| use of digoxigenin-labelled probes for detection and host-range studies of tomato yellow leaf curl geminivirus. | we studied the host range of tomato yellow leaf curl virus (tylcv) in some agronomically important tomato species. transmission tests with the natural vector bemisia tabaci from tomato to sweet pepper, eggplant, cucumber, melon, zucchini and spinach showed that these species did not develop symptoms and did not support viral replication. these species therefore do not constitutive a reservoir of the virus and can be cultivated as alternatives to tomato in the most affected areas. for host-range ... | 1991 | 1796214 |
| tomato yellow leaf curl virus from sardinia is a whitefly-transmitted monopartite geminivirus. | the genome of an isolate of tomato yellow leaf curl virus from sardinia, italy (tylcv-s), a geminivirus transmitted by the whitefly bemisia tabaci, has been cloned and sequenced. the single circular dna molecule comprises 2770 nucleotides. genome organisation closely resembles that of the dna a component of the whitefly-transmitted geminiviruses with a bipartite genome. a 1.8 mer of the tylcv-s genome in a binary vector of agrobacterium tumefaciens is infectious upon agroinoculation of tomato pl ... | 1991 | 1840676 |
| tomato yellow leaf curl virus: a whitefly-transmitted geminivirus with a single genomic component. | the genome of the tomato yellow leaf curl virus (tylcv), a bemisia tabaci-transmitted geminivirus, was cloned. all clones obtained were of one genomic molecule, analogous to dna a of african cassava mosaic virus. nucleotide sequence analysis of the tylcv genome showed that it comprises 2787 nucleotides, encoding six open reading frames, two on the virion strand and four on the complementary strand. all of them have counterparts in other geminiviruses. dimeric copies of the cloned viral genome we ... | 1991 | 1926771 |
| acquisition of tomato yellow leaf curl virus by the whitefly bemisia tabaci. | tomato yellow leaf curl virus (tylcv) genomic dna can be detected by southern blot analysis in nucleic acid extracted from a single whitefly. acquisition of tylcv by individual whiteflies in relation to the length of the access period, the virus concentration in, and the developmental stage of plant tissues was studied. the frequency of tylcv detection increased with the length of the access-period; dna was detected in 15% of whiteflies tested after a period of access to infected tissue of 30 mi ... | 1991 | 1940856 |
| the nucleotide sequence of abutilon mosaic virus reveals prokaryotic as well as eukaryotic features. | the complete nucleotide sequence of abutilon mosaic virus (west indian isolate, abmva) is presented. the resulting genomic structure resembles that of other geminiviruses which are transmitted by the whitefly bemisia tabaci: abmv possesses a bipartite circular genome with bidirectional orientation of the open reading frames (orf). both components have a common region of 180 bases with 99% homology while the rest of their sequence is distinct. eukaryotic regulatory transcription elements precede ... | 1990 | 2219703 |
| the occurrence in the body of bemisia tabaci of a factor apparently related to the phenomenon of "periodic acquisition" of tomato yellow leaf curl virus. | | 1967 | 6017403 |
| chinese squash leaf curl virus: a new whitefly-transmitted geminivirus. | coat protein (cp) gene of the chinese squash leaf curl virus (sqlcv-c) was amplified through pcr, cloned and completely sequenced. based on the comparisons at the levels of both cp gene nucleotide and cp-deduced amino acid sequences with other geminiviruses, sqlcv-c is confirmed to be distinct from the american squash leaf curl virus (sqlcv-e). it is a new geminivirus transmitted by whitefly bemisia tabaci, which infects dicotyledonous plants and is more closely related to the indian cassava mos ... | 1995 | 7755872 |
| congruent evolution between whiteflies (homoptera: aleyrodidae) and their bacterial endosymbionts based on respective 18s and 16s rdnas. | whiteflies (family aleyrodidae) possess heritable eubacterial endosymbionts sustained in specialized organ-like structure called mycetomes. comparisons of distances between the ash whitefly, siphoninus phillyreae, and two biotypes ("a" and "b") of the sweetpotato whitefly, bemisia tabaci, based on sequence analysis of genes for 18s rrnas (rdnas), were equivalent to the distances represented by the 16s rdnas of their respective endosymbionts. this finding indicates that evolutionary divergence in ... | 1993 | 7763374 |
| biochemical identification of interbreeding between b-type and non b-type strains of the tobacco whitefly bemisia tabaci. | polyacrylamide gel electrophoresis and a kinetic microplate assay were used to detect heterozygotes resulting from a cross between b-type and non b-type strains of the whitefly bemisia tabaci. both strains were homozygous for different esterase and acetylcholinesterase (ache) enzymes, and heterozygotes were produced in one of two crosses between b-type females (diploid) and non b-type males (haploid). in reciprocal crosses, however, no female offspring were produced, indicating that fertilizatio ... | 1995 | 7794236 |
| acquisition and transmission of agrobacterium by the whitefly bemisia tabaci. | whiteflies transmit many different plant pathogens. we show here that the whitefly bemisia tabaci can also acquire agrobacterium tumefaciens from liquid cultures and from crown galls, and transmit it to plants. cloned tomato yellow leaf curl virus (tylcv) dna and a. tumefaciens tumor-inducing functions were used as reporter genes. whiteflies were fed through membranes on cultures of agrobacterium at::pty4 containing a dimeric copy of an infectious tylcv genomic clone between the t-dna borders of ... | 1994 | 7873782 |
| polymerase chain reaction detection of viruliferous bemisia tabaci (homoptera: aleyrodidae) with two tomato-infecting geminiviruses. | the sweetpotato whitefly, bemisia tabaci (gennadius), is an important pest worldwide. a new biotype of sweetpotato whitefly, biotype b, causes damage by direct feeding and by the transmission of plant viruses, such as geminiviruses. in the mediterranean area, tomato yellow leaf curl geminivirus (tylcv) is the most serious disease of tomatoes. another whitefly-transmitted geminivirus, tomato mottle geminivirus (tomov), is presently a serious problem in tomato production in west-central and southw ... | 1994 | 7962950 |
| whitefly transmission and efficient ssdna accumulation of bean golden mosaic geminivirus require functional coat protein. | bean golden mosaic geminivirus (bgmv) has a bipartite genome composed of two circular ssdna components (dna-a and dna-b) and is transmitted by the whitefly, bemisia tabaci. dna-a encodes the viral replication proteins and the coat protein. to determine the role of bgmv coat protein systemic infection and whitefly transmission, two deletions and a restriction fragment inversion were introduced into the bgmv coat protein gene. all three coat protein mutants produced systemic infections when coinoc ... | 1994 | 8091659 |
| comparative epidemiology of three tropical whitefly-transmitted geminiviruses. | spatial and temporal patterns of spread of african cassava mosaic, okra leaf curl and tobacco leaf curl viruses in west africa, east africa and india share some general characteristics. by comparing the results and running new analyses on available data, it is shown that the epidemiology of these viruses is controlled by the same key variables. for instance, spatial spread is characterised by strong border effects due to accumulation of whitefly vectors (bemisia tabaci) on the wind-exposed field ... | 1993 | 8268255 |
