不同杀虫剂对锡兰玻壳蚧的室内毒力及田间防效

【目的】锡兰玻壳蚧是我国余甘子上新发现的重要害虫,对农业生产及生态安全构成严重威胁。本研究旨在筛选出高效理想的防治药剂,为生产中科学用药提供依据。【方法】采用浸渍法测定8种杀虫剂对锡兰玻壳蚧的室内毒力,采用喷雾法评价5种毒力较好药剂的田间防效。【结果】室内毒力测定结果表明:毒死蜱、啶虫脒、吡虫啉、阿维菌素、甲维盐对1、2龄若虫的毒力较强,48 h致死中浓度(LC₅₀)分别为11.1245、26.2376 mg·L^-1,17.5381、26.1910 mg·L^-1,27.5896、34.2868 mg·L^-1,26.5876、38.8034 mg·L^-1,29.0528、43.0443 mg·L^-1;毒死蜱和阿维菌素对3龄若虫、雌成虫的毒力较强,48 hLC₅₀分别为87.3427、495.8339 mg·L^-1,95.4751、1131.6430 mg·L^-1;螺虫乙酯、吡丙醚和高效氯氟氰菊酯对各虫期的毒力均较弱;吡虫啉、阿维菌素、啶虫脒、甲维盐对各龄若虫的毒力比差异较小,毒死蜱的毒力比差异较大,但后者对各龄若虫的毒力均较强。田间防效结果表明:毒死蜱和阿维菌素对田间种群增长抑制效果最好,药后7 d防效分别为96.90%、92.00%;吡虫啉、甲维盐和啶虫脒对低龄若虫种群速杀效果较好,药后7 d防效分别为78.06%、67.62%、62.78%。【结论】锡兰玻壳蚧的化学防治应于1~2龄若虫期进行,推荐阿维菌素、毒死蜱、吡虫啉、甲维盐和啶虫脒轮换使用;3龄雌若虫及雌成虫盛发期推荐使用毒死蜱和阿维菌素防治。     

不同药剂对欧洲甘蓝粉虱2种表型的毒力及田间药效

[目的] 欧洲甘蓝粉虱B型和L型是近年来新入侵我国的粉虱类害虫。探究当前欧洲甘蓝粉虱2种表型对不同杀虫剂的敏感性水平，能为合理选择高效杀虫剂进行科学防治提供依据。[方法] 采用浸叶法和喷雾法，对油麦菜上的欧洲甘蓝粉虱进行室内毒力测定和田间药效试验。[结果] 室内毒力测定结果表明：阿维菌素原药对B型和L型成虫毒力均最高，LC₅₀分别为0.57、3.54 mg·L^-1；甲维盐对B型和L型若虫毒力最高，LC₅₀分别为0.65、2.29 mg·L^-1。田间药效试验结果表明：5%阿维菌素EW对B型成虫和L型若虫防效最好，分别为65.77%和94.86%；22%氟啶虫胺腈SC对L型成虫的防治效果最好，防效为92.07%；60%啶虫脒WP对B型若虫的防效最好，为95.65%。[结论] 推荐在田间交替使用5%阿维菌素EW、22%氟啶虫胺腈SC和60%啶虫脒WP防治欧洲甘蓝粉虱B型和L型，同时应加强抗药性监测。     

云南弥渡县番茄潜叶蛾的发生情况及田间防治效果

外来入侵性害虫番茄潜叶蛾Tuta absoluta(Meyrick)于2018年3月26日在云南弥渡县被发现,为明确其发生为害情况,筛选出有效的防治药剂,阻止该虫的发生和蔓延,本研究采用性诱剂进行田间调查分析了番茄潜叶蛾的发生情况,通过田间药效试验比较噻虫嗪、噻虫胺、虫螨腈、苏云菌杆菌、乙基多杀菌素、阿维·氯虫苯甲酰胺、噻虫·高氯氟和阿维·灭蝇胺对番茄潜叶蛾的防治效果.调查结果表明该虫在番茄种植区域均有发生,大棚番茄地发生尤其严重,为害株达100％,百叶幼虫量55.00～101.67头/百叶,周诱蛾量4.70～61.20头/板,果子的为害率达19.33％,最高达40％.田间药效的结果表明:33％阿维·灭蝇胺SC防效较好,药后3 d防效达74.30％,其次30％虫螨腈SC、6％阿维·氯虫苯甲酰胺SC和6％乙基多杀菌素SC药后3 d防效64.25％、67.98％、54.85％,药后5 d防效79.08％、79.00％、73.45％,药后7 d防效81.60％、80.45％、65.70％.结果表明番茄潜叶蛾在弥渡县大棚发生为害较为严重,性诱剂对成虫有良好的诱集效果,虫螨腈、阿维·氯虫苯甲酰胺、乙基多杀菌素和阿维·灭蝇胺可作为幼虫的防治药剂.     

