J. K. Brown is an Associate Professor in the Department of Plant Sciences, UA and has an adjunct appointment in the Department of Biological Sciences at the University of Puerto Rico, and in the Department of Entomology, University of Arizona.

 

Dr. Judith Brown                                 Drs. Julio Bird & J Brown in Puerto Rico

        

 

Areas of research are the molecular epidemiology of whitefly-transmitted geminiviruses (Genus: Begomovirus, Family: Geminiviridae), the mechanisms involved in virus-vector specificity at whole system, cellular, and molecular levels including the whitefly-virus ‘transmission pathway’, and outcomes of variability biotypes/genotypes of Bemisia tabaci (Gennadius) that influence disease spread and the evolution of begomoviruses.

 

 

 

 

 

 

 

Symptoms of Squash                        B. tabaci, the                    Symptoms of Tomato

leaf curl virus Arizona                         whitefly vector                  mottle virus in Florida

Begomoviruses are emergent plant viruses that cause yield-limiting diseases of dicotyledonous plants widely used as food, fiber, and ornamentals. Begomoviruses are distributed worldwide in dry tropical and tropical locations, and in fringe subtropical-temperate locales such as the US Sunbelt States where mild climatic conditions prevail. These viruses are unique among plant viruses owing to their twinned or geminate particle morphology and a circular, single-stranded DNA genome.  New World begomoviruses have a bipartite genome arrangement, while Old World viruses can be bipartite or monopartite.  Satellite

DNAs are also associated with certain viral genomes, contributing to symptom development, as has been found for Cotton leaf curl virus-Pakistan (NIBGE and John Innes laboratories) and Cotton leaf curl virus-Sudan (AZ laboratory).

 

 

Typical geminate’ or paired

Icosahedral virions of

whitefly-transmitted geminiviruses

 

 

 

Arrangement of viral ORFs for A and B components (chromosomes)

of a typical bipartite begomovirus

 

Begomoviruses are transmitted in a persistent manner by a single species of whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae).  Distinct variants of the whitefly vector are known. Precisely how they vary and the ways in which variability influence disease epidemiology and the evolutionary courses of the begomoviruses that they transmit are not well understood.

Begomoviruses are classified as a genus based on their ability to infect dicotyledonous hosts, transmissibility by the whitefly vector B. tabaci, and placement in the begomovirus clade based on analysis of the A component (bipartite) or full length genome (monopartite) sequences.  In the absence of such complete information, provisional identification is established based on the sequence of the viral coat protein gene (V1 ORF) which is the most highly conserved begomoviral sequence. 

This phylogenetic tree illustrates the relationships between full length and A component sequences of well-studied begomoviruses from New and Old World locales and representative plant species.  Their closest relatives are geminiviruses transmitted by non-whitefly hemipteran vectors.

I.  A major research effort involves is the molecular epidemiology of begomoviruses, using comparative phylotaxonomic approaches.

Research involves identification and characterization of new and emerging begomoviruses that threaten agriculture, worldwide.  A PCR-molecular phylogenetic method for establishing provisional virus identity and thereby, tracking their distribution on a global basis is available at GEMINIDETECTive (http://gemini.biosci.arizona.edu ).  This website has been established with generous support received from The Common Fund for Commodities-Cotton, Cotton Incorporated-USA, National Biological Control Institute, USDA-Foreign Agriculture Service-OICD, and technical help of N. Merchant (ARL, UA).  Tools available at the site permit user-friendly begomovirus identification based upon a DNA sequence comparison of the ‘core’ or middle region of the coat protein gene (core Cp) employed as an informative molecular sequence.  Information is provided about the universal primers that target this 576-579 bp fragment for all begomoviruses.  Viral identity can be predicted using the sequence and a BLAST algorithm installed at the site that searches the reference sequence database for well-characterized begomoviruses plus sequences for field isolates obtained in the Arizona lab for viruses of different hosts and geographic locales, worldwide. Other information available at the site includes general features of Begomoviruses, a global distribution map, and degenerate primers and PCR conditions. Individual pages providing relevant information about recognized begomovirus species can be accessed through a link to the BLAST output, or can be accessed through the begomovirus ‘list’ page. Photographs illustrating symptom phenotypes in important hosts, host range information, and key references are also provided. This is the first PCR-based diagnostic tool by which accurate provisional identification of begomoviruses can be achieved.

