Resistance Monitoring of Field Populations of Panonychus citri to Three Pesticides

[Objectives]The paper was to investigate the development of Panonychus citri resistance to commonly used pesticides in major citrus producing areas in China,and to screen out new green and efficient agents for its control and prevention.[Methods]The resistance changes of field populations of P.citri to abamectin,pyridaben,and bifenazate in 12 locations across five provinces in China were compared using the leaf disc impregnation method.[Results]P.citri in the tested areas exhibited the most severe resistance to abamectin,with approximately 91.7%of the field populations showing high levels of resistance to abamectin(112.1-560.5 times);50%of P.citri populations exhibited high levels of resistance to pyridaben(123.0-202.7 times),while the remaining populations showed intermediate levels of resistance(25.6-80.3 times);except for the Zhejiang Xiangshan 2019 and Jiangxi Yudu 2019 populations,which exhibited a medium level of resistance to bifenazate,the remaining 10 monitored populations demonstrated a high level of resistance to bifenazate(140.4-686.1 times).[Conclusions]It is advisable to discontinue the use of abamectin and bifenazate due to significant resistance observed in populations of P.citri monitored in 12 locations across 5 provinces.It is recommended to reduce the frequency of pyridaben use and alternate with other acaricides that have different mechanisms of action due to the varying degrees of resistance developed.

Overview of Occurrence,Prevention and Control of Panonychus citri in China

In order to further promote the prevention and control research of Panonychus citri and improve its control effect,this paper summarizes the main influencing factors of the outbreak,main control technology and drug resistance of P.citri,and puts forward the research focus and control strategy.

Acaricidal Activity of Boenninghausenia sessilicarpa Against Panonychus citri

Acaricidal activity of Boenninghausenia sessilicarpa against Panonychus cirri was tested in the laboratory. Four solvents were used to prepare crude extracts, petroleum ether, chloroform, ethyl acetate, and ethanol, among which ethanol was the most effective one. The results suggested that ethanol extracts of B. sessilicarpa had eminent acaricidal and ovicidal activities. Concentrated extracts were prepared using petroleum ether, chloroform, ethyl acetate, or distilled water as solvent. Mite mortality rates in the concentrated extracts by petroleum ether, chloroform, or distilled water were significantly lower than those by ethyl acetate. The LC50 values of eggs and female mites were 0.7639 and 1.1033 mg mL^-1, respectively. After liquid chromatography and thin layer chromatography, the concentrated extracts were separated into 14 groups of fractions and further tests for their acaricidal and ovicidal activities were conducted. Fraction 2 was found to possess higher acaricidal and ovicidal activities. The mortality of eggs and adult mites were 85.83 and 63.07%, respectively. Moreover, fraction 2 showed moderate oviposition inhibition effect （0.8795） against P. citri when the used dose was higher than 2.5 mg mL^-1

Analyses of Numerical Responses and Main Life Parameters for Determining the Suppression of Amblyseius cucumeris on Panonychus citri

In this paper, the numeral response and main parameters of experimental population life table were analyzed for determining the suppressing ability of Amblyseius cucumeris on Panonychus citri. The result showed that: (1) Under 21-31°C and 1 - 9 prey densities/leaf fragment condition, the prey consumptions of A. cucumeris increased with the temperature or prey density; (2) In 1:3 predator-prey ratio treatment, the suppression of P. citri (Ro=34.0053; T=19.4369; t=3.8204) was rather weak, it was enhanced as the ratio over 5:30, and the populations of P. citri in these treatments can be fully controlled within 4-5 days; (3) Under 25±1°C, 80-85% RH and 15L: 9D illumination conditions, the net reproductive rate, mean generation duration and the time for population double increase of P. citri (Ro=34.0053; T=19.4369; t=3.8204) were higher than those of A. cucumeris (Ro=21.8750; T=16.8943; t=3.7954). While the intrinsic rate of increase and finite rate of increase of the former (rm=0.1814; λ=1.1989) were lower than those of the latter (rm=0.1826; λ=1.2004). These results indicated that A. cucumeris is a desirable bio-control agent to suppress P. citri at lower population stage in citrus orchard.

