BACKGROUND:Sublethal pesticide risk to biological control agents is often judged by survival alone, although predators that survive exposure may still lose predatory performance. Here, we quantified the functional response of F1 and F2 Orius similis (third- to fifth-instar nymphs and male and female adults) to second-instar Frankliniella occidentalis after exposure to imidacloprid at the lethal concentrations causing 10% or 20% mortality (LC10 and LC20, respectively) through residual contact or prey-mediated ingestion. RESULTS:All stages retained a Holling type II response, but the magnitude and expression of impairment were strongly stage-, route-, concentration-, and generation-dependent. Fifth-instar nymphs and adults contributed most to prey suppression, whereas younger nymphs were most sensitive to performance loss. Residual contact tended to increase handling time, especially in younger nymphs, whereas prey-mediated ingestion more consistently reduced attack rate; both routes affected multiple functional-response parameters. Some control-standardized deficits were evident in the F2 generation, particularly in younger nymphs. CONCLUSION:Sublethal imidacloprid eroded the predatory performance of O. similis in a route-specific and generation-dependent manner during continuous multigenerational exposure, indicating that compatibility with this predator should be judged using functional endpoints in addition to survival in integrated pest management programs. © 2026 Society of Chemical Industry.

ABSTRACT Neonicotinoid residues can compromise biological control in integrated pest management, yet the role of exposure duration is rarely quantified for predatory bugs. Here, we compared short‐term (24 h) and long‐term sublethal exposure to imidacloprid (LC 10 and LC 20 ) on the predatory performance of Orius similis against the western flower thrips Frankliniella occidentalis . Across nymphal instars and adults, prolonged exposure consistently reduced daily predation and weakened functional response parameters, with lower attack rates ( a ), longer handling times ( T h ) and reduced control capacity ( a / T h and 1/ T h ). All treatments conformed to Holling type II, but long‐term exposure amplified the decline in searching efficiency across prey densities. These results indicate that chronic, low‐dose imidacloprid pressure can cumulatively erode predator efficacy even when acute toxicity is low, highlighting the need to account for exposure duration when coordinating imidacloprid applications with releases or conservation of Orius ‐based biocontrol programs.

Although the use of chemical insecticides to control Frankliniella occidentalis is widespread, it may also affect its dominant predators such as Orius similis. To understand the consequences of imidacloprid on the growth, development, and reproduction of O. similis, we investigated its toxicity and selected the concentrations of LC10 and LC20 for both contact and stomach toxicity tests. Using the age-stage two-sex life table theory, we evaluated the impact of imidacloprid on the life table of the O. similis population. The results showed that the LC10 and LC20 values for each developmental stage of O. similis were lower under contact treatment than those under stomach toxicity treatment. After treatment with imidacloprid, the average oviposition by O. similis decreased compared to the control, and the net reproductive rate, gross reproduction rate, intrinsic rate of increase, and finite rate of increase were also lower than the control. The results also indicated that the peak value of age-stage-specific fecundity of O. similis was delayed by 1–2 days after imidacloprid treatment. Predictions for population growth of O. similis under unrestricted conditions showed that at 60 days, the population size of the control treatment was 2.06 times and 3.20 times that of LC10 contact and stomach toxicity treatment, respectively. For LC20 concentration, the control treatment's population size was 2.75 times and 3.87 times, respectively. Exposure to imidacloprid at different concentrations and treatment with contact and stomach toxicity had adverse effects on the growth and population growth of O. similis. Under imidacloprid stomach toxicity treatment, O. similis showed longer growth time and a slower population growth rate, indicating strong adaptability to the contact environment.