II Variability of the B. tabaci Species Complex: Influence on Disease Spread and Begomovirus Evolution

Begomoviruses have evolved a highly dependent relationship between their host plant and whitefly vector. Work in our lab has demonstrated a surprising degree of biotic and genetic variation within B. tabaci, yet members of the taxon are considered a single species, which is referred to by most as the ‘B. tabaci species complex’. Certain aspects of variation between B. tabaci ‘types’ (previously, races, strains, biotypes) directly influence vector-mediated dispersal of begomoviruses, thereby, also potentially influencing epidemiology and consequently the evolution of begomoviruses. Along these lines we have pursued a critical examination of morphological, biological, and genetic polymorphisms for a suite of B. tabaci from different hosts and geographic sites, worldwide.  These data and results from mating studies indicate that B. tabaci is probably a group of sibling species that cannot be by differential morphological characters

 

 

 

 

 

 

Biotypes/genotypes of B. tabaci adults          Fourth instar–morphological ID to species-

are impossible to distinguish                          No definitive characters for biotic variants

Phylogenetic tree showing predicted relationships between B. tabaci from representative locations, worldwide, based on the whitefly mitochondria COI gene.  All B. tabaci collections group as one large clade, with subclades divided primarily by extant geographic origin.  Outgroups are Bemisia berbericola from North America and Trialeurodes vaporariorum, the greenhouse whitefly.

To investigate the influence of distinct vector variants on the epidemiology of begomovirus-incited diseases, we developed a molecular approach to enable the tracking of B. tabaci variants based mitochondria cytochrome oxidase gene (COI) polymorphism. We have shown that the mt COI reflects biogeographic relationships for variants examined to date. Current work involves COI phylotaxonomic predictions to study new vector outbreaks, including the cassava mosaic disease epidemic in Uganda and other east African countries (with J. Legg, IITA).  Studies are also underway to genotype other B. tabaci on the African continent (with C. Rey, University of Witwatersrand, and South Africa).

 

 

III.                Virus-Vector Specificity and the Whitefly Genome Project

The whitefly Bemisia tabaci is the exclusive vector of begomoviruses, worldwide. Variants of this whitefly vector generally have moderate to broad host ranges, while the viruses they transmit are characterized by moderate to narrow host capabilities. Although the basis for the specificity between begomoviruses and their whitefly vector is not well understood, begomoviruses and their vectors clearly exemplify co-evolved biological complexes. Begomoviruses are transmitted in a persistent, circulative manner by B. tabaci and the viral nucleocapsid is thought to constitute the sole viral-encoded transmission determinant. Evidence suggests that several kinds of whitefly proteins may interact with viral capsid, collectively, constituting ‘the transmission pathway’ and virus-vector specificity. Elucidating the cellular and molecular basis for this specificity will enhance our fundamental understanding of such complex interactions between ‘organisms’ of distinct kingdoms, and will enable disease control by targeting key of sites in the pathway to interfere with virus transmission. A whitefly genome project is currently being established to enable mining of whitefly genes important to whitefly-mediated virus transmission, insecticide resistance, metabolic regulation using ESTs and microarray analysis.

 

 

           

 

 

 

 

Schematic of whitefly transmission                 Launching the Whitefly Genome Project

Pathway and possible points of specificity       Sicily, Spring 2001. C McKenzie-USDA)

(courtesy R Rosell)                                            H. Czosnek-Hebrew Univ, and JK Brown-   UA (not present: M.R. Vilarinho de Oliveira (EMBRAPA) and R. Shatters-USDA)

 

Collaborators – Many thanks to ALL:                                                 

AGERI, Giza Egypt (Dr. M. Madkour)

British Museum (J. Martin)

CARDI, Jamaica (Dr. F. McDonald)

California Department of Food & Agriculture (R. Gill)

EMBRAPA, Brasil (Dr. M.R. Vilarinho de Oliveira)

Hebrew University (Dr. H. Czosnek)

IITA-Nigeria and Uganda (Dr. J. Legg) 

John Innes Centre (Drs. ID Bedford, R. Briddon, J. Stanley)

NIBGE, Faisalabad Pakistan (Dr.K. Malik)                                Cotton leaf curl virus-PAK

Ohio State University (Dr. D. Bisaro)                                                       

Purdue (Dr. R. Martyn & IPM CRSP)

