微小花蝽的发生及其对西花蓟马的捕食作用

本文研究了不同种植模式下月季上微小花蝽种群的发生特点及其对西花蓟马的捕食作用,结果表明:在昆明月季种植区,微小花蝽每年有2个发生高峰期,分别是4～5月份和8～9月份,其中,以4～5月份种群发生量最高;露地月季田块上的微小花蝽种群密度明显高于温室大棚;微小花蝽在不同月季品种上的种群密度也有所差异,月季艳粉品种上的蓟马种群密度高于超级品种。微小花蝽对西花蓟马的功能反应符合HollingⅡ型:Na=1.2330N/(1+0.02333N),1天内1头微小花蝽成虫对西花蓟马成虫的最大捕食量和最佳寻找密度分别为16.9头和7.7头。     

银川设施辣椒上西花蓟马与花蓟马的种群竞争及发生态势

西花蓟马是危害蔬菜、花卉等植物的世界性入侵害虫,本文研究了西花蓟马入侵后银川设施辣椒上的蓟马种群动态,为深入了解西花蓟马和花蓟马的种群竞争关系及其发生态势提供依据。本研究通过大量采集银川设施辣椒蓟马、制作玻片标本进行显微镜观察鉴定,以及通过室内西花蓟马与花蓟马两个种群混合饲养和单种群饲养研究,明确了银川设施辣椒上西花蓟马和花蓟马的发生分布情况、种群竞争及发生趋势。结果表明:银川设施辣椒上西花蓟马种群数量明显占优势,占总量的73.62%,极显著多于花蓟马种群数量;两种群单独生存并经过一个世代,两种群的虫口数量和雌性比均无显著差异;两个种群混合饲养条件下,西花蓟马种群虫口数量和雌性比均略高于花蓟马。分析表明,共存时西花蓟马具有较强的竞争能力,对银川设施辣椒本土蓟马种群造成较大威胁,为做好该虫的预测预报及有效控制奠定基础。     

辣椒开花对西花蓟马种群的影响

为揭示寄主植物开花与否对西花蓟马种群增长的作用,研究了辣椒是否有花对不同密度下西花蓟马种群数量的影响。结果显示,开花辣椒上的西花蓟马种群数量明显高于无花辣椒,在接入30头/株密度下,7 d、14 d、21 d和28 d 4个时间段开花辣椒上西花蓟马种群数量分别是未开花的2.3倍、1.5倍、1.8倍和2.5倍;15头/株密度下,开花辣椒上种群数量是未开花的2.0倍、1.3倍、1.5倍和1.7倍。结果表明,开花的辣椒植株对西花蓟马种群数量的增长有明显的促进作用。     

花粉和植物不同生长阶段对西花蓟马种群的影响

在凤仙花的Impulse Orange和Cajun Carmine品种上开展了花粉和植物不同生长阶段对西花蓟马种群的影响。结果表明:在植物未开花前,添加花粉和不添加花粉西花蓟马的种群数量差异显著,添加花粉能显著增加两个品种上西花蓟马的种群数量,其西花蓟马数量分别为174.50、43.67头,而未添加花粉时分别为138.33头和27.00头。在植物开花后,添加花粉对西花蓟马的种群数量虽有一定影响,但差异不显著。植物不同生长发育阶段对西花蓟马的种群数量影响很大,无论是添加花粉还是不添加花粉,在两个品种上均表现为开花后的数量显著大于开花前的数量,说明凤仙花植物本身的花对西花蓟马种群的迅速增长影响很大。     

西花蓟马在不同辣椒品种上的实验种群生命表

为探讨西花蓟马Frankliniella occidentalis在不同辣椒品种上的发生及为害规律,以5个辣椒品种作为试验材料,组建西花蓟马种群生命表。结果表明,从西花蓟马各个虫态的发育历期来看,‘杭椒五号’和‘太空辣’比较适合蓟马生长繁殖,其次为‘洋大帅’,‘娇龙’、‘74-82’最不适合西花蓟马生存。西花蓟马在5个品种上的存活曲线类型不同,在‘杭椒五号’上的存活曲线偏向A型;在‘洋大帅’、‘太空辣’品种上偏向B型;在‘娇龙’、‘74-82’品种上则偏向于C型。通过种群参数分析表明西花蓟马比较喜好取食‘洋大帅’、‘太空辣’、‘杭椒五号’3个品种,‘娇龙’和‘74-82’品种则不利于西花蓟马的生长繁殖。     