多杀菌素对天敌昆虫白蛾周氏啮小蜂的毒力评估

[目的] 生物防治与化学防治相结合是害虫综合防治的重要策略,蛹寄生蜂白蛾周氏啮小蜂是一种重要的天敌昆虫,在美国白蛾的生物防控中起关键作用。本研究旨在评估农林生产中常用的广谱、低毒杀虫剂多杀菌素对白蛾周氏啮小蜂的安全性。[方法] 采用药膜法检测多杀菌素对小蜂的毒力,并检测亚致死浓度多杀菌素处理后,小蜂体内解毒酶活性的变化。[结果] 多杀菌素对小蜂无短期（1 h）触杀作用,但随施药时间延长,其对小蜂的毒杀作用增强,25 mg·L^-1多杀菌素施药2 h后,可诱导约18.67%小蜂个体死亡。施药4 h后,不同浓度多杀菌素对小蜂的毒杀作用差异最明显,低浓度（5 mg·L^-1）多杀菌素可诱导11.33%小蜂死亡,而中、高浓度多杀菌素（≥ 15 mg·L^-1）可诱导77.33%~88.00%个体死亡。施药6 h后,LC₅₀值达7.44 mg·L^-1,安全系数为0.31,属高风险性农药。此外,亚致死浓度多杀菌素可明显诱导小蜂羧酸酯酶活性提高,对乙酰胆碱酯酶与谷胱甘肽-S-转移酶活性具有剂量效应。[结论] 多杀菌素对白蛾周氏啮小蜂的毒力作用较强,在美国白蛾生防区需慎用。     

草地贪夜蛾应急防控药剂田间药效筛选

【目的】比较28种杀虫剂对玉米草地贪夜蛾Spodoptera frugiperda的田间防治效果,为防控新入侵农业害虫提供科学依据。【方法】采用常规喷雾法,对大喇叭口期玉米全株均匀喷雾,药前1 d及药后1、3和7d调查挂牌标记玉米上草地贪夜蛾幼虫活虫数。【结果】试验结果表明,乙基多杀菌素、甲氨基阿维菌素苯甲酸盐、氯虫苯甲酰胺等8种化学农药对草地贪夜蛾防治效果较好;生物农药均没体现出较好的防治效果,推测可能与其作用方式有关。【结论】在28种杀虫剂中,筛选出乙基多杀菌素、甲氨基阿维菌素苯甲酸盐、氯虫苯甲酰胺、溴氰虫酰胺、甲氧虫酰肼、氟氯氰菊酯、乙多-甲氧虫和甲氧-茚虫威8种对草地贪夜蛾具有较好防治效果的药剂。     

紫茎泽兰对四环素的吸收特性

[目的] 探究四环素在水和紫茎泽兰间的传递以及在紫茎泽兰体内的累积特征。[方法] 利用高效液相色谱检测紫茎泽兰幼苗在水培过程中对四环素的吸收及其在根茎叶中的积累。[结果] 在10~20 mg·L^-1四环素的处理浓度范围内,紫茎泽兰根、茎、叶均能吸收并积累四环素,且吸收累积量均随处理浓度和处理时间的增加而升高。当紫茎泽兰在20 mg·L^-1四环素的水培液处理20 d时,茎中的四环素累积量最高,为（59.34±3.86）mg·kg^-1;根中的次之,为（52.52±5.89）mg·kg^-1;而叶中的最低,为（23.19±4.17）mg·kg^-1。此外,紫茎泽兰茎的四环素富集系数最大,根的次之,叶的最小。[结论] 紫茎泽兰能够较好地从水培液中吸收并累积四环素,具有吸收净化四环素污染水源的潜力。     

