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1.
BACKGROUND: B and Q biotypes of the whitefly, Bemisia tabaci (Gennadius), are generally regarded as the most significant given their global distribution and strong resistance to insecticides. Since these biotypes can coexist and differ markedly in their insecticide resistance profiles, a rapid but reliable means of discriminating between them would be a valuable complement to resistance monitoring and management programmes. Recently, PCR‐based methods have been developed to determine the biotype status of B. tabaci populations. However, these require post‐amplification procedures, which increase time and labour. RESULTS: The authors have developed an allelic discrimination real‐time PCR assay using fluorescent dye‐labelled probes to distinguish the B and Q biotypes. The assay targets a single nucleotide polymorphism (SNP) in the mitochondrial cytochrome oxidase I (mtCOI) gene. To evaluate the assay, DNA was extracted from individual whiteflies of six known biotype strains, and all scored correctly as either a B or Q biotype. As further validation, 72 individuals from field samples collected in different parts of the world were also tested by the assay. No failed reactions were observed, with all 72 samples scoring clearly as either the B or Q biotype. CONCLUSION: The development of this rapid and high‐throughput assay has important potential for routine monitoring of B and Q biotypes on ornamental plants and for the screening of B. tabaci populations in countries where these biotypes are not yet established. Copyright © 2007 Society of Chemical Industry  相似文献   

2.
The global invasion of certain Bemisia tabaci biotypes provides opportunities to compare the competency of virus transmission between invasive and indigenous biotypes. Here we report on the acquisition, retention and transmission of Tomato Yellow Leaf Curl Virus (TYLCV) by the invasive B, Q and indigenous ZHJ2 biotypes of B. tabaci from Zhejiang, China. For all whitefly biotypes, TYLCV DNA was detected within a 30-min acquisition access period (AAP) to infected leaves. The percentage of adults with viral DNA increased with the length of AAP and reached 100% after 10–12 h. Following acquisition, viruliferous B, Q and ZHJ2 adults retained TYLCV DNA for the rest of their lives. Transmission was achieved with one B/Q adult per plant at the frequency of 50–55%, which rose to 100% with 10 insects per plant. In contrast, transmission of the virus was not observed with one ZHJ2 adult per plant in the experiments, and the transmission frequency rose to only 30–45% when whitefly adults increased to 5–10 per plant. These new data will help in the determination of the pest status of the whitefly biotypes as virus vectors in the regions of invasion, and so help in the development of management strategies.  相似文献   

3.
The recent upsurgence ofBemisia tabaci (Genn.) as an important insect pest and vector ofTomato yellow leaf curl virus (TYLCV) is directly linked to serious damage to tomato crops grown throughout Japan. The molecular genetic identification and phylogenetic relationships of 12B. tabaci populations collected from representative locations in Japan were determined based on the mitochondrial cytochrome oxidase I (mtCOI) sequence. Phylogenetic analysis of the whitefly mtCOI sequence indicated that both the invasive B and Q biotypes now occur in Japan. The Q biotype was found at four locations: Mihara in Hiroshima, Nishigoshi in Kumamoto, Miyanojo and Okuchi in Kagoshima prefectures; the remaining eight collections were identified as the B biotype. This is the first report of the introduction of Q biotype in Japan. http://www.phytoparasitica.org posting July 21, 2006.  相似文献   

4.
BACKGROUND: Resistance to numerous insecticide classes in Bemisia tabaci Gennadius has impaired field control efficacy in south‐eastern China. The biotype and resistance status of B. tabaci collected from these areas was investigated. RESULTS: Two different biotypes of B. tabaci (B‐biotype and Q‐biotype) were detected in south‐eastern China, and the samples collected from geographical regions showed a prevalence of the Q‐biotype and the coexistence of B‐ and Q‐biotypes in some regions. Moderate to high levels of resistance to two neonicotinoids were established in both biotypes (28–1900‐fold to imidacloprid, 29–1200‐fold to thiamethoxam). Medium to high levels of resistance to alpha‐cypermethrin (22–610‐fold) were also detected in both biotypes. Four out of 12 populations had low to medium levels of resistance to fipronil (10–25‐fold). Four out of 12 populations showed low levels of resistance to spinosad (5.7–6.4‐fold). All populations tested were susceptible to abamectin. CONCLUSION: The Q‐biotype B. tabaci is supplanting the B‐biotype which used to be ubiquitous in China. Field populations of both B‐ and Q‐biotypes of B. tabaci have developed high levels of resistance to imidacloprid and thiamethoxam. Abamectin is the most effective insecticide against adult B. tabaci from all populations. Copyright © 2010 Society of Chemical Industry  相似文献   

