Groundnut virus research at ICRISAT

Several virus diseases of groundnut have been reported in India based on symptoms, host range and biological properties. These properties are now regarded as inadequate to identify a virus. Characterization should be based on serology, electron microscopy, transmission and physico-chemical properties. Three economically important virus diseases (bud necrosis, clump and peanut mottle) and several virus diseases of minor importance in India have now been fully characterized.....

Transmission of tomato spotted wilt virus, the causal agent of bud necrosis of peanut, by Scirtothrips dorsalis and Frankliniella schultzei

An important disease of groundnuts in India has recently been shown to be caused by tomato spotted wilt virus (TSWV), which is transmitted by thrips. The results are given of further studies on Scirtothrips dorsalis Hood (which had earlier been shown to be a vector), on the role of Frankliniella schultzei (Tryb.) as a vector and on the application of the haemagglutination technique to detect viral antigen in thrips. Both species of thrips were able to transmit the virus from groundnuts to groundnuts and urd bean (Vigna mungo), but F. schultzei was the more efficient. Haemagglutination tests detected viral antigens in extracts from both species that had been exposed to infected leave

Radiative energy and momentum transfer for various spherical shapes: a single sphere, a bubble, a spherical shell and a coated sphere

We use fluctuational electrodynamics to determine emissivity and van der Waals contribution to surface energy for various spherical shapes, such as a sphere, a bubble, a spherical shell and a coated sphere, in a homogeneous and isotropic medium. Near-field radiative transfer and momentum transfer between flat plates and curved surfaces have been studied for the past decades, however the investigation of radiative heat transfer and van der Waals stress due to fluctuations of electromagnetic fields for a single object is missing from literature. The dyadic Green's function formalism of radiative energy and fluctuation-induced van der Waals stress for different spherical configurations have been developed. We show (1) emission spectra of micro and nano-sized spheres display several emissivity sharp peaks as the size of object reduces, and (2) surface energy becomes size dependent due to van der Waals phenomena when size of object is reduced to a nanoscopic length scale.Comment: 8 pages, 3 figure

Seed protectants for healthy exports

Dry formulations of three insecticides (chlorpyriphos, fenvalerate and carbaryl) were compared for their efficacy against rice moth, Corcyra cephalonica (Stainton) and groundnut bruchid Caryedon serratus Oliver, in the context of identifying a suitable alternative to aldrin. Fenvalerate 4 g/kg seed showed quick action and killed all the Corcyra eggs, and Caryedon grubs and adults, within 48 h. Chlorpyriphos and carbaryl were less effective, although the former showed high persistency. Fenvalerate and carbaryl were significantly superior to a range of rates of chlorpyriphos up to 180 DAT, and were on par with aldrin. For seed exports that require storage of 60 days or more, chlorpyriphos could be used as an effective replacement for aldrin. The chemicals tested hid no deleterious effects on seed viability of pearl millet and groundnut up to 180 days at ambient temperature during storag

Epidemiology and control of groundnut bud necrosis and other diseases of legume crops in India caused by tomato spotted wilt virus

Tomato spotted wilt virus (TSWV) was first reported in India in tomato in 1964 (Todd et dl., 1975). The occurrence of TSWV on a legume in ~India was first recorded in 1968 (Reddy et dl., 1968). The "bud necrosis disease" of groundnut, caused by TSWV, is now considered to be one of the most damaging groundnut diseases in India (Ghanekar et al., 1979a; Reddy, 1980). Bud necrosis is likely to have been present in India for some time although it has only recently become economically important. TSWV has also been reported on groundnuts in Brazil (Costa, 1941), the United States of America (Halliwell & Philley, 1974), South Africa (Klesser, 1966) and Australia (Helms et al., 1961). This chapter considers the epidemiology and control of bud necrosis and gives a brief account of other economically important diseases of legumes in India caused by TSWV

Field Diagnosis of Chickpea Diseases and their Control

Chickpea is an important cool season food crop grown mainly in dry lands. The crop suffers from serious diseases which affect it in all growth stages. The pathogens that affect chickpea include fungi, bacteria, viruses, and mycoplasma. Among these, the most important are fungi, affecting roots, stems, leaves, flowers, and pods. This information bulletin provides information on the distribution of major diseases, field symptoms, environmental conditions favoring these diseases and control measures. Color photographs are included to facilitate identification of the diseases. An index of the technical terms used is also given

Performance of plate-based cytokine flow cytometry with automated data analysis

BACKGROUND: Cytokine flow cytometry (CFC) provides a multiparameter alternative to ELISPOT assays for rapid quantitation of antigen-specific T cells. To increase the throughput of CFC assays, we have optimized methods for stimulating, staining, and acquiring whole blood or PBMC samples in 96-well or 24-well plates. RESULTS: We have developed a protocol for whole blood stimulation and processing in deep-well 24- or 96-well plates, and fresh or cryopreserved peripheral blood mononuclear cell (PBMC) stimulation and processing in conventional 96-well round-bottom plates. Samples from both HIV-1-seronegative and HIV-1-seropositive donors were tested. We show that the percent response, staining intensity, and cell recovery are comparable to stimulation and processing in tubes using traditional methods. We also show the equivalence of automated gating templates to manual gating for CFC data analysis. CONCLUSION: When combined with flow cytometry analysis using an automated plate loader and an automated analysis algorithm, these plate-based methods provide a higher throughput platform for CFC, as well as reducing operator-induced variability. These factors will be important for processing the numbers of samples required in large clinical trials, and for epitope mapping of patient responses

Bud necrosis of groundnut (Arachis hypogaea) in India caused by tomato spotted wilt virus

Chlorotic ringspots or chlorotic leaf specking, terminal bud necrosis, axillary shoot proliferation and severe stunting of groundnut (Arachis hypogaea) were shown to be caused by tomato spotted wilt virus (TSWV). All 28 species of plants tested were susceptible to the virus. Cowpea (Vigna unguiculata cv. C-152) was found to be a good assay host. TSWV remained infective in buffered sap of groundnut at a dilution of 10-2.5, after storage for 4 h at room temperature (30 oC) and for 10 min at 40 but not 45 oC. The haemagglutination test was adapted to detect TSWV in crude extracts of groundnut. Sap from infected groundnut and tomato contained spherical membrane-bound virus particles 70 to 90 nm diameter. The virus was transmitted by thrips (Scirtothrips dorsalis). The prevalence of TSWV in India and the high incidence in groundnut indicates that the virus is economically importan