Secondary Metabolites of Entomopathogenic Fungi, Biological Alternative for the Control of Agricultural Pests and Disease: Present and Perspectives

The use of entomopathogenic fungi (EF) in recent years has been highly effective against the different orders of insects considered pests of agricultural importance and their conidia have been commonly applied, but it has been reported that these are sensitive to the environmental conditions. For this reason, biopesticides products have been formulated based on secondary metabolites, recently. These biomolecules participate as biological control agent, such as: cyclic depsipeptides, amino acids, polyketides, polyphenols and terpenoids, affecting their morphology, life cycle and insect behavior. The use of secondary metabolites of entomopathogenic fungi opens the possibility of application in a more efficient way for the control of agricultural pests in a compatible with the environment and human health;therefore, it is important to know, analyzing the type of molecules, their effects, and their different methods of application.

Parasitoid wasps as effective biological control agents

Biological control(biocontrol) is a safe, sustainable approach that takes advantage of natural enemies such as predators, parasitic insects or pathogens to manage pests in agroecosystems. Parasitoid wasps, a very large evolutionary group of hymenopteran insects, are well-known biological control agents for arthropod pests in agricultural and forest ecosystems. Here, we summarize the recent progress on the application of parasitoid wasps in biocontrol in China for the last five years. These include species diversity of parasitoid wasps, identification of dominant parasitoid wasps associated with insect pests and biocontrol practices(three types of biological control, i.e., classical, augmentative and conservation biological control) in several Chinese agroecosystems. We then treat different mass-rearing and release technologies and the commercialization of several parasitoid wasp species. We also summarize other work that may have a potential use in biocontrol, including the effect of plant volatiles on parasitoids and recent advance in the molecular mechanisms underlying the host regulation by parasitoid wasps. Future research area and applied perspectives are also discussed, noting that advances in biocontrol technologies in Chinese agriculture informs research at the global level.

Control of Lymantria dispar L. by biological agents

The experiment on control of Lymantria dispar L by using different kinds ofbiological measures, including nuclear polyhedrosis virus (NPV) of Lymantria dispar L., BtMP-342,sex-attractant as well as botanical insecticide, was carried out in the forest regions of InnerMongolia in 2003. Two concentrations (2.632x10^6 PIB ? ml^(-1) and 2.632x10^7 PIB ?ml^(-1)) of Lymantria dispar L. NPV were sprayed on the 2rd-instar-larvae of L. dispar and 70% and77.8% control effect were obtained respectively. BtMP0-342 was applied to the 3rd- and 4th-instarlarvae and the control effect was around 80%. The sex-attractant provided by Canada Pacific ForestryResearch Center also showed a good result in trapping L. dispar adults. The self-produced botanicalinsecticide, which was extracted from a kind of poisonous plant distributed in Daxing'an Mountains,China, exhibited a good control result in controlling the larvae of L. dispar, and 82% mortalitywas observed when spraying primary liquid of the botanical insecticide on the 3rd-5th-instar-larvaein lab.

Fire Blight Disease Caused by Erwinia amylovora on Rosaceae Plants in Kyrgyzstan and Biological Agents to Control This Disease

Erwinia amylovora species were isolated from the blossoms, exudates, infected fruits, leaves and bent branches of diseased apple, pear and hawthorn trees, selected in the Chy, Osh and Jalal Abad regions. Biochemical and pathogenicity tests, alongside PCR analyses, were conducted to identify the local isolates of Erwinia amylovora. The alternative antagonistic microorganisms which combat bacterium E. amylovora were tested within in vitro and in vivo conditions. The results revealed the ability of Streptomyces antagonistic bacteria to decrease fire blight severity on pear and apple trees during the first stage of the fire blight disease in leaf tissues. Streptomyces strain C1-4 suppressed E. amylovora disease symptoms in the leaf tissues and excised apple and pear shoots. The incidence of fire blight on leaves was reduced by about 70% with two applications of bacterial antagonists. Further studies at different locations in Kyrgyzstan, using large scale application, would allow for stronger recommendations to be made, including studies and recommendations on their ability to prevent disease and to use them as main components in an integrated pest management program.