Insecticides are an indispensable and important tool for agricultural production. However, the inappropriate application of insecticides can cause damage to the food chain and ecosystem. Orius similis is an important predatory and natural enemy of Frankliniella occidentalis. Imidacloprid is widely used to control pests, but will inevitably exert adverse effects on O. similis. In order to determine the effect of different imidacloprid treatments on the ability of O. similis to prey on the 2nd-instar nymphs of F. occidentalis, we determined the toxicity and predation of imidacloprid on different stages of O. similis under contact and ingestion treatments. In addition, we used the Holling disc equation to evaluate the ability of O. similis to search and exhibit predatory activity following contact and ingestion treatments. Analysis showed that the highest LC10 and LC20 values for imidacloprid contact and ingestion toxicity treatment were 17.06 mg/L and 23.74 mg/L, respectively. Both imidacloprid treatments led toa reduction in the predatory of O. similis on prey. The functional responses of the 3rd to 5th instar nymphs, along with female and male O. similis adults to the 2nd-instar nymphs of F. occidentalis were consistent with the Holling type II response following contact and ingestion with imidacloprid. However, following imidacloprid treatment, the handing time (Th) of O. similis with single F. occidentalis was prolonged and the instantaneous attack rate (a) was reduced after imidacloprid treatment. The predatory capacity (a/Th) of female O. similis adults when treated with the LC10 concentration of imidacloprid by ingestion was 52.85; this was lower than that of the LC10 concentration of imidacloprid in the contact treatment (57.67). The extent of predation of O. similis on the 2nd-instar nymphs of F. occidentalis was positively correlated with prey density, although the search effect was negatively correlated with prey density. The most extensive search effect was exhibited by adult O. similis females. Simulations with the Hessell-Varley interference model showed that an increase in the number of O. similis would reduce search efficiency regardless of whether they were treated with imidacloprid or not. Thus, O. similis, especially female adults, exhibited strong potential for controlling the 2nd-instar nymphs of F. occidentalis. The toxicity of ingestion following treatment with the same concentration of imidacloprid in O. similis was greater than that of contact treatment. When using O. similis to control F. occidentalis in the field, we should increase the number of female adults released, and prolong the interval between imidacloprid treatment and O. similis exposure. This strategy will improve the control ability of O. similis, coordinate both chemical and biological control, reduce the impact of pesticides on the environment, and improve the efficiency of agricultural production.

为探究溴氰菊酯对南方小花蝽Orius similis捕食番茄潜叶蛾Tuta absoluta能力的影响,本研究以溴氰菊酯对南方小花蝽的致死中浓度为处理浓度,采用药膜法处理南方小花蝽成虫,然后让存活的南方小花蝽取食番茄潜叶蛾卵及1龄幼虫,分析溴氰菊酯对其捕食功能反应及捕食行为的影响.结果表明,经致死中浓度的溴氰菊酯处理后,南方小花蝽捕食番茄潜叶蛾的能力及行为均受到影响,功能反应模型仍符合Holling Ⅱ模型,但南方小花蝽处理猎物的时间延长,控害效能降低,搜寻效应下降,成虫对卵和1龄幼虫的日最大捕食量分别下降了 47.37粒/皿、9.47头/皿;而处理1粒番茄潜叶卵和1头1龄幼虫所用的时间分别延长了 777.6 s和3 456.0 s,同时南方小花蝽搜寻、行走、捕食番茄潜叶蛾卵的行为时间分别缩短了 444.2、750.2、919.6 s,静止和梳理时间则分别延长了 1 677.6、403 s,对番茄潜叶蛾卵和1龄幼虫的捕食量分别降低了 4头和1头.因此,溴氰菊酯对南方小花蝽捕食能力产生了抑制作用,在田间防控番茄潜叶蛾时应延长溴氰菊酯与南方小花蝽使用的间隔时间,更好地协调化学与生物防治.

