茶尺蠖和灰茶尺蠖内共生菌Wolbachia的分子检测及序列分析

【目的】对茶尺蠖Ectropis obliqua及其近缘种灰茶尺蠖E.grisescens体内共生菌Wolbachia进行分子鉴定,确定两者体内Wolbachia的感染率及其进化地位,为进一步探讨其对茶尺蠖和灰茶尺蠖的潜在影响提供科学依据。【方法】采用Wolbachia的16S r RNA、fts Z和wsp基因特异性引物,通过PCR扩增法检测了我国3个茶尺蠖地理种群(浙江杭州、余杭和江苏无锡)和3个灰茶尺蠖地理种群(浙江新昌、湖北浠水和江西南昌)中Wolbachia的感染情况,并进行测序和序列分析。【结果】茶尺蠖和灰茶尺蠖都感染了Wolbachia,灰茶尺蠖的Wolbachia感染率为100%,但茶尺蠖的Wolbachia感染率在22%~95%,且PCR产物电泳得到的条带微弱。wsp序列在茶尺蠖和灰茶尺蠖种间、种内无差异;但16S r RNA序列在茶尺蠖和灰茶尺蠖种间、种内差异为0.362%~0.727%之间;茶尺蠖样本未成功扩增出fts Z序列,灰茶尺蠖样本获得2条fts Z基因序列差异为1.647%。基于Wolbachia的16S r RNA和wsp基因构建的系统发育树表明,本研究中茶尺蠖和灰茶尺蠖种群所感染的Wolbachia全部属于B组的Pip亚组。【结论】茶尺蠖和灰茶尺蠖均被B组Pip亚组的Wolbachia感染,但感染率相差很大,这为研究Wolbachia对茶尺蠖和灰茶尺蠖生物学及生态学的影响奠定了基础。     

灰茶尺蠖和茶尺蠖绿色防控技术研究进展

灰茶尺蠖和茶尺蠖作为鳞翅目两个近缘种,是茶园最重要的两种害虫。目前化学农药仍是茶园防治尺蠖的重要手段,容易导致“3R”问题,不利于茶园的可持续发展。本文从农业防治、物理防治、生物防治、化学生态防治和化学防治五个方面就灰茶尺蠖和茶尺蠖的绿色防控进行了综述。强调加强茶园田间管理和尺蠖监测预警,合理布局茶树品种,强化保护利用茶园本土天敌,科学高效地协调使用核型多角体病毒、性诱、灯诱等技术,从而实现对灰茶尺蠖和茶尺蠖的绿色防控技术集成应用,减少其对茶树的危害,为茶园优质安全生产提供强有力的保障。     

联苯菊酯与茚虫威对茶尺蠖中肠细胞结构及血淋巴解毒酶的影响

【目的】茶尺蠖Ectropisobliqua Prout是茶树上的重要害虫,本研究旨在研究茶园常用农药联苯菊酯与茚虫威两种农药对该虫中肠细胞结构及血淋巴酶活性的影响,为日后更好防治该虫提供理论基础。【方法】采用浸梢法在室内测定了5龄茶尺蠖幼虫对联苯菊酯与茚虫威的半致死浓度LC50值。采用LC_(50)浓度药液进一步处理茶尺蠖,通过透射电镜观察了联苯菊酯与茚虫威对茶尺蠖中肠细胞结构的影响,以及血淋巴中谷胱甘肽-S-转移酶(GSTs)、乙酰胆碱酯酶(AChE)和羧酸酯酶(CarE)3种解毒酶的酶活性变化。【结果】联苯菊酯与茚虫威对5龄茶尺蠖幼虫的LC_(50)值分别为5.884 mg.L~(-1)与0.268 mg.L~(-1)。透射电镜显示,中肠柱状细胞的微绒毛大量解体、散乱分布于肠腔中,胞内细胞器向顶膜转移,并发生明显的形变。酶活检测结果表明,经联苯菊酯处理后,GSTs的酶活基本不变,而AchE和CarE的酶活性被显著诱导。经茚虫威处理后,GSTs、AchE和CarE的酶活性均被显著抑制。【结论】联苯菊酯与茚虫威不仅具有破坏茶尺蠖中肠柱状细胞的微绒毛,使各细胞的牢固性与紧密性缺失,还会破坏柱状细胞内部的细胞器功能。联苯菊酯在血淋巴中的解毒代谢与酯酶(AChE和CarE)有关,与转移酶(GSTs)无关,而茚虫威与酯酶(AChE和CarE)和转移酶(GSTs)两者均有关。     

