Cotton leaf curl disease (CLCuD) is a severe disease of cotton that occurs in Africa and Pakistan/northwestern India. The disease is caused by begomoviruses in association with specific betasatellites that differ between Africa and Asia. During survey of symptomatic cotton in Sindh (southern Pakistan) Cotton leaf curl Gezira virus (CLCuGV), the begomovirus associated with CLCuD in Africa, was i...

The nomenclature of papaya viruses has been a source of confusion, primarily because symptomatology has been used extensively for describing papaya viruses. Although the literature is confusing and causal viruses for each of the diseases are not well identified, it appears that papaya viral diseases can generally be grouped as ring spot, mosaic and leaf curl, associated with poty, potex and gem...

In recent years leaf curl disease of cotton has become a major limiting factor in the production of cotton, which is an important fiber cash crop. In the last two decades or more, leaf curl disease in cotton took on epidemic proportions in Pakistan. In the early 1990’s cotton leaf curl disease (CLCuD) appeared in the bordering parts of India in the states of Rajasthan and Punjab and spread to e...

Begomoviruses are plant-infecting viruses, which are transmitted by the whitefly vector Bemisia tabaci. They have a genome of single-stranded DNA that consists of either a single (monopartite) or two components (bipartite) with a component size of approximately 2.8 kb. Many monopartite begomoviruses in the Old World have been found to be associated with betasatellite and alphasatellite molecule...

Tomato production in the Mediterranean region and elsewhere is under constant threat of the whitefly-transmitted begomoviruses that cause Tomato yellow leaf curl disease (TYLCD). Sequencing has indicated that the generic ‘TYLCV’ includes a large number of viruses and strains. We studied the distribution of the tomato yellow leaf curl disease-associated viruses in Egypt, Israel, Jordan and Leban...

Cotton leaf curl disease (CLCuD) is the major biotic constraint to cotton production on the Indian subcontinent, and is caused by monopartite begomoviruses accompanied by a specific DNA satellite, Cotton leaf curl Multan betasatellite (CLCuMB). Since the breakdown of resistance against CLCuD in 2001/2002, only one virus, the "Burewala" strain of Cotton leaf curl Kokhran virus (CLCuKoV-Bur), and...

Geminivirus, which causes yellow leaf curl disease of wax gourd plants, was detected using polymerase chain reaction with geminivirus-specific primers. The complete genomic sequence of a geminivirus isolated from wax gourd was determined by sequencing overlapping DNA fragments. The genome consisted of 2739 nucleotides, contained 5 open reading frames (ORFs) typical of geminiviruses, 2 ORFs on t...

We study connections between four different types of results that are concerned with vector-valued functions u : Ω → R of class L(Ω) on a domain Ω ⊂ R: Coercivity results in H(Ω) relying on div and curl, the Helmholtz decomposition, the construction of vector potentials, and the global div-curl lemma. Key-words: Friedrichs inquality, coercivity, div-curl lemma, compensated compactness

Given a sequence of Galerkin spaces Xh of curl conforming vector fields, we state necessary and sufficient conditions under which it is true that the scalar product uh ·uh of two sequences of vector fields uh, uh ∈ Xh converging weakly in L, converges in the sense of distributions to the right limit, whenever uh is discrete divergence free and curluh is precompact in H−1. The conditions on Xh a...

Cotton leaf curl virus disease (CLCuD) is caused by a suite of whitefly-transmitted begomovirus species and strains, resulting in extensive losses annually in India and Pakistan. RNA-interference (RNAi) is a proven technology used for knockdown of gene expression in higher organisms and viruses. In this study, a small interfering RNA (siRNA) construct was designed to target the AC1 gene of Cott...