Control Effects of a New Sex Pheromone Trap and Biological Agents on Sesamia inferens Walker and Argyroploce schistaceana (Snellen)

This study was conducted to explore and seek high-efficiency and safe green control techniques on sugarcane borers,promote green control of diseases and pests of sugarcane and build a resource-conserving,environmentally friendly and sustainable governance system of diseases and pests of sugarcane.A new sex pheromone trap of sugarcane borers,abamectin· Bacillus thuringiensis (Bt) and tebufenozide were selected and applied in field trials.The use of the new sex pheromone trap of sugarcane borers (6 traps/hm 2) in combination with 0.05% abamectin·10 billion active gemmae/g B.thuringiensis (Bt) WP (1.8 kg/hm 2) or new sex pheromone trap of sugarcane borers (6 traps/hm 2) in combination with 200 g/L tebufenozide SC (1.5 L/hm 2) were the best in the sugarcane production.New sex pheromone trap of sugarcane borers should be installed in early march,and biological agents were mixed with water 900 kg per hectare and sprayed evenly sugarcane plants at the beginning of April.Their control effects of dead heart rate and bored stalk rate could be more than 69.98% and 49.09%,respectively,which were superior to that of the control pesticide 3.6% bisultap GR (90 kg/hm 2).The results showed that new sex pheromone trap of sugarcane borers in combination with abamectin· B.thuringiensis (Bt) or tebufenozide was the optimum mode of green control techniques on sugarcane borers.When it was alternately or coordinately used with other technology,it could delay the emergence and development of drug resistance,and it was worthy of widespread popularization and application in sugarcane area.

The Use and Exchange of Biological Control Agents for Food and Agriculture

The report sets out to summarize the past and current situation regarding the practice of biologicalcontrol inrelationtothe use and exchange of genetic resources relevant for BCAs.It considers the twomain categories of biological control:classical and augmentative.Allowing access to BCAs for use inanother country imposes no risk of liability to the source country.Local scientific knowledge abouthabitats,fauna andflora,can be

EFFECTIVENESS COMPARISON OF BIOCONTROL AGENTS TO CONTROL FOREST PESTS

Fungi and bacteria as insecticides have been tested to control forest pests for more than ten years, they are the saine kind of biocontrol agent with the different conentrations. thesame kind of the biocontrol agent with the different origin areas, and the mixtures of the different kinds of biocontrol agents. The infection mechanism of virus was discussed. moreover. the mfluence of these biocontrol agents on the small animals was also evaluated.

Dosage Screening and Effect Evaluation of Biological Agents against Cotton Verticillium Wilt through Drip Irrigation

