Searchlight trapping reveals seasonal cross-ocean migration of fall armyworm over the South China Sea

The fall armyworm(FAW), Spodoptera frugiperda, is a migratory noctuid pest that has recently invaded eastern Asia. From 2017 up till 2020, searchlight trapping was used to assess the extent of FAW migration across the South China Sea. Molecular and morphology-based identification confirmed that FAW made its first appearance on Yongxing Island on 11 April 2019, with most trapped individuals belonging to the S. frugiperda "corn-strain". Carbon isotope analysis further showed that FAW moths originated from C4 host plants, while trajectory analyses revealed that migratory S. frugiperda adults are able to cross the South China Sea and enter mainland China. This long-distance migration process plausibly results in frequent genetic mixing between domestic FAW populations and those of neighboring Southeast Asian countries. Overall, this work provides unique insights into FAW migration across eastern Asia and ultimately can help advance pest forecasting, risk assessment and area-wide pest management.     

Ovipositional responses of Spodoptera frugiperda on host plants provide a basis for using Bt-transgenic maize as trap crop in China

Spodoptera frugiperda, the pest fall armyworm(FAW), is widespread in more than 100 countries. To date, planting insectresistant transgenic crops is one of the main control methods in its native countries. In this study we evaluated Bt-transgenic maize(Bt maize) and non-transgenic(conventional) maize and six other host plants in greenhouse pot experiments and field trials for oviposition preference by the Chinese populations of FAW. In laboratory trials, female moths preferred to oviposit on maize with no significant preference between conventional and Bt maize. However, after conventional and transgenic maize were exposed to FAW larvae and damaged, oviposition was significantly higher on transgenic maize than on the conventional one. Field trials showed that for plants less damaged at an early stage(seedling stage), oviposition of FAW on transgenic and conventional maize was significantly higher than that on wheat, sorghum, foxtail millet, peanut and soybean while showing no significant difference between transgenic or conventional maize. FAW adults mainly laid eggs on Bt maize, while the larval density and leaf damage rating or percentage of damaged plants were significantly lower than on conventional maize. Larval density and its damage on conventional maize were significantly higher than that on Bt maize and the other five hosts. Thus, maize is a highly preferred and suitable host for S. frugiperda feeding and ovipositing, and Bt maize can be used as trap crop to protect other crops.     

Migration of invasive Spodoptera frugiperda(Lepidoptera: Noctuidae) across the Bohai Sea in northern China

The fall armyworm(FAW), Spodoptera frugiperda(J. E. Smith), is an important agricultural pest with a strong migratory ability. While the species is native to the Americas, it has recently invaded China, ravaging crops in many provinces(autonomous regions, municipalities). Its long-distance migration, which is critical to understand for pest management programs, has been well studied in its native region. In other regions however, the moth's migration patterns have not yet been characterized. Here, the migratory behavior of FAW populations in China was studied on an isolated island located in the center of the Bohai Strait from spring to autumn 2019, the year in which FAW first reached this region, by using searchlight trapping, stable carbon isotopes and trajectory simulation. The main results were summarized as follows:(i) The number of FAW moths caught by searchlight trapping provided direct evidence that the species migrated across the Bohai Sea.(ii) Species identification was confirmed by both morphology and molecular methods, and only the "corn-strain" that preferentially infests maize and sorghum was found in the collections.(iii) Stable carbon isotope measurements showed that up to 95.07% of captured moths displayed the C4 isotope signature, thus providing additional evidence that this species is a migrant as there are no major C4 plants at the trapping site.(iv) Backward trajectory analysis indicated that the pest now threatens to expand its range into the agriculturally important region of Northeast China, and thus authorities in this region should be vigilant to the threat posed by this species. Together, these findings add to our knowledge concerning the occurrence of FAW in northern China, and will help us to develop sustainable and effective monitoring, forecasting, and pest management strategies.     

