Advance of entomopathogenic nematodes

This paper summarized the history and present condition of studying and utilizing entomopathogenic nematodes at home and abroad, expounded its taxonomy, life cycle and the mechanism with symbiotic bacteria killing host insect. Taxonomy, mycelial form, pathogenic function and anti-bacteria function of symbiotic bacteria were introduced. Production and utilization of entomopathogenic nematodes, the characteristic genetic improvement by use of biological engineering technology, as well as the existing problem and applying foreground were also discussed.

Interactions between Entomopathogenic Nematodes and Entomophagous Insects

The objective of this review article is to clarify the different interactions between entomopathogenic nematodes, as bio-control agents, against other bio-control agents (parasitoids and predators) proposed by the researchers. Thus, it gives clear information concerning the potential of combining them as a part of Integrated Pest Management (IPM) programs against insect pests. Some laboratory studies showed that the treatment of predacious insects by entomopathogenic nematodes (EPNs) at different concentrations can infect and kill the treated larva, nymphs and adults of predators. The percentages of mortality were found to be high (up to 100%), moderate (15% - 35%) or low (3% - 7%). Other studies revealed the resistant of treated predators to nematode-infection. Some predators that were offered infected prey avoid feeding on such prey and, in contrast, the soil predators (ants and mites) consumed the offered cadavers as well as the infective juvenile of the nematodes and did not show any detrimental effects. Mostly, parasitoids cannot complete their development inside or on nematode-infected hosts if parasitism occurs before or early after infection. The parasitoid females may avoid laying eggs in the infected hosts or cannot discriminate between healthy and infected hosts. A field study demonstrated that applying EPNs combined with the predator, Labidura riparia significantly reduced the population of the target pest compared to the nematode or the predator alone. Also, two field experiments indicated that the combination of parasitoids and nematodes can be successful for insect pest management.

Susceptibility of Economic Dipteran Fruit Flies to Entomopathogenic Nematodes

The present review article demonstrates laboratory and field evaluations of entomopathogenic nematodes(EPNs)against different developmental stages of fruit flies.The virulence of the EPNs differed clearly even on the same insect species and/or by the same nematode species.Such differences might be attributed to some reasons such as the method of treatment as well as the concentrations of the tested nematodes.Fruit flies are among the most important insect pests infesting vegetables and fruits causing considerable losses in the yields worldwide.In laboratory studies,the tested nematodes proved to be highly virulent to larvae as percentage of mortality may reach 100%.As for treated pupae,at different ages,the results are variable and controversially;some studies revealed their moderate or high susceptibility to nematode infection and others indicated low susceptibility or resistance to infection.Treated adults,or those emerged from treated larvae or pupae,are also susceptible to infection.In semi-field and field trials,EPNs proved to be successful for reducing the populations of some fruit flies with up to 85%at concentrations not less than 100 infective juveniles(IJs)/cm^2 of soil.However,the field applications of commercial EPNs have been recommended to be 2.5-5 x 10^9 IJs/ha(25-50 IJs/cm^2 of soil).

Pathogenicity of bacterium, Xenorhabdus nematophila isolated from entomopathogenic nematode (Steinernema carpocapsae) and its secretion against Galleria mellonella larvae

The entomopathogenic bacterium, Xenorhabdus nematophila was isolated from the hemolymph of Galleria mel- lonella infected with Steinernema carpocapsae. The bacterial cells and its metabolic secretions have been found lethal to the Galleria larvae. Toxic secretion in broth caused 95% mortality within 4 d of application whereas the bacterial cells caused 93% mortality after 6 d. When filter and sand substrates were compared, the later one was observed as appropriate. Similarly, bacterial cells and secretion in broth were more effective at 14% moisture and 25 °C temperature treatments. Maximum insect mortality (100%) was observed when bacterial concentration of 4×106 cells/ml was used. Similarly, maximum bacterial cells in broth (95%) were penetrated into the insect body within 2 h of their application. However, when stored bacterial toxic secretion was applied to the insects its efficacy declined. On the other hand, when the same toxic secretion was dried and then dissolved either in broth or water was proved to be effective. The present study showed that the bacterium, X. nematophila or its toxic secretion can be used as an important component of integrated pest management against Galleria.