| replication of tomato yellow leaf curl virus (tylcv) dna in agroinoculated leaf discs from selected tomato genotypes. | the leaf disc agroinoculation system was applied to study tomato yellow leaf curl virus (tylcv) replication in explants from susceptible and resistant tomato genotypes. this system was also evaluated as a potential selection tool in breeding programmes for tylcv resistance. leaf discs were incubated with a head-to-tail dimer of the tylcv genome cloned into the ti plasmid of agrobacterium tumefaciens. in leaf discs from susceptible cultivars (lycopersicon esculentum) tylcv single-stranded genomic ... | 1993 | 8400142 |
| identification of a whitefly species by genomic and behavioral studies. | an introduced whitefly species, responsible for over a half billion dollars in damage to u.s. agricultural production in 1991, is morphologically indistinguishable from bemisia tabaci (gennadius). however, with the use of polymerase chain reaction-based dna differentiation tests, allozymic frequency analyses, crossing experiments, and mating behavior studies, the introduced whitefly is found to be a distinct species. recognition of this new species, the silverleaf whitefly, is critical in the se ... | 1993 | 8418497 |
| analysis of the nucleotide sequence of the treehopper-transmitted geminivirus, tomato pseudo-curly top virus, suggests a recombinant origin. | the genome of tomato pseudo-curly top virus (tpctv), originating from florida, has been cloned and sequenced. tpctv is the only geminivirus identified with a vector specificity which falls outside the cicadellidae (leafhoppers) and aleyrodidae (whiteflies). infectivity of the cloned viral genome was demonstrated by agrobacterium-mediated inoculation of several host species. progeny virus was transmissible by the treehopper vector of tpctv, micrutalis malleifera (fowler). the genome of tpctv show ... | 1996 | 8638404 |
| association of geminivirus infection with yellow green mosaic disease of cucumis sativus: diagnosis by nucleic acid probes. | geminivirus association with yellow mosaic disease of c. sativus has been investigated by dot/slot blot hybridization tests using nucleic acid probe derived from dna-b of indian tomato leaf curl geminivirus. the disease was transmitted experimentally on c. sativus by whitefly, bemisia tabaci. some weeds were also found to harbour geminivirus infection in dot/slot blot hybridization tests. | 1996 | 8792653 |
| virus-like particles and rickettsia-like organisms in male germ and cyst cells of bemisia tabaci (homoptera, aleyrodidae) | | 1996 | 8812613 |
| quantitative determination of tomato yellow leaf curl geminivirus dna by chemiluminescent assay using digoxigenin-labeled probes. | a quantitative dot-blot hybridisation assay was developed for tomato yellow leaf curl geminivirus (tylcv). the assay is based on chemiluminescent detection of viral and plasmid dna using digoxigenin-labeled probes on nylon membranes. the response-error relationship was studied and a square root transformation was found to stabilise the variance of the response. an asymmetric sigmoid (gompertz) curve was used to describe the dose-response relationship. the detection limits and the precision profi ... | 1996 | 8919821 |
| engineering resistance against tomato yellow leaf curl virus (tylcv) using antisense rna. | one of the most severe diseases of cultivated tomato worldwide is caused by tomato yellow leaf curl virus (tylcv), a geminivirus transmitted by the whitefly bemisia tabaci. here we describe the application of antisense rnas to interfere with the disease caused by tylcv. the target of the antisense rna is the rare messenger rna of the rep protein, encoded by the c1 gene. transgenic nicotiana benthamiana plants expressing c1 antisense rna were obtained and shown to resist infection by tylcv. some ... | 1997 | 9037152 |
| efficient whitefly transmission of african cassava mosaic geminivirus requires sequences from both genomic components. | clones of two subgroup iii geminiviruses, the common strain of tomato golden mosaic virus (cstgmv) and african cassava mosaic virus originating from kenya (acmv-k), were shown to be non-transmissible by whitefiles. lack of transmissibility of cloned acmv-k was investigated by exchanging genomic components with a whitefly-transmissible acmv isolate from nigeria (acmv-nog). neither pseudorecombinant was transmissible, indicating that defects in both genomic components contributed to the lack of tr ... | 1997 | 9225057 |
| coat protein gene replacement results in whitefly transmission of an insect nontransmissible geminivirus isolate. | geminiviruses are transmitted by whiteflies, leafhoppers, or treehoppers. the whitefly species bemisia tabaci (gennadius) is the most efficient vector of subgroup iii geminiviruses. an isolate of abutilon mosaic virus (abmv), a bipartite geminivirus, was not detectable in the dna extract from insects by southern blot analysis, nor was the isolate transmissible by the b-biotype of b. tabaci, although the virus dna was amplified (by pcr) from some insects. in contrast, sida golden mosaic virus (si ... | 1997 | 9325236 |
| long-term association of tomato yellow leaf curl virus with its whitefly vector bemisia tabaci: effect on the insect transmission capacity, longevity and fecundity. | the association between tomato yellow leaf curl geminivirus (tylcv, israeli isolate) and its insect vector, the whitefly bemisia tabaci, was investigated. insects that emerged during a 24 h period were caged with tylcv-infected plants for a 48 h acquisition access period, then with egg-plants--a tylcv non-host--for the rest of their lives. while tylcv dna was associated with the whiteflies during their entire adult life, the amount of capsid protein rapidly decreased and was not detectable in th ... | 1997 | 9349491 |
| [host plants of bemisia tabaci (homoptera: aleyrodidae) in cuba]. | the sweet potato white fly, bemisia tabaci, is an important pest of tomatoes and beans, among other crops, which transmits viral diseases. since the second quarter of 1989 a significant population increase of this pest has been noted in several cultivated plants. from 1989 to 1992, a survey was done throughout the country, chiefly in vegetable and bean-producing areas. they occur in 119 species (42 families), a great increase over the previous record of four species. worldwide, this report repre ... | 1997 | 9404518 |
| evidence for transovarial transmission of tomato yellow leaf curl virus by its vector, the whitefly bemisia tabaci. | the whitefly bemisia tabaci is the only vector of the tomato yellow leaf curl geminivirus (tylcv). the insect transmits the virus in a persistent-circulative manner. tylcv dna was detected by polymerase chain reaction and by southern blot hybridization in progeny (eggs, first and second instars, adults) of single viruliferous whiteflies that developed on eggplant or on cotton (two tylcv nonhost plants). furthermore, tylcv dna was present in the progeny of insects that had acquired the virus thro ... | 1998 | 9454703 |
| defective forms of cotton leaf curl virus dna-a that have different combinations of sequence deletion, duplication, inversion and rearrangement. | tobacco and tomato plants inoculated at least 9 months previously with a pakistani isolate of cotton leaf curl virus (clcuv-pk), a whitefly-transmitted geminivirus, contained substantial amounts of circular dsdna molecules that were mostly about half the size of clcuv-pk dsdna-a. they appeared to be derived from clcuv-pk dna-a by various combinations of sequence deletion, duplication, inversion and rearrangement and, in a few instances, insertion of sequences of unknown origin. each of ten tobac ... | 1998 | 9634094 |
| havana tomato virus, a new bipartite geminivirus infecting tomatoes in cuba. | the cloning and nucleotide sequence of a new bipartite geminivirus found in cuba is described. dna a (2620 nt) and dna b (2586 nt) presented a genomic structure resembling that of other geminiviruses transmitted by bemisia tabaci. both components had a common region of 168 nt with a 95% identity. typical elements involved in replication and transcription were found in this region, though group-characteristic arrangement of iterons was not conserved in this virus. sequence was compared with gemin ... | 1998 | 9787659 |
