Insecticide resistance management strategies against the western flower thrips, Frankliniella occidentalis

Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is an economically important pest of a wide range of crops grown throughout the world. Insecticide resistance has been documented in many populations of WFT. Biological and behavioural characteristics and pest management practices that promote insecticide resistance are discussed. In addition, an overview is provided of the development of insecticide resistance in F. occidentalis populations and the resistance mechanisms involved. Owing to widespread resistance to most conventional insecticides, a new approach to insecticide resistance management (IRM) of F. occidentalis is needed. The IRM strategy proposed consists of two parts. Firstly, a general strategy to minimise the use of insecticides in order to reduce selection pressure. Secondly, a strategy designed to avoid selection of resistance mechanisms, considering cross-resistance patterns and resistance mechanisms.     

Esterase inhibition by synergists in the western flower thrips Frankliniella occidentalis

BACKGROUND: Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is among the most important crop pests in the south‐eastern region of Spain. Its increasing resistance to insecticides constitutes a serious problem, and understanding the mechanisms involved is therefore of great interest. Use of synergists to inhibit the enzymes involved in insecticide detoxification is widely used to determine their responsibility for insecticide resistance. However, they do not always act as intended or expected, and caution must be exercised when interpreting synergist results. RESULTS: Laboratory‐selected strains of WFT were used to analyse the effects of the synergists piperonyl butoxide (PBO), S,S,S‐tributyl phosphorotrithioate (DEF) and methiocarb on total esterase activity. Significant differences were found, indicating esterase activity inhibition by DEF, a lower effect for methiocarb and a small inhibition of the activity by PBO. Esterase isoenzyme inhibition by these compounds showed a similar result; this assay revealed an extreme sensitivity of Triplet A (resistance‐associated esterases) to DEF. In an in vivo assay carried out with these compounds at different incubation times, only DEF caused posterior in vitro esterase activity inhibition, with a maximum effect 1 h after treatment. CONCLUSION: In this work, only DEF shows true synergistic inhibition of WFT esterases. Copyright © 2011 Society of Chemical Industry     

阿维菌素与三种杀虫剂对西花蓟马的联合毒力

阿维菌素是防治西花蓟马的常用药剂,为筛选出对西花蓟马具有增效作用的阿维菌素与其他药剂的混配组合,采用浸叶法测定了阿维菌素、毒死蜱、吡虫啉和吡蚜酮等药剂对西花蓟马2龄若虫的毒力,并通过共毒因子法和共毒系数法分别确定了最佳药剂配伍和最佳复配比例。结果表明,阿维菌素与毒死蜱复配表现出明显的增效作用;阿维菌素与毒死蜱比值为2∶8与8∶2时,增效作用最显著;阿维菌素与吡蚜酮、吡虫啉均表现出拮抗作用。     

西花蓟马抗药性研究进展

西花蓟马是世界范围内蔬菜和花卉上的重要害虫之一,使用化学药剂是防治西花蓟马的主要手段,目前西花蓟马已对有机氯、有机磷、氨基甲酸酯、拟除虫菊酯、阿维菌素和多杀菌素等多种杀虫剂产生了抗药性。本文从抗药性现状、抗性机制和抗性治理等几个方面介绍了国内外有关西花蓟马抗药性的研究进展。     

Metabolic mechanisms of insecticide resistance in the western flower thrips, Frankliniella occidentalis (Pergande)

The interactions between six insecticides (methiocarb, formetanate, acrinathrin, deltamethrin, methamidophos and endosulfan) and three potential synergists (piperonyl butoxide (PBO), S,S,S-tributyl phosphorotrithioate (DEF) and diethyl maleate (DEM)) were studied by topical exposure in strains selected for resistance to each insecticide, and in a susceptible strain of Frankliniella occidentalis (Pergande). In the susceptible strain PBO produced appreciable synergism only of formetanate, methiocarb and methamidophos. Except for endosulfan, PBO synergized all the insecticides to varying degrees in the resistant strains. A very high level of synergism by PBO was found with acrinathrin, which reduced the resistance level from 3344- to 36-fold. PBO slightly synergized the carbamates formetanate (4.6-fold) and methiocarb (3.3-fold). PBO also produced a high synergism of deltamethrin (12.5-fold) and methamidophos (14.3-fold) and completely restored susceptibility to both insecticides. DEF did not produce synergism with any insecticide in the resistant strains and DEM was slightly synergistic to endosulfan (3-fold). These studies indicate that an enhanced detoxification, mediated by cytochrome P-450 monooxygenases, is the major mechanism imparting resistance to different insecticides in F occidentalis. Implications of different mechanisms in insecticide resistance in F occidentalis are discussed.     