联苯肼酯与2种杀螨剂复配对柑橘全爪螨的联合毒力

柑橘全爪螨是一种世界性害螨,目前对许多药剂已经产生抗性。药剂复配是治理抗性问题,延长药剂使用寿命的重要手段。为筛选出增效明显的复配新产品,本文选取联苯肼酯作为标准药剂,与阿维菌素和氟啶胺分别进行复配,并采用叶碟喷雾法测定其联合毒力及增效作用。结果表明,联苯肼酯、阿维菌素和氟啶胺的单剂LC 50分别为16.43、0.29 mg/L和12.63 mg/L。联苯肼酯与阿维菌素复配比例为19∶1和15∶5的共毒系数分别为135.02和158.40,具有增效作用。联苯肼酯与氟啶胺在6∶4、7∶3、5∶5、9∶1、8∶2复配比例的共毒系数分别为466.28、410.61、370.22、311.15和275.85,增效作用显著。

虱螨脲与其他药剂对柑橘全爪螨的联合毒力

为筛选与虱螨脲复配对柑橘全爪螨[Panonychus citri(McGregor)]具有增效作用的农药,采用喷雾法测定了虱螨脲与哒螨灵、阿维菌素、联苯肼酯、丁氟螨酯、炔螨特、虫螨腈复配后对柑橘全爪螨雌成螨的联合毒力,并通过测定共毒因子和共毒系数对各复配组合的联合毒力进行评价.结果表明,共毒因子大于20的有8组,其中虱螨脲与丁氟螨酯按质量比1000∶287复配时,共毒因子最高达79.78;共毒系数大于120的有10组,其中虱螨脲与阿维菌素、丁氟螨酯、哒螨灵分别按质量比1000∶22,1000∶240,1000∶1173复配时,共毒系数更大,增效作用更明显,其共毒系数分别为156.65,140.43,159.03,LC_(50)分别为42.463 mg/L,25.740 mg/L,39.619 mg/L.因此,虱螨脲与哒螨灵按质量比1000∶1173复配时,对柑橘全爪螨具有最佳的防治效果.研究结果为田间害螨防治及虱螨脲的科学合理使用提供了理论基础.

生物防治与化学防治协同处理防治柑橘全爪螨的温室试验

通过对在重庆市潼南区柏梓镇潼南柠檬脱毒种苗繁育中心的4号大棚中设置的6个处理,在化学防治的基础上选择用药后的不同时间释放捕食螨,以探究生-化协同防治柑橘全爪螨的效果.试验结果表明,施用阿维菌素后第6 d释放捕食螨对柑橘全爪螨的防效最好,虫口减退率和防治效果均可以达到98%以上;且相较于单一施用化学农药持效期更长,约为1.5月,而单一施用化学农药持效期只能维持在10 d左右.由气象因子数据和柑橘全爪螨发生动态相关性分析结果可知,施用化学农药后可提高柑橘全爪螨种群对高温的抗逆性;施用阿维菌素后第6 d释放捕食螨天气积分指数对柑橘全爪螨的影响最大,说明微气候也会对柑橘全爪螨的防治产生影响.研究结果为柠檬产业害螨绿色防治提供了更精细化的方案.

Genome-wide analysis of Panonychus citrimicro RNAs witha focus on potential insecticidal activity of 4 micro RNAs toeggs and nymphs

Panonychus citriMcGregor(Acari:Tetranychidae),a destructive citrus pest,causes considerable annual economic losses due to its short lifespan and rapid resistancedevelopment.MicroRNA(miRNA)-induced RNA interference is a promising approachfor pest control because of endogenous regulation of pest growth and development.Tosearch for miRNAs with potential insecticidal activity inP.citri,genome-wide analysis ofmiRNAs at different developmental stages was conducted,resulting in the identificationof 136 miRNAs,including 73 known and 63 novel miRNAs.A total of 17 isomiRNAsand 12 duplicated miRNAs were characterized.MiR-1 and miR-252-5p were identified asreference miRNAs forP.citriandTetranychus urticae.Based on differential expressionanalysis,treatments with miR-let-7a and miR-315 mimics and the miR-let-7a antagomirsignificantly reduced the egg hatch rate and resulted in abnormal egg development.Over-expression or downregulation of miR-34-5p and miR-305-5p through feeding significantlydecreased the adult eclosion rate and caused molting defects.The 4 miRNAs,miR-let-7a,miR-315,miR-34-5p,and miR-305-5p,had important regulatory functions and insectici-dal properties in egg hatching and adult eclosion.In general,these data advance our un-derstanding of miRNAs in mite biology,which can assist future studies on insect-specificmiRNA-based green pest control technology.