棉铃虫成虫不同性比结构对繁殖力的影响

[目的]为棉铃虫的综合治理和预测预报提供依据和参考。[方法]在室内将棉铃虫雌、雄蛾按单倍性比和双倍性比设置10个处理,研究棉铃虫成虫不同性比结构对繁殖力的影响。[结果]随着性比结构中雄蛾比例的增加,产卵前期缩短,产卵期增长,雌蛾寿命延长,卵孵化率增加。不同性比结构下,单雌产卵量在786.6~922.6粒之间浮动。在同一性比结构中,卵孵化率随产卵时间的推移而增加,以产卵高峰日为最高。同一性比结构不同倍比相比,单倍性比处理的卵孵化率相对较高。[结论]不同性比结构对棉铃虫成虫的产卵前期、产卵期、成虫寿命、产卵量和卵孵化率都有一定的影响。     

性诱剂对主害代棉铃虫的诱杀效应研究

利用性诱剂诱杀江苏沿海地区三、四代棉铃虫的试验、示范结果表明 ,每 0 .1 3 4公顷棉田放置 1个诱芯盆的诱蛾效果较好且经济 ,与相同面积棉田内插放 40个树枝把的诱蛾效应比较 ,前者所诱雄蛾量增加 3 6.3 1 %～ 45 .5 9% ,雌蛾交配率下降 3 5 .64 %～ 44 .75 % ,田间落卵量降低 9.90 %～ 1 5 .0 5 % ,幼虫量减少 7.69%～ 1 2 .3 6% ,蕾铃被害量下降 4.49%。室内的性比试验证实 ,棉铃虫雌蛾的产卵量与群体中雌蛾的性比比例呈负相关     

不同性信息素和灯具诱杀烟草斜纹夜蛾·烟青虫·棉铃虫的效果和评价

[目的]探究利用性信息素和杀虫灯诱杀控制烟草害虫的效果。[方法]通过性信息素不同基质诱芯和佳多杀虫灯对云南保山腾冲烟区烟草斜纹夜蛾(Spodoptern litura)、烟青虫(Helicoverpa assulta)、棉铃虫(Helicoverpa armigera)3种害虫进行了田间诱杀对比试验,并对防治成本进行了评价。[结果]使用昆虫性信息素和杀虫灯诱杀斜纹夜蛾、棉铃虫具有一定效果,其中使用性信息素诱捕器的诱杀效果明显优于杀虫灯,性信息素中PVC基质诱芯诱杀害虫的性能优于橡胶基质诱芯,以对斜纹夜蛾的诱捕能力最强、控制作用持续、效果显著;不同放置密度、高度诱捕器对斜纹夜蛾、棉铃虫的诱杀效果有差异,悬挂高度以距离地面100～150 cm较佳;从成本控制来看,单位面积内以低密度区的成本最低,比常规用药区减少44%以上。[结论]利用性信息素和杀虫灯诱杀斜纹夜蛾、棉铃虫等害虫具有经济、安全、高效的特点,是一项绿色环保的生物物理防治技术,具有大面积推广应用前景。     

东亚飞蝗光电诱导的气吸捕集效应研究

为给蝗虫趋光捕集装置的研制提供技术支持,利用光照作用下蝗虫气吸滑移捕集试验装置,测试了蝗虫趋光气吸滑移捕集效果,分析了蝗虫趋光响应原因,探讨了蝗虫趋光气吸滑移捕集机理。结果表明：蝗虫视觉定向有效激发的光照诱导信息是蝗虫趋光响应的前提,频闪交变光照有效控制蝗虫行为取向、增强蝗虫趋光视觉敏感性及激发视觉敏锐性是其趋光响应的诱因,且蝗虫趋光视觉活性效应激发基础上,频闪交变偏振光强化蝗虫趋光视觉行为响应的敏感性,蝗虫响应偏振恒定光照的弱敏感性可通过提高光照强度来增强;6 m·s-1捕集入口负压风速气吸趋光蝗虫捕集进入的有效实现,需要蝗虫趋光敏感行为的激发,且在0～50 mm距离内增效显著,可有效激发蝗虫生物摩擦控制的趋光调控行为敏感性,加速蝗虫趋光滑移捕集行为的实现;6 m·s-1捕集入口负压风速、15°倾斜调控光照形成的偏振光可有效促使30°滑移面上蝗虫视觉敏感响应,弱化蝗虫滑移摩擦控制效应,增强趋光捕集行为调控强度,增效趋光捕集效果,相应趋光捕集率达到85%。     

