Induction of detoxification enzymes by triazine herbicides in the fall armyworm, Spodoptera frugiperda (J.E. Smith)

The inductive effect of six triazine herbicides on a variety of detoxification enzymes was investigated in fall armyworm (Spodoptera frugiperda) larvae maintained on an artificial diet. Dietary atrazine induced nine microsomal oxidase activities ranging from 1.3- to 21.6-fold, 12 glutathione S-transferase activities ranging from 1.3- to 4.2-fold, four hydrolase activities ranging from 1.3- to 2.9-fold, and two reductase activities ranging from 1.5- to 5.1-fold, depending on the enzyme assayed and tissue source (midgut vs. fat body) used. Simazine, cyanazine, ametryn, tebutryn, and terbuthylazine also induced these detoxification enzymes. The induction of microsomal oxidase (aldrin epoxidase) ranged from 1.2- to 11-fold, glutathione S-transferase (CDNB) ranged from 1.3- to 4-fold, and general esterase ranged from 1.4- to 4.1-fold, depending on the tissue source examined. In general, fat bodies were more inducible than midguts with respect to these detoxification enzymes, especially the microsomal oxidases. The induction by atrazine was associated with decreased toxicity of carbaryl, permethrin and indoxacarb, but increased toxicity of methyl parathion, phorate, and trichlorfon.     

Insensitivity of acetylcholinesterase in a field strain of the fall armyworm, Spodoptera frugiperda (J.E. Smith)

Acetylcholinesterase (AChE) was purified from adult heads of the fall armyworm (Spodoptera frugiperda) by using a two-step procedure involving gel filtration on a Sephadex G-200 column and affinity chromatography on a procainamide-ECH Sephadex 4B column. Both susceptible and field strains possessed two AChE isozymes, namely, AChE-1 and AChE-2, with subunit molecular weights of 63.7 and 66.1 kDa. The purified AChE had an apparent K_m value of 33.5 μM and a V_max of 7.07 μmol/min/mg protein in the susceptible strain. The apparent K_m and the V_max were 2.2- and 2.0-fold higher, respectively, in the field strain than in the susceptible strain. The purified AChE from the field strain was 17- to 345-fold less sensitive than that from the susceptible strain to inhibition by carbamates (carbaryl, eserine, methomyl, and bendiocarb) and organophosphates (methyl paraoxon and paraoxon), insensitivity being highest toward carbaryl. The results further support the notion that insensitive AChE played an important role in the insecticide resistance observed in the field strain.     

The mechanisms of carbaryl resistance in the fall armyworm,Spodoptera frugiperda (J. E. Smith)

The physiological mechanisms of resistance to carbaryl were investigated in a carbaryl-resistant strain of the fall armyworm, Spodoptera frugiperda (J. E. Smith). Piperonyl butoxide greatly reduced the resistance level from 90- to 6-fold, indicating that microsomal cytochrome P-450-dependent monooxygenases may play a major role in resistance. This finding is consistent with metabolic data in which the oxidative metabolism of carbaryl by midgut homogenates was five times more active in the resistant strain than in the susceptible strain. In addition, the resistant strain showed increased activities of microsomal hydroxylation and epoxidation compared to the susceptible strain. Cuticular penetration studies using [¹⁴C]carbaryl revealed that 55% of the applied radioactivity remained on the cuticle of resistant larvae while 32% remained on susceptible larvae 24 hr after topical treatment. The resistance appeared to be unrelated to target site insensitivity. It is concluded that the high level of resistance to carbaryl in this insect was mainly due to enhanced oxidative metabolism of the insecticide (via hydroxylation and epoxidation) with reduced cuticular penetration playing a very minor role, if any.     

Microsomal sulfoxidation of phorate in the fall armyworm,Spodoptera frugiperda (J. E. Smith)

Microsomal sulfoxidation in fall armyworm (Spodoptera frugiperda) larvae was examined using phorate as substrate. The system required NADPH and was inhibited by CO and by piperonyl butoxide. Sulfoxidase activity was found in the alimentary canal, fat body, and Malpighian tubules, with the midgut being the most active. Microsomal substrates such as aldrin, heptachlor, biphenyl, and methyl parathion significantly inhibited the enzyme activity whereas p-nitroanisole and p-choloro-N-methylaniline had no effect. Enzyme activity increased during larval development, reaching a maximum shortly before pupation. Allelochemicals (monoterpenes, indoles, and flavones), drugs (phenobarbital and 3-methylcholanthrene), and host plants (corn cotton, parsnip, and parsley) significantly increased the enzyme activity. Increased phorate sulfoxidation through enzyme induction was found to decrease oral toxicity of phorate to the larvae. Analyses of internal insecticide revealed that, at various intervals, induced larvae retained less phorate and its oxidative metabolites than the controls. It was concluded that induction of phorate sulfoxidase activity results in an overall increase in the rate of phorate detoxication in this insect.     