Rothamsted Experiment Station (P. Jones)              

South Africa (G. Pietersen)

Texas A&M University (Dr. T. Isakeit)

USDA European Biocontrol Lab (Dr. A. Kirk)

USDA Citrus Lab/Genomics Center

(C.McKenzie/R.Shatters)

University Del Valle, Guatemala (M. Palmieri)

University of Puerto Rico (Dr. Julio Bird)

Univ of Witswatersrand, South Africa (Dr. C. Rey)   

ZAMORANO (Dr. M. M. Doyle)                                   Vegetable production - Guatemala           

 

 

 

 

 

 

 

    Begomovirus symptoms in Kenaf                        Cucurbit leaf curl virus discovered in

    Texas (courtesy T. Isakeit, TAMU)                      1998-99 in AZ, CA, TX, and Mexico

                                                                                   (courtesy M. Olsen, UA)

                       

Exotic Tomato yellow leaf curl virus-Puerto               New melon virus-Guatemala 2000

Rico (courtesy J. Bird-UPR)                                       (Melon chlorotic leaf curl virus)

 

Selected Scientific Works and Publications

Websites

Brown, JK and SD Wyatt.  Copyright 1998.  GEMINIDETECTive

URL: http://gemini.biosci.arizona.edu

Book Chapters & Compendia

Brown, J.K. 1990.  An update on the whitefly-transmitted geminiviruses in the Americas and the Caribbean Basin.  FAO Plant Prot. Bull. 39:5-23.

Brown, J.K. and J. Bird. 1992.  Whitefly-transmitted geminiviruses in the Americas and the Caribbean Basin: past and present.  Plant Dis. 76:220-225.

Brown, J.K. 1992.  Virus diseases of cotton.  Pages 275-330 in: Cotton Diseases.  R. J. Hillocks, ed.  Commonwealth Agricultural Bureaux International, Oxon, United Kingdom.  415 pp.

Brown, J.K.  1994. The Status of Bemisia tabaci (Genn.) as a pest and vector in world agroecosystems.  FAO Plant Prot. Bull.  42: 3-32.

Brown, J.K., D. Frohlich and R.C. Rosell, 1995.  The sweetpotato/silverleaf whiteflies: biotypes of Bemisia tabaci (Genn.), or a species complex?  Ann. Rev. Entomology 40: 511-534.

Brown, J.K. 1996.  Chapter 5 in: Molecular biology and epidemiology of Subgroup III, Geminviridae.  Plant-Microbe Interactions Review Series, G. Stacey and N. Keen, (eds) Chapman and Hall, pp 125-195.

Brown, J.K. 2000.  Molecular markers for the identification and global tracking of whitefly vector-begomovirus complexes.  Virus Research 71:233-260.

Brown, J.K. 2001.  The Molecular Epidemiology of Begomoviruses. Chapter 13 in: Trends in Plant Virology (J. A. Khan and J. Dykstra), The Haworth Press, Inc., NY (in press).

Brown, J.K. and H. Czosnek.  2001.  Whitefly Transmitted Viruses.  Chapter in: Advances in Botanical Research (in press). 

Brown, J.K. 1997. Viruses of cucurbits. In: Compendium of Cucurbit Viruses, American Phytopathological Society, St. Paul MN.

Brown, J.K. 2001. Plant Virus and Mycoplasma Diseases of Cotton.  Pages XX In: Cotton Compendium. American Phytopathological Society, St. Paul, MN. XX pp (in press).

Brown, J.K. 2001. Begomoviruses of peppers. In: Compendium of Pepper Viruses, American Phytopathological Society, St. Paul, MN (submitted).

 

Refereed Journal Articles

Brown, J.K. and M.R. Nelson.  1984.  Geminate particles associated with cotton leaf crumple disease in Arizona.  Phytopathology 74:987-990.

Brown, J.K. and M.R. Nelson. 1986.  Whitefly-borne viruses of melons and lettuce in Arizona.  Phytopathology 76:236-239.

Brown, J.K., M.R Nelson, and R.C. Lambe. 1986. Cotton leaf crumple virus transmitted from naturally infected bean from Mexico.  Plant Dis. 70:981.

Rosemeyer, M.E., J.K. Brown, and M.R. Nelson. 1986. Five viruses isolated from field-grown buffalo gourd, Cucurbita foetidissima HBK, a potential crop for semi-arid lands.  Plant Dis. 70:405-409.