甲氰菊酯与单甲脒复配对桔全爪螨Pnonychus citri的增效作用研究

将甲氰菊酯和单甲脒通过复配对桔全爪螨进行室内毒力测定,表明两种药剂的各种配比均对桔全爪螨存在着不同程度的增效作用,其中以甲氰菊酯与单甲脒按1:4的比例复配增效作用最为明显,共毒系数达到373。田间药效试验也表明,20％的混剂乳油(4％甲氰菊酯+16％单甲脒)的药效明显高于20％的甲氰菊酯乳油和25％的单甲脒乳油。

基于形态和分子数据的山东梨园新成灾害螨柑橘全爪螨的鉴定

【目的】本研究旨在准确鉴定山东梨园一种新成灾害螨,为其进一步研究和有效防控奠定基础。【方法】采用体视显微镜直接观察雌成螨的形态特征,制作雄成螨的侧面观玻片标本,观察其阳茎形态特征,进行形态鉴定。从单头雌成螨中提取基因组总DNA,以螨类特异性引物扩增线粒体细胞色素氧化酶亚基Ⅰ(cytochrome oxidase subunitⅠ,COⅠ)基因及核糖体DNA第一内转录间隔区(internal transcribed spacer 1,ITS1)和第二内转录间隔区(internal transcribed spacer 2,ITS2)基因并测序,所得序列在NCBI网站上进行Blastn比对,下载与其一致性高的相关基因序列构建系统发育树和计算遗传距离,进行分子鉴定。【结果】结果表明,梨树上害螨的雌成螨背部有粗大突起,可确定为全爪螨属Panonychus害螨。雄螨阳茎特征与柑橘全爪螨Panonychus citri的很相似,其COⅠ,ITS1和ITS2基因序列均与柑橘全爪螨的相应序列具有很高的同源性(核苷酸序列一致性在99%以上),基于COⅠ,ITS1和ITS2基因序列计算的其与柑橘全爪螨间的遗传距离均远低于其与全爪螨属其他种间的遗传距离;在基于COⅠ,ITS1和ITS2基因序列构建的系统发育树上,梨树上害螨均分别与柑橘全爪螨以很高的置信度(分别为99%,99%和100%)聚在同一分支。【结论】形态特征结合分子数据分析可以确定山东梨园中新暴发成灾的害螨为柑橘全爪螨,说明柑橘全爪螨在中国的分布范围北移了,需引起高度重视。

噻虫嗪与螺虫乙酯混用对柑橘矢尖蚧和全爪螨的田间防治效果

为了筛选出能有效控制柑橘矢尖蚧和全爪螨的二元复配剂,采用田间小区试验研究了40%噻虫嗪·螺虫乙酯SC与其相应的2种单剂(21%噻虫嗪SC和22.4%螺虫乙酯SC)、生产上常用的100 g/L联苯菊酯EC和15%唑虫酰胺SC对柑橘矢尖蚧和全爪螨的防治效果。结果表明:40%噻虫嗪·螺虫乙酯SC对柑橘矢尖蚧的防治效果好,兼治柑橘全爪螨且持效期长,药后7~30 d对矢尖蚧的防治效果为92.44%~98.02%,药后3~30 d对全爪螨的防治效果为60.57%~84.86%;22.4%螺虫乙酯SC60 mg/kg对柑橘矢尖蚧和全爪螨高效,药后7~30 d对矢尖蚧的防治效果为85.45%~91.37%,药后3~30 d对全爪螨的防治效果为78.56%~95.12%;21%噻虫嗪SC 60 mg/kg和15%唑虫酰胺SC 50 mg/kg对柑橘矢尖蚧的防治效果一般而对全爪螨的防治效果较差,药后7~30 d对矢尖蚧的防治效果分别为62.73%~79.52%和49.90%~75.97%,药后3~30 d对全爪螨的防治效果分别为16.46%~53.09%和29.95%~70.11%;100 g/L联苯菊酯SC 30 mg/kg对矢尖蚧有一定效果、对全爪螨的效果较好,药后7~30 d对矢尖蚧的防治效果为23.35%~62.95%,药后3~30 d对全爪螨的防治效果为74.19%~88.74%。因此,在柑橘生产实践中,当矢尖蚧发生达到防治指标而全爪螨发生较轻时,只需喷施1次40%噻虫嗪·螺虫乙酯SC 80 mg/kg;若矢尖蚧和全爪螨发生均达到防治指标时,还应喷施1次22.4%螺虫乙酯SC 60 mg/kg。