浙江茶尺蠖地理种群已分化成为不同种

【目的】明确茶尺蠖Ectropis obliqua Prout不同地理种群的种群分化和生殖隔离程度。【方法】对分别在浙江杭州和衢州两地田间采集的茶尺蠖杭州种群（H）和衢州种群（Q）两个种群,进行形态学鉴定、生物学特征观察以及正反交试验。【结果】形态学与生物学观察结果表明,除Q种群的体形较大和体翅颜色略深外,两个种群的外部形态、生殖器解剖结构和雌蛾产卵量等基本相同。遗传杂交试验结果表明,无论是正交还是反交,杂交后均能获得子一代（F1）;与种群内自交相比,杂交后雌成虫的产卵量下降,卵的孵化率显著降低;幼虫的历期明显缩短且化蛹时间分布不规则,蛹重变轻;蛹的羽化率降低,羽化的成虫雌雄性比严重失调。【结论】茶尺蠖杭州种群（H）和衢州种群（Q）两个种群存在生殖隔离,有明显的种群分化,应属于不同种。     

食物对四个茶尺蠖地理种群发育和生殖的影响

【目的】明确不同成熟度茶树叶片对浙江等4个地理种群茶尺蠖Ectropis oblique Prout发育和生殖的影响,旨在揭示不同地理种群茶尺蠖对不同质量食物的适应力差异,为制定各地茶尺蠖种群的差异化防治策略提供依据。【方法】通过对浙江、湖北、福建和江西等地茶尺蠖种群饲喂嫩叶、成叶和老叶3种不同成熟度的茶树叶片后,对比研究其发育历期、死亡率以及内禀增长率等生长发育与生命表参数。【结果】不同地理种群茶尺蠖发育历期存在显著差异,且均以成叶处理发育历期最短;幼虫3龄前死亡率以老叶处理死亡率最高(达33%),嫩叶处理最低(达15%),每雌产卵量以嫩叶处理最高(达362.23粒),老叶处理最低(达56.67粒);在内禀增长率、净繁殖率、种群加倍时间、周限增长率等5个生命表参数方面,各地理种群在成叶处理下差异不显著(P>0.05),嫩叶和老叶处理下差异显著(P<0.05)。通过茶树叶片内含物与茶尺蠖发育相关性分析,发现不同地理种群生命参数与各物质成分的相关性不尽一致,分别有2种物质与湖北种群、江西种群相关性最大,分别有1种物质与浙江种群、福建种群密切相关。【结论】浙江、福建、湖北和江西4地区茶尺蠖种群在取食适应性方面存在明显差异。其中,浙江种群取食不同发育成熟度茶树叶片后的适应性较强,在幼虫期存活率、每雌产卵量和世代净繁殖率(R0)等重要参数方面都较突出;而湖北种群对老叶这一不良食物的适应能力最弱(死亡率最高、净繁殖率较低);江西种群对老叶的适应能力较弱(死亡率较高、净繁殖率最低)。     

茶核·苏云菌悬浮剂对灰茶尺蠖的田间防控应用

【目的】茶尺蠖核型多角体病毒EcobNPV是一种重要的昆虫病原微生物,可侵染茶尺蠖Ectropis obliqua和灰茶尺蠖Ectropisgrisescens2种宿主。为探明茶尺蠖核型多角体病毒制剂的田间应用技术,对影响防效的3个因子喷施方式、剂量和虫龄进行研究。【方法】采用植保无人机和人工喷施2种喷施方式,比较茶核·苏云菌悬浮剂（1×104 PIB·2 000 IU/μL）防治灰茶尺蠖的效果;设置75、150和375 mL/667 m²3种剂量,比较茶核·苏云菌悬浮剂对灰茶尺蠖的防治效果;并比较其对灰茶尺蠖1龄、2龄和3龄不同虫龄的防治效果。【结果】在相同剂量下,用植保无人机和人工喷施病毒制剂对灰茶尺蠖的总防效分别为69.0%和67.6%,两者无显著差异;在75、150和375 mL/667 m23种剂量,比较茶核·苏云菌悬浮剂对灰茶尺蠖的防治效果;并比较其对灰茶尺蠖1龄、2龄和3龄不同虫龄的防治效果。【结果】在相同剂量下,用植保无人机和人工喷施病毒制剂对灰茶尺蠖的总防效分别为69.0%和67.6%,两者无显著差异;在75、150和375 mL/667 m² 3种剂量下病毒制剂对灰茶尺蠖的防效差异显著,其中375 mL/667 m2 3种剂量下病毒制剂对灰茶尺蠖的防效差异显著,其中375 mL/667 m²剂量下的防效最高,150 mL/667 m2剂量下的防效最高,150 mL/667 m²其次,150 mL/667 m2其次,150 mL/667 m²和375 mL/667 m2和375 mL/667 m²剂量对灰茶尺蠖的总防效均在90%以上;病毒制剂对灰茶尺蠖1龄、2龄和3龄幼虫的防效分别为93.3%、78.7%和67.8%,对1龄幼虫的防效显著高于3龄。【结论】茶核·苏云菌悬浮剂防治灰茶尺蠖可选用植保无人机喷施,剂量可选用150-375 mL/667 m2剂量对灰茶尺蠖的总防效均在90%以上;病毒制剂对灰茶尺蠖1龄、2龄和3龄幼虫的防效分别为93.3%、78.7%和67.8%,对1龄幼虫的防效显著高于3龄。【结论】茶核·苏云菌悬浮剂防治灰茶尺蠖可选用植保无人机喷施,剂量可选用150-375 mL/667 m²,以1龄幼虫期喷施防效为最佳。     