镍离子对尖叶莴苣氮素吸收和生长生理的影响

以‘全年油麦菜’尖叶莴苣为试验材料,采用水培方式,研究3个浓度(0 mg·L^-1、0.1 mg·L^-1、1 mg·L^-1)Ni²⁺在22.4 mg·L^-1 N处理下对尖叶莴苣氮素吸收的生长及生理影响。结果显示：(1)尖叶莴苣根系和地上部生物量随处理时间的增加呈上升趋势。与对照T₁(0 mg·L^-1 Ni²⁺、112 mg·L^-1 N)相比,T₂处理(0 mg·L^-1 Ni²⁺、22.4 mg·L^-1 N)对尖叶莴苣根系及叶片生长具有一定抑制作用,植株鲜重、干重、根冠比、根系长度、平均直径、表面积、体积、根尖数、分根数、叶片表面积和体积在T3处理(0.1 mg·L^-1 Ni²⁺、22.4 mg·L^-1 N)下显著高于对照,T₄处理(1 mg·L^-1 Ni²⁺、22.4 mg·L^-1 N)对尖叶莴苣根系及其叶片生长具有一定促进作用,但对其根尖数和分根数表现出一定抑制性。(2)随着Ni²⁺浓度的增加,尖叶莴苣叶片叶绿素a、叶绿素b和总叶绿素含量呈先升后降的变化规律,且均在T₃处理下显著提高。(3)随着处理时间的增加,尖叶莴苣叶片的净光合速率(P_n)、气孔导度(G_s)和蒸腾速率(T_r)逐渐上升,胞间CO₂浓度(C_i)逐渐下降,且T₃处理叶片的G_s显著高于对照,其C_i最低,P_n最大。(4)施加Ni²⁺对尖叶莴苣有机酸、可溶性蛋白和可溶性糖含量以及SOD和POD活性有显著影响,在T₃处理下有机酸含量降低,可溶性糖和可溶性蛋白含量显著增加,SOD和POD活性显著提高。(5)T₃处理尖叶莴苣根系中N及叶片中B和Ca含量较高;根系中Ni含量高于叶片,T₃处理叶片中的Ni含量较低,Mg含量较高;植株体内Cu含量随Ni²⁺浓度增加而下降。研究表明,外源Ni²⁺处理能影响低氮条件下(22.4 mg·L^-1 N)尖叶莴苣幼苗生长及生理状况,适宜浓度(0.1 mg·L^-1)Ni²⁺可有效提高尖叶莴苣根系对氮素的吸收利用效率,减少氮素施用量,促进尖叶莴苣根系和地上部叶片生长,增加光合色素含量,并提高净光合速率,进而改善植株的产量和营养品质。     

不同药剂对Q型烟粉虱的防治效果评价

研究不同药剂对Q型烟粉虱Bemisia tabaci(Gennadius)的防治效果,为该虫的化学药剂防治提供理论依据。以烟粉虱成虫为试材,采用浸叶法,进行10种药剂对烟粉虱的室内毒力测定实验;采用喷雾法,在大棚黄瓜田进行10种单剂和9种混剂对烟粉虱的防治效果试验。其中阿维菌素对烟粉虱成虫的毒力最高,其LC50为2.8609mg/L,精高效氯氟氰菊酯对烟粉虱成虫的毒力最低,其LC50为389.1049mg/L,乙基多杀菌素对烟粉虱成虫无杀虫效果。9种药剂对烟粉虱成虫的毒力大小顺序为:阿维菌素啶虫脒高效氯氟氰菊酯高效氯氰菊酯氟啶虫胺腈氟啶虫酰胺螺虫乙酯噻虫嗪精高效氯氟氰菊酯。10种药剂在田间对烟粉虱的防效依次为:噻虫嗪阿维菌素氟啶虫胺腈氟啶虫酰胺精高效氯氟氰菊酯啶虫脒螺虫乙酯高效氯氟氰菊酯高效氯氰菊酯乙基多杀菌素。9种混剂的防效试验表明,有6种混剂对烟粉虱的防治效果比单剂防治效果好,其中效果最好的是阿维菌素与三种新烟碱类药剂的混用。     