5.
At least 20 genetic biotypes, with varying degrees of biological characterization, are currently recognized within theBemisia tabaci (Hemiptera: Aleyrodidae) species complex. Their identification relies on a set of different molecular techniques. However, none of the available markers is completely adequate, due to technical difficulties or lack of reproducibility. We therefore developed a method for rapid biotyping ofB. tabaci populations. The five biotypes (B, Q, M, S and T) reported until now in the Mediterranean Basin have been tested by PCR amplification of the cytochrome oxidase I mitochondrial gene followed by restriction with the enzymeTru9I. The digestion patterns produced by this enzyme were able to identify the five biotypes clearly. Digestion with another enzyme,TaqI, discriminated only between biotypes B and Q. The newly developed method enables rapid biotyping and can be applied in studies aimed at assessing biotype distribution and competition at least in the Mediterranean area. http://www.phytoparasitica.org May 14, 2006.  相似文献   

6.
The biotype status of samples of the whiteflyBemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) collected from several field and greenhouse sites in Israel during 1999–2000 was determined by polyacrylamide gel electrophoresis (PAGE) for general esterases, and by RAPD-PCR using primers of arbitrary sequence. Results of this survey provide the first published evidence for the occurrence of theB. tabaci Q biotype, alongside the more widely distributed B biotype. Based on the collected samples, it appears that both the B and Q biotypes are present in Israel, and that field populations consist of a mixture of the two biotypes. A possible link betweenB. tabaci biotypes and insecticide resistance is discussed. Contribution no. 508/02 from the Inst. of Plant Protection, ARO, The Volcani Center, Bet Dagan, Israel. http://www.phytoparasitica.org posting Dec. 5, 2002.  相似文献   

7.
烟粉虱基因组和转录组研究及展望   总被引：1，自引：1，他引：0  
烟粉虱Bemisia tabaci(Gennadius)是世界性的重要害虫,为物种复合体,其中少数隐种近30年来入侵世界各国,并暴发成灾。在我国,最近几年MED隐种已经逐渐替代了之前入侵的MEAM1隐种,成为我国农田生态系统中的主要致害隐种。基因组和转录组研究的不断深入极大地推动了烟粉虱入侵机制、隐种替代机制、种系发生、不同隐种或地理种群鉴定、抗药性机制、烟粉虱与共生菌互作等领域的研究。本文简要综述了烟粉虱基因组和转录组测序的研究进展,介绍了转录组数据在种的分化和鉴定、共生菌的互作及抗药性研究领域的应用。  相似文献   

8.
为明确L-阿拉伯糖对B型和Q型烟粉虱毒性及其取食行为的影响,调查了饲喂含有L-阿拉伯糖人工饲料后烟粉虱的死亡率,利用刺吸电位技术(EPG)记录其取食行为,并观察了饲喂后其在人工饲料膜上的刺孔数量及直径。结果表明,B型和Q型烟粉虱的校正死亡率均随L-阿拉伯糖浓度及饲喂时间的增加而升高;在3种浓度下,B型烟粉虱校正死亡率均显著高于Q型烟粉虱;在5%、10%浓度下,Q型烟粉虱校正死亡率分别在第5天和第3天达100%,B型烟粉虱分别在第3天和第2天达到100%;5%L-阿拉伯糖对B型烟粉虱取食行为影响比Q型大;在5%浓度下,B型和Q型烟粉虱在膜上的刺孔数量总体少于对照组。研究表明,L-阿拉伯糖对烟粉虱具有杀虫活性,且对B型和Q型烟粉虱的毒性效果不同。  相似文献   

