the activities of the extracts were determined by tip culture assay.The assay results show that both extracts inhibited mycelium growth and toxin production,and the inhibitory activities of the extracts increased as their concentrations increased.The results of this study suggest that marine actinomycetes are biologically important for the control of mycotoxins,and that these bacteria could be used as novel biopesticides against mycotoxins.展开更多
文摘Biological insecticides have gained importance in modern society because they cause minimal environmental harm and reduce pests’ability to develop resistance.Nomuraea rileyi,a facultative entomopathogenic fungus,is suitable for infecting lepidopteran pests,including Spodoptera litura and Helicoverpa armigera.This work aims to identify a suitable semi-solid fermentation medium to increase the conidia production of N.rileyi and enhance its biological control ability as mycoinsecticide.Research is carried out on broken rice,wheat,sorghum,and corn as substrates,both with and without nutrient addition.It also covers incubation under set conditions,colony harvesting,and conidial yield and germination determination using a haemocytometer.All the study was conducted using a completely randomized design(CRD)and a test of significance was set at p<0.05 using analysis of variance(ANOVA).This work aimed to establish the effect of various substrates on growth and conidia formation in N.rileyi.The highest conidia count of 10×10^(8)CFU/g on day 15.The result was obtained from BR+Nu followed by sorghum 7×10^(8)CFU/g,corn 7×10^(8)CFU/g and wheat 6.5×10^(8)CFU/g.Thus,post-drying,the highest corresponding viability was observed in the product containing BR+Nu–6.20×10^(8)CFU/g.Adding rice bran(BR+RB,150 g each)still increases conidial yield up to 14×10^(8) CFU/g at 15 DAI.These indings thus assert that broken rice and supplementation affect conidia yield and viability.
文摘In this study, toxicity and control efficiency of three nicotine biopesticides against pomegranate aphids were determined via indoor toxicity test and field effica- cy test, aiming at screening the appropriate reagent for prevention and control of pomegranate aphids. The results of indoor toxicity test showed that LC^o of reagent 1, reagent 2 and reagent 3 reached 10 270, 12 810 and 13 040 mg/L, respectively. The results of field efficacy test showed that control efficacy of reagent 1, reagent 2 and reagent 3 reached 60.52%, 34.60% and 46.99%, respectively. Overall, reagent 1 （91% ultrafine powder of tobacco leaves, 3% silicone oil, 2% sasangua cake, 2% emulsifier, 2% ascorbic acid） exhibited the highest control efficiency against pomegranate aphids, which can be further popularized and utilized.
基金financially supported by the Jiangsu Agricultural Scientific Self-innovation Fund,China (CX(15)1057)the Fund of Science and Technology of Jiangsu Province,China (BE2015342)the National Key Research and Development Program of China (2017YFD0200400 and 2016YFD0300706)
文摘The green miridbug,Cyrtorhinus lividipennis,is an important predator of the rice brown planthopper,Nilaparvata lugens.In this study,the selective toxicity of seven commercial biopesticides for C.lividipennis was examined under laboratory conditions; abamectin was the most selective to C.lividipennis,followed by matrine and azadirachtin.Veratridine,rotenone,Bacillus thuringiensis and Beauveria bassiana showed less selectivity for C.lividipennis.Subsequently,matrine,abamectin and azadirachtin were selected for sublethal assessments with respect to C.lividipennis due to their high toxicities to N.lugens.C.lividipennis treated with sublethal concentrations(LC10 and LC20) of the three biopesticides could distinguish volatiles released from healthy and N.lugens-infested plants indicating that the biopesticides tested did not affect the foraging ability of surviving miridbugs.Azadirachtin decreased the consumption capability of C.lividipennis when the densities of N.lugens were 20,30,40 and 50 insects per vial.Sublethal concentration treatment did not impact the pre-oviposition period or egg hatchability of C.lividipennis.However,the fecundity of C.lividipennis exposed to azadirachtin and abamectin increased by 27–41% compared to the untreated individuals.In summary,abamectin or matrine together with C.lividipennis could be considered an effective,sustainable pest management strategy for rice.