为明确辣椒田蓟马及主要捕食性天敌昆虫种类和发生规律.于2019年和2020年对昆明市盘龙区辣椒田的蓟马及主要捕食性天敌昆虫的种类及种群数量进行了调查,并进行了时间生态位分析.结果表明,辣椒田蓟马种类共有10种,优势种为西花蓟马Frankliniella occidentalis、黄蓟马Thrips flavus、八节黄蓟马T.flavidulus和花蓟马F.intonsa,其中西花蓟马的优势度最高,两年分别为0.593和0.551;主要捕食性天敌昆虫有南方小花蝽Orius similis、二叉小花蝽O.bifilarus和异色瓢虫Harmoniaaxyridis,其中南方小花蝽优势度最高,两年分别为0.759和0.728.两年中,西花蓟马的种群数量随时间变化波动幅度最大,在7月中上旬数量最高值两年分别为66.5头/m2和61.5头/m2,而捕食性天敌昆虫活动高峰时间滞后于蓟马.2019年黄蓟马时间生态位宽度最高,为0.80;2020年八节黄蓟马时间生态位宽度最高,为0.87.黄蓟马和八节黄蓟马同其他优势种蓟马的生态位重叠指数高,两种蓟马在时间序列上活动情况相似.3种捕食性天敌的时间生态位宽度和生态位重叠指数相近,在辣椒田存在一定的竞争作用.辣椒田蓟马发生量大且种类呈现多样性,其中西花蓟马种群数量较高,应着重对其进行防治.南方小花蝽、二叉小花蝽、异色瓢虫是控制辣椒蓟马的主要捕食性天敌昆虫,在辣椒花期前以及各种农事操作时尽可能保护其种群数量,增强天敌对蓟马的自然控害功能.

为明确西花蓟马在不同种植环境菊苗上的种群活动规律与季节消长动态,采用五点取样,利用粘虫板诱集法对不同种植环境菊苗上西花蓟马种群动态进行调查,分析了 2018-2020年在不同种植环境下前茬苗上西花蓟马对后茬苗的影响.结果表明:西花蓟马种群数量在前茬苗和后茬苗上均出现先增加后减少的趋势,西花蓟马主要发生期的时长与菊苗种植时间的长短有关;在不同种植环境下,前茬苗上西花蓟马的主要发生期均集中在3月末—6月末,种群数量最多时露地可达654.6头·板-1,单体棚可达373.8头·板-1,连栋大棚可达146.4头·板-1;后茬苗上主要发生期集中在7月中旬—10月中旬,种群数量最多时单体棚为551.2头·板-1,露地为134.3头·板-1,连栋大棚为57.7头·板-1;前茬苗上西花蓟马主要发生期的种群数量露地＞单体棚＞连栋大棚,后茬苗上西花蓟马主要发生期的种群数量单体棚＞露地＞连栋大棚;前茬苗上西花蓟马对后茬苗上西花蓟马的影响露地＞单体棚＞连栋大棚.连栋大棚内西花蓟马种群数量最小且在连栋大棚内前茬苗对后茬苗西花蓟马种群数量影响最小,可以有效控制菊苗上的西花蓟马种群数量.

Frankliniella occidentalis Pergrande is important invasive pests in China, causing damage to agricultural production, and Orius similis Zheng is the dominant predator species of F. occidentalis. A two-year survey was conducted to determine the population density of F. occidentalis and O. similis, on chili (Capsicum annuum L.) and maize (Zea mays L.) crops and surrounding weed species, which included white clover (Trifolium repens L.), St. John's wort (Hypericum beanii N. Robson), alfalfa (Medicago sativa L.) and beggarticks (Bidens pilosa L.) in Kunming, southern China. The activity of F. occidentalis on these 6 host plant species was determined using the quartile method. F. occidentalis mainly damaged plants during their flowering stage. The main activity period of F. occidentalis occurred earlier on H. beanii and T. repens than on C. annuum. The peak activity of F. occidentalis occurred in the middle of May (on T. repens). During the whole activity period, the highest thrips densities were recorded on H. beanii among all of the sampled host plant species, followed by C. annuum. The lowest density was recorded on B. pilosa. Dynamics of immature F. occidentalis were more irregular than that of adults. The highest density of O. similis was recorded on Z. mays. It was 2.27–26.43-fold (2017) and 2.01–19.09-fold (2018) higher than that on other host plant species. This study showed that F. occidentalis could migrate between C. annuum and surrounding weeds. The weeds were the main source of thrips on C. annuum. The results indicated that Z. mays can be planted around C. annuum fields as a potential banker plant, to attract O. similis to control F. occidentalis on C. annuum, T. repens and B. pilosa. The flowering period of plants and surrounding plant species has a great effect to the population activities of F. occidentalis and predator O. similis on crops.