Drip irrigation of biological agents is an important green pathway to prevent diseases in Xinjiang cotton fields, especially soil-borne diseases. In order to clear the suitable dosage of different biological agents for controlling cotton Verticillium wilt, field split plot experiment was designed to research the control effects of Bacillus subtilis WP (15, 30 and 45 kg/hm^2), Shibeijian Trichoderma harzianum (15, 18 and 24 kg/hm^2), Yufeng“99”(15, 22.5 and 30 kg/hm^2), Zhongnonglukang (30, 45 and 60 kg/hm^2) and Athomin (45, 60 and 75 kg/hm^2) on cotton Vertillium wilt in 2016 and 2017. The disease control effect against cotton Verticillium wilt, cotton growth, cotton yield and fiber quality were compared and analyzed by biometrical method. The results showed that five biological agents significantly reduced the incidence rate and disease index of cotton Verticillium wilt, and the average control effect reached 33.50%-74.94%. The control effect of Shibeijian T. harzianum dripped at the dosage of 18 kg/hm^2 was significantly higher than that dripped at 15 and 24 kg/hm^2. There was no significant difference between different application dosages in Athomin treatment. The control effect of the remaining three agents had significantly positive correlation with application dosage. Five biological agents had obvious promotion effects on cotton growth, and the cotton height, width of the top fourth leaf, fruit branch number and boll number per plant were increased in different levels. The cotton height and width of the top fourth leaf had no obvious changes with the increase of dosage, while the fruit branch number and boll number increased with the increasing dosage. Meanwhile, these biological agents significantly advanced the maturity of cotton. Except for Athomin treatment, the cotton seed yield in other treatments showed an increasing trend and increased significantly with the increasing dosage. The cotton fiber length and fiber breaking tenacity were improved slightly, but cotton quality had not been improved conspicuously. Therefore, according to disease control effect, cotton growth and yield performance, the suitable drip dosage of biological agents were as follows: Yufeng "99" 30 kg/hm^2, Zhongnonglukang 60 kg/hm^2, B. subtilis WP 45.0 kg/hm^2, and Shibejian T. harzianum 18.0 kg/hm^2. The drip dosage of Athomin still needs to be further studied.

Physical-biological Collaborative Prevention and Control of Facility Strawberry Continuous Cropping Diseases

The aim was to develop green strawberry varieties,control soil-borne diseases from facility strawberry continuous cropping,improve the safety and quality of strawberries and promote the healthy and stable development of the strawberry industry. Based on the production practices in recent years,we summarized the physical-biological collaborative prevention and control technology for the disease of facility strawberry continuous cropping facilities,established the technical goals,the main types of soil-borne diseases,and the physical-biological collaborative control prevention and control technologies,mainly including the specific methods and technical points of solar high temperature disinfection technology and biological bacterial fertilizer（ agent） treatment technology.

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.

Rice(Oryza sativa L.)plant protection using dual biological control and plant growth-promoting agents:Current scenarios and future prospects

Various microorganisms live in association with different parts of plants and can be harmful,neutral,or beneficial to plant health.Some microbial inhabitants of plants can control plant diseases by contesting with,predating on,or antagonizing plant pathogens and by inducing systems for plant defense.A range of methods,including plant growth-promoting microorganisms(PGPMs)as biological control agents(BCAs)(BCA-PGPMs)are used for the biological management and control of plant pathogens.Some BCAs interact with plants by inducing resistance or priming plants without direct interaction with the pathogen.Other BCAs operate via nutrient competition or other mechanisms to modulate the growth conditions for the pathogen.Generally,PGPMs can be applied alone or together with other chemicals or carriers to control various crop diseases.This review highlights the effective types of BCA-PGPMs and their applications,roles,carrier based-formulations,and responses to rice(Oryza sativa L.)pathogens.Future plant disease management prospects are promising,and growers’increasing demand for BCA-PGPM products can be exploited as an effective approach to the management of plant diseases,as well as to improve yield,environmental protection,biological resources,and agricultural system sustainability.

微生物种衣剂的研制及其对玉米茎腐病的防效评价

本研究通过平板对峙、种子发芽性状和室内盆栽试验,筛选对玉米茎腐病防效优良的木霉菌株,通过助剂理化性质测定、生物相容性分析及正交试验,明确助剂种类、用量和最佳组合,研制生物种衣剂,并进行玉米茎腐病防效验证。结果表明:从实验室保存的109株木霉中,筛选到17株木霉对禾谷镰孢具有较好拮抗活性,抑制率均>70%,6株木霉菌株对苗期茎腐病的防治效果最佳,防效80.33%~85.64%。分别以筛选的棘孢木霉Tr34和非洲哈茨木霉Tr35为活性成分,10^(6)厚垣孢子数/mL,辅以黄原胶0.2%,木质素磺酸钠2%,北农成膜剂1,5%,100 mg/mL链霉素1%,制备100万孢子/mL棘孢木霉生物种衣剂(简称Tr34生物种衣剂)和100万孢子/mL非洲哈茨木霉生物种衣剂(简称Tr35生物种衣剂)。两种生物种衣剂药种质量比例分别为1:200和1:100时,对苗期茎腐病的防效最好,分别为81.14%和83.18%。本研究研制的Tr34生物种衣剂和Tr35生物种衣剂可以有效降低玉米茎腐病的发生,为进一步田间应用奠定基础。