文摘Biopesticides are derivatives of plants, microorganisms and insects. Substances from plants and animals have been used to manage diseases in crops, animals and humans. Reliance on nature to heal nature is a practise for many people around the world. Use of natural products was overtaken by synthetic chemicals due to their efficacy, reliability and quick knock down effect. However, synthetic pesticides have become a health hazards for humans and environment due to their toxicity and pollution. Biopesticides are potential alternatives to synthetic pesticides. Sources of biopesticides are readily available, easily biodegradable, exhibit various modes of action, are less expensive and have low toxicity to humans and non-target organisms. Neem, pyrethrum, cotton and tobacco are known sources of botanical pesticides and have already been commercialized. Other sources of botanical pesticides include garlic, euphorbia, citrus, pepper among others. Species of Trichoderma, Bacillus, Pseudomonas, Beauveria have been commercialized as microbial pesticides. Biopesticides are however faced with challenges of formulation, registration, commercialization, acceptance and adoption. This paper describes several aspects of biopesticide development, including but not limited to, their sources, production, formulation, commercialization, efficacy and role in sustainable agriculture.
文摘The present research aimed at producing a biopesticide with proper formulation of invert emulsion (water-in-oil type) and effective strain of?Trichoderma harzianum?then, testing it against pathogens of postharvest mold infections(Botrytis cinerea?&?Penicillium expansum) on fresh fruits of apple and pear. The?proper formulation of invert emulsion (IE#3) used for biopesticide production has the following ingredients (100% w/w): soybean oil (28.50%), coconut oil (19.50%), oil-soluble emulsifier: Tween 20 (2.0%), glycerine (4.25%), water-soluble emulsifier:?dehymuls k (0.75%),?sterile distilled water (22.5%) and conidial suspension of the effective strain ofT. harzianum?“TrichoPAL1” in water (22.5%, concentration 1 ×?107?conidia/ml). Testing efficacy of the produced biopesticide has indicated a significant reduction in the disease lesion diameter of mold infections on wounded apple and pear fruits stored at?20℃?± 1℃?compared to the untreated fruits or control (reduction from up to 38.75 to about 7.50 mm, respectively, according to?the type of mold infections and fruit type). Also, the treatment with the produced biopesticide has resulted in?a long protection period from mold infections on wounded and un-wounded fresh fruits of apple and pear stored under controlled and semi-commercial conditions(up to 2.5 months according to the type of mold infections and fruit type). In conclusion, the overall results have demonstrated the effectiveness of produced biopesticide on stored fruits under controlled and semi-commercial conditions therefore,?it is recommended to test this effectiveness on marketed fruits stored under variable conditions before applying it at a large scale.
基金Supported by Scientific and Technological Innovation Platform Construction Project for Biological Control Resources Exploration and Utilization in Yunnan Province(202207AB110009)。
文摘[Objectives]The paper was to search for biopesticides with good control effect on grape gray mold.[Methods]A randomized field trial was carried out to compare the control effects of 100 million CFU/g Trichoderma harzianum WDG,200 million spores/g Trichoderma WP,24% validamycin AS,0.3% matrine AS on grape gray mold.[Results]Of the 4 biopesticides,200 million spores/g Trichoderma WP had the highest control effect on grape gray mold,with the control effect of 73.38% at 7 d post the second application,significantly higher than those of 100 million CFU/g T.harzianum WG and 0.3% matrine AS;the control effect was 75.77% at 14 d post the second application,significantly higher than those of other 3 biopesticides.[Conclusions]The 200 million spores/g Trichoderma WP shows a good control effect on grape gray mold with a long-lasting control effect,so it is more is for the control of summer black grape gray mold in Jianshui County.
文摘Neem extract is an alternative insecticide for organic farming and is an allowed component for commercial biopesticide in Korea. However, crop protection properties are not consistent in commercial products. In this report, quantitative analysis of commercial biopesticides for the four insecticidal limonoids of neem extract-azadirachtin A, azadirachtin B, deacetylsalannin and salannin, was conducted through solid phase extraction method with lipophilic-hydrophilic balanced material. The recoveries of the four limonoids ranged from 80.5% to 105%, and their limit of quantitation ranged from 0.028 mg/L to 0.356 mg/L. On the five imported neem extracts, the total contents of the four bioactive limonoids extracted were from 321 mg/L to 5810 mg/L, but there were big variations in the relative composition of the limonoids. The total limonoidal concentrations in 23 commercial bio-pesticides made from neem showed from below LOQ to 7190 mg/L with significant differences in the relative composition. These differences determine the biopesticide’s efficacy on pests, therefore, tracking the active ingredients is necessary for the quality control of commercial bio-pesticides.