9.
The sweet potato whitefly, Bemisia tabaci (Gennadius) (Hemiptera:Aleyrodidae), is an invasive and damaging pest of field crops worldwide. The neonicotinoid insecticide imidacloprid has been widely used to control this pest. We assessed the species composition (B vs. Q), imidacloprid resistance, and association between imidacloprid resistance and the expression of five P450 genes for 14–17 B. tabaci populations in 12 provinces in China. Fifteen of 17 populations contained only B. tabaci Q, and two populations contained both B and Q. Seven of 17 populations exhibited moderate to high resistance to imidacloprid, and eight populations exhibited low resistance to imidacloprid, compared with the most susceptible field WHHB population. In a study of 14 of the populations, resistance level was correlated with the expression of the P450 genes CYP6CM1 and CYP4C64 but not with the expression of CYP6CX1, CYP6CX4, or CYP6DZ7. This study indicates that B. tabaci Q has a wider distribution in China than previously reported. Resistance to imidacloprid in field populations of B. tabaci is associated with the increased expression of two cytochrome P450 genes (CYP6CM1 and CYP4C64).  相似文献   

10.
Pyrethroid and organophosphate resistance-associated mutations have been recently reported in the whitefly Bemisia tabaci (Gennadius), a major pest of protected and outdoor crops worldwide. Here, we developed simple PCR–agarose gel visualization based assays for reliably monitoring the L925I and T929V pyrethroid resistance mutations in the B. tabaci para-type voltage gated sodium channel and the iAChE F331W organophosphate resistance mutation in the acetylcholinesterase enzyme ace1.PCR-RFLP assays were developed for detecting the L925I and the F331W resistance mutations. A highly specific PASA was developed for detecting the T929V mutation. The molecular diagnostic tools were used to monitor the frequency of the resistance mutations in a large number of field caught Q biotype B. tabaci from Crete (Greece), where both organophosphates and pyrethroids are extensively used. The F331W mutation was fixed in all field individuals examined. The pyrethroid resistance mutations were detected in high frequencies: 0.38 and 0.54 for L925I and T929V, respectively. The simple diagnostics are accurate and robust, to be used alongside classical bioassays to prevent ineffective insecticide applications, and for early identification of the spreading of resistant Q biotype populations into new regions around the globe.  相似文献   

11.
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12.
The spatial dispersal patterns ofTomato yellow leaf curl virus (TYLCV) disease vectored by the B and Q biotypes of the whiteflyBemisia tabaci in tomato glasshouses were compared. Tomato plants were arranged in glasshouses and TYLCV-infected plants were placed in the center of each plot. Adult whiteflies of each biotype were released onto TYLCV-infected plants and the insects were then freely dispersed in the glasshouses under high or moderate temperature conditions. The abundance and spatial distribution of dispersed whiteflies did not differ between the B and Q biotypes in tomato glasshouses. The disease incidence and dispersion of TYLCV as a result of short-distance movement of the whiteflies were also similar between the two biotypes, although on several investigation dates there was a tendency for the disease incidence caused by the B biotype to be slightly greater than that caused by the Q biotype. These results demonstrated that the aspects of spatial spread of TYLCV vectored by the B and Q biotypes ofB. tabaci in tomato glasshouses are similar. http://www.phytoparasitica.org posting Dec. 11, 2007.  相似文献   