10种药剂处理对杨梅凋萎病的防控效果评价

为有效控制杨梅凋萎病发生,减少农残,保证果品安全,在湖南省通道县杨梅基地设置4月25日和5月10日(采果前)喷施0.5%小檗碱水剂500倍液等5种药剂各1次+7月5日(采果后)30%苯甲·咪鲜胺悬浮剂3000倍液等2种药剂1次,共10个药剂组合处理,比较不同药剂处理的病枝减退率、病情指数减退率和相对防效。结果表明,不同药剂处理的杨梅凋萎病的病枝减退率为15.29%~74.07%,相对防效为22.23%~80.00%。其中,杨梅成熟前喷施0.5%小檗碱水剂500倍液2次+采果后喷施30%苯甲·咪鲜胺悬浮剂3000倍液1次处理的防控效果最佳,其病枝减退率达到74.07%,相对防效达到80.00%;杨梅成熟前喷施0.5%小檗碱水剂500倍液2次+采果后喷施40%吡醚·戊唑醇悬浮剂3000倍液,防控效果次之,其病枝减退率为65.35%、相对防效为75.56%;其他处理的相对防效均低于55%。因此,杨梅生产上推荐在杨梅成熟前喷施0.5%小檗碱水剂500倍液,采果后喷施30%苯甲·咪鲜胺3000倍液防控杨梅凋萎病,以避免杨梅果实农残超标且达到较好防控效果。

物理诱变技术在提升有益微生物拮抗香蕉真菌病原菌方面的研究进展

香蕉真菌性病害是香蕉生产中的主要病害之一,可严重阻碍香蕉产业的可持续发展。而生物防治技术,尤其是利用生防菌的策略,为该问题提供了一个可持续的解决方案。尽管生物防治具有潜在的应用前景,但生防菌在田间的有效定殖和稳定防病能力仍是挑战。本研究聚焦于物理诱变技术对生防菌的改良效果,旨在提升其对香蕉真菌性病原的拮抗能力。利用物理诱变技术对生防菌株进行诱变改良可显著提高生防菌对寄主的定殖能力和病害的防治效果。为了明确物理诱变技术对提升生防菌田间防效的作用,本文综合分析了不同物理诱变技术的类型、作用机理以及它们在提升生防菌拮抗真菌病原体中的应用。同时,文中还探讨了突变菌株筛选与鉴定的方法,并对比了各技术的优缺点。特别指出了传统物理诱变技术在控制突变方向、提高效率及稳定性方面的局限,并提出了离子束、脉冲强光和空间诱变等新型物理诱变技术的潜在优势。通过归纳现有研究和展望未来发展方向,本文旨在为物理诱变技术在增强生防菌对植物病害防治效果的应用提供理论依据,并对其在未来香蕉真菌性病害管理中的应用潜力进行展望。

不同药剂防控番茄潜叶蛾药效对比试验

为筛选出防控番茄潜叶蛾的高效、低毒、低残留的生物药剂,2022年选用6%乙基多杀菌素悬浮剂(艾绿士)、31%阿维·灭蝇胺悬浮剂、20%氯虫苯甲酰胺悬浮剂等3种生物药剂在阿克苏市进行药效试验。试验结果表明,3种生物药剂均对番茄潜叶蛾幼虫有一定防效及抑制作用。从防治效果来看,20%氯虫苯甲酰胺悬浮剂速效性、持效性、防效最高,药后14 d防效为90.32%;其次为6%乙基多杀菌素悬浮剂(艾绿士),在药后14 d持续性较好,防效81.49%。在实际生产中,建议轮换用药。