5种杀虫剂对黑粪蚊的毒力及对平菇菌丝生长的影响

[目的]黑粪蚊为食用菌生产中的危险害虫之一,通过杀虫剂的毒力测定和对平菇菌丝生长抑制试验,拟筛选获得理想的黑粪蚊防治杀虫剂。[方法]采用毒饵法测定了5种杀虫剂对黑粪蚊幼虫的室内毒力,并研究各杀虫剂对平菇菌菌丝生长的抑制情况。[结果]20%甲氰菊酯乳油、14%阿维·虫螨腈悬浮剂和20%甲维·吡丙醚悬浮剂对黑粪蚊的校正死亡率达80%以上,对黑粪蚊幼虫均有较好的杀灭效果,而苏云金杆菌（以色列亚种）悬浮剂对黑粪蚊幼虫的杀虫效果不理想。5种杀虫剂对平菇菌丝生长均有一定抑制作用,且农药品种间存在极显著差异,20%甲氰菊酯乳油抑制率最高,高浓度480 mg·L^-1处理的抑制率可达16.85%,14%阿维·虫螨腈悬浮剂的抑制率最低,高浓度140 mg·L^-1处理的抑制率仅为5.83%。[结论]本研究中14%阿维·虫螨腈悬浮剂用于平菇菌中黑粪蚊防治效果最好,研究结果将为食用菌黑粪蚊的药剂防治提供理论指导。     

皂荚提取物的杀螺活性

[目的]研究皂荚生物农药活性,开发利用皂荚资源,发展环境友好的绿色植物源农药。[方法]采用室内生测和田间试验研究皂荚壳乙醇提取物的杀螺活性。[结果]皂荚提取物对福寿螺有显著的毒杀活性,对幼螺和成螺72 h的LC₅₀分别为40.56、109.83 mg·L^-1。田间试验表明,皂荚提取物对福寿螺有较好的防效,施用40 g·m^-2的皂荚提取物处理7 d后卵块减少率为100.00%（成螺失去产卵的能力）,防效为（99.12±1.26）%。[结论]皂荚提取物对福寿螺较好的生物防治效果,是一种潜在的生物杀螺剂。     

不同杀虫剂对西花蓟马的室内毒力及田间药效

【目的】西花蓟马是一种世界性的危险性入侵害虫,筛选防治西花蓟马的有效药剂可为生产中科学用药提供依据。【方法】通过室内毒力测定和田间药效试验,测定了2种化学药剂和8种生物药剂对西花蓟马成虫的致死中浓度(LC_(50))和药后不同时期的防治效果。【结果】室内毒力测定依据LC_(50)值将各药剂对西花蓟马的敏感性由高到低依次排序为乙基多杀菌素(0.1958 mg·L~(-1))、印楝素(0.9399 mg·L~(-1))、苦参碱(1.2483 mg·L~(-1))、阿维菌素(1.8096 mg·L~(-1))、高效氯氰菊酯(4.4458 mg·L~(-1))、藜芦碱(10.7628 mg·L~(-1))、鱼藤酮(18.1898 mg·L~(-1))、吡虫啉(46.3964 mg·L~(-1))、松脂酸钠(131.5214 mg·L~(-1))、苏云金杆菌(446.2318 mg·L~(-1));田间药效试验发现,乙基多杀菌素和吡虫啉防治西花蓟马均表现出较强的速效性和持效性,药后1～14 d的防效分别可达84%和73%以上;其次是藜芦碱,药后1～14 d的防效可达48.15%～61.37%;高效氯氰菊酯的防效较低,药后14 d的防效为46.22%;生物药剂阿维菌素、苏云金杆菌、苦参碱、印楝素的速效性均较低,但防效随施药后时间的延长而逐渐上升;鱼藤酮持效性最低。【结论】乙基多杀菌素和吡虫啉可推荐为生产中防治西花蓟马的首选药剂,植物源药剂藜芦碱和生物药剂阿维菌素可作为交替使用药剂。     

