Application Technology of Biocontrol Agents against Pepper Blight（ Phytophthora capsici） in Greenhouse in Qinghai Province

[ Objective ] The paper was to explore the combined application technique of organic fertilizer and two biocontrol agents against pepper blight in green- house hot pepper in Qinghai Province. [Method] By L4 （23）orthogonal design, the effects of combined application of two biocontrol agents against pepper blight and organic fertilizer on control effects against pepper blight and the yield of hot pepper were studied in greenhouse hot pepper base in Ledu County of Qinghai Province. [ Result] The effects of various factors affecting the relative control effect against pepper blight in sequence were biecontrol agent A5 〉 biecontrol agent B2 〉 organic fertilizer, and the optimal combination was organic fertilizer 1 800 kg/hm^2, agent B2 30 kg/hm^2 and agent A5 45 kg/hm^2. The effects on hot pepper yield in sequence were organic fertilizer 〉 biocontrol agent B2 〉 biocontrol agent AS, and the optimal combination was organic fertilizer 900 kg/hm^2 , agent 132 15 kg/hm^2, agent A5 22.5 kg/hm2. [ Conclusion] Combined with control effect of pepper blight and yield benefit, the application technique of biocontrol agents pro- moted in local hot pepper production could be confirmed as follows ： agent A5 45 kg/hm^2, agent B2 15 kg/hm^2, organic fertilizer 900 kg/hm^2 ; the field control effect at this moment could reach 76.31%, the yield could reach 35 573 kg/hm^2 , and the newly increased output value could be 13 029 yuan/hm^2 with input and output ratio of 1： 7.9.

Biocontrol of Strawberry Anthracnose Caused by Colletotrichum fragariae

[Objective] The aim was to explore biocontrol approaches of strawberry an-thracnose. [Method] With hyphal growth inhibition method, bacteriostatic activities of Bacil us subtilis and Osthole on strawberry anthracnose were measured and field test was carried out. [Result] The results show that both of Bacil us subtilis and Osthole were of higher bacteriostatic activity on strawberry anthracnose, and the values of EC50 were 0.007 5 mg/L and 1.063 0 ml/L, respectively. The result of field test show that the prevention effects of Bacil us subtilis （600-750 g/hm2） and 25% prochloraz （600 ml/hm2） both achieved higher than 76%, 7 and 14 d after triple medical applica-tions with rains sheltered or in open field. But the effects were of extremely signifi-cant differences with that of Osthole （1 800-2 700 ml/hm2） （P〈0.01）. [Conclusion] Bacil us subtilis can be made use of for control ing strawberry anthracnose.

Utilization of winery wastes for Trichoderma viride biocontrol agent production by solid state fermentation

Biocontrol agents are safe and environmental friendly alternatives for pesticides in agriculture application. Trichoderma viride WEBL0703 performed a high level of antagonistic activity toward a broad spectrum of phytopathogens and was determined as a biocontrol agent, which was produced by solid state fermentation using grape marc and wine lees. The maximum yield of T. viride conidia was up to 6.65 × 10^9 CFU/g initial dry substrate （IDS） after 10 d fermentation. As important enzymes for protecting plants from disease, chitinase, β-glucanase, and pectinase yields were 47.8 U/g IDS, 8.32 U/g IDS and 9.83 U/g IDS, respectively. These results show that it is feasible to convert winery wastes to a value-added and environmental friendly biocontrol agent.

Complete genome sequence of Bacillus thuringiensis Bt185, a potential soil insect biocontrol agent

Bacillus thuringiensis Bt185 and its insecticidal spectrum-expanded engineering strains are considered as potential biocontrol agents to soil insect Holotrichia parallela,Holotrichia oblita or Anomala corpulenta.Here we reported the complete genome of strain Bt185,it harbors eight plasmids,and plasmid p BT1850294 carries three cry8 genes.