| a groel homologue from endosymbiotic bacteria of the whitefly bemisia tabaci is implicated in the circulative transmission of tomato yellow leaf curl virus. | evidence for the involvement of a bemisia tabaci groel homologue in the transmission of tomato yellow leaf curl geminivirus (tylcv) is presented. a approximately 63-kda protein was identified in b. tabaci whole-body extracts using an antiserum raised against aphid buchnera groel. the groel homologue was immunolocalized to a coccoid-shaped whitefly endosymbiont. the 30 n-terminal amino acids of the whitefly groel homologue showed 80% homology with that from different aphid species and groel from ... | 1999 | 10087228 |
| identification of genes directly and indirectly involved in the insect transmission of african cassava mosaic geminivirus by bemisia tabaci. | the inability to transmit progeny virus resulting from the cloned components of an isolate of african cassava mosaic virus originating from kenya (acmv-k) has been shown to be due to defects in both genomic components. this was achieved by the production of infectious pseudorecombinants between acmv-k and the cloned components of a whitefly-transmissible acmv isolate originating from nigeria (acmv-nog). the exchange of gene fragments between acmv-k and acmv-nog has been used to demonstrate that ... | 1999 | 10334034 |
| identification of a novel circular single-stranded dna associated with cotton leaf curl disease in pakistan. | recent reports have suggested that cotton leaf curl virus (clcuv), a geminivirus of the genus begomovirus, may be responsible for cotton leaf curl disease in pakistan. however, the causal agent of the disease remains unclear as clcuv genomic components resembling begomovirus dna a are unable to induce typical disease symptoms when reintroduced into plants. all attempts to isolate a genomic component equivalent to begomovirus dna b have been unsuccessful. here, we describe the isolation and chara ... | 1999 | 10364503 |
| clones of cotton leaf curl geminivirus induce symptoms atypical of cotton leaf curl disease. | the causative agent of cotton leaf curl disease has previously been shown to be transmissible by the whitefly bemisia tabaci (gennadius) and a begomovirus (geminiviridae) was shown to be associated with the disease. this virus was provisionally called cotton leaf curl virus (clcuv) although no causal relationship between virus and disease was shown. in the present study full-length clones of clcuv, equivalent to the dna a component of bipartite begomoviruses, were obtained. the clones of clcuv w ... | 2000 | 10766303 |
| tomato yellow leaf curl geminivirus (tylcv-is) is transmitted among whiteflies (bemisia tabaci) in a sex-related manner. | tomato yellow leaf curl virus (tylcv) is the name given to a complex of geminiviruses infecting tomato cultures worldwide. tylcv is transmitted by a single insect species, the whitefly bemisia tabaci. herein we show that a tylcv isolate from israel (tylcv-is) can be transmitted among whiteflies in a sex-dependent manner, in the absence of any other source of virus. tylcv was transmitted from viruliferous males to females and from viruliferous females to males but not among insects of the same se ... | 2000 | 10775612 |
| mating interactions between two biotypes of the whitefly, bemisia tabaci (hemiptera: aleyrodidae) in australia. | the biological consequences of mating interactions between indigenous and exotic biotypes of bemisia tabaci (gennadius) in australia were studied using a combination of field and laboratory experiments. the key results of the interaction between the b and eastern australian biotypes were reduced population increase, a marked increase in the proportion of male progeny, fewer eggs produced by females paired with males of different biotype and no difference in the numbers of eggs per unmated female ... | 2000 | 10948369 |
| cytological and molecular evidence that the whitefly-transmitted cucumber vein yellowing virus is a tentative member of the family potyviridae. | cucumber vein yellowing virus (cvyv) is widespread in cucurbits in the middle east. cvyv has filamentous particles and is transmitted by bemisia tabaci by the semi-persistent mode. it has not yet been assigned to a specific genus or family. ultramicroscopic observations revealed numerous cylindrical cytoplasmic inclusions in melon and cucumber cells infected by cvyv isolates from israel and jordan. depending on the section orientation, the inclusions appeared as pinwheels or as bundles. in addit ... | 2000 | 10950987 |
| host range and symptom variation of pseudorecombinant virus produced by two distinct bipartite geminiviruses. | within the whitefly group only the species bemisia tabaci (gennadius) is the vector. most whitefly-transmitted geminiviruses possess bipartite dna genomes, dnas a and b. although they are closely related to each other, the production of viable pseudorecombinants between bipartite geminiviruses by reassortment of infectious cloned components is generally limited to strains of a particular virus. following exchange of cloned genomic components of sida golden mosaic virus (sigmv/hoyv) and abutilon ... | 2000 | 10963348 |
| tomato leaf curl virus from bangalore (tolcv-ban4): sequence comparison with indian tolcv isolates, detection in plants and insects, and vector relationships. | tomato leaf curl virus (tolcv) is a whitefly (bemisia tabaci) transmitted geminivirus (family geminiviridae, genus begomovirus) causing a destructive disease of tomato in many regions of india, east asia and australia. while tolcv isolates from australia and taiwan have a single genomic component (designated dna-a), those from northern india have two components (dna-a and dna-b). the tolcv isolates from southern india (bangalore) previously cloned seem to have a dna-a-like monopartite genome. we ... | 2000 | 11003471 |
| variation in the bemisia tabaci s. l. species complex (hemiptera: aleyrodidae) and its natural enemies leading to successful biological control of bemisia biotype b in the usa. | parasitoids of the bemisia tabaci (gennadius) species complex collected in spain and thailand were evaluated as biological control agents of b. tabaci biotype b in cole crops in texas, usa. parasitoids were identified by morphological and rapd-pcr analyses. the most abundant parasitoid from spain was eretmocerus mundus mercet with apparent field parasitism of 39-44%. in thailand, encarsia formosa gahan, e. transvena timberlake, e. adrianae lopez-avila, eretmocerus sp. 1 and sp. 2 emerged, with a ... | 2000 | 11020790 |
| the groel protein of the whitefly bemisia tabaci interacts with the coat protein of transmissible and nontransmissible begomoviruses in the yeast two-hybrid system. | we have previously suggested that a groel homolog produced by the whitefly bemisia tabaci endosymbiotic bacteria interacts in the insect hemolymph with particles of tomato yellow leaf curl virus from israel (tylcv-is), ensuring the safe circulative transmission of the virus. we have now addressed the question of whether the nontransmissibility of abutilon mosaic virus from israel (abmv-is) is related to a lack of association between groel and the virus coat protein (cp). translocation analysis h ... | 2000 | 11040131 |
| cotton leaf curl virus disease. | cotton is one of the most important crops of pakistan, accounting for over 60% of foreign exchange earnings. the present epidemic of cotton leaf curl disease (clcud) originated in the punjab region near the city of multan and was first reported in 1985, although it was noted in this region as early as 1967. by the early 1990s, clcud had become the major limitation to cotton production in pakistan and it has now spread into india and, more recently, south and west into other provinces of pakistan ... | 2000 | 11137169 |