西花蓟马传播病毒病的研究进展

西花蓟马［Frankliniella occidentalis (Pergande)］是一种世界性的重要农业害虫,目前在69个国家和地区已有报道。西花蓟马能以持久性的方式传播番茄斑萎病毒属(Tospovirus)的病毒,所传播病毒造成的经济损失远远大于其本身所造成的损失。因此,许多学者对西花蓟马及其传播的番茄斑萎病毒属病毒进行了大量研究。本文主要综述了近年来西花蓟马传播病毒的种类、番茄斑萎病毒属病毒的结构以及西花蓟马的传毒机制等方面的研究进展。     

西花蓟马天敌种类及主要种类的控害潜能

西花蓟马[Frankliniella occidentalis(Pergande)]是国际上备受关注的检疫性有害生物,近年来该虫分布范围不断扩大,对农作物、园林园艺植物的危害日趋加重,发挥天敌对该虫的自然控制作用已引起人们广泛重视。本文根据国内外研究报道,总结和记述了西花蓟马的天敌种类及其主要种类对西花蓟马的控制作用。西花蓟马的天敌约有60种,其中天敌昆虫50种,昆虫病原线虫5种,虫生真菌5种。同时,对主要天敌种类小花蝽、昆虫病原线虫和虫生真菌对西花蓟马的捕食寄生及控制潜力进行了阐述。     

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.     

10种杀虫剂对4种蓟马的毒力及对西花蓟马的田间药效评价

蓟马对农作物的危害逐年加重, 为筛选防治蓟马的高效低毒药剂, 采用叶管药膜法测定了10种常用药剂对4种蓟马的室内毒力, 并开展了田间防效试验。室内毒力测定结果表明, 6%乙基多杀菌素SC和10%虫螨腈SC对4种蓟马的毒力相对较高, 25%噻虫嗪WG和5%甲维盐EC的毒力较低, 西花蓟马和瓜蓟马对10种药剂的敏感性低于花蓟马和烟蓟马。田间药效结果表明, 25%噻虫嗪WG、10%溴虫氟苯双酰胺SC和4.5%高效氯氰菊酯EC对西花蓟马的防效较高, 药后7 d药效最高达到90%以上。综合室内毒力和田间药效试验结果, 推荐4.5%高效氯氰菊酯EC和10%溴虫氟苯双酰胺SC为防治蓟马的首选药剂, 可与25%噻虫嗪WG、48%多杀霉素SC、1.8%阿维菌素EC和10%吡丙醚SC等药剂轮换使用。     

西花蓟马在中国的适生性分布研究初报

根据西花蓟马生物学及生态学特性的研究,利用地理信息系统ArcView 3.2分析预测了该虫在中国可能适生分布范围。结果表明,西花蓟马在中国可能的最适宜分布范围大体在16.53-30.77°N,97.85-121.9°E范围内,涉及华南、西南、华东地区的11个省(自治区、市)的123个县(市或地区);潜在适宜分布范围大体在25.43-48.77°N,75.23-132.96°E范围内,涉及华东、华南、西南、华中、西北、华北共28个省(自治区、直辖市)的468个县(市或地区)。     

室内药剂交替使用对西花蓟马抗药性发展的影响

分别单独使用毒死蜱、多杀菌素和两种农药交替使用连续处理西花蓟马(Frankliniella occidentalis)18代,采用浸渍法从第6至第18代每隔2世代测定3个汰选种群对毒死蜱和多杀菌素的敏感性.结果表明,毒死蜱和多杀菌素交替汰选种群比单一药剂连续汰选种群抗性上升趋势缓慢,F18代时交替使用汰选种群对毒死蜱和多杀菌素的抗性倍数分别为10.89倍和17.19倍,而毒死蜱单一汰选种群对毒死蜱的抗性倍数达到24.19倍,多杀菌素单一汰选种群对多杀菌素的抗性倍数达到20.78倍.因此,交替或轮换使用药剂可以延缓西花蓟马抗药性的发展.     

Resistance to spinosad in the western flower thrips, Frankliniella occidentalis (Pergande), in greenhouses of south-eastern Spain

Susceptibility to spinosad of western flower thrips (WFT), Frankliniella occidentalis (Pergande), from south-eastern Spain was determined. LC(50) values of the field populations without previous exposure to spinosad collected in Murcia in 2001 and 2002 ranged from 0.005 to 0.077 mg L(-1). The populations collected in Almeria in 2003 in greenhouses were resistant to spinosad (LC(50) > 54 mg L(-1)) compared with the authors' highly susceptible laboratory strain. The highly sensitive laboratory strain leads to very high resistance ratios for the field populations (>13 500), but these ratios do not necessarily mean resistance problems and control failures (spinosad field rate 90-120 mg L(-1)). The populations collected in Murcia from some greenhouses in 2004 were also resistant to spinosad (RF > 3682). Spinosad overuse, with more than ten applications per crop, produced these resistant populations in some greenhouses. Spinosad showed no cross-resistance to acrinathrin, formetanate or methiocarb in laboratory strains selected for resistance towards each insecticide. Correlation analysis indicated no cross-resistance among spinosad and the other three insecticides in 13 field populations and in nine laboratory strains. The synergists piperonyl butoxide (PBO), S,S,S-tributyl phosphorotrithioate (DEF) and diethyl maleate (DEM) did not enhance the toxicity of spinosad to the resistant strains, indicating that metabolic-mediated detoxification was not responsible for the spinosad resistance. These findings suggest that rotation with spinosad may be an effective resistance management strategy.     