Microbial control of diamondback moth, Plutella xylostella L. （Lepidoptera： Yponomeutidae） using bacteria （Xenorhabdus nematophila） and its metabolites from the entomopathogenic nematode Steinernema carpocapsae

Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X.nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage.

A comparative analysis of entomoparasitic nematodes <i>Heterorhabditis bacteriophora</i>and <i>Steinernema carpocapsae</i>

Heterorhabditis bacteriophora and Steinernema carpocapsae are microscopic entomoparasitic nematodes (EPNs) that are attractive, organic alternatives for controlling a wide range of crop insect pests. EPNs evolved with parasitic adaptations that enable them to “feast” upon insect hosts. The infective juvenile, a non-feeding, developmentally arrested nematode stage, is destined to seek out insect hosts and initiates parasitism. After an insect host is located, EPNs enter the insect body through natural openings or by cuticle penetration. Upon access to the insect hemolymph, bacterial symbionts (Photorhabdus luminescens for H. bacteriophora and Xenorhabdus nematophila for S. carpocapsae) are regurgitated from the nematode gut and rapidly proliferate. During population growth, bacterial symbionts secrete numerous toxins and degradative enzymes that exterminate and bioconvert the host insect. During development and reproduction, EPNs obtain their nutrition by feeding upon both the bioconverted host and proliferated symbiont. Throughout the EPN life cycle, similar characteristics are seen. In general, EPNs are analogous to each other by the fact that their life cycle consists of five stages of development. Furthermore, reproduction is much more complex and varies between genera and species. In other words, infective juveniles of S. carpocapsae are destined to become males and females, whereas H. bacteriophora develop into hermaphrodites that produce subsequent generations of males and females. Other differences include insect host range, population growth rates, specificity of bacterial phase variants, etc. This review attempts to compare EPNs, their bacterial counterparts and symbiotic relationships for further enhancement of mass producing EPNs in liquid media.

Biocontrol potential of entomopathogenic nematode,Heterorhabditis indica against pink bollworm,Pectinophora gossypiella(Saunders)(Lepidoptera:Gelechiidae)

Background The emergence of pink bollworm(PBW),Pectinophora gossypiella(Saunders)(Lepidoptera:Gelechiidae),in cotton due to Bt resistance and concealed feeding habit has created a need for alternative,eco-friendly,and cost-effective control methods.This study aimed to evaluate the bio-efficacy and reproductive potential of two native strains of entomopathogenic nematodes(EPNs),Heterorhabditis indica,namely CICR-HI-CL and CICR-HI-MN,against PBW larvae and pupae under in-vitro conditions.Results The larval assay revealed that strain CICR-HI-CL exhibited higher potency than strain CICR-HI-MN against 2nd,3rd,and 4thinstar larvae,with median lethal dose(LD50)values of 5.45,4.45,and 4.60 infective juveniles(IJs)per larva,respectively.In case of pupal bioassay,both EPN strains demonstrated greater virulence when applied directly(LD50values:29.65 and 73.88 IJs per pupa for strains CICR-HI-CL and CICR-HI-MN,respectively)compared to soil application(147.84 and 272.38 IJs per pupa).Both EPN strains successfully penetrated and reproduced on 4thinstar larvae,resulting in maximum production of 19.28 and 20.85 lakh IJs per larva in the next generation when inoculated at 30 IJs per larva.Conclusion The present study has generated useful information on the virulence and reproductive potential of two strains of EPN H.indica(CICR-HI-CL and CICR-HI-MN)against PBW,a dreaded pest of cotton.Higher virulence and reproductive potential of EPN strains demonstrated their ability to multiply,sustain and perpetuate on larval and pupal stages of PBW.The knowledge generated will help formulate effective management strategies for PBW with the inclusion of EPN as a potential biological control candidate.The soil-dwelling life stages viz.,last instar hibernating larvae and pupae of PBW can be the ideal weak links to make a successful use of H.indica for sustainable management of PBW in the cotton ecosystem.However,before taking these EPN strains to field for managing PBW,detailed studies investigating their biocontrol potential against PBW under field conditions are needed.