沃尔巴克氏菌调控小茶尺蠖和灰茶尺蠖杂交卵孵化

【目的】明确沃尔巴克氏菌Wolbachia对茶尺蠖两近缘种杂交卵孵化的影响及相关机制。【方法】使用2.5 mg/mL四环素浸液处理1 min后的新鲜茶树叶片连续饲喂灰茶尺蠖Ectropis grisescens幼虫3代,建立不携带Wolbachia的灰茶尺蠖种群。通过携带和不携带Wolbachia的灰茶尺蠖成虫分别与小茶尺蠖E.obliqua成虫进行杂交,探究Wolbachia对二者杂交卵孵化的影响。同时利用iTRAQ技术检测并分析携带和不携带Wolbachia的灰茶尺蠖精子蛋白的差异。【结果】与自然携带Wolbachia的灰茶尺蠖相比,去除Wolbachia后的灰茶尺蠖与小茶尺蠖杂交卵孵化率从3.92%显著提高到56.20%,表明Wolbachia诱导胞质不亲合。精子蛋白差异分析显示,携带和不携带Wolbachia的灰茶尺蠖的精子蛋白中,共有128个蛋白显著差异表达,其中KEGG数据库注释到45个差异蛋白富集到鞘脂类代谢、唾液分泌、溶酶体、鞘脂信号通路和鞘糖脂生物合成等106个通路中,其中鞘脂类代谢通路中与神经酰胺合成相关的神经酰胺酶和磷酸酯酶显著上调表达。【结论】共生菌Wolbac...     

茶尺蠖生物防治进展

茶尺蠖Ectropis obliqua Prout是茶园中的重要害虫,对它的生物防治研究国内已做了较多的工作.本文从茶尺蠖的研究基础-大量饲养和它的病原性天敌、捕食性天敌、寄生性天敌及信息素等方面对茶尺蠖的生物防治研究作了综述.     

灰茶尺蠖核型多角体病毒对灰茶尺蠖的致病性研究

采取室内毒力测定和田间防效调查相结合的方法,对灰茶尺蠖核型多角体病毒(Ectropis grisescensnucleopolyhedrovir-us)的致病力进行了研究。毒力测定结果表明,该病毒对2龄灰茶尺蠖幼虫的剂量对数-死亡机率值回归方程为y=-0.8774 0.9498x,LC50=1.5417×106PIB.mL-1;田间用浓度为1×107、1.5×107和2×107PIB.mL-1的EgNPV防治灰茶尺蠖,防效分别达58.81%、89.51%和94.81%。     

浙江茶区茶尺蠖两近缘种的遗传分化及分布

【目的】为了揭示浙江省茶区灰茶尺蛾Ectropis grisescens和小茶尺蠖Ectropis obliqua两近缘种的分布情况。【方法】利用线粒体细胞色素氧化酶Ⅰ(mt COⅠ)基因作为分子标记,对采自浙江省17个地点茶园的茶尺蠖533个样品进行了鉴定,并分析了灰茶尺蛾和小茶尺蠖在浙江的地理分布情况。【结果】在调查的17个地点中,11个地点的茶尺蠖样品全部为灰茶尺蛾,另外3个地点(安吉、余杭和龙坞)采集的样品全部为小茶尺蠖,其余的3个地点(杭州西湖、杭州临安和杭州富阳)为两近缘种的混发区。【结论】在浙江省茶区,灰茶尺蛾的分布范围较广,小茶尺蠖的分布范围较窄,同时存在两近缘种的混发区。     