Brown, J.K., J.D. Mihail, and M.R. Nelson.  1987.  The effects of cotton leaf crumple virus on cotton inoculated at different growth stages.  Plant Dis. 71:699-703.

Brown, J.K. and M.R. Nelson.  1987.  Host range and vector relationships of cotton leaf crumple virus.  Plant Dis. 71:522-524.

Brown J.K and M.R Nelson.  1988.  Transmission, host range, and virus-vector relationships of chino del tomate virus (CdTV), a whitefly-transmitted geminivirus from Sinaloa.  Plant Dis. 72:866-869. 

Brown, J.K. and M.R. Nelson.  1989.  Characterization of watermelon curly mottle virus, a geminivirus distinct from squash leaf curl virus.  Ann. Appl. Biol. 115:243-252.

Brown, J.K., O. Pozo-Campodonico and M.R. Nelson. 1989.  A whitefly-transmitted geminivirus of pepper causing tigre disease.  Plant Dis. 73:610.

Brown, J.K., M.A. Chapman and M.R. Nelson. 1989.  Disease of common bean caused by a whitefly-transmitted geminivirus.  Plant Dis. 73:81.

Brown, J.K. and B.T. Poulos. 1990. Serrano golden mosaic virus: a new whitefly-transmitted geminivirus of pepper and tomato in the U.S. and Mexico. Plant Dis. 74:720.

Wilson, F.D., and J.K. Brown.  1991.  Inheritance of resistance to cotton leaf crumple virus in cotton. J. of Heredity 82:508-509.

Costa, H.S., J.K. Brown, and D.N.Byrne. 1991.  Host plant selection by the whitefly, Bemisia tabaci  (Genn.) (Homoptera: Aleyrodidae) under greenhouse conditions. J. Appl. Entomol. 112:146-152.

Costa, H.S., J.K. Brown, and D.N. Byrne.  1991. Life history traits of the whitefly Bemisia tabaci  (Genn.) (Homoptera: Aleyrodidae) on six virus-infected or healthy plant species.  Environ. Entomol. 20: 1102-1107.

Costa, H.S., and J.K. Brown. 1991. Variation in biological characteristics and in esterase patterns among populations of Bemisia tabaci (Genn.) and the association of one population with silverleaf symptom development.  Entomol. Exp. Appl. 61:211-219.

Swanson, M. M., J.K. Brown, B.T. Poulos, and B.D. Harrison.  1992.  Genome affinities and epitope profiles of whitefly-transmitted geminiviruses from the Americas.  Ann. appl. Biol. 121:285-296.

Brown, J.K., D. Fletcher and J. Bird.  1993.  First report of Passiflora leaf mottle caused by a whitefly-transmitted geminivirus in Puerto Rico.  Plant Dis. 77:1264.

Brown, J.K., A.M. Idris, and D. Fletcher. 1993.  Sinaloa tomato leaf curl virus (STLCV), a new geminivirus of tomato and pepper in northwestern Mexico.  Plant Disease 77:1264.

Costa, H.S., J.K. Brown, S. Sivasupramaniam, and J. Bird.  1993.  Regional distribution, insecticide resistance, and reciprocal crosses between the `A' and `B' biotypes of Bemisia tabaci.  Insect Sci. and Applic. 14:127-138. 

Kirk, A.A., L.A. Lacey, N. Roditakis, and J.K. Brown.  1993.  The status of Bemisia tabaci (Hom:Aleyrodidae), Trialeurodes vaporariorum (Hom:Aleyrodidae) and their natural enemies in Crete.  Entomophaga 38: 405-410.

Bedford, I.D., P.G. Markham, J.K. Brown and R.C. Rosell.  1994.  Geminivirus transmission and biological characterization of whitefly (Bemisia tabaci) biotypes from different world regions.  Ann. appl. Biol. 125: 311-325.

Coats, S.A., J.K. Brown, and D.L. Hendrix.  1994.  Biochemical characterization of biotype-specific esterases in the whitefly Bemisia tabaci Genn. (Homoptera:Aleyrodidae).  Insect Biochem. Mol. Biol. 24: 723-728.

McGrath, M.T., D. Gilrein, and J.K. Brown.  1994.  First report of squash silverleaf disorder and the `B' biotype whitefly in New York.  Plant Dis. 78: 641.

