The whitefly Bemisia tabaci Genn. is a pervasive pest and vector of plant viruses. The existence of B. tabaci biotypes and numerous whitefly-transmitted geminiviruses (begomoviruses) affecting food and industrial crops, has become a major constraint to agricultural development in tropical and subtropical regions of the world. The predominant whitefly and begomovirus method of control has been t...

W. B. Hunter, University of Florida, Gulf Coast Research and Education Center, 5007 60 St. E., Bradenton 342039324; E. Hiebert, University of Florida, Plant Pathology Department, 1453 Fifield Hall, Gainesville 32611-0680; S. E. Webb, University of Florida, Central Florida-REC, 5336 University Ave., Leesburg 34748-8232; J. H. Tsai, University of Florida, Ft. Lauderdale-REC, 3205 S.W. College Ave...

Plants infected with DNA viruses produce massive quantities of virus-derived, 24-nucleotide short interfering RNAs (siRNAs), which can potentially direct viral DNA methylation and transcriptional silencing. However, growing evidence indicates that the circular double-stranded DNA accumulating in the nucleus for Pol II-mediated transcription of viral genes is not methylated. Hence, DNA viruses m...