Prevalence and stability of insecticide resistances in field population of Spodoptera litura (Lepidoptera: Noctuidae) from Huizhou,Guangdong Province,China

The field population of Spodoptera litura from Huizhou, Guangdong Province, China was evaluated for resistance to 21 insecticides, including conventional and new chemistry insecticides. Extreme levels of resistance were observed to metaflumizone and emamectin benzoate with resistance factors of 234.1 and 183.3, respectively. Resistance to abamectin was also high (perhaps extremely high) and over 71.9-fold. The Huizhou population of S. litura possessed high resistance to deltamethrin (96.5-fold) and moderate resistance to beta cyfluthrin and lambda cyhalothrin but remained susceptible to bifenthrin. Moderate resistance to chlorantraniliprole (22.3-fold), endosulfan (22.2-fold), tebufenozide (10.7-fold) and thiodicarb (14.3-fold), and low-level resistance to fipronil, indoxacarb and spinosad were also reported in this population. This field population remained susceptible to acetamiprid, chlorfenapyr, chlorfluazuron, hexaflumuron, chlorpyrifos, pyridalyl and spinetoram. The stabilities of resistance to metaflumizone, emamectin benzoate, deltamethrin, chlorantraniliprole and endosulfan were evaluated, the resistance level decreased when the insecticide stress was removed, suggesting stop of the application of insecticides with high level resistance could be implemented into the resistance management. Because S. litura from Huizhou developed resistance to multiple insecticides, integration of different control practices, especially the rotation of insecticides with biocontrol agents, should be performed in the management of this pest. The results suggested the suspension of the application of insecticide to which S. litura had developed high level of resistance in order to mitigate the resistance status, and the use of the insecticides to which this pest remained sensitive, including spinetoram, pyridalyl, indoxacarb, hexaflumuron, chlorfluazuron, chlorfenapyr and bifenthrin, could be incorporated into the alternating application for resistance management.     

Could resistance to insecticides in Plutella xylostella (Lep., Plutellidae) be overcome by insecticide mixtures?

Abstract: To investigate if synergism occurs between pyrethroids, organophosphates and new insecticides, we tested representatives of these compounds (bifenthrin, chlorpyrifos, spinosad, indoxacarb and emamectin) against the diamondback moth (Plutella xylostella). Larvicidal activity of these insecticides was assessed separately and together on a susceptible strain (Lab‐UK) of P. xylostella as well as a field population collected from Multan. The field population showed significant resistance to chlorpyrifos (331 100‐fold), bifenthrin (45 200‐fold), emamectin (1800‐fold), spinosad (11‐fold) and indoxacarb (5600‐fold) when compared with the Lab‐UK population. When insecticides were mixed based on LC₅₀ and tested at serial concentrations against Lab‐UK, significant synergy (CI < 1) occurred between bifenthrin, spinosad and emamectin. In contrast, the interaction between bifenthrin and indoxacarb was additive (CI = 1). The toxicity of bifenthrin against the field population increased significantly (P < 0.01) when combined with spinosad, emamectin and indoxacarb. Synergistic effects could be attributed to the complementary modes of action by these insecticide classes acting on different components of nerve impulse transmission (which are not identical for bifenthrin and indoxacarb either). However, chlorpyrifos/bifenthrin mixture was not significantly different either from bifenthrin or chlorpyrifos alone, indicating an additive affect. In combination with spinosad and emamectin, tested against the resistant field population, the toxicity of chlorpyrifos increased significantly and even more so with indoxacarb. Mixtures could also give rise to multiple resistance that may extend across other chemical classes and thus become difficult to manage. Therefore, alternative strategies such as mosaics or rotations should be considered. That is, though synergistic effects have been found, this should not be followed up as a strategy to manage resistant field populations.     