5种杀虫剂对西花蓟马和花蓟马的毒力及其生理酶活性的影响

【目的】探究不同杀虫剂对重要入侵害虫西花蓟马及其本地近缘种花蓟马的毒力及对保护酶和解毒酶活性的影响,为进一步研究2种害虫的抗性管理提供依据。【方法】采用浸渍法测定5种田间常用杀虫剂对西花蓟马和花蓟马的毒力,并测定杀虫剂亚致死浓度(LC25)下2种蓟马体内保护酶和解毒酶活性的差异。【结果】不同杀虫剂对2种蓟马的毒力依次为:乙基多杀菌素甲维盐阿维菌素吡虫啉噻虫嗪,乙基多杀菌素对西花蓟马和花蓟马的LC_(50)分别为0.28和0.03 mg·L~(-1)。不同药剂的亚致死剂量(LC_(25))对西花蓟马和花蓟马体内保护酶和解毒酶活性普遍具有诱导作用。其中,阿维菌素对西花蓟马超氧化物歧化酶(SOD)活性诱导作用最强,为326.40 U·mg~(-1),是对照的9.37倍,而乙基多杀菌素对花蓟马SOD活性诱导作用最强,为245.35 U·mg~(-1),是对照的9.32倍;吡虫啉对西花蓟马和花蓟马过氧化物酶(POD)诱导作用最强,分别为298.67和246.79 U·mg~(-1),是对照的37.10和20.57倍;阿维菌素对西花蓟马和花蓟马过氧化氢酶(CAT)和羧酸酯酶(CarE)诱导作用最强,分别为298.67、246.79 U·mg~(-1)(CAT活性)和12.53、11.99 U·mg~(-1)(CarE活性);乙基多杀菌素对西花蓟马和花蓟马谷胱甘肽转移酶(GST)和乙酰胆碱酯酶(AChE)诱导作用最强,分别为77527.59、66927.39 U·mg~(-1)(GST活性)和2.34、2.22 U·mg~(-1)(AChE活性)。【结论】5种杀虫剂中,乙基多杀菌素对2种蓟马的毒力最强;西花蓟马对杀虫剂的解毒代谢能力强于花蓟马。     

丁氟螨酯对二斑叶螨生长发育的影响

【目的】丁氟螨酯是一种新型酰基乙腈类非内吸性杀螨剂,对害螨的各个螨态都有很高活性,具有较高的应用价值。本文评价了丁氟螨酯对二斑叶螨生长发育的影响,以期为合理用药和二斑叶螨的综合防治提供理论依据。【方法】采用浸叶法测定丁氟螨酯对二斑叶螨成螨与卵的致死中浓度、雌成螨产卵量、各螨态存活率以及各发育历期的影响。【结果】经丁氟螨酯处理后,二斑叶螨日均产卵量和总产卵量下降,各螨态发育历期延长;LC₇₀、LC₅₀、LC₃₀剂量处理二斑叶螨雌成螨后,每雌日均产卵量为(2.09±0.17)、(3.02±0.22)、(3.39±0.13)粒,每雌总产卵量为(29.29±2.31)、(42.32±3.01)、(47.41±1.77)粒,与空白对照差异显著(P<0.05,df=3);不同剂量处理二斑叶螨卵后,各螨态发育历期的延长程度不同,但成功孵化的卵能完成发育历期,LC 70剂量延长卵历期至(4.45±0.07)d、前若螨历期至(2.75±0.04)d、后若螨历期至(2.61±0.05)d和总历期至(12.53±0.18)d,LC 50剂量延长前若螨历期至(2.52±0.08)d、后若螨历期至(2.67±0.09)d和总历期至(12.22±0.18)d,LC 30剂量延长前若螨历期至(2.45±0.06)d和总历期至(11.53±0.08)d,与空白对照差异显著(P<0.05,df=3)。【结论】丁氟螨酯能对二斑叶螨的生长发育产生明显影响,降低二斑叶螨的产卵能力,抑制卵孵化,延长发育历期,从而降低二斑叶螨种群的发育速率,对该螨的种群控制有积极意义。     