昆虫病原线虫防控苹果蠹蛾的影响因素

苹果蠹蛾(Cydia pomonella L.)是一种重要的世界性害虫,目前已在我国9个省(自治区、直辖市)发现,对我国苹果、梨等果树产业构成了严重威胁。目前,化学防治仍是防控苹果蠹蛾的主要措施,化学农药大量使用导致农药残留严重超标,影响果实品质及人类健康,因此研发新的生防制品具有重要意义。昆虫病原线虫具有主动寻找寄主害虫的能力,具有生物防治苹果蠹蛾越冬幼虫的应用潜能。本文从防控苹果蠹蛾的昆虫病原线虫高效品系以及影响其防控效果的因子(温度、湿度、紫外线等)进行了综述,以期为田间有效利用昆虫病原线虫防控苹果蠹蛾提供参考。

昆虫病原线虫N-Yz1对水稻二化螟的控制作用

昆虫病原线虫N-Yz1是自二化螟罹死虫体分离的小卷蛾斯氏线虫,作为防治二化螟的生物因子具有广泛应用潜力。本文通过小卷蛾斯氏线虫N-Yz1对二化螟幼虫的侵染过程、不同龄期二化螟的感染和田间二化螟的控制作用分析,研究N-Yz1对水稻二化螟的控制作用及防治技术。结果表明,N-Yz1对二化螟具有较强的侵染活性,可以直接穿透昆虫表皮入侵虫体组织。病原线虫的迁移依赖接触表面游离水的存在,线虫个体侵染能力也表现出显著差异性,直接影响到N-Yz1的感染速度和感染效率。N-Yz1对不同龄期的二化螟都具有较高的致死活性,低龄幼虫(1~2龄)敏感性高于高龄幼虫(3~5龄)。室内模拟试验表明,水稻拔节期使用N-Yz1对二化螟防效不高,2.4×10^(5) IJs/m^(2)剂量仅为37.3%,而防治稻茬越冬代二化螟防效明显提高,N-Yz1相同剂量防效达85.2%。田间试验进一步证明,夏季稻田2.4×10^(5) IJs/m^(2)剂量N-Yz1防治二代二化螟防效21.23%,增加使用剂量可以提高控制效果;而春季稻茬田应用N-Yz1,1.2×10^(5) IJs/m^(2)剂量药后15 d防效达53.7%,45 d后高达79.1%。因此,可以针对稻茬二化螟主要繁殖虫源,采用N-Yz1防治稻桩中越冬代二化螟幼虫,显著降低害虫发生基数,控制水稻钻蛀害虫二化螟的发生和危害。

夜蛾斯氏线虫SRP 18-91共生菌代谢产物及其抑菌活性研究

为了明确夜蛾斯氏线虫SRP 18-91共生菌发酵液对植物致病菌的抑制作用,本研究采用抑制菌丝生长速率法测定夜蛾斯氏线虫SRP 18-91共生菌发酵液对5种植物致病真菌的抑制作用,试验结果表明草莓炭疽菌和大豆疫霉菌对共生菌发酵液具有较高的敏感性,其中对大豆疫霉菌的抑制率最高可达96.8%,对炭疽病菌的抑制率最高可达90.8%。温室盆栽试验结果表明,发酵液原液对大豆孢囊线虫的防治效果达61.47%。通过16S rRNA鉴定,夜蛾斯氏线虫SRP 18-91共生菌为伯氏致病杆菌;通过液相色谱-质谱联用法(LC/MS)对发酵液粗提物进行组分测定结果表明,共生菌发酵液粗提物的主要组成成分为三萜类化合物、戊酸代谢物、戊霉素、羟基喹啉和氨基酸类化合物,其中发酵48 h的共生菌发酵液粗提物中8-羟基喹啉组分丰富度最高。

昆虫病原线虫对暗黑鳃金龟的致病力

为了筛选防治暗黑鳃金龟Holotrichia parallela的优良昆虫病原线虫品系,本文通过室内生测,比较了7个昆虫病原线虫品系对暗黑鳃金龟1龄末幼虫的致病力,并明确了其最佳侵染条件。生测结果表明,不同昆虫病原线虫品系对暗黑鳃金龟1龄末幼虫均有一定的致病力,其中樱桃异小杆线虫Heterorhabditis bacteriophora(D26-6)对暗黑鳃金龟幼虫致病力最强,在处理9 d后,暗黑鳃金龟幼虫的校正死亡率达到了100%。此外,温度、土壤湿度以及线虫施用剂量对D26-6线虫的致病力均会产生一定的影响,其侵染暗黑鳃金龟幼虫的适宜温度为25℃、适宜土壤含水量为18%;当暗黑鳃金龟幼虫与D26-6线虫比为1:100时,处理11 d后暗黑鳃金龟幼虫的校正死亡率可达到100%。