西花蓟马田间种群对常用杀虫剂的抗性现状及防治对策

【目的】西花蓟马Frankliniella occidentalis在中国是一种严重危害温室蔬菜的入侵害虫。本研究旨在了解该害虫在中国的抗药性现状,为防治该害虫提供理论支持。【方法】采用Munger cell法测定了北京,山东寿光和青岛以及云南晋宁和呈贡等5个地区西花蓟马田间种群对多杀菌素、毒死蜱、阿维菌素、甲维盐、氟氯氰菊酯、溴虫腈、灭多威、吡虫啉和啶虫脒9种杀虫剂的抗药性水平,同时利用这些田间种群测定了多功能氧化酶抑制剂胡椒基丁醚（PBO）、谷胱甘肽S 转移酶抑制剂顺丁烯二酸二乙酯（DEM）和羧酸酯酶抑制剂三丁基三硫磷酸酯（DEF）对多杀菌素、吡虫啉和甲维盐的增效作用。【结果】生物测定结果表明,北京、晋宁及呈贡种群分别对多杀菌素产生了34.45, 47.45和64.45倍的高水平抗性;晋宁种群对灭多威和甲维盐分别产生了16.58和11.03倍的中等水平抗性;呈贡种群对甲维盐、啶虫脒、吡虫啉、阿维菌素、溴虫腈分别产生了24.17, 21.69, 20.05, 16.45和10.31的中等水平抗性;青岛种群对啶虫脒和吡虫啉产生了17.70和12.49倍的中等水平抗性;寿光种群没有对任何杀虫剂产生高等或中等水平抗性。增效剂生物测定结果表明,对于吡虫啉和甲维盐,多功能氧化酶抑制剂PBO在所有田间种群上均有显著的增效作用。谷胱甘肽S-转移酶抑制剂DEM在呈贡、寿光和青岛种群中对吡虫啉存在显著增效作用;在北京、呈贡和寿光种群中,DEM对甲维盐存在显著增效作用。羧酸酯酶抑制剂DEF在呈贡、晋宁和青岛种群中对吡虫啉存在显著增效作用;在北京、呈贡和晋宁种群中,DEF对吡虫啉存在显著增效作用。但所有增效剂在各田间种群中对多杀菌素均无显著增效作用。【结论】结果提示：在使用多杀菌素防治西花蓟马时,应与其他杀虫剂轮换使用;此外,可通过添加酶抑制剂来增强甲维盐和吡虫啉对西花蓟马的防效。     

Monitoring of diamondback moth (Lepidoptera: Plutellidae) resistance to spinosad, indoxacarb, and emamectin benzoate

Six to nine populations of the diamondback moth, Plutella xylostella (L.), were collected annually from fields of crucifer vegetables in the United States and Mexico from 2001 to 2004 for baseline susceptibility tests and resistance monitoring to spinosad, indoxacarb, and emamectin benzoate. A discriminating concentration for resistance monitoring to indoxacarb and emamectin benzoate was determined based on baseline data in 2001 and was used in the diagnostic assay for each population in 2002-2004 together with a discriminating concentration for spinosad determined previously. Most populations were susceptible to all three insecticides, but a population from Hawaii in 2003 showed high levels of resistance to indoxacarb. Instances of resistance to spinosad occurred in Hawaii (2000), Georgia (2001), and California (2002) as a consequence of a few years of extensive applications in each region. The collaborative monitoring program between university and industry scientists we discuss in this article has provided useful information to both parties as well as growers who use the products. These studies provide a baseline for developing a more effective resistance management program for diamondback moth.     

新疆和云南番茄潜叶蛾种群对六种杀虫剂的敏感性及其与解毒酶活性的关系

【目的】番茄潜叶蛾Tuta absoluta 是新入侵我国的对番茄具有毁灭性危害的入侵害虫,目前入侵我国的番茄潜叶蛾种群对杀虫剂的抗性尚无报道。本研究旨在明确新疆和云南番茄潜叶蛾田间种群对6种常用杀虫剂的敏感性及其与解毒酶活性的关系。【方法】采用浸叶法测定6种常用杀虫剂对番茄潜叶蛾新疆和云南种群2龄幼虫的室内毒力。通过对2龄幼虫的生物测定确定3种增效剂［CYP450抑制剂胡椒基丁醚(PBO)、酯酶抑制剂磷酸三苯酯(TPP)和GST抑制剂丁烯二酸二乙酯(DEM)］对氯虫苯甲酰胺的增效作用。采用酶活性分析测定室内敏感种群和田间抗性种群(新疆种群) 2龄幼虫体内解毒酶［细胞色素P450酶(CYP450)、谷胱甘肽S-转移酶(GST)和羧酸酯酶(CarE)］活性,以确定杀虫剂抗性与解毒酶活性的关系。【结果】番茄潜叶蛾云南种群对6种杀虫剂的敏感性由高到低依次为甲维盐、溴虫腈、多杀菌素、茚虫威、氯虫苯甲酰胺和高效氯氰菊酯。新疆种群对6种杀虫剂的敏感性由高到低依次为甲维盐、溴虫腈、氯虫苯甲酰胺、多杀菌素、茚虫威和高效氯氰菊酯。与室内敏感种群相比,云南和新疆种群对氯虫苯甲酰胺的抗性水平最高,抗性倍数分别为212.7和169.3倍。生物测定结果表明,3种增效剂PBO, TPP和DEM均对氯虫苯甲酰胺无明显增效作用。酶活性测定结果表明,番茄潜叶蛾室内敏感种群和田间抗性种群之间2龄幼虫中CYP450, GST和CarE活性无显著差异。【结论】番茄潜叶蛾新疆和云南种群对测试的6种杀虫剂产生不同程度的抗性,对氯虫苯甲酰胺的抗性最高,番茄潜叶蛾对杀虫剂的抗性与解毒酶活性无关。本研究的结果对番茄潜叶蛾的田间防治和杀虫剂抗性治理具有指导意义。     