棉铃虫和烟夜蛾生殖行为比较研究

在(27±1)℃,光周期14L:10D的条件下对棉铃虫(Helicoverpa armigera)和烟夜蛾(Helicoverpa assulta)的生殖行为进行了比较研究.结果表明:(1)2种夜蛾雌蛾或雄蛾的交配能力之间均无显著差异;3日龄蛾的交配率较高,6日龄前棉铃虫的交配率均显著高于烟夜蛾;不同蛾龄下烟夜蛾的交配...     

Population occurrence of the fall armyworm,Spodoptera frugiperda(Lepidoptera: Noctuidae), in the winter season of China

Fall armyworm(FAW), Spodoptera frugiperda(J.E. Smith), has become an important pest in Chinese agricultural systems since its invasion on 11 December 2018. After its establishment, FAW months in the year-round breeding region have become the main source population migrating to other areas in China. Field investigations were conducted in tropical and subtropical regions to improve understanding of its year-round breeding area in China. The results showed that FAW larval density was significantly correlated with the seasonal temperature of the location surveyed. The FAW larvae maintained a high density in the tropical area and were frequently found in sites of the south subtropical region, but were absent from the north subtropical region and the northern part of the central subtropical region. These results indicated that FAW can reproduce annually in the tropical and south subtropical regions of China, including Hainan, Taiwan and the southern area of Fujian, Guangdong, Guangxi, Guizhou, and Yunnan. Hence, great effort should be made to monitor and control FAW in the year-round breeding region to suppress the population density of this area and to reduce migration of moths into northern parts of China. This study clarifies the occurrence area of the pest in winter in China and provides much valuable information for its population forecasting and management.     

思茅松毛虫成虫肠道细菌多样性

【目的】 研究野外采集的思茅松毛虫（Dendrolimu kikuchii）成虫的肠道细菌多样性,为思茅松毛虫的防治和云南松（Pinus yunnanensis）等树木的保护奠定基础。【方法】 分别提取思茅松毛虫雄蛾和雌蛾的肠道总DNA,基于Illumina NovaSeq（PE250）平台运用高通量技术对肠道细菌16S rDNA基因V3~V4区进行测序和分析,分析雄虫和雌虫的肠道菌群的结构多样性。【结果】 从思茅松毛虫成虫中共获得1 278个操作分类单元（OTUs）,涵盖28个门75个纲173个目296个科550个属。在门水平上,雄蛾和雌蛾的优势菌为变形菌门（Proteobacteria,雌81.27%/雄81.17%）;在科水平上,雄蛾的优势菌科是鞘脂单胞菌科（Sphingomonadaceae,49.16%）和丛毛单胞菌科（Comamonadaceae,19.09%）,雌蛾的优势菌科是欧文氏菌科（Erwiniaceae,34.09%）和丛毛单胞菌科（Comamonadaceae,16.68%）;在属水平上,雄蛾的优势菌属是鞘氨醇单胞菌属（Sphingomonas,48.09%）,雌蛾的优势菌属是泛生菌属（Pantoea,31.58%）。思茅松毛虫雌蛾肠道细菌的物种多样性比雄蛾丰富。雄蛾肠道中丰度差异显著性最高的菌群为α-变形菌纲（Alphaproteobacteria）,雌蛾肠道中丰度差异显著性最高的菌群为γ-变形杆菌纲（Gammaproteobacteria）。【结论】 思茅松毛虫成虫肠道具有丰富的细菌资源。     