文摘The biopesticide was prepared from locally available low cost ingredients: dried beef blood, molasses and mineral salts (ZnCl2, MgCl2, MnCl2, CaCl2CaCl2, and FeCl3) which were used as medium for the laboratory scale production of Bacillus thuringiensis (B.t.) bio-pesticide by shake flask technique. Indigenous B.t. isolate PA-Sb- 46.3 which produced two crystals—bi-pyramidal and cuboidal was found 73.6 times toxic against H. armigera than reference strain Bacillus thuringiensis var. kurstaki (HD-I-S-1980) used. Medium was fermented for 72 hours at 30℃ ± 2℃ and 160 rpm. 72 h fermented medium showed 95% - 99% sprulation, with spore yield of 3.97 × 109 spores/ml, and LC50 value to 1st instar larvae of H. armigera was 0.53 μg/ml diet. Preservatives and diluents used in the biopesticide were found to be effective to store at room temperature over a period of 30 months. These observations suggested that the biopesticide produced was effective and highly economical for the industrial scale production to manage H. armigera in Pakistan.
文摘Successive cartridge clean-up method for the simultaneous determination of matrine and oxyma- trine in biopesticides containing Sophora flavescens extract was developed and validated by UPLC. The clean-up method was established with ENVI-Carb (0.5 g) and C18 SPE (0.5 g) cartridges for the bioactive alkaloid in biopesticides from S. flavescens, and the eluate was analyzed to quantify the matrine and oxymatrine by UPLC. The developed method was validated, and the recovery and LOQ of both materials were 105.0% and 103.6%, and 0.050 and 0.684 mg·kg-1, respectively. Of the twenty one samples, the total content of matrines were analyzed by using the developed method and the result showed the developed successive clean-up method could contribute to the manufacture and control of biopesticides including matrines, and can be ap- plied to the method development for the analysis of alkaloid materials in biopesticides.
文摘Black Sigatoka disease (BSD) is a foliar disease caused by <em>Mycosphaerella fijiensis</em>, responsible of reduction of the photosynthetic area of banana plant and yield at harvest since it has an influence on fruit physiology. The control of BSD relies on the use of chemicals which are not affordable for the small holder farmers and increase the cost of production. Moreover, this chemical control is ineffective, negatively impacting the environment and human health, and is at the origin of strain resistance. <em>Tithonia diversifolia</em> is known as rich in many compounds such as mineral elements, defense metabolites, some phytochemicals;and it is increasingly used in agriculture. Recently, the protective effect of <em>Tithonia diversifolia</em> liquid extract against BSD development on plantain vivoplants in the nursery was highlighted. The aim of our study was to evaluate the efficacy of a biopesticide base on <em>Tithonia diversifolia</em> on the BSD development in a plantain field under high disease pressure. The effect of<em> Tithonia diversifolia</em> biopesticide on <em>Mycosphaerella fijiensis</em> mycelial growth<em> in vitro</em> was evaluated. An experimental field at the flowering stage was selected and treated with the biopesticide base on <em>Tithonia diversifolia</em> at three different concentrations: undiluted (100%), diluted at 1/2 (50%) and diluted at 1/4 (25%) for 17 weeks. The disease severity, the number of functional leaves, the youngest spotted leaf (YSL) and the youngest necrotic leaf (YNL) were evaluated in course of time. The biopesticide treatments significantly (P < 0.001) reduce the BSD severity in course of time, but it is more effective for the most diluted concentration (25%). The number of leaves increases in course of time as well as the rank of the YSL and the YNL confirming the efficiency of BSD control. The efficacy of this biopesticide base on <em>Tithonia diversifolia</em> could be a hopeful ecoresponsible solution for the plantain sector in general and in particular for poor small farmers.
文摘Cowpea, Vigna unguiculata L. Walp, is an important food grain legume in Niger facing production losses due to insect pests. This study aims to determine the efficiency of non-chemical methods for managing these pests. A trial was conducted during the 2020 and 2022 cropping seasons at the INRAN station in the Maradi region. A Fischer experimental design with 6 repetitions was used to compare 4 treatments: synthetic chemical pesticide;the entomopathogenic fungus Beauveria bassiana;aqueous extracts of neem seeds, and control. Observations were carried out every three days. The cowpea pod-sucking bug, pod borer, and thrips were the main insect pests recorded. In terms of effectiveness, the synthetic pesticide was the best treatment. It reduced insect pest densities by 71.35% to 90.40% in 2020 and by 35.11% to 42.13% in 2022. Grain yields varied between treatments. Neem seed extract followed the synthetic pesticide and significantly reduced insect infestations in both years. The synthetic pesticide and neem seed extract resulted in yields 3 to 5 times higher than the control treatment in 2020. By contrast, B. bassiana 115 and neem seed extract produced similar yields in 2022. Therefore, the results of this study showed that B. bassiana 115 and neem seed extract have insecticidal potential and could be used as an ecological alternative for managing cowpea insect pests in the Sahel.