Neal, Jr., J.W., B.A. Leonhardt, J. K. Brown, J. Bentz, E. D. Devilbiss, 1994.  Cuticular lipid composition of Trialeurodes vaporariorum (West) and Bemisia tabaci (Genn.) biotypes A and B (Homoptera:Aleyrodidae) and the affect of different host plant species. Annals of Ent. Soc. of America 87:  609-618.

Anthony, N., J.K. Brown, P.G. Markham, and R. H.  ffrench-Constant.  1995.  Molecular analysis of cyclodiene resistance-associated mutations among populations of the sweetpotato whitefly Bemisia tabaci .  Pestic. Biochem. & Physiology 51: 220-228.

Brown, J.K., S. Coats, I D. Bedford, and P.G. Markham, J. Bird, and D.R. Frohlich.  1995.  Characterization and distribution of esterase electromorphs in the whitefly, Bemisia tabaci (Genn.) (Homoptera:Aleyrodidae).  Biochemical Genetics 33: 205-214.

Costa, H.S., D.M. Wescot, D.E. Ullman, R. Rosell, J.K Brown, and M.W. Johnson.  1995.  Morphological variation in Bemisa  endosymbionts.  Protoplasma 189: 194-202.

Rosell, R., J.E. Lichty, and J.K. Brown.  1995.  Ultrastructure of the mouthparts of adult sweetpotato whitefly, Bemisia tabaci  (Gennadius) (Homoptera: Aleyrodidae).  Int. J. of Insect Morphol. & Embryol.  24: 297-306.

Thomas, J.C., D.G. Adams, C.L. Nessler, J.K. Brown, and H.J. Bohnert. 1995.  Tryptophan decarboxylase, tryptamine, and reproduction of the whitefly.  Plant Physiol 109: 717-720.

Costa, H.S., D.M. Wescot, D.E. Ullman, R.C. Rosell, J.K Brown, and M.W. Johnson.  1996.  Virus-like particles in the mycetocytes of the sweetpotato whitefly, Bemisia tabaci  (Homoptera: Aleyrodidae).  J. Invert. Pathology 67: 183-186.

Torres-Pacheco, I., J. A. Garzon-Tiznado, J. K. Brown, A. Becerra-Flora, and R. Rivera-Bustamante.  1996.  Detection and distribution of geminiviruses in  Mexico and the southern United States.  Phytopathology 86: 1186-1192.

Wyatt, S.D., and J.K. Brown.  1996. Detection of subgroup III geminivirus isolates in leaf extracts by degenerate primers and polymerase chain reaction.  Phytopathology 86: 1288-1293.

Anthony, N. M., J.K.Brown, R. Feyereisen, and R. H. ffrench-Constant.  1997.  Diagnosis and characterization of insecticide insensitive acetylcholinesterase in three populations of the sweetpotato whitefly Bemisia tabaci.  Pesticide Biochemistry 52: 39-46.

Rosell, R.C., I. D. Bedford, D.R. Frohlich, R. J. Gill, P.G. Markham, and J.K. Brown.  1997.  Analyses of morphological variation in distinct populations of Bemisia tabaci.  Ann. Entomol. Soc. of Am. 90: 575-589.

Idris, A. M. and J.K. Brown.  1998.  Sinaloa tomato leaf curl geminivirus: biological and molecular evidence for a new subgroup III virus.  Phytopathology 88: 648-657.

Salvucci, M., Rosell, R.C., and Brown, J.K.  1998. Uptake and metabolism of leaf proteins by the silverleaf whitefly. Archives of Insect Biochemistry and Physiology 39:155-165.

Brown, J.K., K.M. Ostrow, Idris, A.M., and D.C. Stenger.  1999. Biotic, molecular, and phylogenetic characterization of bean calico mosaic virus, a distinct Begomovirus species with affiliation in the squash leaf curl virus cluster.  Phytopathology 89:273-280.

Frohlich, D., I. Torres-Jerez, I.D. Bedford, P.G. Markham, and J.K. Brown.  1999. A phylogeographic analysis of the Bemisia tabaci species complex based on mitochondrial DNA markers.  Molecular Ecology 8:1593-1602.

Paximadis, M., A.M. Idris, I. Torres-Jerez, A. Villarreal, M.E.C. Rey,  and J.K. Brown.  1999. Characterization of geminiviruses of tobacco in the Old and New World.  Arch. of Virol.  144: 703-717.