13.
For the UK, Bemisia tabaci poses a threat primarily to protected vegetable crops due to the transmission of several plant-pathogenic viruses. There are at least 24 different biotypes of B. tabaci that cannot be differentiated through morphological traits. The B (Middle East-Asia Minor 1 species) and Q (Mediterranean species) biotypes are widely considered to be the most important and, as such, the ability to rapidly and precisely biotype B. tabaci interceptions is vital when developing effective control strategies. Intercepted adult/pupal B. tabaci received from the UK Plant Health and Seeds Inspectorate (PHSI) during 2002–2003 (n?=?60) and 2010–2011 (n?=?42) were both biotyped and tested for the presence of Tomato yellow leaf curl virus (TYLCV) and Tomato yellow leaf curl Sardinia virus (TYLCSV) using a real-time PCR assay based on TaqMan? chemistry. The positive results indicated that during 2002–2003 the Q biotype comprised 68.3?% of the interceptions whilst in 2010–2011 it comprised 66.7?% of the B. tabaci samples intercepted. Only three of the B biotypes collected during 2002–2003 were positive for TYLCSV, two originating from Israel and the other of unknown origin. The implications in regards to pest management of the insect are discussed.  相似文献   

14.
The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is an important pest due to its capacity for producing strong infestations and transmitting plant viruses. The New World putative species of B. tabaci complex (NW) is the indigenous whitefly of the Americas, but only the invasive Middle East-Asia Minor 1 putative species of B. tabaci complex (MEAM1), commonly referred to as the “B biotype” was identified in a limited scope sampling in Venezuela. Similarly to MEAM1 invasions elsewhere, in this South American country there has been an increase in the geographic range and abundance of B. tabaci, and in the number of viruses that it transmits since the late 1980s. We estimated the diversity of B. tabaci to elucidate their role in the epidemiology of geminiviruses in Venezuela. Thirteen microsatellite loci were screened in samples collected from 19 localities in ten major agricultural states. A Bayesian clustering method (Structure) grouped the samples into two genetic groups. Control samples from whiteflies NW and MEAM1 and partial sequencing of the mitochondrial cytochrome oxidase I gene showed that our samples of B. tabaci populations from Venezuela fall within NW and MEAM1 groups. In this survey, MEAM1 was predominant over NW whitefly in a proportion of 35:1. No evidence was observed for gene flow between indigenous and invader whitefly. Altogether, our results stress the urgency for controlling the proliferation of the invasive whitefly.  相似文献   

15.
BACKGROUND: Bemisia tabaci Gennadius Q‐biotype has readily developed resistance to numerous insecticide classes. Studies in the Mediterranean area are needed to clarify the resistance status and cross‐resistance patterns in this invasive whitefly biotype. The levels of resistance in nymphs of seven strains of B. tabaci Q‐biotype from south‐eastern Spain to representative insecticides were determined. RESULTS: Six populations had low to moderate levels of resistance to azadirachtin (0.2‐ to 7‐fold), buprofezin (11‐ to 59‐fold), imidacloprid (1‐ to 15‐fold), methomyl (3‐ to 55‐fold), pyridaben (0.9‐ to 9‐fold), pyriproxyfen (0.7‐ to 15‐fold) and spiromesifen (1‐ to 7‐fold), when compared with a contemporary Spanish Q‐biotype reference population (LC50 = 2.7, 8.7, 15.2, 19.9, 0.34, 20.9 and 1.1 mg L?1 respectively). A single population collected from a greenhouse subject to intensive insecticide use exhibited generally higher resistance levels to the same array of compounds (31‐, 1164‐, 3‐, 52‐, 9‐, 19‐ and 3‐fold respectively). Pyridaben and spiromesifen were extremely effective against nymphs of all strains, with LC50 values significantly below recommended application rates. CONCLUSION: In contrast to previous reports, high rates of efficacy exist for numerous insecticide classes against B. tabaci Q‐biotype populations in these intensive agricultural regions of south‐eastern Spain. This probably reflects the recent and significant reductions in exposure that have resulted from a wider uptake of IPM technologies and strategies. However, the continued presence of resistance genes also suggests that a reversion to levels of high insecticide exposure could result in a rapid selection for resistance. Copyright © 2009 Society of Chemical Industry  相似文献   

