Sweet potato (Ipomoea batatas) and related Ipomoea species are frequently infected by monopartite begomoviruses (genus Begomovirus, family Geminiviridae), known as sweepoviruses. Unlike other geminiviruses, the genomes of sweepoviruses have been recalcitrant to rendering infectious clones to date. Thus, Koch's postulates have not been fullfilled for any of the viruses in this group. Three novel...

The yellowing strain of Soybean dwarf virus (SbDV-YS) causes yellowing and yield loss in common bean (Phaseolus vulgaris). The most effective control is achieved through breeding for resistance. An indeterminate climbing cultivar with a white seed coat, 'Oofuku', is resistant to SbDV-YS in inoculation tests. We crossed 'Oofuku' with an elite cultivar, 'Taisho-Kintoki', which is SbDV-YS-suscepti...

According to the nutrient-translocation hypothesis, yellowing tree leaves are colonized by aphids at the end of the growing season owing to improved availability of nutrients in the phloem sap after chlorophyll degradation. We measured aphid densities on potted Betula pendula seedlings in a field site where a small proportion of foliage rapidly turned yellow before normal autumn coloration as a...

Virus diseases are the major cause of economic losses in commercial cucurbit production in Lebanon. Besides mosaic inducing viruses, which have been noted for several years, greenhouse-grown cucumber and melon were often observed with severe yellowing symptoms that started as interveinal mottle on the older leaves and developed into severe yellowing symptoms as the leaves became older. The inci...

Eight proprietary genotypes of glandular-haired alfalfa, Medicago sativa L., supplied by two different companies, were compared for the degree and types of resistance to the potato leafhopper, Ernpoasca fabae (Harris), and hopperburn. A tube cage no-choice bioassay was developed to test leafhopper mortality, feeding, settling preferences, severity of hopperburn symptoms (in this case, defined a...

UNLABELLED SUMMARY Taxonomy: There are three members of the genus Polerovirus (family Luteoviridae) that induce yellowing of sugar beet: Beet mild yellowing virus (BMYV), Beet chlorosis virus (BChV) and Beet western yellows virus-USA (BWYV-USA, Fig. 1). Non-beet-infecting isolates of BWYV found particularly within Europe have now been re-named Turnip yellows virus (TuYV). Species-specific antib...

Tomato yellow leaf curl China virus (TYLCCNV) is a monopartite begomovirus associated with different betasatellites. In this study, we investigate two different isolates of Tomato yellow leaf curl China betasatellite (TYLCCNB) to determine what features of the viral genome are required for induction of characteristic phenotypic differences between closely-related betasatellite. When co-agroinoc...

ABSTRACT A novel whitefly-transmitted member of the family Potyviridae was isolated from a squash plant (Cucurbita pepo) with vein yellowing symptoms in Florida. The virus, for which the name Squash vein yellowing virus (SqVYV) is proposed, has flexuous rod-shaped particles of approximately 840 nm in length. The experimental host range was limited to species in the family Cucurbitaceae, with th...

It is well known that the peripheral visual system declines with age: the yellowing of the lens causes a selective reduction of short-wavelength light and sensitivity losses occur in the cone receptor mechanisms. At the same time, our subjective experience of colour does not change with age. The main purpose of this large-scale study (n = 185) covering a wide age range of colour-normal observer...