为探明不同种植环境辣椒上的蓟马种类、优势种西花蓟马及其天敌南方小花蝽在辣椒上的种群动态和日活动规律,本试验采用五点取样,使用盘拍法对大棚(螺丝辣)和露地种植(螺丝辣、太空椒和云南皱皮辣)的3种辣椒上蓟马和南方小花蝽进行了调查,分析两种种植环境下蓟马的种类组成差异及两种昆虫的动态差异,并采用蓝色诱虫板监测西花蓟马的日活动规律.结果表明:露地辣椒田共有10种蓟马,大棚辣椒田共有6种蓟马,两种环境下西花蓟马均是优势种;西花蓟马的发生高峰期在6月末至7月中旬,2019年在大棚和露地的种群数量最高分别达33.4和18.0头·株-1,2020年最高分别为32.2和17.9头.株-1;南方小花蝽种群数量高峰期在7月中旬,高峰期晚于西花蓟马10～20 d;不同辣椒上,西花蓟马数量均为主要发生期显著高于发生早期和晚期(P＜0.05),而南方小花蝽数量在主要发生期和发生晚期最高(P＞0.05);在两种昆虫的主要发生期,西花蓟马在大棚螺丝辣上数量最高(P＜0.05),南方小花蝽则是露地螺丝辣上最高(P＜0.05);西花蓟马的昼夜活动规律显示其在夜间的活动较少,日间活动较多,主要活动时间段集中在露地12:00-16:00、大棚10:00-18:00.辣椒种植环境能显著影响蓟马种类组成、西花蓟马和天敌南方小花蝽的种群发生,大棚种植环境能促进西花蓟马种群数量的增长,但会抑制南方小花蝽数量.大棚辣椒种植地周围可以适当增加露地辣椒种植数量,以增加南方小花蝽自然种群数量,进而提高天敌对西花蓟马的自然控制能力.

为研究草地贪夜蛾在玉米田周围杂草上的生长发育情况,对草地贪夜蛾田间防控提供参考,本研究在(28±1)℃,相对湿度(70±5)％,光周期L//D=16 h//8 h的人工气候箱条件下,选用玉米Zea mays及玉米田常见的主要杂草扁穗雀麦Bromus catharticus、白花三叶草Tri olium repens、三叶鬼针草Bidens pilosa,探究了草地贪夜蛾在这4种植物上不同虫态的发育历期、蛹重以及卵的孵化率、1～3龄幼虫对4种植物的选择性等.结果 表明:草地贪夜蛾在4种植物上均可完成整个世代的生长发育.其中三叶鬼针草处理的草地贪夜蛾幼虫期和蛹期最长,分别为15.97 d和8.33d;三叶鬼针草处理下草地贪夜蛾蛹重为107.90 mg,显著低于其他3种植物处理的蛹重(P＜0.05),玉米、白花三叶草、扁穗雀麦处理的蛹重分别为243.50、239.97、235.80mg;草地贪夜蛾在4种植物上产卵量具有显著差异(P＜0.05),白花三叶草上最高,为2 302粒,三叶鬼针草上最低,为827粒;草地贪夜蛾1～3龄幼虫在玉米、扁穗雀麦和白花三叶草上的发育适合度高于三叶鬼针草.草地贪夜蛾在玉米田周围常见3种杂草上可完成生长发育,在防治草地贪夜蛾时,玉米收获后应尽快清除田边杂草,以减少第二季或者次年玉米上的种群基数.