Rosell, R.C., I. Torres-Jerez, and  J.K. Brown.  1999.  Temporal pathway of geminivirus in whitefly extracts, saliva, hemolymph and honeydew.  Phytopathology 89: 239-246.

Brown, J.K., K.M. Ostrow, A. M. Idris, and D. C. Stenger.  2000.  Chino del tomate virus: relationships to other begomoviruses and the identification of A component variants that affect symptom expression.  Phytopathology 90:546-552.

Brown, J.K., T.M. Perring, A.D. Cooper, I.D. Bedford, and P.G. Markham. 2000.  Genetic analysis of Bemisia (Homoptera: Aleyrodidae) populations by isoelectric focusing electrophoresis.  Biochem. Genet. 38: 13-25.

Kirk A.A., Lacey L.A., Brown, J.K., Ciomperlik, M.A., Goolsby, J.A., Vacek, D.C., Wendel, L.E., Napompeth, B..  2000. Variation within 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.  Bull Entom Res. 90: 317-327.

Brown, J. K., A. M. Idris, I. Torres-Jerez, G. K. Banks, and S. D. Wyatt.  2001. The core region of the coat protein gene is highly useful for establishing the provisional identification and classification of begomoviruses.  Arch. of Virol.: 146: 1-18.

Ghanim, Murad, R.C. Rosell, L.R. Campbell, H. Czosnek, J.K. Brown, and D.E. Ullman.  2001.  Microscopic analysis of the digestive, salivary and reproductive organs of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) biotype B.  J. of Morphol. 248:22-40.

Idris, A.M., Smith, S.E, and Brown, J.K.  2001. Ingestion, transmission, and persistence of Chino del tomate virus (CdTV), a New World begomovirus, by Old and New World biotypes of the whitefly vector Bemisia tabaci.  Annals of Appl. Biol. (in press).

 

Short Communications

Brown, J.K., H.S. Costa, and F. Laemmlen. 1991.  First incidence of whitefly-associated squash silverleaf (SSL) of Cucurbita, and of white streaking (WSt) disorder of cole crops in Arizona and California.  Plant Dis. 76:426.

Isakeit, T., Robertson, N. L., Brown, J. K., and Gilbertson, R.L.  1994.  First report of Squash leaf curl virus on watermelon in Texas.  Plant Dis. 78: 1010.

Brown, J. K., J. Bird, G. Banks, M. Sosa, K. Kiesler, I. Cabrera, and G. Fornaris.  1995.  First report of a whitefly-transmitted geminivirus epidemic in tomato in Puerto Rico.  Plant Dis. 79: 1250.

Idris, A. M., J. Bird, and J.K. Brown.  1999. First report of a bean-infecting begomovirus from Macroptilium lathyroides in Puerto Rico that is distinct from bean golden mosaic virus.  Plant Disease 83: 1071.

Idris, A.M., H. Lee, and J. K. Brown.  1999.  First report of chino del tomate and pepper hausteco geminiviruses in greenhouse-grown tomato in Sonora, Mexico.  Plant Disease 83: 396.

Idris, A. M., G. Rivas-Platero, I. Torres-Jerez, and J.K. Brown.  1999.  First report of Sinaloa tomato leaf curl virus in Costa Rica.  Plant Disease 83: 303.

Brown, J.K., A.M. Idris, M. Olsen, M.E. Miller, T. Isakeit, and J. Anciso.  2000. Cucurbit leaf curl virus, a new whitefly-transmitted geminivirus in Arizona, Texas, and Mexico. Plant Dis: 84: 809.

Idris, A.M.,  and J. K. Brown.  2000. Identification of new, monopartite begomovirus associated with leaf curl disease of cotton in Gezira, Sudan.  Plant Dis. 84: 809.

Pietersen, G., A.M. Idris, K. Krüger, and J.K. Brown.  2000.  Tomato curly stunt virus, a new begomovirus within the TYLCV-IS cluster causing a severe disease of tomato in South Africa.  Plant Dis. 84: 810.

Brown, JK, A.M. Idris, D Rogan, M.H., Hussein and M. Palmieri.  2001. Melon chlorotic leaf curl virus, a new begomovirus associated with Bemisia tabaci infestations in Guatemala.  Plant Dis. 85: 1027.