粘虫不同迁飞世代雄蛾对性诱反应的田间观察

本试验对田间两个不同迁飞世代粘虫成虫的性诱反应作了观察,并且同其对糖醋液的趋性进行了比较。结果表明:迁入代雄蛾对性诱剂反应强烈,迁出代雄蛾对性诱剂基本上不反应。这种现象与迁入迁出世代中雌蛾在生殖滞育上存在显著差别相对应。因此,本文提出粘虫雄蛾存在类似于雌蛾的“生殖滞育”的可能性,并指出雄性“生殖滞育”对了解迁飞机理的意义。     

Mutagenesis of odorant coreceptor Orco reveals the distinct role of olfaction between sexes in Spodoptera frugiperda

Odorant receptor (OR) is crucial for insects to detect and recognize external chemical cues closely related to their survival. The insect OR forms a heteromeric complex composed of a ligand-specific receptor and a ubiquitously odorant receptor coreceptor (Orco). This study used the CRISPR/Cas9 technique to knock out (KO) Orco and reveal its essential role in acting on OR-meditated olfactory behavior in a critical invasive agricultural pest, the fall armyworm (FAW), Spodoptera frugiperda. Electroantennogram (EAG) results suggested that the Orco mutants of both male and female moths severely reduced their electrophysiological responses to the eight tested plant volatiles and two sex pheromones. However, the Orco gene played distinct roles in mating behavior between sexes: the mating behavior was fully disrupted in mutated males but not in mutated females. The oviposition result indicated that the Orco KO females displayed reduced egg laying by 24.1% compared with the mated wild type (WT) females. Overall, these results strongly suggest that Orco is an excellent target for disrupting FAW’s normal behavior and provides a feasible pest control approach.     

Windborne migration routes of newly-emerged fall armyworm from Qinling Mountains–Huaihe River region,China

The fall armyworm(FAW, Lepidoptera: Noctuidae), Spodoptera frugiperda(J. E. Smith), invaded China in mid-December 2018; since then, it has become a great threat to Chinese agricultural production. Qinling Mountains–Huaihe River region(QM–HRR) is the transitional zone between northern and southern China, an important region for both corn and wheat production. Based on the actual occurrence of QM–HRR invaded by FAW in 2019, daily mean surface air temperature and nocturnal wind conditions at 925 hPa were examined, and migratory routes of FAW moths originated in QM–HRR were modeled by a forward-trajectory-analysis approach. The results indicated that migratory activities of FAW adults emerged in QM–HRR were initiated from late June. The moths from western QM–HRR, where has complex topographic terrain, mainly flied to Ningxia and Inner Mongolia before mid September. However, FAW moths from the eastern QM–HRR primarily engaged in high-altitude northward transport assisted by the prevailing southerly winds before mid August, and the North China Plain was identified as the main destination of FAW. Meanwhile, the migration trajectories of FAW moths had a possibility to reach the Northeast China Plain. From mid August, FAW moths in eastern QM–HRR largely migrated southward and returned to the Yangtze River Valley. This study provides detailed information on the occurrence and migration routes of FAW moths from QM–HRR and will be helpful for early warning and development of integrated pest management strategies for the control of this exotic insect pest.     

紫外线胁迫对棉铃虫成虫乙酰胆碱酯酶和羧酸酯酶的影响

为了探讨紫外线胁迫与棉铃虫体内乙酰胆碱酯酶(ACHE)及羧酸酯酶(CarE)活性之间的关系,分析比较了两种酶活性在紫外线照射不同时间(0min,30min,60min,90min)下的变化情况。结果表明:棉铃虫经过紫外线照射不同时间后,体内的AChE活性均有所降低,且在30min时达到显著水平;紫外线照射对棉铃虫体内的CarE活性有一定的抑制作用,紫外线30min、60min和90min CarE活性均显著低于对照。     