| assessment of insecticide resistance in five insect pests attacking field and vegetable crops in nicaragua. | field populations of hypothenemus hampei (ferrari), plutella xylostella (l.), spodoptera exigua (hübner), helicoverpa zea (boddie) and bemisia tabaci (gennadius) were tested for resistance to several insecticides commonly used in nicariagua. assays were conducted to estimate the ld50s or lc50s and the corresponding resistance ratios. a diagnostic concentration was used to discriminate between susceptible and resistant strains of h. hampei. the tests with >6,000 h. hampei adults collected from si ... | 2000 | 11142313 |
| carbamate and organophosphate resistance in cotton pests in india, 1995 to 1999. | monitoring for organophosphate and carbamate resistance was carried out on five major insect pests of cotton collected from 22 cotton-growing districts across india. resistance was monitored in helicoverpa armigera (hübner) and pectinophora gossypiella (saunders) for the period 1995-1999 and for spodoptera litura (fabricius), earias vittella (fabricius) and bemisia tabaci (gennadius) in a survey conducted during the 1997-98 cropping season. of the 53 field strains of h. armigera, only four were ... | 2001 | 11228586 |
| detection of tomato leaf curl geminivirus in its vector bemisia tabaci. | geminiviruses are single-stranded dna plant infecting viruses that cause major losses in important crops in tropical and subtropical countries. tomato leaf curl virus (tlcv) belonging to the genera begomovirus, is a whitefly-transmitted geminivirus that causes a severe leaf curl disease in tomato (lycopersicon esculentum). the importance of this disease has prompted a great need for a rapid identification of tlcv in its hosts and vector. polymerase chain reaction (pcr) is the most sensitive appr ... | 2000 | 11272420 |
| alkaline phosphatase activity in whitefly salivary glands and saliva. | alkaline phosphatase activity was histochemically localized in adult whiteflies (bemisia tabaci b biotype, syn. b. argentifolii) with a chromogenic substrate (5-bromo-4-chloro-3-indolylphosphate) and a fluorogenic substrate (elf-97). the greatest amount of staining was in the basal regions of adult salivary glands with additional activity traced into the connecting salivary ducts. other tissues that had alkaline phosphatase activity were the accessory salivary glands, the midgut, the portion of ... | 2001 | 11304750 |
| genetic diversity of iberian populations of bemisia tabaci (hemiptera: aleyrodidae) based on random amplified polymorphic dna-polymerase chain reaction. | the genetic structure of six iberian populations of the whitefly bemisia tabaci, two of them biotype q, one biotype b, and the other three a mixture of both, has been studied using random amplified polymorphic dna-polymerase chain reaction (rapd-pcr). a total of 336 individuals was completely discriminated by means of 234 scored bands. separate analyses of molecular variance of haploid males and diploid females using the pairwise number of differences between haplotypes showed that biotypes cont ... | 2001 | 11348498 |
| molecular characterization of a novel defective dna isolated from tobacco tissues infected with tobacco leaf curl virus. | defective dna of tobacco leaf curl virus (tlcv) was identified in tlcv-infected tobacco plants. the defective dna was cloned and sequenced. the sequence showed it was about half the size of the tlcv dna-a, and was derived from tlcv dna-a by a large deletion. the defective dna contained the intergenic region and part of the ac1 (rep) gene of tlcv, and also novel open reading frames (orfs). the immunotrapping tests showed the defective dna was associated with geminate particles, suggesting it coul ... | 2001 | 11394577 |
| how species-specific is the phoretic relationship between the broad mite, polyphagotarsonemus latus (acari: tarsonemidae), and its insect hosts? | broad mite, polyphagotarsonemus latus (acari: tarsonemidae), is a serious plant pest in tropical and subtropical regions. phoretic associations between broad mite and two genera of whiteflies (insecta: homoptera: aleyrodidae). namely bemisia and trialeurodes, have been reported from different parts of the world. our purpose was to determine the specificity of the association between the mite and its phoretic hosts. two host plants, potatoes and cucumbers, were used to study these relationships i ... | 2001 | 11523917 |
| encarsia species (hymenoptera: aphelinidae) of australia and the pacific islands attacking bemisia tabaci and trialeurodes vaporariorum (hemiptera: aleyrodidae)--a pictorial key and descriptions of four new species. | after the recent introduction of the pest whitefly bemisia tabaci (gennadius) biotype b into australia, research was undertaken to study the parasitoids of the long established native b. tabaci and trialeurodes vaporariorum (westwood). the genus encarsia contains species which are important biological control agents of whiteflies and hard scales. the taxonomy of the encarsia species attacking b. tabaci and t. vaporariorum in australia and the pacific islands is revised. dna sequencing of the 28s ... | 2001 | 11583600 |
| phytoseiid predators as potential biological control agents for bemisia tabaci. | mites of the family phytoseiidae are known to be predators of whiteflies in several agroecosystems, especially of bemisia tabaci gennadius, a pest with high resistance to chemical insecticides that occurs in greenhouses in temperate regions. we collected predatory mites that were found to co-occur with whiteflies in the middle east for control of b. tabaci: tvphlodromus athiasae (porath and swirski), neoseiulus barkeri hughes, tvphlodromips swirskii (athias-henriot), euseius scutalis (athias-hen ... | 2001 | 11603735 |
| tomato yellow leaf curl china virus: monopartite genome organization and agroinfection of plants. | the complete dna sequence (2734 nucleotides) of the monopartite genome of tomato yellow leaf curl china virus (tylccnv), a begomovirus transmitted by the whitefly bemisia tabaci, was determined. the circular genomic dna contains six open reading frames (orfs) encoding proteins of molecular weights >10 kda, of which two (v1 and v2) are located on the virion-sense strand and four (c1, c2, c3 and c4) on the complementary-sense strand. the orfs are comparable to those of other whitefly-transmitted b ... | 2001 | 11682126 |
| quantitation of cucurbit yellow stunting disorder virus in bemisia tabaci (genn.) using digoxigenin-labelled hybridisation probes. | a cost-efficient hybridisation assay was developed to estimate the amount of cucurbit yellow stunting disorder virus (cysdv) in bemisia tabaci (gennadius) whiteflies infesting protected cucumber crops. cdna from the coat protein (cp) gene and the hsp70 homologue protein gene from cysdv were obtained by reverse transcriptase-pcr from viruliferous whiteflies and cloned into plasmids. digoxigenin (dig)-labelled cdna probes reacted with extracts from these whiteflies applied on nylon membranes. prec ... | 2002 | 11849688 |
| cotton whitefly (bemisia tabaci) resistance to organophosphate and pyrethroid insecticides in pakistan. | resistance to three organophosphate and four pyrethroid insecticides was monitored from 1992 to 2000 in field populations of adult whiteflies, bemisia tabaci, from pakistan using a leaf-dip method. there was generally a very high resistance to dimethoate and deltamethrin, and a moderate resistance to monocrotophos during 1992 to 1996. from 1997 to 2000, resistance to these insecticides dropped to low levels because of less reliance on them for whitefly control, and introduction of new chemistrie ... | 2002 | 11852647 |