Compatibility and interaction between Bacillus thuringiensis and certain insecticides: perspective in management of Tuta absoluta (Lepidoptera: Gelechiidae)

Bacillus thuringiensis var. kurstaki (Berliner) (Bt) has been suggested as a biological control agent for Tuta absoluta (Meyrick). The objective of this study was to determine the interaction between abamectin, azadirachtin, indoxacarb, chlorantraniliprole, dichlorvos and metaflumizone with Bt. Effect of recommended doses of the chemical insecticides on colonisation of Bt was also investigated in culture medium. Except for metaflumizone, none of the chemicals tested reduced the colonisation of Bt compared with control. Interaction between Bt and the chemical insecticides on 2nd-instar larvae was also assessed. In interaction tests, Bt was applied at LC₅₀ level, 0, 12, 24 or 36 h after treating the larvae with LC₁₀ or LC₂₅ of the chemical insecticides. An antagonistic effect was observed in all treatments where Bt was applied immediately after the chemical insecticide. Also, antagonism was observed when treatment with Bt was done 12 h after azadirachtin and metaflumizone applications. Applying Bt 12 and 24 h after treatment with LC₂₅ of chlorantraniliprole, dichlorvos and abamectin resulted in synergism. But, synergism with LC₁₀ of dichlorvos and abamectin was observed only after 12 h. Additive effect was observed in the rest of the time and concentration combinations. Based on the results obtained, simultaneous use of the chemical insecticides tested and Bt is not recommended for T. absoluta control; and an appropriate time interval should be taken into consideration accordingly.     

Impact of some insecticides and their mixtures on the population of tomato borers,Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) and Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in tomato crop at Upper Egypt

Impact of some insecticides and their mixtures (Emamectin benzoate, Imidaclopride, Chlorfenapyr, Indoxacarb, Profenofos, Pyridalyl, Methomyl and Teflubenzuron) were evaluated against the tomato borers, Tuta absoluta (Meyrick) and Helicoverpa armigera (Hübner) population in tomato crop at Upper Egypt. Results of LC₅₀ values indicated that Emamectin benzoate was the most toxic compound (LC₅₀ 0.461%) against T. absoluta, larvae. The carbamate insecticide, Methomyl, followed this descending order, showing almost similar toxicity, while Teflubenzuron and Chlorfenapyr were less effective (LC₅₀ 1.054 and 3.165%, respectively). Pyridalyl was found to be the most effective insecticide against larval stage of H. armigera. (LC₅₀ 0.513%). The corresponding toxicities of the other tested insecticides, arranged according to their LC₅₀ values in descending order were as follow: Methomyl, Emamectin benzoate, Profenofos, Imidaclopride, Teflubenzuron, Indoxacarb and Chlorfenapyr. Their LC₅₀ values were ranged between (0.513 and 0.872%). While, their toxicity indexes were ranged between (92.432 and 58.830%, respectively). On the other hand, there were no differences occurred among the treatments. Mean of percent infestation was decreased six weeks after six sprayings, and the per cent reduction in infestation was 79.73, 80.22, 78.41, 80.88, 80.50, 78.30, 79.64 and 78.25% using Emamectin benzoate, Methomyl, Imidaclopride, Pyridalyl, Profenofos, Indoxacarb, Teflubenzuron and Chlorfenapyr, respectively. The efficiency of the tested insecticides was increased with increasing the number of sprays from two to six causing reduction in insect borer infestation ranged between 68.02 and 80.88%, respectively. Generally, the tested insecticides and their mixtures achieved a considerable reduction in T. absoluta and H. armigera population.     