16.
A new approach for the simultaneous identification of the viruses and vectors responsible for tomato yellow leaf curl disease (TYLCD) epidemics is presented. A panel of quantitative multiplexed real‐time PCR assays was developed for the sensitive and reliable detection of Tomato yellow leaf curl virus‐Israel (TYLCV‐IL), Tomato leaf curl virus (ToLCV), Bemisia tabaci Middle East Asia Minor 1 species (MEAM1, B biotype) and B. tabaci Mediterranean species (MED, Q biotype) from either plant or whitefly samples. For quality‐assurance purposes, two internal control assays were included in the assay panel for the co‐amplification of solanaceous plant DNA or B. tabaci DNA. All assays were shown to be specific and reproducible. The multiplexed assays were able to reliably detect as few as 10 plasmid copies of TYLCV‐IL, 100 plasmid copies of ToLCV, 500 fg B. tabaci MEAM1 and 300 fg B. tabaci MED DNA. Evaluated methods for routine testing of field‐collected whiteflies are presented, including protocols for processing B. tabaci captured on yellow sticky traps and for bulking of multiple B. tabaci individuals prior to DNA extraction. This work assembles all of the essential features of a validated and quality‐assured diagnostic method for the identification and discrimination of tomato‐infecting begomovirus and B. tabaci vector species in Australia. This flexible panel of assays will facilitate improved quarantine, biosecurity and disease‐management programmes both in Australia and worldwide.  相似文献   

17.
The whitefly Bemisia tabaci has been a serious pest in protected tomato crops since 1995 in the south of Portugal (Algarve), causing severe losses mainly resulting from Tomato yellow leaf curl virus (TYLCV), first reported in the autumn/winter season. In order to manage and control the B. tabaci/TYLCV complex, experimental field trials were carried out between 1997 and 2000. Several control methods were tested, such as the application of white screen nets to windows and doors, chemical treatments against B. tabaci and the use of cucumber as a trap crop. The results show that the percentage of plants with TYLCV symptoms mainly reflects B. tabaci infestation level in the first 6 weeks. Screen net protection was the control method that clearly provided a low incidence of plants with TYLCV symptoms in the autumn/winter season. Additionally, insecticide treatments, made weekly in the first 6 weeks, may give improved protection. In the winter/spring season, the B. tabaci/TYLCV complex is a minor problem because of the low populations of B. tabaci and the climatic conditions. Information about the work in progress and results was given to growers through visits to the experimental fields and oral presentations.  相似文献   

18.
Pyriproxyfen, a novel juvenile hormone mimic, is a potent suppressor of embryogenesis and adult formation of the sweetpotato whitefly, Bemisia tabaci (Gennadius), and the greenhouse whitefly, Trialeurodes vaporariorum (Westwood). Dipping of cotton or tomato seedlings infested with 0 to 1-day-old eggs in 0.1 mg litre?1 resulted in over 90% suppression of egg hatch of both B. tabaci and T. vaporariorum. Older eggs were affected to a lesser extent. Exposure of whitefly females to cotton or tomato seedlings treated with pyriproxyfen resulted in oviposition of non-viable eggs. The LC90 values for egg viability of B. tabaci and T. vaporariorum exposed to treated plants were 0.05 and 0.2 mg litre?1, respectively. Treatment of whitefly larvae with 0.04–5 mg litre?1 resulted in normal development until the pupal stage; however, adult emergence was totally suppressed. Second instars of B. tabaci exposed to 5 mg litre?1 pyriproxyfen, excreted honeydew at a level similar to the control level until the fourth instar (pupation), after which a strong reduction was observed. Inhibition of egg-hatch on the lower surface of cotton leaves was observed when their upper surface was treated with 1–25 mg litre?1, indicating a pronounced translaminar effect. These findings indicate that pyriproxyfen is an efficient control agent of both B. tabaci and T. vaporariorum. The compound has been used successfully for controlling whiteflies in Israeli cotton fields since 1991. Adults of B. tabaci collected from a rose greenhouse and from adjacent cotton fields were monitored during 1991–1993 for their susceptibility to pyriproxyfen. A high level of resistance was recorded in whiteflies collected from a greenhouse after three successive applications of pyriproxyfen. Based on LC50 values, the resistance ratio for egg-hatch suppression was 554-fold and, for adult emergence failure, 10-fold. However, a single treatment of pyriproxyfen in cotton fields during the summer season (according to an insecticide resistance management (IRM) strategy) did not alter appreciably the susceptibility of B. tabaci to this compound. In order to prevent development of resistance, an attempt should be made to restrict its use to one treatment per crop season applied during the peak activity of the pest. Pyriproxyfen can be alternated with other novel compounds such as buprofezin and diafenthiuron for controlling whiteflies in cotton, vegetables and ornamentals as part of integrated pest management (IPM) and IRM strategies. In pyriproxyfen- or buprofezin-resistant strains of B. tabaci or T. vaporariorum, no appreciable cross-resistance was observed among pyriproxyfen, buprofezin and diafenthiuron.  相似文献   