对铜绿丽金龟具有高致病力的昆虫病原线虫的筛选

为筛选对铜绿丽金龟Anomala corpulenta幼虫具有生防潜力的昆虫病原线虫品系,测定了9个昆虫病原线虫品系对铜绿丽金龟1龄幼虫的致病力,以及不同施用剂量、环境温度及土壤相对湿度条件对线虫致病力的影响。生测结果表明,樱桃异小杆线虫品系Heterorhabditis beicherriana D26-6对铜绿丽金龟幼虫致病力最高,处理11 d后的校正死亡率达到了98.3%;对线虫D26-6致病力的单因子测定发现,侵染铜绿丽金龟幼虫的最佳剂量为150 IJs/头、最佳温度范围为20~30℃、最佳土壤湿度为18%,有较好的开发应用潜力。

昆虫病原线虫对红火蚁的致病力及田间防控效果

红火蚁Solenopsis invicta Buren是一种国际重大外来入侵生物,严重危害农林生产、生命健康、公共安全和生态环境。本研究在室内条件下测定了小卷蛾斯氏线虫Steinernema carpocapsae All品系、长尾斯氏线虫S.longicaudum X-7品系和芫菁夜蛾斯氏线虫S.feltiae SN品系对红火蚁的致病力,并筛选出高致病力品系及其对红火蚁的田间防控效果。结果表明,不同昆虫病原线虫对红火蚁不同虫态的致病力存在显著差异。3种线虫对红火蚁幼虫具有较高的致病力,处理3 d后,幼虫的累计校正致死率均为100%。3种线虫对工蚁的致病力均较弱,处理10 d后的校正死亡率均小于30%。与芫菁夜蛾斯氏线虫SN品系相比,长尾斯氏线虫X-7品系和小卷蛾斯氏线虫All品系对蛹和生殖蚁具有较强的致病能力,10 d后累计校正死亡率均达到90%以上。田间试验表明,施用小卷蛾斯氏线虫All品系对红火蚁工蚁的防控效果最高可达63.7%,且不会增加红火蚁的迁巢风险。综上所述,小卷蛾斯氏线虫All品系和长尾斯氏线虫X-7品系为红火蚁的高致病品系,田间施用小卷蛾斯氏线虫All品系对红火蚁工蚁具有显著的控制作用,可推荐用于红火蚁的生物防治。

昆虫病原线虫共生菌及代谢产物对根结线虫的防治作用

为探讨不同种昆虫病原线虫(EPN)共生菌对根结线虫病的防治效果,开展了温室盆栽定量接种试验;为明确EPN共生菌的代谢产物对根结线虫卵孵化和二龄幼虫活性的影响,进行了室内生测试验。结果表明,Meloidogyne incognita(M.incognita)在中蔬4号番茄上接种剂量为1000、2000和5000个卵·株^(−1)时,昆虫病原线虫共生菌Xb-IGA和Pl-IGA对M.incognita卵的繁殖均有较好的抑制效果,抑制效果为59.4%~73.9%。Meloidogyne hapla(M.hapla)在VFNT番茄上接种剂量为2000个卵·株^(−1)时,昆虫病原线虫共生菌Pl-IGA对M.hapla卵的繁殖抑制效果最好,可达74.5%,与常规药剂阿维菌素(82.2%)差异不显著。4种EPN共生菌均能有效降低M.incognita和M.hapla侵染后的发病程度,对番茄根部生长有不同程度的促进作用。在生测试验7 d时,4种昆虫病原线虫共生菌代谢产物的2倍稀释液和5倍稀释液对M.incognita和M.hapla卵孵化抑制率为55.1%~94.8%,对M.incognita二龄幼虫校正死亡率为34.2%~47.8%,对M.hapla二龄幼虫校正死亡率为59.6%~79.9%。因此,昆虫病原线虫共生菌及其代谢产物对根结线虫是非常有潜力的生物杀线虫资源。