| exchange of three amino acids in the coat protein results in efficient whitefly transmission of a nontransmissible abutilon mosaic virus isolate. | geminiviruses are transmitted in a circulative manner by whiteflies, leafhoppers, or treehoppers. the whitefly species bemisia tabaci (genn.) is the vector for members of the genus begomovirus. the closely related bipartite central american begomoviruses abutilon mosaic virus (abmv), sida golden mosaic virus originating from costa rica (sigmv-cr), and sida golden mosaic virus originating from honduras (sigmv-hoyv) were used to study transmission by their insect vector. the abmv isolate is defect ... | 2001 | 11883001 |
| effect of geminivirus infection and bemisia infestation on accumulation of pathogenesis-related proteins in tomato. | the whitefly, bemisia tabaci biotype b, has been shown to cause pathogenesis-related (pr) proteins to accumulate in plants as a result of direct feeding, but their specific role in plant defensive systems is unclear. our objective was to compare accumulation of tomato pr proteins (beta-1,3-glucanase, chitinase, peroxidase, p2 and p4) in response to whitefly, with or without tomato mottle virus (tomov) infection. tomato pr protein response was measured over time in plants divided into three treat ... | 2002 | 11921078 |
| insecticidal 2-hydroxy-3-alkyl-1,4-naphthoquinones: correlation of inhibition of ubiquinol cytochrome c oxidoreductase (complex iii) with insecticidal activity. | the insecticidal and in vitro activities of four homologous series of 2-hydroxy and acetoxy-3-substituted-1,4-naphthoquinones have been measured and correlated with their (log) octanol/water partition coefficients (log ko/w). in vitro activity against mitochondrial complex iii was only exhibited by 2-hydroxy-3-alkyl-1,4-naphthoquinones, indicating that the 2-acetoxy compounds act as proinsecticides. good correlation was observed between in vivo activity against the two-spotted spider mite, tetra ... | 2002 | 11975169 |
| discovering new insect viruses: whitefly iridovirus (homoptera: aleyrodidae: bemisia tabaci). | adult whiteflies, bemisia tabaci (gennadius), collected from the field were screened for viral pathogens using a cell line from the silverleaf whitefly, b. tabaci, b biotype (syn. b. argentifolii). homogenates from the field-collected whiteflies were applied to cell cultures and checked for cytopathic effects (cpe). cells were observed to develop cytoplasmic inclusions and to have a change in morphology. cells displaying cpe were observed using a transmission electron microscope and found to be ... | 2001 | 12009803 |
| evaluation of peracid activated organophosphates in studies of insecticide resistance conferred by insensitive acetylcholinesterases. | peracid activated organophosphorus (op) insecticides were evaluated against electric eel and a range of insect acetylcholinesterases (ache). incubation of chlorpyrifos and sulprofos with meta-chloroperoxybenzoic acid (mcpba) produced active metabolites capable of distinguishing between ache enzymes conferring op susceptibility and resistance in populations of the tobacco whitefly, bemisia tabaci gennadius, and the beet armyworm, spodoptera exigua hubner. these products were also active against e ... | 2002 | 12020023 |
| whiteflies (bemisia tabaci) issued from eggs bombarded with infectious dna clones of tomato yellow leaf curl virus from israel (tylcv) are able to infect tomato plants. | we have reported previously that tomato yellow leaf curl virus from israel (tylcv) penetrates the reproductive system of its vector, the whitefly bemisia tabaci biotype b, and may be transmitted to progeny. in order to mimic this phenomenon and to understand how tylcv accompanies the development of the insect, we have bombarded b. tabaci eggs with an infectious dna clone of tylcv. after a linear full-length genomic copy of tylcv dna was delivered to eggs, the dpni-sensitive dna became circular a ... | 2002 | 12038688 |
| a distinct bemisia tabaci (gennadius) (hemiptera: sternorrhyncha: aleyrodidae) genotype cluster is associated with the epidemic of severe cassava mosaic virus disease in uganda. | during the 1990s, an epidemic of cassava mosaic virus disease caused major losses to cassava production in uganda. two factors associated with the epidemic were the occurrence of a novel recombinant begomovirus, eacmv-ug, and unusually high populations of the whitefly vector, bemisia tabaci. here we present molecular evidence for the occurrence of two cassava-colonizing b. tabaci genotype clusters, ug1 and ug2, one of which, ug2, can be consistently associated with the cmd epidemic in uganda at ... | 2002 | 12074729 |
| co-adaptation between cassava mosaic geminiviruses and their local vector populations. | four cassava mosaic geminivirus (cmg) isolates; african cassava mosaic virus from namulonge, uganda (acmv-[nam]), east african cassava mosaic virus from mtwara, tanzania (eacmv-[mtw]), eacmv-uganda from namulonge (eacmv-ug[nam]) and indian cassava mosaic virus from trivandrum, india (icmv-[tri]) were compared for their ability to be transmitted by four colonies of cassava whitefly, bemisia tabaci (gennadius), collected from namulonge (nam), mtwara (mtw), kumasi (kum) and trivandrum (tri). with 2 ... | 2002 | 12076831 |
| nucleotide sequence and phylogenetic analysis of cucurbit yellow stunting disorder virus rna 2. | the complete nucleotide sequence of cucurbit yellow stunting disorder virus (cysdv) rna 2, a whitefly (bemisia tabaci)-transmitted closterovirus with a bi-partite genome, is reported. cysdv rna 2 is 7,281 nucleotides long and contains the closterovirus hallmark gene array with a similar arrangement to the prototype member of the genus crinivirus, lettuce infectious yellows virus (liyv). cysdv rna 2 contains open reading frames (orfs) potentially encoding in a 5' to 3' direction for proteins of 5 ... | 2002 | 12086142 |
| tryptophan decarboxylase, tryptamine, and reproduction of the whitefly. | tryptophan decarboxylase (tdc) from catharanthus roseus (periwinkle) converts tryptophan to the indole-alkaloid tryptamine. when the tdc gene was expressed in transgenic tobacco, the 55-kd tdc enzyme and tryptamine accumulated. bemisia tabaci (sweetpotato whitefly) reproduction on transgenic plants decreased up to 97% relative to controls. production of tryptamine, its derivatives, or other products resulting from tdc activity may discourage whitefly reproduction and provide a single-gene-based ... | 1995 | 12228625 |
| toxicological and mechanistic studies on neonicotinoid cross resistance in q-type bemisia tabaci (hemiptera: aleyrodidae). | the tobacco whitefly, bemisia tabaci gennadius (homoptera: aleyrodidae) is a serious pest in numerous cropping systems and has developed a high degree of resistance against several chemical classes of insecticides. one of the latest group of insecticides introduced to the market were the neonicotinoids (chloronicotinyls), acting agonistically on insect nicotinic acetylcholine receptors. resistance to neonicotinoid insecticides has recently been shown to occur, especially in q-type b tabaci in so ... | 2002 | 12233176 |
| efficiency of insect exclusion screens for preventing whitefly transmission of tomato yellow leaf curl virus of tomatoes in israel. | tomato yellow leaf curl virus (tylcv) is the most frequently occurring virus in tomatoes in the middle east, and the most harmful one. it is transmitted solely by the whitefly bemisia tabaci (gennadius). within 4-6h of inoculative feeding, a whitefly can transmit tylcv to a healthy plant with 80% probability. the symptoms are apparent after two to three weeks whereupon fruit-set is effectively terminated. the only means of controlling tylcv is by controlling the whitefly. until 1990 this was exc ... | 2002 | 12241562 |