四川省草地贪夜蛾世代区划

为明确草地贪夜蛾Spodoptera frugiperda在四川省不同地区的发生世代,本文根据四川省2019年、2020年草地贪夜蛾虫情及2010年-2019年近10年气温数据,利用有效积温法则对四川省草地贪夜蛾发生世代数进行预测,并运用ArcGIS进行Kriging插值分析,获得四川省草地贪夜蛾世代区划.结果表明,基...     

草地贪夜蛾迁飞行为与监测技术研究进展

草地贪夜蛾Spodoptera frugiperda原产于美洲的热带和亚热带地区,广泛分布于美洲大陆。2016年入侵到非洲,迅速蔓延到撒哈拉以南的整个区域。2018年入侵到印度。联合国粮农组织(FAO)发出警告,草地贪夜蛾很有可能从印度蔓延到东南亚及中国南部为主的亚洲地区。为掌握草地贪夜蛾在国外的发生与迁飞为害规律,加强我国对草地贪夜蛾的入侵控制和监测预警,本文综述了草地贪夜蛾在美国、加勒比海国家、墨西哥以及非洲国家的迁飞行为规律、性诱剂、灯光诱捕以及迁飞路径的分子鉴定等监测预警技术的研究进展,从而为我国植保人员对该虫的监测提供技术指导。针对草地贪夜蛾在世界范围内的迁飞规律和入侵特点,结合我国农作物种植结构以及气候特点,提出加强对草地贪夜蛾的监测与检疫的建议。     

草地贪夜蛾在安徽地区越冬能力初探

草地贪夜蛾的生长发育、繁殖和分布与环境温度密切相关,为探明该虫在安徽地区的越冬能力,本研究利用人工接虫的方式模拟草地贪夜蛾冬季的田间存活状态,调查幼虫存活率、龄期、植株被害率,并利用线性模型预测草地贪夜蛾田间发育历期。结果表明:草地贪夜蛾在田间平均气温低于10℃并持续8~10 d时死亡率达到100%;10月15日接入的草地贪夜蛾幼虫无法完成完整世代周期,但仍能为害玉米幼苗,接虫后30 d玉米植株的被害率均达100%;根据模型公式,采用10月15日至11月18日期间的温度预测发育历期,得到卵、幼虫、蛹以及整个世代的发育历期分别为9.23、46.86、40.70、69.38 d。本研究初步探明了草地贪夜蛾在安徽地区的越冬规律,研究结果为虫情监测和防控提供科学依据。     

Induction of microsomal oxidases by host plants in the fall armyworm,Spodoptera frugiperda (J. E. Smith)

Larvae of the fall armyworm (Spodoptera frugiperda (J. E. Smith)) were maintained on a semidefined artificial diet until the end of the fifth instar and the newly molted sixth-instar larvae were then fed fresh leaves of various host plants for 2 days prior to microsomal oxidase assays. The order of the midgut aldrin epoxidase activity of larvae after feeding on these plants was: corn > Bermuda grass > cotton > cowpeas > cabbage > peanuts > sorghum > alfalfa > millet > soybean. The ratios of aldrin epoxidase, p-nitroanisole O-demethylase, and p-chloro-N-methylaniline N-demethylase activities for soybean- and corn-fed larvae were 4.5, 6.3, and 2.7-fold, respectively. The induction was affected by the age and developmental stage of the corn plant with mature leaves from old plants being more active. Higher epoxidase activities were also observed in mature larvae reared on corn plants since egg stage as compared with those on soybean plants. Monoterpenes such as α-pinene, β-pinene, limonene, menthol, and peppermint oil were found to induce the midgut epoxidase activity. Corn-fed larvae were more tolerant of the insecticides methomyl, acephate, methamidophos, diazinon, trichlorfon, monocrotophos, permethrin, and cypermethrin than soybean-fed larvae.     