不同鲜食玉米品种鞘腐病抗病性及生防菌剂防病效果研究

为明确不同鲜食玉米品种对鞘腐病抗性、鞘腐病在玉米不同生态位叶鞘的分布特征及生防菌剂对病害的防治效果,测定了15个福建省主推玉米品种对鞘腐病的田间抗性,选用6个不同抗性水平的玉米品种为研究对象,于乳熟期调查了不同玉米品种各叶鞘的病情及9种生防菌剂处理对“上品”关键叶鞘病害的控制效果。结果表明,参试玉米对鞘腐病表现中抗、中感和感病的品种分别有5个、7个和3个。在屏南自然发病试验地和福州人工辅助接种试验地,6个玉米品种“上品(感病)”、“京科糯2000(感病)”、“天贵糯932(感病)”、“农科368(中感)”、“泰鲜甜2号(中抗)”、“闽甜986(中抗)”穗上第1叶鞘至穗下第3叶鞘平均病情指数分别为35.05、44.75、45.54和39.78,而其他叶鞘平均病情指数介于6.67~28.77之间。在屏南试验地有4个玉米品种(上品和天贵糯932除外)和福州试验地有6个玉米品种病情严重度在各生态位叶鞘上均呈显著正态性分布(P>0.05)。施用生防菌剂能明显抑制感病品种“上品”鞘腐病病情,稀释20、50倍的8×10^(9) CFU/mL枯草芽胞杆菌T122F发酵液和5×10^(9) CFU/mL解淀粉芽胞杆菌NJ-1发酵液对病害的防效分别为46.37%、44.78%和44.03%、41.06%,稀释500倍的400亿芽胞/g枯草芽胞杆菌水溶性粉剂、1000亿芽胞/g解淀粉芽胞杆菌水溶性粉剂和30亿芽胞/g甲基营养型芽胞杆菌可湿性粉剂的防病效果分别达44.25%、36.81%和46.26%,比150μg/mL的25%吡唑醚菌酯乳油防效(59.50%)和12.5%氟环唑悬浮剂的防效(54.82%)略低。表明利用生防菌剂预防玉米鞘腐病具有较好的应用前景,本研究结果为鲜食玉米病害绿色防控提供科学依据。

香蕉枯萎病4株生防菌株的诱变改良及抑菌机制初探

香蕉是我国亚热带地区重要的经济作物之一,而香蕉枯萎病的发生严重阻碍了香蕉产业的发展。生物防治技术因其绿色环保、持久抗病等特点,已成为近年来香蕉枯萎病防治的研究热点之一。防病高效、作用机制多样的生防菌株是香蕉枯萎病生物防治的重要基础。本研究通过对已获得的4株不同种类的生防菌进行紫外-亚硝酸钠复合诱变,得到了具有良好防效的诱变菌株,抑菌活性最高提升186.24%,防治效果最高提升46.54%。对得到的4株诱变株的防病机制进行了初步探究,结果表明:菌株Ba62v对香蕉枯萎病菌的菌落生长抑制率最高,同时还可以诱导香蕉苗中SOD活性;菌株Blz02v对香蕉苗具有较好的促生作用,同时可以诱导香蕉苗的POD和SOD活性;菌株Bc11v对病菌的孢子萌发抑制率最高,同时可诱导香蕉苗的PPO、CAT和SOD活性;菌株Pt05v对病菌的产孢抑制率最高,同时可诱导香蕉苗的POD、PPO和SOD活性。4株生防菌诱变株对病原菌和寄主的主要作用机制各不相同,存在复配增效的生防潜力,为今后抗病复合菌剂的开发利用提供了重要的菌株资源,具有良好的应用前景。