| distribution and genetic diversity of tomato-infecting begomoviruses in brazil. | tomato-infecting begomoviruses have been reported throughout brazil since the introduction of the b biotype of bemisia tabaci. here, we report a large scale survey on the distribution and genetic diversity of tomato-infecting begomoviruses. tomato samples with typical begomovirus symptoms were collected in seven different states, comprising the major tomato growing areas of the country. viruses were detected by polymerase chain reaction (pcr) using universal primers for the genus begomovirus. pc ... | 2003 | 12556993 |
| susceptibility of field populations of adult bemisia tabaci gennadius (homoptera: aleyrodidae) and eretmocerus sp (hymenoptera: aphelinidae) to cotton insecticides in burkina faso (west africa). | research was conducted in 14 cotton fields (3-10 ha) selected in seven localities (two fields per locality) in burkina faso, with the objectives of: (1) estimating bemisia tabaci gennadius (homoptera: aleyrodidae) population abundance, (2) assessing the levels of parasitism by encarsia spp and eretmocerus spp (hymenoptera: aphelinidae) and (3) estimating the susceptibilities of the pest and of an eretmocerus sp to the insecticides currently sprayed on cotton. yellow sticky cards and a leaf-turni ... | 2003 | 12558104 |
| relative effects of the insecticide thiamethoxam on the predator podisus nigrispinus and the tobacco whitefly bemisia tabaci in nectaried and nectariless cotton. | the predaceous stinkbug podisus nigrispinus (dallas) (heteroptera: pentatomidae) feeds on plants as well as on arthropod prey. the question arises whether feeding on plants might expose the predator to systemic insecticide via ingestion of the active ingredient or its metabolites through plant sap of treated plants. this interaction was investigated with nectaried and nectariless cotton plants cropped in pots and treated with the systemic insecticide thiamethoxam at 0.5, 1.0 and 2.0 mg per plant ... | 2003 | 12639049 |
| biochemical study of resistance to imidacloprid in b biotype bemisia tabaci from guatemala. | systemic uptake bioassays using excised cotton leaves confirmed resistance to imidacloprid in a guatemalan population of the tobacco whitefly bemisia tabaci gennadius. polyacrylamide gel electrophoresis of naphthyl esterases identified the insects as b-types. upon collection from the field, resistance was determined to be 58-fold relative to a susceptible strain originating in the imperial valley of california. resistance levels increased to 126-fold in this population during its continuous expo ... | 2003 | 12639053 |
| survey of bemisia tabaci (hemiptera: aleyrodidae) biotypes in italy with the description of a new biotype (t) from euphorbia characias. | | 2003 | 12762868 |
| developmental rates of two congeneric parasitoids, encarsia formosa and e. pergandiella (hymenoptera: aphelinidae), utilizing different egg provisioning strategies. | endoparasitic hymenoptera vary in the extent to which they provision their eggs and thus in the degree to which they appear to rely on their hosts for resources during embryonic development. in this study, developmental rates were examined in two congeneric parasitoid species, encarsia formosa and e. pergandiella, that provision their eggs to different degrees. e. formosa eggs are much larger than e. pergandiella eggs. e. formosa eggs hatch significantly earlier than the eggs of e. pergandiella ... | 2002 | 12770098 |
| phylogenetic evidence for two new insect-associated chlamydia of the family simkaniaceae. | on the basis of 16s-23s ribosomal dna analyses, the whitefly bemisia tabaci (sternorrhyncha, aleyrodidae) and the eriococcid eriococcus spurius (sternorrhyncha, eriococcidae) were each found to harbor novel related chlamydial species within the family simkaniaceae. the generic designation fritscheagen. nov. is proposed to accommodate the two species, f. bemisiaesp. nov. and f. eriococci sp. nov. the finding of chlamydial 16s-23s ribosomal dna in b. tabaci is consistent with a previous electron m ... | 2003 | 12783192 |
| plastic cup traps equipped with light-emitting diodes for monitoring adult bemisia tabaci (homoptera: aleyrodidae). | equipping the standard plastic cup trap, also known as the cc trap, with lime-green light-emitting diodes (led-plastic cup trap) increased its efficacy for catching bemisia tabaci by 100%. few eretmocerus eremicus rose and zolnerowich and encarsia formosa gahan were caught in led-plastic cup traps. the led-plastic cup traps are less expensive than yellow sticky card traps for monitoring adult whiteflies in greenhouse crop production systems and are more compatible with whitefly parasitoids relea ... | 2003 | 12852586 |
| insecticide resistance in egyptian populations of the cotton whitefly, bemisia tabaci (hemiptera: aleyrodidae). | three collections of bemisia tabaci were taken from cotton and vegetable crops at the beginning of the growing season in egypt. these displayed marked resistance to the carbamates carbosulfan (ca 20- to 50-fold) and aldicarb (ca 40- to 80-fold) and moderate resistance to the pyrethroids cypermethrin (ca 10- to 30-fold) and lambda-cyhalothrin (ca 10- to 25-fold). they displayed no resistance to the organophosphates profenofos and pirimiphos-methyl, or to imidacloprid. another population, collecte ... | 2003 | 12916767 |
| detection of tomato yellow leaf curl virus by loop-mediated isothermal amplification reaction. | the genomic dna molecule of tomato yellow leaf curl virus (tylcv), a whitefly-transmitted geminivirus, was amplified from total dna extracts of tylcv-infected tomato (lycopersicon esculentum) by the use of loop-mediated isothermal amplification (lamp). the procedure was also used to amplify tylcv dna from total dna extracts of individual whiteflies (bemisia tabaci) that had fed on tylcv-infected plants. one of the characteristics of the lamp method is its ability to synthesize an extremely large ... | 2003 | 12951210 |
| wolbachia infections of the whitefly bemisia tabaci. | we report the first systematic survey for the presence of wolbachia endosymbionts in aphids and whiteflies, particularly different populations and biotypes of bemisia tabaci. additional agriculturally important species included were predator species, leafhoppers, and lepidopterans. we used a polymerase chain reaction (pcr)-based detection assay with ribosomal 16s rdna and wolbachia cell surface protein (wsp) gene primers. wolbachia were detected in a number of whitefly populations and species, w ... | 2003 | 14506854 |
| field efficacy and baseline toxicities of pyriproxifen, acetamiprid, and diafenthiuron against bemisia tabaci gennadius (homoptera: aleyrodidae) in burkina faso (west africa). | bioassays were conducted in 2001 and 2002 to estimate toxicities and dose-response relationships of 24 bemisica tabaci gennadius populations to pyriproxifen, acemitaprid, and diafenthiuron. lc50s ranging from 0.014 to 0.096 mgl(-1), 0.60 to 1.3 mgl(-1), and 3.5 to 6.7 mgl(-1) were observed respectively for pyriproxifen, acemitaprid, and diafenthiuron. these lc50s much lower than the field doses recommended for each compound. a fast increase in rates of mortality within a narrow range of lethal c ... | 2003 | 14649707 |
| bemisia tabaci (homoptera: aleyrodidae) biotypes in india. | host plant performance, esterase, and virus transmission tests revealed cassava-strain and sweetpotato-strain populations of whitefly bemisia tabaci (gennadius) biotypes in india. individuals from the sweetpotato-reared population did not breed on cassava, manihot esculenta crantz, and the cassava-strain-reared individuals failed to develop on sweetpotato, ipomoea batatus (l.) lam. eggplant, solanum melongena l., and tobacco, nicotiana tabacum l., were common hosts for both biotypes. the cassava ... | 2003 | 14994796 |