Interaction of HaNPVs with two novel insecticides against Helicoverpa armigera Hubner (Noctuidae: Lepidoptera)

Nucleopolyhedrosis viruses can be utilized for effective management of agriculture pests. Their efficacy can be increased if they are mixed with certain insecticides. In the current study, HaNPV was mixed with two insecticides: spinetoram and emamectin benzoate in various combinations and applied to larvae of H. armigera in laboratory conditions. There were a total of 15 combinations of HaNPV with each of the two insecticides in addition to five doses of HaNPV and three doses of insecticides alone. The synergistic and antagonistic effects of combinations were explored. The results revealed that there was synergistic effect of HaNPV @ 0.5 × 10⁹ PIB/ml × Spinetoram @ 40, 20, 10 ml/100 L of water. In case of emamectin benzoate, synergistic effects were recorded at 1 × 10⁹ PIB/ml HaNPV × emamectin benzoate @ 100 ml/100 L of water. However, 0.5 × 10⁹ PIB/ml HaNPV has synergistic effects with all three doses of emamectin benzoate. The results suggested that HaNPV can be used in combination with spinetoram and emamectin benzoate for the management of resistant population of H. armigera.     

矿物油乳剂对烟蚜茧蜂的安全性评价

【目的】矿物油乳剂因其安全性好、杀虫谱广、不易产生抗性等优点,被广泛用于果蔬、农作物、园林害虫的防治,但有关其对害虫天敌烟蚜茧蜂的安全性尚不明确。因此,本文研究矿物油乳剂对烟蚜茧蜂不同发育阶段的安全性,为更好地协调蚜虫的化学防治和生物防治提供理论依据。【方法】在实验室条件下采用药膜法和浸渍法测定了不同浓度(150、250、350、450倍液)矿物油乳剂对烟蚜茧蜂各发育阶段的影响。【结果】矿物油乳剂对烟蚜茧蜂成虫的影响较小,无明显胃毒作用,但有一定的触杀作用,以最高浓度150倍液(4986.960 mg·L-1)处理24 h后的存活率依然高达92%;矿物油乳剂对烟蚜茧蜂寄生蚜有较高的致死率,LC50为859.541 mg·L-1,该浓度远远低于此次供试的最低浓度450倍液(1662.320 mg·L-1),说明矿物油乳剂对烟蚜茧蜂卵和幼虫的安全性较差;矿物油乳剂对烟蚜茧蜂蛹期羽化率的影响较显著,处理组的僵蚜与对照组的僵蚜相比,羽化高峰期均滞后1 d,且羽化率随着处理浓度的增大而下降(450倍液时羽化率为81.25%,150倍液时仅为47.75%)。【结论】当蚜虫发生严重时,可考虑在烟蚜茧蜂成虫期协调使用矿物油乳剂进行联合控制,但矿物油乳剂的使用浓度和施用时间还有待进一步确定。     

Assessing the resistance risk to emamectin benzoate in Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae): selection,cross-resistance dynamics and estimates of realized heritability

Emamectin benzoate, a non-systemic, translaminar, and broad spectrum insecticide, is excessively used in cotton. It kills the pest by suppressing the muscle contraction. Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) is one of the major sap sucking pests of cotton in many countries and has been shown resistance to various insecticides. In this study, we have continuously selected P. solenopsis with emamectin benzoate in the laboratory from G₃ to G₁₈ to determine the resistance development and resistance risk to emamectin benzoate and also to evaluate the dynamics of cross-resistance (CR) development with three other insecticides. After continuing selection of P. solenopsis for 16 generations with emamectin benzoate, the emamectin selected strain (Ema-SEL) developed a 280.15-fold resistance when tested at G₁₉. Ema-SEL strain showed no CR to abamectin (0.28–1.65-fold), and profenofos (0.12–0.29-fold), but a very low to low CR to cypermethrin (6.02–11.29-fold). Abamectin was negatively cross-resistant with emamectin benzoate in Ema-SEL strain at G₁₃, G₁₅ and G₁₉ while profenofos also exhibited similar results at G₁₃, G₁₅, G₁₇ and G₁₉. Realized heritability (h²) of resistance to emamectin benzoate was 0.24 from G₃ to G₁₉. The results of projected rate of resistance development showed that if h² = 0.24, 0.34, and 0.44 at slope = 1.08, then 2.03, 1.43, and 1.11 generations, respectively are required for tenfold increase in LC₅₀ at 95 % selection intensity. Results of the present study suggested that P. solenopsis has the ability to develop resistance to emamectin benzoate but it can be managed by the alternate use of other insecticides including abamectin, profenofos and cypermethrin due to lack of/or very low to low CR with these insecticides.