Evaluation of agro-based waste substrates for micropropagule formation in biocontrol fungi,Trichoderma asperellum and T.harzianum

Trichoderma species have shown efficiency on biocontrol of phytopathogens.For commercial application,it must be propagated in mass scale using a cost-effective method.As an alternative way to effectively deliver biocontrol fungi inoculum to the field;seven agro-based wastes including rice bran,biochar,empty fruit bunches,coconut fibre,compost,topsoil and mixed soil were used in this study for evaluating mass multiplication of Trichoderma species.Based on the evaluation of colony-forming units(cfu)among the agro-based waste media used,coconut fibre is the most suitable in promoting the sporulation of Trichoderma asperellum and T.harzianum.Trichoderma asperellum C1667 showed the higher micropropagule count through incubation period compared to T.harzianum C1675.After 120 days on the agro-based waste media,T.asperellum C1667 and T.harzianum C1675 produced the highest(7.717×10^(5)cfu/g and 6.836±13.79×10^(5)cfu/g)coconut fibres,respectively.Meanwhile,the mixed soil appeared with the lowest cfu.Coconut fibres were shown as a great biocomposting medium for both Trichoderma species.Findings of the present study are valuable for disease management using agro-based wastes as a cost-effective medium for biocontrol agents like Trichoderma species.

Metabolites Composition of Bacillus subtilis HussainT-AMU Determined by LC-MS and Their Effect on Fusarium Dry Rot of Potato Seed Tuber

Fusarium dry rot is considered to be the most critical soilborne and postharvest disease that damages potato tubers worldwide when they are stored for a long time.This study was performed to demonstrate the effect of crude extract,culture filtrate,and cell suspension obtained from the bacterium Bacillus subtilis Hussain T-AMU,on the net house and field.From oil-contaminated soil,through the serial dilution method,biosurfactant bacteria were isolated on nutrient agar medium.To isolate and screen the prospective biosurfactant strain,various biosurfactant screening methods were used.Standard protocols were carried out for morphological,molecular,and chemical characterization.The disease incidences were significantly decreased under net house and field conditions after treatment with biosurfactant extract(20%,70%),culture filtrate(23%,49%),and bacterial cell suspension(46%,27%),respectively.These results indicate a significant effect of B.subtilis HussainT-AMU against Fusarium oxysporum.The characterization of the partially purified extract by gas-chromatography indicated the existence of a high amount of methyl ester fatty acids.The quantitative analysis determined the presence of lipopeptide-surfactin,fengycin,and iturin in the biosurfactant extract.Scanning electron microscopy revealed that morphological variation was revealed in the structure of stomata size in leaves and in the mycelia of the pathogen that was investigated.This promising biocontrol agent can be a plausible option for further research and can also be used for the production of green biomolecules at an additional industrial level.

A Systematic Review of Terrestrial Plant Invasion Mechanisms Mediated by Microbes and Restoration Implications

Terrestrial invasive plant species continue to wreak havoc on a global economic and ecological scale. With the advent of climate change and pending future catastrophes, the spread of resilient invasive plants will only increase exponentially. Here, the search continues for a better understanding of the below-ground microbially driven mechanisms involved in plant invasion where other above-ground mechanisms have been exhausted. Microbes govern the world around us and interact with every living and non-living facet of the world. To reinforce the important underpinnings of the role of microorganisms in plant invasion, a systematic review of recently published articles was undertaken. Using the ScienceDirect database, five (5) search queries were used to generate 1221 research articles. After a two-step reduction was made based on relevance of the articles, a final total of 59 articles were retrieved. An additional 18 relevant articles were also assessed through the PubMed database for analysis to account for other invasive plants. Thirty-seven (37) invasive species were investigated where soil physiochemical and microbial community structure changes were most prevalent (32% & 39% respectively) while enhanced mutualism, allelopathy and pathogen accumulation were reported less (16%, 10% & 3% respectively). In all invasive species assessed, the impact on plant invasion and inability of the native plants to compete was due to specific microbial associations of the invasive plant or disruption of the soil microbial community. This microbial community shift coincided with changes in physiochemical properties of the soil and the subsequent negative soil feedback for native plants. There is still an expanding potential for the use of biocontrol agents to aid restoration once the underpinnings of biotic resistance and enemy release are understood in a microbial and physiochemical context. The active and functional microbial community structure of the invasive plant rhizosphere and adjacent soil in its native and non-native region can offer a better inference of how they can be controlled using novel-below ground biocontrol methods.