19.

BACKGROUND

Bemisia tabaci is a globally significant agricultural pest including in Australia, where it exhibits resistance to numerous insecticides. With a recent label change, buprofezin (group 16), is now used for whitefly management in Australia. This study investigated resistance to pyriproxyfen (group 7C), spirotetramat (group 23) and buprofezin using bioassays and available molecular markers.

RESULTS

Bioassay and selection testing of B. tabaci populations detected resistance to pyriproxyfen with resistance ratios ranging from 4.1 to 56. Resistance to spirotetramat was detected using bioassay, selection testing and sequencing techniques. In populations collected from cotton, the A2083V mutation was detected in three populations of 85 tested, at frequencies ≤4.1%, whereas in limited surveillance of populations from an intensive horticultural region the frequency was ≥75.8%. The baseline susceptibility of B. tabaci to buprofezin was determined from populations tested from 2019 to 2020, in which LC50 values ranged from 0.61 to 10.75 mg L−1. From the bioassay data, a discriminating dose of 200 mg L−1 was developed. Recent surveillance of 16 populations detected no evidence of resistance with 100% mortality recorded at doses ≤32 mg L−1. A cross-resistance study found no conclusive evidence of resistance to buprofezin in populations with high resistance to pyriproxyfen or spirotetramat.

CONCLUSIONS

In Australian cotton, B. tabaci pest management is challenged by ongoing resistance to pyriproxyfen, while resistance to spirotetramat is an emerging issue. The addition of buprofezin provides a new mode-of-action for whitefly pest management, which will strengthen the existing insecticide resistance management strategy. © 2023 Commonwealth of Australia. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

20.
Milbemectin has a chemical structure close to the group of avermectins, which are derived fromStreptomyces avermitilis, and is considered primarily an efficient miticide. Effects of milbemectin on the sweetpotato whitefly,Bemisia tabaci Gennadius, were investigated under laboratory and field conditions. In bioassays conducted under controlled chamber conditions, the compound affected 1st instars ofB. tabaci, resulting in a LC90 of 0.06 mg a.i. I-1. Later stage larvae were much less affected. Milbemectin is highly photodegradable in sunlight. In laboratory assays, when treated cotton seedlings were subjected to 3 h of sunlight before being exposed toB. tabaci adults, no mortality of the whiteflies was observed. Milbemectin at a concentration of 2 mg a.i. I-1 applied in combination with 0.2% ‘Ultra Fine’ mineral oil showed a residual activity of 67% adult mortality 10 days after application, whereas milbemectin alone had no appreciable activity. The effect of milbemectin on whitefly populations in a cotton field was compared with that of cypermethrin and of untreated control. Although milbemectin was not applied with mineral oil, it was more effective than cypermethrin in controlling the whitefly populations. This insecticide/miticide seems not to affect appreciably natural enemies ofB. tabaci. Milbemectin may be considered a compound with the potential for controllingB. tabaci populations. Mineral oils enhanced the potency of milbemectin on both whitefly larvae and adults. http://www.phytoparasitica.org posting July 27, 1999. Contribution No. 501/99 from the Inst. of Plant Protection, Agricultural Research Organization.  相似文献   

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