| whitefly transmission of sweet potato viruses. | three genera of plant viruses, begomovirus (geminiviridae), crinivirus (closteroviridae) and ipomovirus (potyviridae), contain members that infect sweet potato (ipomoea batatas) and are transmitted by whiteflies. the begomoviruses, sweet potato leaf curl virus (splcv) and ipomoea leaf curl virus (ilcv), and the ipomovirus sweet potato mild mottle virus are transmitted by bemisia tabaci, the sweet potato whitefly. the crinivirus, sweet potato chlorotic stunt virus (spcsv), is transmitted by b. ta ... | 2004 | 15036843 |
| tylcsv dna, but not infectivity, can be transovarially inherited by the progeny of the whitefly vector bemisia tabaci (gennadius). | the transovarial transmission of two species of begomovirus, tomato yellow leaf curl virus (tylcv) and tomato yellow leaf curl sardinia virus (tylcsv), through generations of bemisia tabaci of the b and q biotypes has been investigated. different life stages of the progeny of viruliferous female whiteflies have been analysed by pcr detection of viral dna and infectivity tests. our results indicate that tylcsv dna can be detected in eggs and nymphs, and to a lesser extent adults, of the first-gen ... | 2004 | 15193923 |
| complete nucleotide sequence of iranian tomato yellow leaf curl virus isolate: further evidence for natural recombination amongst begomoviruses. brief report. | complete nucleotide sequence of the iranian strain of tomato yellow leaf curl virus (tylcv-ir) was determined and compared with some begomoviruses. the complete sequence of tylcv-ir clustered together with tylcv and tylcv-mid from israel. a similar relationship holds when the deduced amino acid sequences of v1, v2, c2 and c3 and nucleotide sequences of ir, and rir were compared. in contrast, phylogenetic analyses of amino acid sequences of c4, c1, and nucleotide sequences of lir revealed that ty ... | 2004 | 15221543 |
| trapping of tomato yellow leaf curl virus (tylcv) and other plant viruses with a groel homologue from the whitefly bemisia tabaci. | to avoid destruction in the haemolymph of their vector, many plant circulative viruses interact with groel homologues produced by insect endosymbiotic bacteria. we have exploited this phenomenon to devise tools allowing trapping of plant viruses by either groel purified from the whitefly bemisia tabaci or by whitefly groel over-expressed in e. coli. pcr tubes or 96-well plates coated with a groel preparation were incubated with cleared sap of virus infected plant leaves or insect vectors. groel- ... | 2004 | 15290375 |
| intra- and interspecific competition between biotypes b and q of bemisia tabaci (hemiptera: aleyrodidae) from spain. | biotypes b and q of bemisia tabaci (gennadius), collected from the islands of tenerife and majorca respectively, were exposed to competition conditions on tomato cv. marmande in the laboratory. both biotypes were established in single and mixed cultures at different densities. increased mortality of biotype q females and immature instars was observed together with a lower rate of fecundity and progeny size compared to biotype b, when reared in single or mixed cultures. the female:male sex ratio ... | 2004 | 15301702 |
| quantitative parameters determining whitefly (bemisia tabaci) transmission of lettuce infectious yellows virus and an engineered defective rna. | in this study, quantitative parameters affecting in vitro acquisition and whitefly (bemisia tabaci) transmission of lettuce infectious yellows virus (liyv) were examined and b. tabaci transmission of an engineered defective rna (d-rna) was demonstrated. virions purified from virus- and virion rna-inoculated chenopodium murale plants and protoplasts of nicotiana tabacum, respectively, were consistently transmitted to plants by b. tabaci when virion concentrations were 0.1 ng microl(-1) or greater ... | 2004 | 15302963 |
| east african cassava mosaic zanzibar virus - a recombinant begomovirus species with a mild phenotype. | cassava plants exhibiting mild symptoms of cassava mosaic disease (cmd) were collected from unguja island, zanzibar. cuttings grown from these plants in the glasshouse produced similar symptoms, which were milder than those caused by other known cassava mosaic geminiviruses (cmgs). the whitefly vector, bemisia tabaci (gennadius), transmitted the putative virus to 27.7% (n = 18) of target plants. total dna extracted from diseased leaves did not yield diagnostic pcr-bands using virus-specific prim ... | 2004 | 15375675 |
| dynamics of resistance to the neonicotinoids acetamiprid and thiamethoxam in bemisia tabaci (homoptera: aleyrodidae). | the dynamics of resistance in the sweetpotato whitefly, bemisia tabaci (gennadius), to the neonicotinoids acetamiprid and thiamethoxam was studied extensively in cotton fields in israel during the cotton-growing seasons 1999-2003. whitefly strains were collected in early and late seasons mainly in three locations in northern, central, and southern israel. the whiteflies were assayed under laboratory conditions for susceptibility to neonicotinoids, as part of the israeli cotton insecticide resist ... | 2004 | 15666764 |
| a new silverleaf-inducing biotype ms of bemisia tabaci (hemiptera: aleyrodidae) indigenous to the islands of the south-west indian ocean. | following the first detection of tomato yellow leaf curl virus (tylcv) from reunion (700 km east of madagascar) in 1997 and the upsurge of bemisia tabaci (gennadius) on vegetable crops, two genetic types of b. tabaci were distinguished using rapd-pcr and cytochrome oxidase i (coi) gene sequence comparisons. one type was assigned to biotype b and the other was genetically dissimilar to the populations described elsewhere and was named ms, after the mascarenes archipelago. this new genetic type fo ... | 2005 | 15705212 |
| insecticide resistance in bemisia tabaci (homoptera: aleyrodidae) populations from crete. | the resistance levels to alpha-cypermethrin, bifenthrin, pirimiphos-methyl, endosulfan and imidacloprid were determined in bemisia tabaci (gennadius) from crete. five b tabaci populations collected from greenhouse and outdoor crops were bioassayed and compared with a reference susceptible strain. bemisia tabaci collected in a floriculture greenhouse exhibited the highest resistance against all insecticides: at lc50, resistance factors were 23-fold for bifenthrin, 80-fold for alpha-cypermethrin, ... | 2005 | 15712366 |
| molecular cloning of coat protein gene of an indian cotton leaf curl virus (clcuv-hs2) isolate and its phylogenetic relationship with others members of geminiviridae. | cotton leaf curl geminivirus is a whitefly (bemisia tabaci genn.) transmitted begomovirus (family geminiviridae) causing a serious disease of cotton in northern india. the very typical symptoms of present isolate (clcuv-hs2) showed thickened veins, dark green discoloration of the leaves with upward curling and leaf like structure known as enation (one in number), which develops into cup-shaped on the reverse side of leaves. the polymerase chain reaction (pcr) based technique can detect the viral ... | 2005 | 15744566 |
| biotypes b and q of bemisia tabaci and their relevance to neonicotinoid and pyriproxyfen resistance. | resistance monitoring for bemisia tabaci field populations to the juvenile hormone mimic, pyriproxyfen, was conducted from 1996 to 2003 in commercial cotton fields in two areas of israel: the ayalon valley (central israel) and the carmel coast (northwestern israel). although the use of pyriproxyfen ceased in these areas in 1996-1997 (because of the resistance), resistance levels to pyriproxyfen declined to some extent in the fields but remained quite stable, and the susceptibility has not been t ... | 2005 | 15756703 |