基金The research has been funded by Natural Sciences and Engineering Research Council of Canada(Grants A4984,STR 202047,SCF 192190-96 and Canada Research Chair).
文摘Introduction Unconventional alternatives such as aerobic and anaerobic effluent from starch industry contain essential nutrients for Btk active ingredient synthesis.Effluent from starch industry is rich in carbon and nitrogen and can replace expensive feedstock used during the fermentation process.Objectives The main objective of this study was to achieve a biopesticide formulation from starch industry wastewater(SIW)with high entomotoxicity(UI/ml)of larvae comparable to Foray 76B,which is a commercial biopesticide.Methods Bacillus thuringiensis var kurstaki HD1(Btk)strain was cultivated and sub-cultured to aerobic,anaerobic digested effluent and SIW.Pre-treatment was carried on these different substrates to enhance the residual carbon required for Btk growth and delta endotoxin synthesis.After 48 hours of fermentation,cells count and delta-endotoxin were determined.A biopesticide formulation containing fermented broth and adjuvants was fed to larvae to determine larvae mortality.Results Btk cell growth and sporulation profile in SIW media displayed a high total cell count and viable spores compared to btk growth in anaerobic or aerobic media after 48h fermentation.The maximum endotoxin concentration in the SIW medium was 435μg/mL,whereas,in anaerobic and aerobic effluent,the maximum concentrations were at 161μg/mL and 136μg/mL,respectively.When acidic treatment was performed at pH 2 for these substrates,entomotoxicity obtained from aerobic and anaerobic biopesticide formulations displayed significantly higher entomoxicity than the untreated ones.The entomotoxicity of SIW treated at pH 2 was equivalent to the standard Foray 76B which is 20,000 IU/μL.Conclusion Anaerobic and aerobic effluent did not contain enough total organic carbon to augment Btk growth and entomo-toxicity.Substrates pre-treated at pH 2 provided significant organic matter for Btk growth and resulted in larval mortality equivalent to the com ercial biopesticide Foray 76B.
文摘Biopesticides are attracting interest as alternatives to conventional pesticides but without many of the non-target effects, promising a better record of safety and sustainability in pest control practices. In this article we summarize and discuss the current status and future promise of biopesticides, including how biopesticides use may increase the quality and safety of the food supply.
基金the National Natural Science Foundation of China(72103188,72061147002,71974220)the Social Science Foundation of Beijing(21JCC100)+1 种基金the National Social Science Foundation of China(18ZDA074)the 2115 Talent Development Program of China Agricultural University.
文摘Excessive application of mineral fertilizers and synthetic pesticides poses a substantial threat to the soil and water environment and food security.Organic fertilizer and biopesticides have gradually become essential technology for reducing mineral fertilizer and pesticide inputs.In the process,the technical environment is critical for promoting farmer behavior related to the adoption of organic fertilizer and biopesticides.This paper analyzes the influence of the technical environment on farmer behavior related to the adoption of organic fertilizer and biopesticides based on a survey of 1282 farmers in Heilongjiang Province,China,using the bivariate probit model.The results indicate that(1)farmer behavior related to the adoption applying organic fertilizer and biopesticides were positively correlated;(2)the technical environment had a significant positive impact on farmer behavior related to the adoption of organic fertilizer and biopesticides;and(3)the technical environment had a heterogeneous effect across different groups of farmers.This research provides insights useful for promoting organic fertilizer and biopesticides to farmers.It can be helpful to bundle relevant environmental technologies,conduct technology training for farmers and strengthen the construction of rural information networks.