草地贪夜蛾性信息素的合成

草地贪夜蛾性信息素具有不伤害天敌、不产生抗药性、对环境安全等优点。其主要活性成分为:(Z)-7-十二碳烯-1-醇乙酸酯、(Z)-9-十二碳烯-1-醇乙酸酯、(Z)-9-十四碳烯-1-醇乙酸酯、(Z)-11-十六碳烯-1-醇乙酸酯、(E)-7-十二碳烯-1-醇乙酸酯和 (9Z, 12E)- 9,12-十四碳二烯-1-醇乙酸酯。本文研究了一种高效、简捷的合成草地贪夜蛾性信息素的新方法,其关键步骤包括:醛与官能团化鏻盐的Wittig偶联、炔的烷基化以及丙二酸与丙醛的Knoevenagel 缩合等反应。其中醛与羟基鏻盐的Wittig反应及Knoevenagel 缩合反应首次用于草地贪夜蛾性信息素的合成。     

入侵川西高原的草地贪夜蛾虫源分析

草地贪夜蛾是2019年入侵我国的重大迁飞性害虫,2019年6月底-7月中旬在川西高原发现草地贪夜蛾幼虫为害。研究川西高原草地贪夜蛾迁入种群虫源地分布及迁飞路径,对丰富草地贪夜蛾迁飞生物学以及川西高原草地贪夜蛾监测预警和防控有重要意义。本文利用基于WRF模式的昆虫三维轨迹分析程序,对入侵川西高原的草地贪夜蛾迁飞路径及天气背景进行了分析。结果表明,6月底-7月中旬川西高原查见的草地贪夜蛾幼虫为6月下旬-7月初迁入成虫繁殖而来。川西高原草地贪夜蛾迁入虫源主要分布在云南西部、西北部,西藏东南部和缅甸北部。草地贪夜蛾可从虫源地随偏西-西南气流经1~3夜迁飞而来,有效迁飞高度为海拔3500~5350 m。降水、下沉气流和低温的综合作用可迫使草地贪夜蛾降落在川西高原。     

草地贪夜蛾对杀虫剂的抗性研究进展

草地贪夜蛾Spodoptera frugiperda (J. E. Smith) 是一种杂食性害虫,原产于美洲热带和亚热带地区,于2019年1月在中国云南省首次被发现后,已迅速向广西、贵州、广东及湖南等地蔓延。草地贪夜蛾寄主广泛,常用化学防治药剂为有机磷类、氨基甲酸酯类和拟除虫菊酯类,田间抗性监测数据显示,其对上述 3 类常用药剂已达中至高等抗性水平。此外,已有研究证明氯菊酯抗性草地贪夜蛾对二嗪类杀虫剂茚虫威无交互抗性;同时已有关于草地贪夜蛾对氟苯虫酰胺和氯虫苯甲酰胺田间和室内抗性的报道,表明其对上述 2 种药剂存在极高的交互抗性风险。草地贪夜蛾的抗药性机理主要涉及表皮穿透性降低、解毒作用增强和靶标敏感性下降等几方面,其中代谢解毒作用增强和靶标敏感性下降是导致草地贪夜蛾对杀虫剂产生抗性的主要机制。文章综述了草地贪夜蛾对传统杀虫剂和新型作用机制杀虫剂的抗性现状及抗性机理等方面的研究进展,以期对当前中国的草地贪夜蛾田间防治及抗性研究和防控提供参考。     

草地贪夜蛾缅甸虫源迁入中国的路径分析

草地贪夜蛾Spodoptera frugiperda(J.E. Smith)对非洲和南亚国家的入侵已对全球粮食安全造成重大影响,该虫2018年年底已在缅甸形成虫源基地,并零星进入中国云南西南部地区。本文利用历史数据分析了缅甸和华南地区春、夏两季(3-8月)925 hPa夜间平均风温场,并模拟预测了缅甸地区草地贪夜蛾在此期间进入中国的迁飞轨迹以及主要降落和波及的地区。结果表明:3-4月盛行的微弱西风不利于远距离迁移,但成虫的自主飞行可形成对云南和广西局部地区的近距离入侵;进入5月份后,随着西南夏季风的加强,云南和广西全境成为缅甸虫源的主要迁入地,并可能波及贵州、广东、海南和湖南等省。因此,4月份之前要重点监控云南和广西地区草地贪夜蛾的发生与为害,此后,应将监控区域扩大至中国中南部地区的各个省份。     

Biocontrol-based management of fall armyworm,Spodoptera frugiperda (J E Smith) (Lepidoptera: Noctuidae) on Indian Maize

Journal of Plant Diseases and Protection - Spodoptera frugiperda (J E Smith) (fall armyworm) (Lepidoptera: Noctuidae), is a key pest of maize that has recently entered in India causing damage and...     