昆虫病原线虫人工培养技术研究与应用进展

昆虫病原线虫是昆虫的专化性寄生天敌,可自主搜寻寄主、杀虫速度快、对环境友好安全,是一类重要的害虫生物防治因子,在害虫可持续治理中具有应用潜力。目前,昆虫病原线虫作为商品化的新型生物杀虫制剂在全球生产销售。然而,昆虫病原线虫的商品化需要高效的人工培养技术。由于昆虫病原线虫的专化性较强,一种成熟的商业化昆虫病原线虫人工培养技术需要根据线虫种类优化。除了优化现有技术,还需研发新的人工培养技术。本文综述了国内外昆虫病原线虫人工培养技术研究和应用的历史和现状,详细介绍了活体培养技术和离体培养技术,讨论了影响昆虫病原线虫产量的主要因素,强调了优化人工培养技术并降低培养成本的必要性。未来,随着人工培养技术的不断优化,在丰富了昆虫病原线虫商品化种类的同时,还可降低农业生产的经济损失,改良土壤环境,具有重要的经济和社会价值。

土壤修复剂协同昆虫病原线虫对黄瓜根际土壤线虫群落的影响

为探索土壤修复剂(soil amendment,SA)协同昆虫病原线虫(Heterorhabditis beicherriana)对南方结节线虫(Meloidogyne incognita)的抑制作用以及对黄瓜根际土壤生态环境的影响,以‘千秋1号’黄瓜为试验品种,采用室内盆栽试验方法,通过设置6个试验组对黄瓜根际土壤线虫群落结构、生态多样性和功能多样性等方面进行研究。结果显示,试验60 d后施入SA和昆虫病原线虫相比其他处理根结植物类寄生线虫减少,小杆属和中杆属等食细菌类线虫增多;营养类群指数和基础成分指数均有所回升,线虫通路比指数显著升高,土壤有机分解以细菌分解为主;线虫区系仍位于土壤养分较好且以细菌降解为主的A区,其他组则从A区逐渐下降到D区。研究表明,SA协同昆虫病原线虫能有效抑制南方根结线虫,同时可以提高土壤线虫的多样性,有效缓解土壤食物网结构退化的趋势。

绿原酸对昆虫病原线虫卡森斯氏线虫寿命及抗氧化活性的调控

为观察绿原酸(CGA)对昆虫病原线虫寿命及抗氧化活性的影响,探究绿原酸对线虫生命活动的调控机制,本文以卡森斯氏线虫作为抗衰老模型,用不同浓度的绿原酸(0、50、100、500、1000μmol/L)处理,探究其对卡森斯氏线虫寿命、抗氧化活性、脂褐素水平、相关基因m RNA表达水平的调控作用,初步探讨绿原酸的潜在作用机理。结果表明,与空白对照组相比,用100μmol/L绿原酸刺激线虫后使处理组最长寿命增加了36.36%,显著抑制体内脂褐素的积累;且该浓度刺激线虫体内的SOD和CAT酶活力,分别提高了1.97倍和2.47倍;此外,q RT-PCR结果显示,100μmol/L CGA喂养线虫后,daf-16、gst-4基因转录水平相比对照分别提高了1.78、3.51,而daf-2基因转录水平呈下降的趋势,降低了0.13。综上可知,绿原酸通过胰岛素/IGF-1信号通路提高昆虫病原线虫卡森斯氏线虫机体的抗氧化能力并延长昆虫病原线虫的寿命。