[目的]明确吡虫啉对南方小花蝽捕食功能反应和寻找效应的影响.[方法]选取0.8、1.6和2.4 mg/L的吡虫啉,以蒸馏水为对照,对南方小花蝽进行处理;分别在西花蓟马密度为30、40和50头/瓶下探究不同吡虫啉质量浓度对南方小花蝽捕食西花蓟马功能的影响.[结果]在3个不同质量浓度吡虫啉下,南方小花蝽对西花蓟马的功能反应均符合HollingⅡ型圆盘方程.南方小花蝽捕食量的差异与吡虫啉质量浓度有一定的关系,突出表现在猎物密度为50头的处理中,吡虫啉质量浓度为2.4 mg/L时南方小花蝽的捕食量显著低于对照(P＜0.05).南方小花蝽对西花蓟马的控制作用和寻找效应在吡虫啉处理下有所下降,吡虫啉质量浓度为0.8 mg/L时影响不显著(P＞0.05),吡虫啉质量浓度为1.6和2.4 mg/L时,南方小花蝽对西花蓟马的控制作用和寻找效应均显著降低(P＜0.05).[结论]吡虫啉对南方小花蝽捕食西花蓟马的数量和功能反应均有影响,在较低质量浓度范围内,随着吡虫啉质量浓度增加,南方小花蝽对西花蓟马的的捕食数量和控制作用降低.

为明确冬季作物花期主要蓟马的组成、空间分布及吡虫啉对其的毒力情况,采用5个聚集度指标、Iwao和Taylor模型对云南省砚山县冬季常见作物花期的主要蓟马种类和空间分布进行研究,并采用浸液饲喂法测定吡虫啉对主要蓟马的毒力.结果表明,冬季花期3种作物上主要蓟马为西花蓟马(Frankliniella occidentalis)、花蓟马(Frankliniella intonsa)、黄蓟马(Thrips flavus)、烟蓟马(Thrips tabaci);不同作物上蓟马的组成比例存在差异,豌豆上的优势种为西花蓟马,萝卜和油菜上的优势种为黄蓟马;黄蓟马在萝卜上的种群密度最高(14.356头/株),花蓟马在豌豆上的种群密度最低(1.889头/株).聚集度指标分析结果表明,4种蓟马在不同作物上均为聚集分布,且蓟马个体间表现出相互吸引;单种蓟马种群密度与聚集度呈正相关性,即随种群密度的增大聚集度增大,蓟马成虫的聚集主要是由自身习性造成.毒力测定结果表明,4种蓟马对吡虫啉的敏感性依次为黄蓟马(LC50=174.263 mg/L)>烟蓟马(LC50=203.089 mg/L)>花蓟马(LC50=263.104 mg/L)>西花蓟马(LC50=390.132 mg/L),西花蓟马表现出相对较高的抗药性.蓟马在常见作物上能安全越冬和危害,成为翌年春季农作物上的虫源,应加强对这些冬季作物上越冬蓟马虫口数量的控制,同时需重点监测西花蓟马对吡虫啉抗药性增强的问题.

为明确无锡市常见园林植物上的蓟马种类及优势种蓟马对杀虫剂的抗性,为防治园林植物上的蓟马提供参考,对无锡市常见园林植物上的蓟马种类进行调查,并选取常用杀虫剂阿维菌素、吡虫啉、高效氟氯氰菊酯对优势种蓟马进行毒力测定.结果 表明,无锡市常见园林植物上的蓟马种类共计13种,其中黄胸蓟马和黄蓟马为本地优势种.阿维菌素、吡虫啉、高效氟氯氰菊酯等3种杀虫剂对黄胸蓟马的LC50值分别为27.50、135.88、441.00 mg/L,对黄蓟马的LC50值分别为15.03、106.19、198.81 mg/L,对这2种蓟马的毒力作用表现为阿维菌素＞吡虫啉＞高效氟氯氰菊酯,且黄蓟马对杀虫剂的敏感度高于黄胸蓟马.说明无锡市园林植物上蓟马种类众多,应加强对蓟马类害虫的防治,建议使用阿维菌素防治无锡市常见园林植物上的蓟马类害虫并注意合理轮换用药以延缓害虫抗性的发展.