Bird, J., A.M. Idris, D. Rogan, and J.K. Brown. 2001.  Introduction of the exotic Tomato Yellow Leaf Curl Virus-Israel in tomato into Puerto Rico.  Plant Dis. 85: 1028.

Idris, A.M. and J.K.Brown.  2001. Three previously unidentified begomoviral genomes from tomato exhibiting leaf curl disease symptoms from Central Sudan.  Plant Dis. (in press)

 

Published Proceedings

Brown, J.K.  1993.  A critical assessment of biotypes of the sweetpotato whitefly in the Americas and adjacent locales from 1989-1992.  Proc. of Taller Centro Americano y Del Caribe Sobre Moscas Blancas.  Turrialba, Costa Rica, Pages 1-9, Aug. 3-5, 1992, 66 pp.

Brown J.K. and J. Bird.  1995.  Variability within the Bemisia tabaci species complex and its relationship to new epidemics caused by geminiviruses.  CEIBA (Zamorano) 36, 73-80.

Brown, J.K., K.R. Wendt, and S.D. Wyatt.  1995.  Genetic variability among squash leaf curl virus isolates by component-specific polymerase chain reaction.  Pages 5-11 in: Proceedings of Cucurbitaceae 94': Evaluation and Enhancement of Cucurbit Germplasm (G. E. Lester and J.R. Dunlap, eds.). South Padre Island, TX. November 1-4, 1994.

Brown, J.K. 1996.  Distribution and genetic variability of whitefly-transmitted geminiviruses of cotton.  Pages 275-279 in: Proceeding of 1996 Beltwide Cotton Conference, Nashville TN, January, 1996.

Brown, J.K. and J. Bird.  1996.  Introduction of an exotic whitefly (Bemisia) vector facilitates secondary spread of Jatropha mosaic virus, a geminivirus previously vectored exclusively by the Jatropha biotype.  Pages 351-353 in:Bemisia '95: Taxonomy, Biology, Damage, Control and Management (D. Gerling and R. T. Mayer, eds).  Intercept Publications, Wimborne, UK.

Brown, J.K., J. Bird, D.R. Frohlich, R.C. Rosell, I.D. Bedford, and P.G. Markham.  1995.  The relevance of variability within the Bemisia tabaci species complex to epidemics caused by Subgroup III geminiviruses.   Pages 77-92 in:Bemisia '95: Taxonomy, Biology, Damage, Control and Management (D. Gerling and R. T. Mayer, eds).  Intercept Publications, Wimborne, UK.

Frohlich, D.R., J.K. Brown, I.D. Bedford, and P.G. Markham.  1996.  Mitochondrial 16S ribosomal subunit as a molecular marker in Bemisia, and implications for population variability.  Pages 143-145 in:Bemisia '95: Taxonomy, Biology, Damage, Control and Management (D. Gerling and R.T. Mayer, eds).  Intercept Public., Wimborne, UK.

Rosell, R.C., I.D. Bedford, P.G. Markham, D.R. Frohlich, and J.K. Brown.  1996.  Morphological variation in Bemisia populations.  Pages 147-149 in: Bemisia '95: Taxonomy, Biology, Damage, Control and Management.  Intercept Publications, Wimborne, UK (D. Gerling and R. T. Mayer, eds.).

Brown, J.K.  1997.  Global diversity and distribution of cotton-infecting geminiviruses: an esssential requisite to developing sustainable disease resistance.  Pages 39-48 in Proceedings of: Technical Seminar at the 56^th Plenary Meeting of the International Cotton Advisory Committee.  Asuncion, Paraguay, October 27-31, 1997.

Brown, J.K.  1997.  Whitefly-transmitted geminiviruses of tomato and phylogenetic relationships predicted from virus coat protein gene sequences.  Pages 140-144 In: Proceedings of First International Conference on the Processing Tomato & First International Symposium on Tropical Tomato Diseases.  Sponsored By: Empresa Pernambucana de Pesquisa Agropecuaria & The American Society for Horticultural Sciences.  Recife, Pernambuco, Brazil.  November 21-22, 1996.

Brown, J.K. 1998.  Global diversity and distribution of whitefly-transmitted geminiviruses of cotton.  Pages 155-161 in: Proceeding of 1998 Beltwide Cotton Conference, San Diego, CA, January, 5-9 1998.

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