胰岛素对昆虫病原线虫卡森斯氏线虫0657L生长发育及其共生细菌伯氏致病杆菌0657L的影响

【目的】为探讨胰岛素对昆虫病原线虫卡森斯氏线虫Steinernema kraussei 0657L生长发育及其共生细菌的影响。【方法】吸取1.5 mL 3000头/mL的卡森斯氏线虫0657L悬浮液侵染大蜡螟Galleria mellonella 3龄幼虫,25℃培养24 h后分离卡森斯氏线虫0657L的共生细菌伯氏致病杆菌Xenorhabdus bovenii 0657L;分别用1∶500胰岛素和1∶5000胰岛素处理伯氏致病杆菌0657L后饲喂卡森斯氏线虫0657L,借助体视显微镜观测伯氏致病杆菌0657L在胰岛素处理1~6 d时的菌落直径并计算生长速率,计算卡森斯氏线虫0657L寿命、存活率、每30 s头部摆动次数和每30 s吞咽次数,评价其平均寿命、运动能力及吞咽能力。【结果】与空白对照组相比,1∶5000胰岛素和1∶500胰岛素处理组伯氏致病杆菌0657L的菌落直径在对数生长期(处理2 d时)可分别增大77.2%和54.0%,生长速率可由空白对照组的68.0μm/d分别提高至120.4和104.7μm/d;卡森斯氏线虫0657L寿命分别延长27.3%和45.5%;卡森斯氏线虫0657L 3龄幼虫每30 s头部摆动次数分别提高56.3%和74.7%,3和4龄幼虫及成虫每30 s吞咽次数分别提高50.9%和65.5%,26.8%和35.2%及23.7%和21.1%。【结论】胰岛素可以显著促进卡森斯氏线虫0657L共生细菌伯氏致病杆菌0657L单菌落的生长和提高其生长速率,能够通过伯氏致病杆菌0657L间接延长卡森斯氏线虫0657L的寿命,提高昆虫病原线虫的运动和吞咽能力。本研究结果可以为延长昆虫病原线虫商品货架期提供科学依据,为昆虫病原线虫的高效生物防治提供理论基础。

基于转录组学分析Xenorhabdus bovienii肽基脯氨酰异构酶ppia-l20基因的表达调控

[目的]前期从广谱抗菌的Xenorhabdus bovienii NN6菌株的胞外蛋白中分离出一种新型杀菌蛋白PPIA-L20,为肽基脯氨酰异构酶A类似物,该蛋白能够抑制尖孢镰刀菌西瓜专化型的孢子的萌发,致使孢子死亡。经过多次试验验证ppia-l20基因的表达水平不稳定,与发酵时间没有明显的相关性。本文旨在探寻调控ppia-l20基因表达的调控因子,进而推测ppia-l20基因表达调控的分子机制,为进一步提高抗菌蛋白的产量提供参考。[方法]对ppia-l20的转录水平进行Real-time PCR分析并与菌株生长曲线进行相关性分析,选择ppia-l20基因表达量差异显著的2个发酵时间点进行转录组学比较,并对表达差异显著的DEG(differential expressed gene)进行GO功能注释、KEGG富集通路和蛋白网络互作分析。[结果]4~84 h发酵菌体中的ppia-l20基因表达趋势不稳定,其转录水平与时间不相关。与ppia-l20低表达量的8 h发酵菌体相比,ppia-l20高表达量的12 h发酵菌体中有466个DEG,包括193个上调基因和273个下调基因。Real-time PCR验证表明基因表达差异趋势与转录组测序结果一致,证明测序结果可信。对差异表达的基因进行GO功能注释、KEGG富集分析,发现DEG的功能与膜形成相关,富集通路与双组分调节系统、磷酸转移酶系统和阳离子抗菌肽抵制通路相关。其中,双组分调节系统中的qseC基因和opmR基因表达量均上调2倍,ppia-l20基因位于阳离子抗菌肽抵制通路,该通路上的nlpE基因(负责编码外膜脂蛋白)显著下调。蛋白互作网络中,PPIA-L20蛋白与位于外膜的AMP结合蛋白TycC、GrsB有互作关系,NlpE蛋白与双组分调节系统中cpxR基因、cpxA基因表达的蛋白有互作关系。[结论]Xenorhabdus bovienii NN6菌株可能通过双组分调节系统通路、阳离子抗菌肽抵制通路上的关键基因nlpE和磷酸转移酶系统共同调控ppia-l20的表达。

昆虫病原线虫防治小白菜黄曲条跳甲的田间效果

为探索防治小白菜黄曲条跳甲的绿色防控方法,本试验比较了昆虫病原线虫、昆虫病原线虫混用化学农药及单用化学农药3种方式对小白菜黄曲条跳甲的田间效果试验。试验结果表明,每667 m^(2)采用昆虫病原线虫3亿尾防治效果好,可有效避免化学药剂安全间隔要求,确保叶菜质量安全。