The efficacy of spinosad against the western flower thrips, Frankliniella occidentalis, and its impact on associated biological control agents on greenhouse cucumbers in southern Ontario

Insecticides are the most commonly used tactic to control western flower thrips (WFT), Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), on greenhouse cucumber. However, WFT has developed resistance to several of the insecticides presently in use. In addition, some of these insecticides adversely affect greenhouse biological control agents used to control WFT, resulting in subsequent pest resurgence. Therefore, there is a need to identify novel insecticides with unique modes of action for use in integrated pest management (IPM) programs to effectively control WFT with minimal impact on associated biological control agents. In laboratory bioassays conducted in 2001, immature and adult WFT and three associated greenhouse biological control agents: Amblyseius cucumeris Oudemans (Acarina: Phytoseiidae), Orius insidiosus Say (Hemiptera: Anthocoridae) and Encarsia formosa Gahan (Hymenoptera: Aphelinidae) were exposed to direct, direct/residual, and residual contact applications of the novel biopesticide, spinosad (Conserve 120 SC), and the industry standard for whitefly control, endosulfan (Thiodan 50 WP). In all three types of assay, spinosad was effective against immature and adult WFT life stages. It showed low toxicity to A. cucumeris, moderate toxicity to O. insidiosus and high toxicity to E formosa. Greenhouse studies involving exposure of immature and adult WFT and adult biological control agents to cucumber leaves sprayed previously with spinosad supported the laboratory data. Spinosad showed low toxicity to A. cucumeris exposed to leaves 1 day after treatment (DAT), moderate toxicity to O. insidiosus 1 and 8 DAT, and high toxicity to E. formosa up to 28 DAT. These data, along with spinosad's unique mode of action, suggest it would be a valuable reduced-risk control agent for greenhouse cucumber IPM programs.     

Relationship between esterase activity and acrinathrin and methiocarb resistance in field populations of western flower thrips, Frankliniella occidentalis

The western flower thrips, Frankliniella occidentalis (Pergande), is a serious pest in the south-east of Spain owing to its direct feeding on crops, transmission of the tomato spotted wilt virus and its very high level of resistance to insecticides. Mechanisms of resistance were examined using field populations of F. occidentalis with different susceptibilities to acrinathrin, methiocarb (selective insecticides), endosulfan, metamidophos and deltamethrin (broad-spectrum insecticides). Esterase activity towards alpha-naphthyl acetate and p-nitrophenyl acetate in resistant strains was significantly higher than in the reference strain (MLFOM) for both model substrates. This higher activity was significantly correlated with acrinathrin and methiocarb resistance.     

东亚小花蝽对西花蓟马、二斑叶螨和桃蚜的捕食能力及捕食选择性研究

室内研究了东亚小花蝽对西花蓟马、二斑叶螨和桃蚜的捕食能力及在3种害虫共存条件下的捕食选择性。试验结果表明,东亚小花蝽对西花蓟马、二斑叶螨和桃蚜均具有捕食能力。捕食能力最初随着猎物数量的增加而增加,当猎物数量不断增加时,其捕食量趋于恒定值。在猎物数量充足时,东亚小花蝽对于二斑叶螨、蚜虫和蓟马的日均捕食量分别为17、12.5头和12头。3种猎物共存时,东亚小花蝽对西方花蓟马的捕食选择性均强于对二斑叶螨和桃蚜。选择性依次为西方花蓟马桃蚜≈二斑叶螨。猎物数量相同时取食西花蓟马的数量为12.6头,二斑叶螨和桃蚜的数量分别1.2头和2.4头。     

Verbena × hybrida flower volatiles attractive to Western flower thrips,Frankliniella occidentalis

Western flower thrips (WFT) are attracted to three flowering verbena cultivars. The volatile components of these cultivars contain different enantiomers of linalool oxide which have been synthesised and one shown to be attractive to WFT.     

Western flower thrips (Frankliniella occidentalis)—occurrence and possibilities for its control in Hungary1

Frankliniella occidentalis was first recorded in Hungary in 1989. The pest has endangered the mass-rearing and distribution of the biological control agents Encarsia formosa and Phytoseiulus persimilis being conducted at the Hódmezövásárhely Institute. Different insecticide active ingredients were studied for elimination of the pest from experimental glasshouses and new methods for monitoring populations of the new thrips. The fungus Verticillium lecanii has been tested as an indirect control agent.