广东地区红掌橘全爪螨危害调查

通过显微观察橘全爪螨生活史与产卵量,开展广东地区红掌橘全爪螨危害普查和调查,结果发现橘全爪螨从若螨发育为雌成螨的当天不产卵,第2天开始每天产卵3~4枚,多则5枚,产卵历时8 d,每雌螨总产卵量约28.40枚。雌螨生命周期约为17.90 d,从卵期、幼螨期、若螨期到成螨期分别为5.56、1.42、2.52和8.40 d。橘全爪螨主要危害红掌中下部老叶,以危害叶背为主,虫害发生初期叶背出现许多灰白色小点,严重时全叶呈灰白色。不同红掌品种橘全爪螨的危害虫情指数差异很大,‘维多’红掌受害最重,虫情指数20.4%;‘朝天娇’‘广花福运’‘红斑比诺’‘满天星’‘莉莉’5个红掌品种受害较轻,虫情指数均小于5.0%。本研究为提前预防螨虫危害和开展有效药剂筛选提供了科学依据。

土荆芥挥发油对化学杀螨剂防控柑橘全爪螨的减量增效作用

【目的】柑橘全爪螨Panonychus citri McGregor,属全球性害螨,可对柑橘产量和品质产生巨大影响,为防控柑橘全爪螨,开展土荆芥挥发油与化学杀螨剂复配对柑橘全爪螨防治效果的研究。【方法】采用25%阿维·乙螨唑悬浮剂、240 g/L螺螨酯悬浮剂、550 g/L阿维·氟啶胺悬浮剂及30%乙唑螨腈悬浮剂4种化学杀螨剂分别和土荆芥挥发油混配及单用开展田间药效试验,评估了10%土荆芥挥发油与上述4种化学杀螨剂复配后对柑橘全爪螨的防治效果。【结果】500 mg/L的土荆芥挥发油和25%阿维·乙螨唑悬浮剂混配药后在14 d和21 d的防治效果分别为90.01%、87.40%均显著优于25%阿维·乙螨唑悬浮剂单用在14 d(48.15%)和21 d(-41.61%)的防治效果。和240 g/L螺螨酯悬浮剂混配药后在7 d和14 d的防治效果分别为93.50%、91.31%均显著优于240 g/L螺螨酯悬浮剂单用在7 d(51.14%)和14 d(34.35%)的防治效果。而其与333mg/L阿维·氟啶胺悬浮剂混配药后1~3 d、250 mg/L乙唑螨腈悬浮剂混配药后21 d的防治效果均显著优于500 mg/L阿维·氟啶胺悬浮剂333 mg/L、乙唑螨腈悬浮剂未减量的单用防治效果。与土荆芥挥发油混配使用时阿维·氟啶胺悬浮剂和螺螨酯悬浮剂在单用供试浓度下减量33.4%、阿维·乙螨唑悬浮剂和乙唑螨腈悬浮剂在单用供试浓度下减量24.9%。【结论】研究表明土荆芥挥发油在和化学杀螨剂复配时有明显的减量增效作用,结果可为降低田间化学杀螨剂的用量提供参考。

柑橘全爪螨对4种杀螨剂的抗性监测及增效作用

为探明近年来柑橘全爪螨田间种群对常用杀螨剂抗性的变化趋势,采用玻片浸渍法于2008—2009年连续2a监测了柑橘全爪螨重庆种群对甲氰菊酯、哒螨酮、阿维菌素和甲维盐4种常用杀螨剂的抗性,同时测定了磷酸三苯酯(TPP)、顺丁烯二酸二乙酯(DEM)和增效醚(PBO)的增效作用。结果表明,柑橘全爪螨对甲氰菊酯的抗性上升速度较快,抗性增长倍数达5.1倍,哒螨酮次之,抗性增长倍数为2.2倍。柑橘全爪螨对阿维菌素的抗性两年间变化很小,相反对甲维盐的敏感性有所升高。增效作用研究表明,TPP对甲氰菊酯、阿维菌素和甲维盐的增效倍数分别为3.2倍、2.0倍和3.8倍。DEM对哒螨酮和甲维盐的增效倍数分别为3.3倍和2.6倍。PBO对甲氰菊酯、阿维菌素、哒螨酮和甲维盐的增效倍数分别为2.7倍、1.7倍、2.4倍和7.2倍。而TPP对哒螨酮以及DEM对甲氰菊酯和阿维菌素均未表现出明显的增效作用。

瑞香狼毒各组分杀螨活性及组分间相互作用的研究

瑞香狼毒根的乙醇索氏提取粗膏及粗膏的正己烷索氏提取物和石油醚索氏提取物对柑桔全爪螨的毒力分别是氧乐果原药毒力的0.34倍、12.8倍和11.5倍,其中可能含有更高毒性的物质.乙醇粗膏的乙酸乙酯索氏提取物对正己烷索氏提取物和石油醚索氏提取物有强烈的抑制减效作用.