Soil Fungal Community Structure Changes in Response to Different Long-Term Fertilization Treatments in a Greenhouse Tomato Monocropping System

Greenhouse vegetable cultivation(GVC)is an example of intensive agriculture aiming to increase crop yields by extending cultivation seasons and intensifying agricultural input.Compared with cropland,studies on the effects of farming management regimes on soil microorganisms of the GVC system are rare,and our knowledge is limited.In the present study,we assessed the impacts of different long-term fertilization regimes on soil fungal community structure changes in a greenhouse that has been applied in tomato(Solanum lycopersicum L.)cultivation for 11 consecutive years.Results showed that,when taking the non-fertilizer treatment of CK as a benchmark,both treatments of Conventional chemical N(CN)and Organic amendment only(MNS)significantly decreased the fungal richness by 16%–17%,while the Conventional chemical N and straw management(CNS)restored soil biodiversity at the same level.Saprotroph and pathotroph were the major trophic modes,and the abundance of the pathotroph fungi in treatment of CNS was significantly lower than those in CK and CN soils.The CNS treatment has significantly altered the fungal composition of the consecutive cropping soils by reducing the pathogens,e.g.,Trichothecium and Lecanicillium,and enriching the plant-beneficial,e.g.,Schizothecium.The CNS treatment is of crucial importance for sustainable development of the GVC system.

Microalgal bioinoculants for sustainable agriculture and their interactions with soil biotic and abiotic components:A review

Modern agricultural practices have posed a detrimental impact on the environment due to their intensive use to meet the food demands of an ever-increasing population.In this context,microalgal bioinoculants,specifically cyanobacteria and green microalgae,have emerged as sustainable options for agricultural practices to improve soil organic carbon,nutrient availability,microbial quality,and plant productivity.An overview of current and future perspectives on the use of microalgal bioinoculants in agriculture practices is presented in this review,along with a discussion of their interactions with soil biotic and abiotic factors that affect soil fertility,plant health,and crop productivity.The benefits of microalgal bioinoculants include releasing agronomically important metabolites(exopolymers and phytohormones)as well as solubilizing soil nutrients.Furthermore,they function as biocontrol agents against soil-borne pathogens and facilitate the establishment of rhizosphere communities of agricultural importance.So far,very few studies have explored the basic mechanisms by which microalgal bioinoculants interact with soil biotic and abiotic factors.In recent years,advanced molecular techniques have contributed to a better understanding of these interactions.

Production of a newly isolated Paenibacillus polymyxa biocontrol agent using monosodium glutamate wastewater and potato wastewater

A phyllosphere bacterial strain EBL-06 was isolated from wheat leaves. The morphology, cultural characteristics, phospholipid fatty acids, physiological and antagonistic fungus activities of this strain were investigated. A phylogenetic tree was constructed by comparing with the published 16S rDNA sequences of the relevant bacteria. The results showed that the isolate EBL-06 was a strain of Paenibacillus polymyxa; this strain performed a high level of antagonistic fungus activity toward a broad spectrum of phytopathogens, such as Botrytis cinerea, Cladosporium cucumerinum, Fusarium spp. The isolate EBL-06 can grow well using monosodium glutamate wastewater （MGW） and potato wastewater （PW） as culture medium. The maximum yield of 6.5 × 10^9 CFU/mL of the isolate EBL-06 anti-fungus biocontrol agent was reached in 15 hr cultivation at 28℃, pH 6.0-7.5 using the mixture of MGW and PW （1：9）.

