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.     

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。     

基于生物防治的西花蓟马治理及思考

西花蓟马Frankliniella occidentalis(Pergande)是世界性的大害虫,对温室中蔬菜花卉造成巨大的危害。20世纪70年代后在世界范围内广泛而迅速地传播蔓延,近年入侵中国。西花蓟马对农药产生了广泛的抗性,使得生物防治一直作为其综合治理中的主导措施。本文综述了世界上西花蓟马生物防治的现状,以期为中国西花蓟马的治理提供一定的借鉴作用。     

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。     

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。     

Effectiveness of insecticide-treated and non-treated trap plants for the management of Frankliniella occidentalis (Thysanoptera: Thripidae) in greenhouse ornamentals

The effectiveness of trap cropping as an integrated control strategy against western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), was explored in potted chrysanthemum, Dendranthema grandiflora (Tzvelev), greenhouse crops. The efficacy of flowering chrysanthemum trap plants, either treated with the insecticide spinosad or untreated, to regulate F. occidentalis populations was tested at different spatial scales (small cage, large cage and commercial greenhouse) and for different time periods (1 or 4 weeks). It was demonstrated that flowering chrysanthemums as trap plants lower the number of adult F. occidentalis in a vegetative chrysanthemum crop and, as a result, reduce crop damage. In the 4 week large-cage trial and the commercial trial, significant differences between the control and the trap plant treatments started to appear in the third week of the experiment. Larvae were only significantly reduced by the presence of trap plants in the 1 week small-cage trials. There were no significant differences between treatments with spinosad-treated and untreated trap plants in the number of F. occidentalis on the crop. This suggests that there was minimal movement of adult F. occidentalis back and forth between the trap plants and the crop to feed and oviposit. It is concluded that the trap plant strategy is a useful tool for integrated pest management against F. occidentalis in greenhouses.     

Integrated pest management in western flower thrips: past,present and future

Western flower thrips (WFT) is one of the most economically important pest insects of many crops worldwide. Recent EU legislation has caused a dramatic shift in pest management strategies, pushing for tactics that are less reliable on chemicals. The development of alternative strategies is therefore an issue of increasing urgency. This paper reviews the main control tactics in integrated pest management (IPM) of WFT, with the focus on biological control and host plant resistance as areas of major progress. Knowledge gaps are identified and innovative approaches emphasised, highlighting the advances in ‘omics’ technologies. Successful programmes are most likely generated when preventive and therapeutic strategies with mutually beneficial, cost‐effective and environmentally sound foundations are incorporated. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Virulence of the entomopathogenic fungus Lecanicillium longisporum against the greenhouse whitefly,Trialeurodes vaporariorum and its parasitoid Encarsia formosa

Understanding the interactions among biological control agents, such as competition for the same host in intraguild predation, is a key component for successful biological control strategies. The pathogenic ability of Lecanicillium longisporum (Petch) Zare and Gams (Ascomycota: Clavicipitaceae) against the greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) and its parasitoid, Encarsia formosa Gahan (Hymenoptera: Aphelinidae) was assessed. Treatment with six serial deposition rates of fungal conidia on cucumber leaf surface indicated that whitefly mean mortalities for isolates LRC190, LRC216 and LRC229 reached 61, 79 and 54% at 2.6 × 10⁷ conidia/mm², respectively. Median lethal time (LT₅₀) values for isolates LRC190, LRC216 and LRC229 were 6.2, 4.9 and 6.9 days, and median lethal dose (LD₅₀) values were 1.2 × 10⁶, 2.9 × 10⁵ and 6.9 × 10⁶ conidia/mm², respectively. The number of surviving parasitoid larvae, pupae and adults decreased with increasing concentrations of fungus, and earlier developmental stages of parasitoid were affected negatively by fungal treatment. Reproductive capacity and longevity of female parasitoid emerging from fungus-treated hosts were not affected by fungus treatment. These results indicate that correct timing of fungal and parasitoid application may mitigate the negative effects due to direct competition for the same host. In this regard, treatment with fungi in later immature stages of the parasitoid was generally positive with minimum risks of deleterious effects.     

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)。     

Soil application of azadirachtin and 3-tigloyl-azadirachtol to control western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae): translocation and persistence in bean plants

To study the systemic effects of active neem ingredients, the substrate of bean plants was treated with a 170 g kg(-1) azadirachtin (NeemAzal-U; Trifolio-M GmbH, Lahnau, Germany, registration pending). This product was used at a dose rate of 10 mg AZA (azadirachtin a) and 1.2 mg 3-tigloyl-azadirachtol (azadirachtin b) per treated bean plant. Afterwards, the translocation and persistence of AZA and 3-tigloyl-azadirachtol and the effects on western flower thrips, Frankliniella occidentalis (Pergande), were studied. Residues of AZA and 3-tigloyl-azadirachtol from substrates with different contents of organic matter [pure culture substrate (CS), CS-sand mixture] and from various plant parts were quantified by high-performance liquid chromatography-mass spectrometry (HPLC-MS). The dissipation trends of AZA and 3-tigloyl-azadirachtol were similar within the same substrates. A slower decline of both active ingredients was measured with CS than with CS-sand mixture. Residue analysis of the bean plants showed that only small proportions of the initial amounts of AZA and 3-tigloyl-azadirachtol applied to the substrate were present in the plant (0.3-8.1%). Variable amounts of residues of the active components in relation to plant parts and time of analysis indicated a different translocation pattern for the two active ingredients. Higher residues of the active ingredients were found in roots and stems after neem application using CS, whereas higher residues were found in leaves after CS-sand mixture treatments. Mortality of F. occidentalis after NeemAzal-U soil applications reached up to 95% on CS-sand mixture, compared with 86% in CS.