广州输入性花卉蓟马的种类组成及种群动态分析

西花蓟马Frankliniella occidentalis(Pergande)是一种世界性的入侵害虫,近年来传入我国并迅速扩散蔓延,持续监测广州市输入性花卉中蓟马的种类组成及种群动态,对西花蓟马的早期监测预警具有重要的意义。2011年4月-2013年7月对广州市岭南花卉市场玫瑰、百合、康乃馨三种输入性花卉的蓟马种类及种群动态进行系统调查,利用用气相色谱-质谱联用仪(GC-MS)对蓟马若虫的表皮碳氢化合物进行分析。结果表明:广州地区输入性花卉上蓟马包括西花蓟马F.occidentalis、烟蓟马Thrips tabaci、花蓟马F.intonsa、黄蓟马T.flavidulus 4种,其中西花蓟马是蓟马优势种,而康乃馨是携带西花蓟马的主要花卉品种。西花蓟马在康乃馨上常年发生,成虫种群消长呈单峰型,高峰期在6-8月,冬季最少。此外,康乃馨上蓟马若虫的各色谱峰保留值与西花蓟马若虫的基本一致,比例为83.33%。     

冀东地区不同玉米品种蓟马发生种类和种群动态

2017年对冀东地区非糯非甜玉米、糯玉米和甜玉米3个品种田间蓟马发生情况进行了调查。经室内种类鉴定,3个玉米品种上发生的蓟马种类相同,均为禾花蓟马[Franklinielle tenuicornis (Uzel)]、稻管蓟马[Haplothrips aculeatus (Fabriecius)]和玉米黄呆蓟马[Anaphothrips obscurus (Müller)]。经田间种群数量调查,玉米大喇叭口期禾花蓟马、稻管蓟马、玉米黄蓟马发生数量均达高峰,虫口密度分别为4 310.0头/百株、3 673.3头/百株、2 936.7头/百株,三者之间差异不显著(P0.05)。调查期间,非糯非甜玉米、糯玉米和甜玉米品种上蓟马发生总量差异不显著(P0.05);3个玉米品种上禾花蓟马均为优势种,分别占蓟马总量的71.96%、83.29%和79.05%,其发生数量显著高于稻管蓟马和玉米黄呆蓟马(P0.05),而禾花蓟马在3个玉米品种上的发生数量差异不显著(P0.05)。     

高温处理西花蓟马若虫对其雌成虫寿命、繁殖力及后代发育的影响

温度是影响昆虫生长发育的重要生态因素之一,高温逆境作为一种绿色防控手段可以有效控制温室害虫种群发展。为了探究高温处理西花蓟马若虫对其种群发展的影响,本试验用41℃和43℃两个温度分别处理西花蓟马初孵若虫2、6、12、24和36h后,观察并记录其雌成虫寿命、繁殖力及后代发育指标的变化情况。结果表明,随着处理时间的延长,两个高温处理后西花蓟马雌成虫寿命,子代若虫总数、成虫总数和总存活率(若虫发育到成虫的存活率)均显著下降,后代雌雄性比呈总体下降趋势。41℃处理后,性比从2.30∶1降低到2.13∶1;43℃处理后从2.25∶1降低到2.07∶1,均明显低于对照的2.69∶1。另外,两性生殖种群相比于孤雌生殖种群更易遭受高温处理的影响。     

南方小花蝽对非洲菊上西花蓟马控制效果评价

为评价南方小花蝽Orius similis对非洲菊上西花蓟马的控制效果，本研究在非洲菊上以2头/m²密度释放南方小花蝽，以西花蓟马的虫口减退率及南方小花蝽对西花蓟马校正防效作为指标评价了其控害效果。结果显示：在释放南方小花蝽前期，南方小花蝽对非洲菊上西花蓟马的控制效果不明显，但随着释放时间延长，控制效果显著提高，释放南方小花蝽21 d后的控制效果高达90.25%，而喷施化学农药的控制效果为-40.93%，释放南方小花蝽的控制效果远高于喷施化学农药处理，表明南方小花蝽对西花蓟马具有更高效持久的控制潜力。     

释放巴氏钝绥螨对温室大棚茄子上西花蓟马及东亚小花蝽数量的影响

在北京市门头沟碧琨种植中心的温室大棚茄子上释放巴氏钝绥螨后,调查统计对茄子上西花蓟马及东亚小花蝽数量的影响。结果表明:释放巴氏钝绥螨对温室大棚茄子上的西花蓟马的种群数量在其高峰期具有一定的压低作用,尤其是释放200头/m2巴氏钝绥螨效果更好。温室大棚茄子上自然发生的本地天敌东亚小花蝽的种群数量,在各处理间的总体趋势相同,随着西花蓟马的数量变化而变化。     

Verbena as a trap crop to suppress thrips-transmitted Tomato spotted wilt virus in chrysanthemums