Actinobacteria-enhanced plant growth, nutrient acquisition, and crop protection:Advances in soil, plant, and microbial multifactorial interactions

Agricultural areas of land are deteriorating every day owing to population increase, rapid urbanization, and industrialization. To feed today’s huge populations, increased crop production is required from smaller areas, which warrants the continuous application of high doses of inorganic fertilizers to agricultural land. These cause damage to soil health and, therefore, nutrient imbalance conditions in arable soils. Under these conditions, the benefits of microbial inoculants (such as Actinobacteria) as replacements for harmful chemicals and promoting ecofriendly sustainable farming practices have been made clear through recent technological advances. There are multifunctional traits involved in the production of different types of bioactive compounds responsible for plant growth promotion, and the biocontrol of phytopathogens has reduced the use of chemical fertilizers and pesticides. There are some well-known groups of nitrogen-fixing Actinobacteria, such as Frankia, which undergo mutualism with plants and offer enhanced symbiotic trade-offs.In addition to nitrogen fixation, increasing availability of major plant nutrients in soil due to the solubilization of immobilized forms of phosphorus and potassium compounds, production of phytohormones, such as indole-3-acetic acid, indole-3-pyruvic acid, gibberellins, and cytokinins, improving organic matter decomposition by releasing cellulases, xylanase, glucanases, lipases, and proteases, and suppression of soil-borne pathogens by the production of siderophores, ammonia, hydrogen cyanide, and chitinase are important features of Actinobacteria useful for combating biotic and abiotic stresses in plants.The positive influence of Actinobacteria on soil fertility and plant health has motivated us to compile this review of important findings associated with sustaining plant productivity in the long run.

Hydrogen cyanide production by soil bacteria: Biological control of pests and promotion of plant growth in sustainable agriculture

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.

A new species of Anastatus(Hymenoptera:Eulpelmidae) from China,parasitizing eggs of Lycorma delicatula(Homoptera:Fulgoridae)

A new species of Anastatus Motschulsky, 1859 （Hymenoptera： Eupelmidae）, A. orientalis Yang ＆ Choi, sp. nov. is described from China. It is a solitary endo-parasitoid in egg of the spotted lanternfly, Lycorma delicatula （White） （Homoptera： Fulgoridae）, which causes damages to many ornamental and fruit trees in China. The brief biology of the new parasitoid is also mentioned. The new species has high potential as a biocontrol agent for suppression of the pest because of its parasitism rates of egg masses 30.4% and of eggs 40.2% respectively with sex ratio of female to male 1.9：1.0, as well as the relative easiness for mass rearing. The detailed feature characters and photos of the new species are supplied. Meanwhile, a key to distinguish the present new species from the other close two （A. japonicus and A. bifasciatus） in the genus is provided. Type specimens are deposited in the Insect Museum, Chinese Academy of Forestry, Beijing, China.

Singing on the wings! Male wing fanning performances affect female willingness to copulate in the aphid parasitoid Lysiphlebus testaceipes （Hymenoptera： Braconidae： Aphidiinae）

Lysiphlebus testaceipes （Hymenoptera： Braconidae： Aphidiinae） is a generalist endoparasitoid attacking more than 100 aphid species. In L. testaceipes, wing fanning is a main male courtship display evoked by a female-borne sex pheromone. However, no information is available on the characteristics and behavioral role of male fanning during courtship in this parasitoid. Here, the courtship behavior of a wild strain ofL. testaceipes was quantified and the male wing fanning performances were analyzed through high-speed video recordings and examined in relation to mating success. Courtship sequence of wild L. testaceipes did not substantially differ from that previously reported for other populations mass reared on aphids. We observed that the male courtship duration did not affect mating success. However, video analysis revealed that the males producing high-frequency fanning signals achieved higher mating success over those that display low-frequency fanning. Wing fanning before successful and unsuccessful courtship differed in amplitude of wing movements and alignment toward the mate, highlighting that frontal courtship positively influence the female mating decisions. This study increases knowledge on sexual behavior in a key parasitoid of aphids, highlighting the importance of wing fanning among the range of sensory modalities used in the sexual communication ofL. testaceipes. From a practical point of view, this information is useful in L. testaceipes-based biocontrol strategies, since it can help to establish parameters for quality checking of mass-reared wasps over time.