表达Cry1Ab和Cry2Ab蛋白的转基因玉米GAB-3对四种主要鳞翅目害虫的抗性评价

为评价表达Cry1Ab和Cry2Ab蛋白的转基因玉米GAB-3对黏虫Mythimna separata（Walker）、亚洲玉米螟Ostrinia furnacalis（Guenée）、棉铃虫Helicoverpa armigera（Hübner）和草地贪夜蛾Spodoptera frugiperda（J. E. Smith）的杀虫效果，采用室内生测的方法研究了GAB-3不同组织器官对以上四种害虫存活率的影响，并通过田间接虫试验进一步测试了GAB-3对黏虫和亚洲玉米螟的抗性。室内生测结果显示：转基因玉米GAB-3心叶期叶片对黏虫、亚洲玉米螟、棉铃虫和草地贪夜蛾具有很强的毒杀作用，苞叶、穗尖、穗轴、花丝、雄穗和籽粒对亚洲玉米螟和棉铃虫具有显著的抗性。田间接虫试验结果显示：心叶期GAB-3高抗黏虫和亚洲玉米螟，穗期GAB-3高抗亚洲玉米螟。上述结果表明，转基因玉米GAB-3对4种主要玉米鳞翅目害虫有很好的杀虫效果，具有较好的商业化应用前景。     

不同干式性诱捕器及性诱芯诱捕亚洲玉米螟雄蛾效果研究

性信息素防治技术一直是我国防治亚洲玉米螟的重要方式之一。为测试不同干式性诱捕器与不同浓度性诱芯对亚洲玉米螟雄蛾的诱捕效果,开展了捕虫室固定或摇摆、进蛾口口径、不同诱捕器类型对田间玉米螟雄蛾的诱捕试验,并对搭配4种性诱芯的桶状诱捕器在不同试验田诱捕玉米螟雄蛾的效果进行研究。结果表明：①捕虫室固定的诱捕器比摇摆的诱捕器诱捕玉米螟雄蛾效果更好;②不同口径的塑料诱捕器中,外口直径14 cm诱捕器诱捕雄蛾效果较好,且对于相同口径诱捕器,橡皮性诱芯诱捕雄蛾效果优于牙签性诱芯;③比较桶状诱捕器、塑料诱捕器和三角板诱捕器,桶状诱捕器的诱捕雄蛾效果最好;④在玉米田、水稻田中,搭配2.6∶1-XP性诱芯的诱捕器诱捕雄蛾数量较多;在大豆田,搭配1∶1性诱芯的诱捕器诱捕雄蛾数量较多。综上所述,捕虫室固定、诱捕器进蛾口越大,诱捕玉米螟雄蛾效果越好;相同诱捕器,配置橡皮性诱芯诱捕雄蛾效果更好,不同作物田地的最佳性诱芯不同。结果为合理使用性诱捕器及性诱芯防治亚洲玉米螟提供理论依据。     

表达Cry1Ab和Cry2Ab蛋白的转基因玉米GAB-3对四种主要鳞翅目害虫的抗性评价

为评价表达Cry1Ab和Cry2Ab蛋白的转基因玉米GAB-3对黏虫Mythimna separata（Walker）、亚洲玉米螟Ostrinia furnacalis（Guenée）、棉铃虫Helicoverpa armigera（Hübner）和草地贪夜蛾Spodoptera frugiperda（J. E. Smith）的杀虫效果,采用室内生测的方法研究了GAB-3不同组织器官对以上四种害虫存活率的影响,并通过田间接虫试验进一步测试了GAB-3对黏虫和亚洲玉米螟的抗性。室内生测结果显示：转基因玉米GAB-3心叶期叶片对黏虫、亚洲玉米螟、棉铃虫和草地贪夜蛾具有很强的毒杀作用,苞叶、穗尖、穗轴、花丝、雄穗和籽粒对亚洲玉米螟和棉铃虫具有显著的抗性。田间接虫试验结果显示：心叶期GAB-3高抗黏虫和亚洲玉米螟,穗期GAB-3高抗亚洲玉米螟。上述结果表明,转基因玉米GAB-3对4种主要玉米鳞翅目害虫有很好的杀虫效果,具有较好的商业化应用前景。     