文摘Plants with bioactive properties are greatly useful in preventing and controlling blood-sucking and disease-vector invertebrates, particularly in developing countries and low-income communities. Their application is a promising alternative to synthetic compounds whose use remains a health, environmental, and economic challenge. However, many are still unknown and unvalued, while others are becoming ignored and threatened. The main objective of this ethnobotanical study is to identify and characterize indigenous and locally grown plants against blood-sucking and disease-vector insects. Salient opportunities and challenges of using these plants are documented and discussed. Semi-structured interviews, using a prepared questionnaire, were conducted with 228 informants. The consensus index (CI) was calculated to analyze the reliability of the collected information. The identified 31 anti-insect plant species belong to 20 botanical families, four morphological categories, and six habitat types. They can be categorized as insecticidal plants (42% of the total), insect repellent (42% of the total), and both insecticidal and insect repellent (16% of the total). More than 54% of these are still abundant in the study area, while about 35.5% have become rare and difficultly accessible. Based on the numerical importance of related anti-insect plant species, the seven targeted blood-sucking insects range in the following decreasing order: Jiggers (16 species) > Fire Ants (9 species) > Flies (8 plants) > Mosquitoes (4 species) > Fleas (2 species) > Bedbugs (1 species) > lice (0 species). The three most commonly used plants, with the highest confirmation indices, are Tetradenia riparia (ICs = 0.712), Eucalyptus globulus subsp. maidenii (ICs = 0.302), and Solanum aculeastrum (ICs = 0.288). The antimicrobial role of many locally grown anti-insect plants and the multiple other associated valorization possibilities are ignored by most informants. Domesticating, propagating, protecting, and promoting the sustainable use of these plants would be an appropriate route for their conservation and continued availability.
文摘Aromatic plant distillation produces residues rich in phenolic compounds known to be bioactive. In this context, residues from the hydrodistillation of Mentha piperita L., Cymbopogon citratus Stapf, and Eucalyptus camaldulensis Dehnh were chemically and biologically analyzed. The ethanol percentages (70%, 50%, and 30%) were evaluated by determining antioxidant activity using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging, total phenolic content, and total flavonoid content. Antifungal activity was evaluated “in vitro” against Fusarium oxysporum, Alternaria alternata, Trametes versicolor, and Coniophora puteana using the diffusion method in malt-agar medium. Antitermite activity was also assessed against Reticulitermes flavipes using the most active extract with low ethanol concentrations (50% and 30%). The optimum ethanol concentration to extract phenolic compounds is 70% for TFC and 30% for TPC, and the antioxidant activity was 0.45 ± 0.01 mg/mL (IC50). The most active extracts were the ethanolic ones, particularly for Eucalyptus camaldulensis, presenting 100% inhibition against the mycelial growth of Coniophora puteana and Alternaria alternata at 1 mg/mL and 0.5 mg/mL, respectively. For antitermite activity, EE50 was the most effective, with a 24% termite survival rate and a degraded food supply surface of 28%. These data suggest the potential use of hydrodistillation residues for biopesticide development.
基金Supported by Circular of the Ministry of Agriculture on Approval of the First Batch of the National Demonstration Zones for Modern Agriculture(NJF[2010]22)Fundamental Research Funds for the Central Universities(XDJK2015C057,SWU114046)~~
文摘In order to mitigate the occurrence and damage of cowpea anthracnose and reduce the chemical pesticide consumption, residue and environmental pollution, the methods of forecasting, randomized block design and statistical analysis were conducted to study the control effect of biopesticide chitosan, biochemical compound Prochloraz-Chitosan and chemical pesticides difenoconazole and thifluzamide by field efficacy trials. The results showed that under serious occurrence of anthracnose in autumn greenhouse cowpea, when the 2% chJtosan AS （2 250 g/hm^2）, 46% Prochloraz-Chitosan EW （450 g/hm^2）, 10% difenoconazole WG （900 g/hm^2, CK） or 24% thifluzamide SC （360 ml/hm^2） were applied three times with an interval of 5-8 d, the control efficiency on day 7, 14 and 20 reached 83%, 78% and 73%, respectively. No significant difference was found in control efficiency among the four kinds of agents. These four kinds of agents, especially chitosan and Prochloraz-Chitosan, could be used as ideal agents for controlling anthracnose, as well as for modern agricultural demonstration zones, pollution-free agricultural products, green agricultural products and organic agricultural products,thereby meeting the develop- ment needs of ＇modern agriculture, green agriculture, organic agriculture and ecological agriculture.