The endoparasitoid Psyllaephagus arenarius benefits from ectoparasitic venom via multiparasitism with the ectoparasitoid Tamarixia lyciumi

As solitary nymphal parasitoids of Pamtrioza sinica,the ectoparasitoid Tamarixia lyciumi and the endoparasitoid Psyllaephagus arenarius act as effective biocontrol agents.Thus,it is necessary to facilitate mass productions of both species.Despite showing an excellent parasitic ability,Ps.arenarius is often trapped fatally inside 5th-instar nymphs of Pa.sinica due to strong host immunity.To improve the emergence rate of Ps.arenarius,we evaluated whether Ps.arenarius could utilize T.lyciumi venom via multiparasitism,so the parasitism characteristics of both species were examined between separate-existence(monoparasitism only)and co-existence(mono-and multiparasitism)systems.Further,the parasitism characteristics of Ps.arenarius on venom-injected hosts with/without T.lyciumi eggs were tested to further identify the facilitator.The results showed the parasitism rate of T.lyciumi was increased while that of Ps.arenarius did not change from separate-existence to co-existence systems.The intrinsic performances of two species in monoparasitism did not differ between separate-and co-existence systems.From monoparasitism(separate-existence)to multiparasitism(co-existence),no differences were detected in the intrinsic performances of T.lyciumi,but those of Ps.arenarius were greatly improved.After T.lyciumi venom injection,the parasitism characteristics of Ps.arenarius did not differ between venom-injected hosts with T.lyciumi eggs and those without,further indicating Ps.arenarius benefited from the venom of T.lyciumi females rather than T.lyciumi egg/larval secretions.Instead of negative effects,multiparasitism with ectoparasitoids improves endoparasitoids due to ectoparasitic venom.The study increases host resource utilization and provides creative ways for mass production of endoparasitoids.

Seed priming with Pseudomonas putida isolated from rhizosphere triggers innate resistance against Fusarium wilt in tomato through pathogenesis-related protein activation and phenylpropanoid pathway

Pathogenesis-related(PR)proteins are one of the major and preliminary proteins accumulated as a defense against biotic stress.This defense response can be induced by using beneficial rhizobacteria,which has been studied in various host-pathogen interactions.In the present study,eleven Pseudomonas isolates were assessed for their potential to ferment sorbitol,reduce nitrate,and produce mycolytic enzymes,1-aminocyclopropane-l-carboxylic acid(ACC)deaminase,phenazine antibiotics,and N-acyl homoserine lactones(AHLs).All isolates were tested against the host-specific pathogen Fusarium oxysporum MTCC1755 in tomato under greenhouse conditions,and shortlisted isolates were tested for their rhizosphere competence.In-vitro test results showed that the isolates were able to produce mycolytic enzymes,including protease,lipase,chitinase,cellulase,and amylase,and the antibiotic phenazine and were negative for pyoluteorin.All the isolates except two were positive for ACC deaminase production.Greenhouse results showed that the isolates M80,M96,and T109 significantly reduced symptoms of Fusarium wilt.Extended greenhouse tests under autoclaved and unautoclaved soil conditions showed that M80,M96,and T109 were excellent rhizosphere competitors and were identified as Pseudomonas putida.In brief,the defense-specific biochemical variations in the host could describe the improved defense against Fusarium wilt occurring in the primed plants.These three Pseudomonas strains could be used as potential biocontrol agents,along with their rhizosphere competence.