The effect of verbena as a trap crop on the occurrence of western flower thrips, Frankliniella occidentalis, and the incidence of Tomato spotted wilt virus (TSWV) in chrysanthemums were investigated. Verbena cvs. Pink Parfait and/or Fancy Parfait were cultivated alongside chrysanthemum cv. Jimba in a greenhouse in the proportion of 17%–25% of the chrysanthemum plants. Verbena plants attracted vector thrips, reducing western flower thrips colonization of chrysanthemum until flower bud initiation, and markedly suppressing TSWV incidence on chrysanthemums until flowering. Significant quantities of linalool oxide pyran were produced by the flower of cv. Fancy Parfait; and the ratio of cis-linalool oxide pyran, an attractant for vector thrips, to the trans-type was approximately 1 : 5. Our results suggest that cultivation of verbena as a trap crop may be useful in integrated pest management programs as a control for thrips-transmitted TSWV in chrysanthemums.     

Association of the western flower thrips (Frankliniella occidentalis) with cultivated sunflower (Helianthus annuus) in Israel

In 1992 and 1993, sunflower (Helianthus annuus L.) crops in Israel were heavily damaged by the western flower thrips (WFT),Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Adult females appear in the heads of sunflower just as the latter begin to blossom; the population decreases towards completion of anthesis. The damage to kernels is greatest at the periphery of the heads, where flowers appear first, and lowest at the center. Fields sown early in the season (in March) are usually the ones infested most by WFT and suffering the greatest damage. Fields sown one month later are less infested, since predatory bugs of the genusOrius are very active at that time.     

Use of azadirachtin as a larvicide or feeding deterrent for control of western flower thrips in orchard systems

Field trials were carried out to assess the efficacy of a 4% azadirachtin (aza)-containing neem seed extract EC, against damage by western flower thrips [Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)] on nectarine crops in the Similkameen Valley, British Columbia, Canada. Several trials were conducted during the years 1993 to 1995 to assess the repellent and larvicidal properties of aza, specifically: whether it was effective against adult or larval thrips; how the effects differed with concentration of aza; and whether female WFT avoided aza-treated flowers. Our results showed that aza has only limited effectiveness as a control agent against WFT on nectarines and the current formulation does not appear to limit larval development sufficiently to be deemed a possible control agent in this field situation.     

Mechanisms conferring resistance of Western flower thrips to bendiocarb

Mechanisms associated with bendiocarb resistance were examined in two strains of western flower thrips, Frankliniella occidentalis (Pergande), that differed in their susceptibility to this carbamate by 13.6-fold. No appreciable differences between the two strains in [¹⁴C] bendiocarb penetration and excretion were detected; however, bendiocarb was metabolised substantially faster by the resistant KCM thrips than by the more susceptible UMC thrips. No appreciable difference between the two strains was found in the sensitivity of acetylcholinesterase activity to inhibition by bendiocarb. It was concluded that bendiocarb resistance in KCM western flower thrips was due to enhanced metabolism that probably was mainly oxidative in nature.     

Developments in the integrated control of Frankliniella occidentalis in capsicum and cucumber1

Since the appearance of the western flower thrips, Frankliniella occidentalis, in European glasshouses, many attempts have been made to improve the biological methods for thrips control, originally based on the control of Thrips tabaci. Introductions of Neoseiulus (Amblyseius) cucumeris have been increased with respect to both numbers per introduction and number of releases. So-called slow-release systems have been developed to ensure better establishment of the predator on the plant. New control agents have been tested: the predatory bug Orius insidiosus and the entomopathogenic fungus Verticillium lecanii. Additional control methods are: 1) the use of polybutenes as an insect glue on yellow polythene covers of the rock-wool mat; 2) newly developed blue sticky traps. These new developments and prospects are discussed.     

M?glichkeiten der Bek?mpfung des Kalifornischen Bl��tenthripses Frankliniella occidentalis (Pergande) mit nachgewiesener Insektizidresistenz in Schnittrosen unter Glas

Due to resistance to insecticides (or plant protecting agents) the western flower thrips Frankliniella occidentalis is difficult to combat in cut roses cultures with conventional methods. In that case the predatory mite Amblyseius cucumeris could be a very effective biological alternative when applied in high numbers of 1000 mites per square meter against low density thrips population. The key to success is early application at the beginning of the vegetative growth before the thirps becomes active and the first larvae appear. The efficiency of the mites is not sufficient when the thirps population density in spring is high. Caused by the fecundity and fast development of Frankliniella occidentalis in higher temperatures, the application of chemical protecting agents in summer could be unavoidable. Because of the proven resistance Western flower thrips developed against the insecticides permitted in Germany, the chemical agents may not be effective. Only an optimal application can provide a satisfactory reduction of the thrips population. The development stage of the roses must be taken into account as well as right application intervals of insecticides. In order to develop a sufficient and effective control of Western flower thrips Frankliniella occidentalis and improve resistance management the application of predatory mites seems to be inevitable in future.     