文摘Currently, plant diseases and insect infestations are mainly controlled by the extraneous application of pesticides. Unfortunately, the indiscriminate use of such agrochemicals can cause ecological and environmental problems, as well as human health hazards. To obviate the potential pollution arising from the application of agrochemicals, biological control of soilborne pathogens or insect pests using antagonistic microorganisms may be employed. Certain soil bacteria, algae, fungi, plants and insects possess the unique ability to produce hydrogen cyanide(HCN), which plays an important role in the biotic interactions of those organisms. In particular, cyanogenic bacteria have been found to inhibit the growth of various pathogenic fungi, weeds, insects, termites and nematodes. Thus, the use of HCN-producing bacteria as biopesticides offers an ecofriendly approach for sustainable agriculture. The enzyme, HCN synthase,involved in the synthesis of HCN, is encoded by the hcnABC gene cluster. The biosynthetic regulation of HCN, antibiotics and fluorescent insecticidal toxins through the conserved global regulatory GacS/GacA system is elaborated in this review, including approaches that may optimize cyanogenesis for enhanced pest control. In addition, the effects of bacterially synthesized HCN on the production of indole acetic acid, antibiotics and fluorescent insecticidal toxins, 1-aminocyclopropane-1-carboxylate deaminase utilization and phosphate solubilization may result in the stimulation of plant growth. A more detailed understanding of HCN biosynthesis and regulation may help to elaborate the precise role of this compound in biotic interactions and sustainable agriculture.
基金Supported by the National Science and Technology Project in Rural Area during the"2th Five-Year Plan",China(Nos.2011AA10A203 and 2011BAD03B02-2)the National Natural Science Foundation of China(No.31201574)+3 种基金the Project of Fujian Provincial Department of Science and Technology,China(No.2011N5003)the State Key Laboratory for Biology of Plant Diseases and Insect Pests,Institute of Plant Protection,Chinese Academy of Agricultural Sciences(No.SKL2012OP05)the Talent Training Program for Distinguished Young Scholars in Universities of Fujian Province,China(No.JA12092)the Science Fund for Distinguished Young Scholars of Fujian Agriculture and Forestry University,China(No.xjq201203)
文摘Chromium(Cr) may cause losses in the yield of field plant, which is one of the favorite habitats of Bacillus thuringiensis(Bt). The purposes of our study were to assess the Cr(VI)-resistance and Cr(VI)-reducing abilities of an indigenous soil isolate of Bt and to determine the factors governing Cr(VI) reduction. Towards this end a novel dichromate-reducing Bt BRC-ZYR2, characterized with insecticidal crystal proteins(ICPs), was isolated from a uranium deposit. Minimum inhibitory concentrations(MICs) of Cr(VI) were determined by broth dilution method and the concentrations of Cr(VI) and total Cr in the supernatant were quantified colorimetrically using 1,5-diphenylcarbazide(DPC) reagent and a mixture of sulfuric-nitric acids, respectively. The isolate contained five ICP genes(cry1Ba, cry1 Bb, cry1Be/cry1 Bf, cry9 Ca and cry9Da) and exhibited a high level of Cr(VI) resistance with MICs of 150 mg L-1at pH 7.0 and 30?C, and 500 mg L-1under optimal conditions(pH 9.0 and 40?C). The total Cr concentration was similar to initial concentration of Cr(VI) under the optimal condition, suggesting that the essential removal of the Cr(VI) was dependent on Bt reduction. Under optimal conditions, the initial Cr(VI) concentrations from 25 to 75 mg L-1significantly decreased in 24 h after incubation. Addition of Mn2+, Co2+, Mo2+and Cu2+activated Bt-mediated Cr(VI) reduction, while Zn2+, Ni2+and glucose were found to inhibit the reduction. Our results indicated that this isolate could be a promising biopesticide with the potential for both insect biocontrol and Cr bioremediation in the field.
基金Supported by the China Ocean Mineral Resources Research and Development Association Project(No.DY125-15-R-01)the National Natural Science Foundation of China(Nos.30870003,31100090)
文摘Thirty-six strains of marine actinomycetes were isolated from a sample of marine sediment collected from the Yellow Sea and evaluated in terms of their inhibitory activity on the growth of Aspergillus parasiticus and the production of norsolorinic acid using dual culture plate assay and agar diffusion methods.Among them,three strains showed strong antifungal activity and were subsequently identified as Streptomyces sp.by 16 S rRNA gene sequencing analysis.The supernatant from the fermentation of the MA01 strain was extracted sequentially with chloroform and ethyl acetate,and the activities of the extracts were determined by tip culture assay.The assay results show that both extracts inhibited mycelium growth and toxin production,and the inhibitory activities of the extracts increased as their concentrations increased.The results of this study suggest that marine actinomycetes are biologically important for the control of mycotoxins,and that these bacteria could be used as novel biopesticides against mycotoxins.