Susceptibility and tissue specificity of Spodoptera frugiperda to Junonia coenia densovirus

The fall armyworm, Spodoptera frugiperda, which destroys many economic crops such as rice and maize, has recently invaded China. Insect viruses as biological control agents play important roles in killing pests. One potential viral insecticide is the environmentally highly infective and virulent densovirus. We successfully rescued Junonia coenia densovirus(JcDV) using its infectious clone in different insect cell lines and larvae of three insect species. Results showed that the lysate of cultured insect cells transfected by the JcDV infectious clone killed the 2 nd instar S. frugiperda. The LD_(50) of homogenate from JcDV-infected Spodoptera litura to the 2 nd instar S. frugiperda(1.76×10~8 viral genome copies per larva during 10 d post infection) was higher than that of the 2 nd instar S. litura(7.39×10~7 Jc DV genome copies) or Helicoverpa armigera larvae(9.71×10~7 JcDV genome copies). The LT_(50) of the S. litura homogenate(2.60×10~9 viral genome copies each larva) to the 2 nd instar S. frugiperda was 6.96 d, longer than that of the S. litura(6.18 d) or the 2 nd instar H. armigera(5.94 d). JcDV could infect the fat body of H. armigera, but not S. frugiperda or S. litura. Although JcDV can infect all three lepidopteran species, their susceptibility to the virus differs. JcDV has great potential as a biological control agent against pests such as S. frugiperda.     

Biology,invasion and management of the agricultural invader: Fall armyworm,Spodoptera frugiperda(Lepidoptera: Noctuidae)

The fall armyworm(FAW), Spodoptera frugiperda(J. E. Smith), is native to the Americas. It has rapidly invaded 47 African countries and 18 Asian countries since the first detection of invasion into Nigeria and Ghana in 2016. It is regarded as a super pest based on its host range(at least 353 host plants), its inherent ability to survive in a wide range of habitats, its strong migration ability, high fecundity, rapid development of resistance to insecticides/viruses and its gluttonous characteristics. The inherently superior biological characteristics of FAW contribute to its invasiveness. Integrated pest management(IPM) of FAW has relied on multiple applications of monitoring and scouting, agricultural control, chemical pesticides, viral insecticides, sex attractants, bio-control agents(parasitoids, predators and entomopathogens) and botanicals. Knowledge gaps remain to be filled to:(1) understand the invasive mechanisms of S. frugiperda;(2) understand how to prevent its further spread and(3) provide better management strategies. This review summarizes the biological characters of FAW, their association with its invasiveness and IPM strategies, which may provide further insights for future management.     

Analysis on the migration of first-generation Mythimna separata (Walker) in China in 2013

Mythimna separata (Walker) is an important pest which can cause serious damages to cereal crops. In the past two decades, several heavy outbreaks have taken place in northern China. In order to develop a fine-scale method of forecasting outbreaks, population data were collected in northern China using searchlight traps and ground light traps. A background weather pattern analysis and trajectory analysis were performed via the Weather Research and Forecast (WRF) and FLEXPART models. Our results showed that heavy migration of first-generation M. separata appeared in northern China in 2013. In Yanqing District, Beijing, the cumulative number of captured adults in searchlight traps was around 250 000 and the daily maximum for trapped moths was 86 000. During the peak period, the majority of M. separata moths arrived after 00:00 every night. The sex ratio (female:male) at each monitoring site was greater than 1 and greatly fluctuated with population dynamics. During the migration peak, prevailing downdraft winds benefited M. separata moths to land passively. Trajectory simulation showed that immigrants were from Anhui, Jiangsu and Hubei provinces and most of them could continue to fly into the northeastern regions of China. These results provide technical support for fine-scale forecasting of the outbreak of M. separata at meso- and micro-scale.