桔全爪螨对哒螨灵抗性的选育及其生化机理

模拟田间药剂的选择压力 ,用哒螨灵对桔全爪螨 (Panonychus citri Mc Gregor)逐代处理 ,以选育其抗药性。结果表明 :选育 12代 ,抗性增长到 35.0倍 ;哒螨灵抗性品系对氧乐果、双甲脒、氯氟氰菊酯、水胺硫磷和炔螨特有交互抗性。通过增效剂和离体酶活性测定证明 :桔全爪螨对哒螨灵的抗性主要与谷胱甘肽 S-转移酶、多功能氧化酶和乙酰胆碱酯酶活性的提高有关。

46种植物提取物对柑橘红蜘蛛的杀螨活性

室内测定了采自桂东北46种植物的54种甲醇提取物对柑橘红蜘蛛的杀螨活性。结果表明：银杏等19种植物的活性高，24h校正死亡率大于90％；狭叶十大功劳等15种植物的活性中等。校正死亡率为60％～90％，其余植物提取物的校正死亡率在60％以下。进一步测定了8种植物提取物对柑橘红蜘蛛的触杀毒力，表明：银杏对柑橘红蜘蛛的毒力最高，LC50值为1．9248g／L。8种植物提取物对试虫的毒力顺序为：银杏〉黄柏〉广西地不容〉厚果鸡血藤〉扛板归〉常山〉江南星蕨〉鱼腥草。

不同柑桔品种上桔全爪螨的生长和种群动态差异

通过田间调查、室内盆栽苗接螨、离体叶片饲养等方法 ,考察了 14个柑桔品种上桔全爪螨种群动态 ,组建了其实验种群生命表 ,结果表明 :该螨在各柑桔品种上的种群密度有明显差异 ,平均密度以北碚 4 4 7、台湾晚白柚和垫江白柚上较高 ,柑新生系最低。雌成螨寿命在台湾晚白柚上最长 ,垫江白柚次之 ,柑新生系最短 ;产卵量以取食台湾晚白柚时最多 ,垫江白柚、五步红心柚次之 ,以柑新生系最少 ;在垫江白柚上的内禀增长率 (rm)最大 ,沙田柚、台湾晚白柚次之 ,金弹最小。根据桔全爪螨实验种群的参数判断 ,金弹和柑新生系属抗螨品种 ,台湾晚白柚、垫江白柚和北碚 4 4 7是感螨品种。从品种归类上来看 ,柚类品种和甜橙中的北碚 4 4 7感螨程度较高 ,金柑属的金弹和宽皮柑桔类的柑新生系感螨程度较低。甜橙类与宽皮柑桔类比较 ,前者感螨程度较高 ,后者相对较低 ,但宽皮柑桔类的早津感螨程度相对较高。

桔全爪螨的抗药性选育及其解毒酶活力变化

在室内模拟田间药剂的选择压力 ,用齐墩螨素和甲氰菊酯对桔全爪螨Panonychuscitri逐代处理 ,以选育其抗药性种群。选育至 12代 ,对齐墩螨素抗性增长到 7 30倍 ,对甲氰菊酯抗性增长到 17 11倍。增效剂和离体酶活性的测定结果表明 ,抗性种群的乙酰胆碱酯酶和多功能氧化酶的活性都提高了 ;推测羧酸酯酶、乙酰胆碱酯酶、多功能氧化酶和谷胱甘肽 S

粉棒束孢对柑橘全爪螨的毒杀活性及其生物学特性

室内测定了粉棒束孢(Paecilomyces farinosus)菌株nq1–1对柑橘全爪螨雌成螨的毒力,并通过单因素试验,分析该菌的生物学特性。结果表明:nq1–1菌株对柑橘全爪螨雌成螨的LC_(50)和LT_(50)分别为1.59×10~7/mL和7.9 d;菌株最适生长和产孢培养基分别为萨氏培养基和PDA培养基;蔗糖和有机氮源(赖氨酸)有利于该菌生长和产孢;菌丝生长和产孢的最适温度均为20℃,最适孢子萌发温度为25~28℃;菌丝生长、产孢以及孢子萌发的最适pH均为6.0;nq1–1菌株具有较强的抗紫外线能力;82.6%氧化亚铜(水分散粒剂)、75%百菌清(可湿性粉剂)、50%喹啉铜(可湿性粉剂)等杀菌剂与菌株相容性较好。nq1–1菌株对柑橘全爪螨有较好的毒杀活性,喜好偏低温、中性以及富含有机营养的环境。