斜纹夜蛾抗药性监测及茚虫威对其解毒代谢酶的影响

【目的】斜纹夜蛾Spodoptera litura (Fabricius)是主要的农业害虫之一。本研究旨在明确该害虫在湖南省5个主要蔬菜种植区的抗药性水平,并探讨该害虫对茚虫威的抗性与解毒代谢酶活性之间的关系,为斜纹夜蛾有效防控及抗性治理提供依据。【方法】采用浸叶法测定了2014-2016年湖南5地斜纹夜蛾田间种群对10种杀虫剂的抗性水平;将斜纹夜蛾敏感种群3龄幼虫在死亡率40%~70%的选择压下用茚虫威进行汰选,比较了斜纹夜蛾敏感种群和抗茚虫威种群的羧酸酯酶、谷胱甘肽S-转移酶和多功能氧化酶对硝基苯甲醚O-脱甲基活性。【结果】湖南5地斜纹夜蛾田间种群对有机磷类杀虫剂产生了26.9~220.2倍的抗性,对氨基甲酸酯类杀虫剂产生了68.3~890.8倍的抗性,对拟除虫菊酯类杀虫剂产生了21.0~267.2倍的抗性,对相对较新型杀虫剂（甲维盐、阿维菌素、茚虫威和溴虫腈）产生了5.2~53.4倍的抗性。经茚虫威汰选后第14代[抗性倍数(resistance ratio, RR)=26.43]斜纹夜蛾羧酸酯酶、谷胱甘肽S-转移酶和对硝基苯甲醚O-脱甲基酶活性分别上升2.86, 1.01和1.83倍。【结论】斜纹夜蛾对多种药剂产生了不同水平的抗性,斜纹夜蛾幼虫羧酸酯酶和对硝基苯甲醚O-脱甲基活性增强可能是斜纹夜蛾对茚虫威的抗性上升的重要因素。     

A field study investigating the insecticidal efficacy against Diaphorina citri Kuwayama on Kinnow mandarin,Citrus reticulata Blanco trees

Asian citrus psyllid is a most damaging insect pest of citrus. In this field study, the efficacy of seven insecticides (emamectin benzoate, bifenthrin, chlorfenapyr, fipronil, imidacloprid, pyriproxyfen and thiamethoxam) was evaluated against Diaphorina citri Kuwayama in the citrus orchard of Kinnow mandarin, Citrus reticulata Blanco. The insecticides revealed a differential and substantial relative efficacy against D. citri compared to the untreated plants. The insecticidal effect attributed as percent reduction in insect population was more prominent after three days of spray: highest reduction values were recorded with thiamethoxam (50.89%), imidacloprid (44.27%) and bifenthrin (42.94%) after first spray, and thiamethoxam (83.36%), imidacloprid (73.20%) and bifenthrin (72.66%) after second spray. Thus, neonicotinoids (thiamethoxam and imidacloprid) and pyrethroid (bifenthrin) resulted as highly effective against D. citri at three days after both sprays. At seven days, imidacloprid (63.53%) and fipronil (62.47%) presented relatively higher population reduction after first spray, and thiamethoxam (92.66%) and chlorfenapyr (89.59%) after second spray. At 12 days, the insecticidal effect on insect population became significantly at par after each spray except chlorfenapyr that reflected high population reduction (93.17%) only after second spray. It is also obvious from the data that there is need of regular monitoring to suppress the psyllids population below threshold level by timely application of the second insecticidal spray.