| severe outbreaks of tomato yellow leaf curl sardinia virus in calabria, southern italy. | during the winter 2003--2004 a serious disease was observed in protected tomato crops in castrovillari, reggio calabria province, southern italy. symptoms consisted in marginal leaf yellowing, leaf curling, plant stunting, flower abortion. the disease was detected in a group of greenhouses (about 10ha) where several tomato cultivars were grown hydroponically. the highest incidence of infection (60-100%) was observed in tomatoes grafted on beaufort drs tomato rootstock. since the symptoms were si ... | 2004 | 15756842 |
| the x-ray structure of a hemipteran ecdysone receptor ligand-binding domain: comparison with a lepidopteran ecdysone receptor ligand-binding domain and implications for insecticide design. | the ecdysone receptor is a hormone-dependent transcription factor that plays a central role in regulating the expression of vast networks of genes during development and reproduction in the phylum arthropoda. the functional receptor is a heterodimer of the two nuclear receptor proteins ecdysone receptor (ecr) and ultraspiracle protein. the receptor is the target of the environmentally friendly bisacylhydrazine insecticides, which are effective against lepidoptera but not against hemiptera or sev ... | 2005 | 15809296 |
| differential transcriptional activity of plant-pathogenic begomoviruses in their whitefly vector (bemisia tabaci, gennadius: hemiptera aleyrodidae). | plant-pathogenic begomoviruses have a complex association with their whitefly vector and aspects concerning virus genetic activity (genome replication and gene transcription) within the insect remain highly controversial. virus transcript abundance was assessed by quantifying selected gene transcripts of tomato mottle virus (tomov, a new world bipartite begomovirus) and tomato yellow leaf curl virus (tylcv, an old world monopartite begomovirus) in whiteflies (bemisia tabaci biotype b) after feed ... | 2005 | 15831966 |
| south west indian ocean islands tomato begomovirus populations represent a new major monopartite begomovirus group. | biological and molecular properties of tomato leaf curl madagascar virus isolates from morondova and toliary (tolcmgv-[tol], -[mor]), tomato leaf curl mayotte virus isolates from dembeni and kahani (tolcytv-[dem], -[kah]) and a tomato yellow leaf curl virus isolate from reunion (tylcv-mld[re]) were determined. full-length dna components of the five isolates from madagascar, mayotte and reunion were cloned and sequenced and, with the exception of tolcmgv-[tol], were shown to be both infectious in ... | 2005 | 15831967 |
| age-specific interaction between the parasitoid, encarsia formosa and its host, the silverleaf whitefly, bemisia tabaci (strain b). | the effect of hostage, the instar of bemisia tabaci (gennadius) parasitized, on the growth and development of encarsia formosa (gahan) was studied. e. formosa was able to parasitize and complete its life cycle no matter which instar of b. tabaci (strain b), [also identified as b. argentifolii (bellows and perring)], was provided for oviposition, but parasitoid development was significantly slower when 1st or 2nd instar b. tabaci rather than 3rd or 4th instars were parasitized. host age influence ... | 2003 | 15841244 |
| whitefly bemisia tabaci (homoptera: aleyrodidae) infestation on cassava genotypes grown at different ecozones in nigeria. | large-scale screening of cassava, manihot esculenta crantz, genotypes for resistance to infestation by whitefly bemisia tabaci gennadius, the vector of cassava mosaic geminiviruses, is limited. a range of new cassava elite clones were therefore assessed for the whitefly infestation in the 1999/2000 and 2000/2001 cropping seasons in experimental fields of international institute of tropical agriculture, ibadan, nigeria. on each scoring day, between 0600 and 0800 hours when the whiteflies were rel ... | 2005 | 15889755 |
| novel chlamydiae in whiteflies and scale insects: endosymbionts 'candidatus fritschea bemisiae' strain falk and 'candidatus fritschea eriococci' strain elm. | bacteria called 'fritschea' are endosymbionts of the plant-feeding whitefly bemisia tabaci and scale insect eriococcus spurius. in the gut of b. tabaci, these bacteria live within bacteriocyte cells that are transmitted directly from the parent to oocytes. whiteflies cause serious economic damage to many agricultural crops; b. tabaci fecundity and host range are less than those of bemisia argentifolii, possibly due to the presence of this endosymbiont. the b. tabaci endosymbiont has been charact ... | 2005 | 16014485 |
| nuclear dna content of the whitefly bemisia tabaci (aleyrodidae: hemiptera) estimated by flow cytometry. | the nuclear dna content of the whitefly bemisia tabaci (gennnadius) was estimated using flow cytometry. male and female nuclei were stained with propidium iodide and their dna content was estimated using chicken red blood cells and arabidopsis thaliana l. (brassicaceae) as external standards. the estimated nuclear dna content of male and female b. tabaci was 1.04 and 2.06 pg, respectively. these results corroborated previous reports based on chromosome counting, which showed that b. tabaci males ... | 2005 | 16048678 |
| the expression of the hydroxyproline-rich glycopeptide systemin precursor a in response to (a)biotic stress and elicitors is indicative of its role in the regulation of the wound response in tobacco (nicotiana tabacum l.). | two hydroxyproline-rich glycopeptide systemin (tobhs) precursor proteins known as preprotobhypsys-a and b were recently discovered in tobacco (nicotiana tabacum l.) [pearce et al. in nature 411:817-820, 2001]. in this work, the effect of elicitors, insect damage, and abiotic stress on the expression of preprotobhypsys-a pptobhs-a) in tobacco plants was evaluated. foliar application of methyl jasmonate preferentially induced the systemic expression of pptobhs-a in leaves phyllotactically one posi ... | 2005 | 16052320 |
| acute oral intragastric pathogenicity and toxicity in mice of paecilomyces fumosoroseus isolated from whiteflies. | paecilomyces fumosoroseus, monospore culture eh-506/3, isolated in mexico from bemisia tabaci whitefly was tested for acute oral intragastric pathogenicity and toxicity in cd-1 mice. animals were inoculated by gavage with only one dose (10(8) conidia/animal) of viable (72 mice), heat-killed (24 mice) fungus and compared to 18 control mice. clinical observations were done daily; mycological and histological tests were performed during necropsies at days 3, 10, 17, and 21 after the inoculation. no ... | 2005 | 16096686 |
| toxicity of sucrose octanoate to egg, nymphal, and adult bemisia tabaci (hemiptera: aleyrodidae) using a novel plant-based bioassay. | the sweetpotato whitefly, bemisia tabaci (gennadius), b biotype, presents a unique problem for vegetable growers by serving as a vector of plant viruses and by inducing physiological disorders of leaves and fruit. an action threshold of a single whitefly is necessary because of the threat of disease in many areas and growers rely heavily on a single class of insecticides (neonicotinoids) for whitefly control. additional control methods are needed to manage this pest in commercial vegetables. ext ... | 2005 | 16156577 |
| genetic structure of the whitefly bemisia tabaci in the asia-pacific region revealed using microsatellite markers. | bemisia tabaci (hemiptera: aleyrodidae) is a haplo-diploid species of sap-feeding insect belonging to the group of insects commonly known as whiteflies. from earlier analyses of mitochondrial and ribosomal markers it has been concluded that in the asia-pacific region there were three major indigenous races as well as a large collection of genotypes with no clear association with any race. this new study uses 15 microsatellite loci and demonstrates that the indigenous asia-pacific genotypes can b ... | 2005 | 16202090 |