为了探明杀虫剂对蓟马类害虫主要天敌昆虫南方小花蝽的影响,选取吡虫啉、高效氟氯氰菊酯和阿维菌素3种常用于防治蓟马的杀虫剂,采用触杀方法对昆明地区3种植物上的南方小花蝽成虫和若虫进行毒力测定.结果表明,南方小花蝽成虫和若虫均对高效氟氯氰菊酯的敏感度最高,不同植物上成虫的24 h LC50值为木香0.577 mg/L、辣椒0.695 mg/L、锦绣杜鹃0.610 mg/L,若虫的24 h LC50值为木香1.855 mg/L、辣椒3.385 mg/L、锦绣杜鹃2.089 mg/L;对吡虫啉的敏感度最低,不同植物上成虫的24 h LC50值为木香8.024 mg/L、辣椒20.183 mg/L、锦绣杜鹃8.900 mg/L,若虫的24 h LC50值为木香10.297 mg/L、辣椒22.607 mg/L、锦绣杜鹃10.338 mg/L.南方小花蝽若虫对杀虫剂的敏感度低于成虫,且取食不同植物上蓟马种群的南方小花蝽对同一种杀虫剂表现出不同的敏感性.南方小花蝽对烟碱类杀虫剂吡虫啉的敏感性较低,应是蓟马类害虫防治中优先选择的杀虫剂,建议在田间使用杀虫剂防治蓟马时尽量避开南方小花蝽种群成虫发生高峰期,以达到保护天敌的目的.

In this study,we aimed to clarify the effects of imidacloprid on interspecific competition between thrips Frankliniella occidentalis and F.intonsa by recording the developmental and fecundity parameters of both species in a competition experiment under laboratory conditions.The LC50 concentrations of imidacloprid in both species were measured by dipping feeding method.Both species were reared on beans in the same cage with a starting ratio of 1 ∶ 1 under pesticide stress at the predetermined LC50 concentration on 2nd instar larvae of F.intonsa.The results showed that there was a consistently higher proportion of females in both species from 25 d to 150 d,with the female excess being higher in F.occidentalis than in that in F.intonsa under imidacloprid stress (P＜0.05).The developmental duration of the immature stages in both species were significantly shorter than in the control,and F.occidentalis developed consistently faster than F.intonsa (P＜ 0.05).The population survival rate and the longevity of male and female adults of F.occidentalis were slightly higher than that of F.intonsa,but the difference was not significant (P＞0.05).The net reproductive rate (R0),the intrinsic rate of increase (rm) and the growth rate (λ) of F.occidentalis were significantly higher than that of F.intonsa.The longevity of both male and female adults,the mean length of generation (T) and population doubling time (DT) of both species in the pesticide treatments were significantly shorter (P ＜0.05) than that in control.Average fecundity,R0,rm and λ in F.occidentalis were significantly higher than that in control (P＜0.05),while average fecundity,R0,T and DT of F.intonsa were significantly lower.Overall,F.occidentalis was more adaptable than F.intonsa to imidacloprid stress,with females being more adaptable than males for both species.Imidacloprid stress is one of the key reasons for the accelerated replacement of F.intonsa by F.occidentalis populations.

To identify the toxicity of current commonly used pesticides to invasive pests,Western flower thrips Frankliniella occidentalis and native closely dominant species flower thrips F.intonsa.The toxicity of six pesticides on this two pests 2nd instar nymphs,female and male in laboratory were conducted use of bean dipping feeding method.The results showed that 6％ Spinetoram was holds the lowest LC50valueon the 2nd instar nymphs and adults,which was 0.611、0.333 mg/L and 1.731、1.202 mg/L for F.occidentalis and F.intonsa,respectively;10％ Pyriproxyfen holds the highest LC50 value on the 2nd instar nymphs and adults,which was 1238.005、845.819 mg/L and 9037.110、4766.376 mg/L for F.occidentalis and F.intonsa,respectively.The toxicity of six pesticides on this two pests state of F.occidentalis and F.intonsa were as follows:Spinetoram ＞ Avermectin ＞ Deltamethrin ＞ Acetamiprid ＞ Imidacloprid ＞ Pyriproxyfen,the role of LC50 for six tested pesticides on F.occidentalis were larger than that on F.intonsa,and females were larger than that on males on both thrips.The sensitivity to pesticides of thrips females than that on males,and the biogenic pesticides hold the better indoor insecticidal efficacy than chemical pesticides,it should be the first choice insecticide in thrips control.