不同玉米品种对草地贪夜蛾抗性的评估及其在防治中的应用前景

草地贪夜蛾Spodoptera frugiperda(J.E.Smith)是今年入侵我国的农业害虫,对我国的玉米等主要粮食作物产生了重要威胁。在草地贪夜蛾有可能成为我国新的长期粮食害虫的背景下,评测不同玉米品种对草地贪夜蛾的抗性,以确定潜在的高抗性品种,对后续培育抗虫品种有重要的指导意义。由于草地贪夜蛾原产于美洲热带及亚热带地区,且玉米的原产地与种内多样性也主要存在于美洲地区,因此以往大部分玉米品种抗虫性评测研究也主要集中于国外。本文汇总了近年来不同玉米品种对草地贪夜蛾抗性的评估结果,简单介绍了关于玉米对草地贪夜蛾抗性机制的研究进展,并结合玉米抗虫研究的经验及国内玉米遗传多样性研究的现状,提出了充分结合玉米种内多样性与多组学数据分析的研究方法,从而快速确定抗性相关的遗传位点与基因,用于现有高产优良玉米杂交品系对草地贪夜蛾抗性的改良。     

草地贪夜蛾对农药主要抗性机制的概述

草地贪夜蛾Spodoptera frugiperda是一种迁飞性害虫,源自美洲,已入侵非洲和亚洲部分国家并暴发成灾,2019年初入侵我国,严重威胁着我国玉米、小麦等粮食作物。目前草地贪夜蛾的防治主要依赖于化学农药和种植转基因作物。因长期使用农药,草地贪夜蛾已经对氨基甲酸酯类、有机磷酸酯类和拟除虫菊酯类等多种杀虫剂产生了不同程度的抗性。草地贪夜蛾对不同种类杀虫剂表现的抗性机制不同,主要有代谢抗性和靶标抗性2种。本文主要从代谢抗性和靶标抗性2个方面分别综述了草地贪夜蛾对不同种类杀虫剂的抗性机制,分析草地贪夜蛾对不同杀虫剂的抗性作用方式,并对草地贪夜蛾抗药性管理和监测进行展望。     

Monitoring of beet armyworm Spodoptera exigua (Lepidoptera: Noctuidae) resistance to chlorantraniliprole in China

Beet armyworm, Spodoptera exigua is a major insect pest of vegetables in China, and has been reported to develop resistance to many broad-spectrum insecticides. Recently registered chlorantraniliprole provides a novel option for control of this pest resistant to other conventional insecticides. The susceptibilities of field collected populations were measured by diet incorporation assay with neonate, obvious variation of susceptibility was observed among the 18 field populations with LC₅₀ values varying from 0.039 to 0.240 mg/liter. Moderate resistant level was discovered in 8 of 18 field populations, other 8 populations had become low level tolerance to chlorantraniliprole, and only one population in all the field colonies remained susceptible. Biochemical assays were performed to determine the potential mechanisms involved in tolerance variation. Field populations displayed varied detoxification enzyme activities, but the regression analysis between chlorantraniliprole toxicities and enzyme activities demonstrated each field population might have specific biochemical mechanisms for tolerance. Artificial selection in laboratory with chlorantraniliprole was carried out, 23 generations of continuous selections resulted in 11.8-fold increase in resistance to chlorantraniliprole, and 3.0-fold and 3.7-fold increases in mixed function oxidase and esterase, respectively. Compared with the susceptible strain kept in laboratory the selection strain had developed 128.6-fold resistance to this insecticide. Synergism assays showed the detoxification enzymes might not involved in the resistance observed in field collected populations and the selected strain.     

不同木薯品种对草地贪夜蛾的抗性鉴定

为探讨草地贪夜蛾 Spodoptera frugiperda对木薯的寄主选择性,采用虫害指数以及发育与繁殖系统鉴定评价20个木薯品种对草地贪夜蛾的抗性。结果显示, C1115、 SC5和Miandian品种对草地贪夜蛾表现为抗虫性, SC15、 SC8、 SC10、 Limin、 SC124和NZ199品种对草地贪夜蛾表现为中抗,SC9、 SC12、 GR891、 SC8002、 SC6068、 GR10、 SC205和TMS60444品种对草地贪夜蛾表现为敏感,BAR900、 KU50、 Bread对草地贪夜蛾表现为高感。与对照甜玉米YT29相比,取食抗、感木薯品种的草地贪夜蛾发育与繁殖均受到显著抑制,其中抗虫木薯品种的抑制效果最好,取食抗虫木薯品种C1115、 SC5、 Miandian的草地贪夜蛾的发育历期最长,幼虫死亡率最高,雌雄成虫寿命最短,单雌产卵量、卵孵化率和雌虫比最低,表明草地贪夜蛾发育与繁殖受到显著抑制可能是抗虫木薯品种对其表现出较低寄主适合度的重要原因。     

Detection of the occurrence of the fall armyworm,Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) strains on maize in Southern Rajasthan India

Journal of Plant Diseases and Protection - The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), a polyphagous lepidopteran pest that is native to tropical and sub-tropical America has...