烟草赤星病拮抗菌的筛选及其生防机理初探

[目的]本研究以烟草赤星病菌为靶标菌,筛选对其拮抗效果较好的生防菌,并对其进行后续的鉴定,同时初步设计试验验证生防机理,为烟草赤星病的拮抗生防菌资源、拮抗菌剂的制备等提供新的参考。[方法]采用初筛复筛获得生防菌后;绘制系统发育树鉴定、抑菌谱系测定、菌株产酶活性测定、对赤星病病菌菌丝生长和孢子萌发的影响、诱抗定量检测、离体叶片防效等方法验证生防机理。[结果](1)筛得2株对于赤星病菌拮抗效果较好的生防菌,经由16S rDNA鉴定发现其分别是枯草芽孢杆菌(Bacillus subtilis)X768与贝莱斯芽孢杆菌(Bacillus velezensis)703;并完成了2株生防芽孢杆菌的抑菌谱系测定,证明其均具有抑菌广谱性;(2)对其生防机理探究过程中,菌株703具备产生纤维素酶、蛋白酶和淀粉酶的能力,菌株X768具备产生纤维素酶、蛋白酶、淀粉酶和脂肪酶的能力;2株生防芽孢杆菌均可抑制赤星病孢子的萌发和影响菌丝正常生长的形态,对于病原菌具有较强的抑制作用;(3)使用qRT-PCR法验证了生防菌对烟草防御基因通路(SA、JA、ET等通路)的影响,其中应用菌株703处理后烟草应用防御通路可能与SA通路、JA通路和泛素连接酶通路相关;而使用菌株X768处理后烟草应用防御通路可能与SA通路和泛素连接酶通路相关。[结论]筛得的具有抑制烟草赤星病作用的生防菌株B.subtilis X768与B.velezensis 703,抑菌谱较广,均可较强效果地抑制赤星病孢子的萌发和菌丝生长,并且2株生防菌均可引起烟草防御基因通路的上调,离体叶片防效效果较好。

尖孢镰刀菌的应用研究进展

尖孢镰刀菌是一种重要的真菌资源,对其在农业、工业生产、食品安全和人类健康等方面的研究与应用具有重要意义。在农业方面,尖孢镰刀菌主要用于生物防控植物病害和杂草、农药研发及植物促生长等研究;在工业方面,尖孢镰刀菌主要用于生产有机酸、酶及其他代谢产物,还可用于工业污染处理及食品安全等研究。近年来针对尖孢镰刀菌应用的研究日益增多,本文综述了尖孢镰刀菌在多领域的应用研究进展,为促进之后实际生产中尖孢镰刀菌的应用提供思路。

生防芽孢杆菌种子处理剂WS20的研制及对甘蓝枯萎病的防治效果

生防芽孢杆菌类微生物制剂能有效控制植物病害。本研究以具有生防潜力的萎缩芽孢杆菌ZY1825菌株发酵液为包衣种子处理剂活性成分,以甘蓝枯萎病病原菌尖孢镰刀菌为指示菌,采用单因素、正交、平板对峙试验和稀释平板计数法,明确了拮抗抑菌效果和生防菌活菌含量,通过对分散剂、成膜剂、稳定剂、防冻剂等助剂的筛选,确定了混合助剂最优配方为:木质素磺酸钠4.00%、羧甲基纤维素0.25%、膨润土1.00%、乙二醇0.50%、大红染料2.00%(均为质量分数)。生防芽孢杆菌种子处理剂WS20配方为:萎缩芽孢杆菌发酵液(9.28×109cfu/mL)与混合助剂体积比为2:1,成膜时间1.45 min,包衣均匀度93.06%,货架期可达150 d,热储和低温稳定性等指标均符合种子处理悬浮剂及微生物制剂的国家相关标准。采用WS20种子处理剂按药种质量比1:30包衣甘蓝种子,对甘蓝枯萎病的盆栽防效达64.94%。研究结果可为芽孢杆菌类生防种子处理剂制备和土传性病害生物防治提供参考。