Biological control of the Western flower thripsFrankliniella occidentalis in cucumber using the entomopathogenic fungusMetarhizium anisopliae

Biological control of the western flower thrips (WFT)Frankliniella occidentalis, using the entomopathogenicMetarhizium anisopliae-7 (M. a-7) strain was studied in three consecutive seasons under greenhouse conditions. Cucumber plants infested with WFT were sprayed with spore suspension of the fungusM. a-7 (0.5 g m^-2), or the soil was treated with dry powder of the fungus (0.5 g m^-2); the control was without fungus application. In the 1997 spring experiment, when the cucumber plants were initially infested with only three or four insects per leaf, the spore suspension spray caused a significant reduction in growth of the thrips population compared with the other treatments and the control. However, in the 1997 summer experiment, when the plants were initially heavily infested with WFT (10–15 insects per leaf), the spray treatment caused only a modest reduction in WFT population growth, and only after 4 weeks of treatment was the reduction significant. In the 1999 experiment, with a low initial WFT population of three or four insects per leaf, the spray treatment was effective in reducing the population growth to a lower level than in the other treatments or control. TheM. a-7 strain was found to be effective in reducing the population growth of WFT under greenhouse conditions, particularly when the initial thrips population was low to moderate. http://www.phytoparasitica.org posting Nov. 4, 2001.     

Comparative analyses of the toxic effects of imidacloprid and spirotetramat on Frankliniella occidentalis (Pergande), the vector of tomato zonate spot virus: a laboratory assay

The tomato zonate spot virus (TZSV) is responsible for substantial yield losses in vegetables, tobacco and other cash crops in China in recent years. The western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera, Thripidae), is the main vector of TZSV in Yunnan Province. Because controlling the population of insect vectors is the most efficient way to prevent epidemics of viral diseases, we conducted laboratory assays to assess the potential of using spirotetramat as an alternative to imidacloprid in controlling F. occidentalis. Our results demonstrated that spirotetramat was significantly more lethal than imidacloprid to F. occidentalis at different concentrations. The LC₃₀, LC₅₀ and LC₉₀ values of spirotetramat were all much lower than those of imidacloprid after the same time of treatment. Frankliniella occidentalis was more sensitive when treated with spirotetramat than imidacloprid at the concentrations of 500, 250, 125 and 62.5mg/L, and the median lethal concentrations (LC₅₀) were 285.53, 82.24 and 11.19mg/L at 12, 36 and 72 hours after treatment, respectively. Spirotetramat caused 100% mortality of F. occidentalis at 500 and 250 mg/L after 48 hours treatment, and at the lowest concentration 125 mg/L at 72 hours after treatment, respectively. Field experiments carried out elsewhere have confirmed our findings. Together they allow us to conclude that spirotetramat is a promising pesticide for the control F. occidentalis in China.     

Insecticide Resistance in the Western Flower Thrips, Frankliniella occidentalis

The western flower thrips, Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) is a serious pest on a wide range of crops throughout the world. F. occidentalis is difficult to control with insecticides because of its thigmokinetic behaviour and resistance to insecticides. Pesticide resistance can have a negative impact on integrated pest management programmes with chemical control as one of the components. Resistance to a number of different insecticides has been shown in many populations of F. occidentalis. This flower thrips has the potential of fast development of resistance owing to the short generation time, high fecundity, and a haplodiploid breeding system. The mechanisms conferring insecticide resistance in insects can be divided into four levels. First, an altered behaviour can aid the insect to avoid coming into contact with the insecticide. Second, a delayed penetration through the integument will reduce the effect of the insecticide at the target site. Third, inside the insect, detoxification enzymes may metabolise and thereby inactivate the insecticide. Fourth, the last level of resistance mechanisms is alterations at the target site for the insecticide. Knowledge of resistance mechanisms can give information and tools to be used in management of the resistance problem. Recently, studies have been carried out to investigate the underlying mechanisms conferring resistance in F. occidentalis. It appears that resistance in F. occidentalis is polyfactorial; different mechanisms can confer resistance in different populations and different mechanisms may coexist in the same population. Possible resistance mechanisms in F. occidentalis include: reduced penetration, detoxification by P450-monooxygenases, esterases and glutathione S-transferases, and alterations of acetylcholinesterase, the target site for organophosphate and carbamate insecticides. Target site resistance to pyrethroids (knockdown resistance) may also be a resistance mechanism in F. occidentalis.