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Irrigation water is a doorway for the pathogen contamination of fresh produce. We quantified pathogenic viruses [human adenoviruses, noroviruses of genogroups I and II, group A rotaviruses, Aichi virus 1 (AiV-1), enteroviruses (EnVs), and salivirus (SaliV)] and examined potential index viruses [JC and BK polyomaviruses (JCPyVs and BKPyVs), pepper mild mottle virus (PMMoV), and tobacco mosaic virus (TMV)] in irrigation water sources in the Kathmandu Valley, Nepal. River, sewage, wastewater treatment plant (WWTP) effluent, pond, canal, and groundwater samples were collected in September 2014, and in April and August 2015. Viruses were concentrated using an electronegative membrane-vortex method and quantified using TaqMan (MGB)-based quantitative PCR (qPCR) assays with murine norovirus as a molecular process control to determine extraction-reverse transcription-qPCR efficiency. Tested pathogenic viruses were prevalent with maximum concentrations of 5.5-8.8 log copies/L, and there was a greater abundance of EnVs, SaliV, and AiV-1. Virus concentrations in river water were equivalent to those in sewage. Canal, pond, and groundwater samples were found to be less contaminated than river, sewage, and WWTP effluent. Seasonal dependency was clearly evident for most of the viruses, with peak concentrations in the dry season. JCPyVs and BKPyVs had a poor detection ratio and correspondence with pathogenic viruses. Instead, the frequently proposed PMMoV and the newly proposed TMV were strongly predictive of the pathogen contamination level, particularly in the dry season. We recommend utilizing canal, pond, and groundwater for irrigation to minimize deleterious health effects and propose PMMoV and TMV as indexes to elucidate pathogenic virus levels in environmental samples.

Alternaria leaf blight disease caused by Alternaria brassicae in mustard (Brassica juncea (L) Czern and Coss) was studied in two crop seasons, 1992 and 1993 in Nepal at Nawalpur, Sarlahi (Tarai) and Khumaltar, Lalitpur (mid hill). At Nawalpur, epidemics of the disease was recorded for both seasons. Weather conditions like humidity, temperature and frequent rainfall played key role for the epidemics. In experimental fields, the disease appeared first in mid-December when the relative humidity was more than 80% with maximum temperature ranging between 18-25 0 C and minimum between 10-14 0 C. At Khumaltar, incidence of the disease was low in both seasons due to low average temperature from December to February. Among cultivars, Krishna and Pusabold were less susceptible than Varuna. Both mancozeb and iprodione had effectively reduced disease in the sprayed plots and increased seed yield by 48% and 130% respectively. The correlation between disease severity and yield, and yield components was negative and highly significant. Average yield loss was estimated to be in the range of 32 to 57%. Seed infection was also significantly higher in non sprayed treatment than sprayed one. The disease showed a negative effect on oil content causing losses on oil between 4.2 to 4.5%.

The mating type, allozyme genotypes of malic enzyme, glucose-6-phosphate isomerase and peptidase loci, and metalaxyl sensitivity of 336 Phytophthora infestans isolates collected in Korea, India, Taiwan, Indonesia, Thailand, Nepal, and China between 1992 and 1997 were determined. Only A1 mating type isolates were detected in India and Taiwan, and only A2 isolates in Korea and Indonesia, while both mating type isolates were detected in Thailand, Nepal, and China. The isolates from Korea, India, Taiwan, and Indonesia had a single allozyme genotype respectively, while the isolates from Thailand, Nepal, and China had two or three allozyme genotypes. Isolates that were highly resistant to metalaxyl were found in Korea, Indonesia, and China. All of the isolates from Taiwan and India, and some of the isolates from Thailand, Nepal, and northern and southern areas of China, belonged to the old population of P. infestans, which was predominant worldwide until the appearance of A2 isolates outside central Mexico. Some of the isolates from Thailand and Nepal were from new populations that have been discovered since the appearance of A2 isolates outside central Mexico. All of the isolates from Korea and Indonesia and most of the isolates from China belonged to two specific populations, which have been rarely detected elsewhere. The occurrence of these separate populations in Asia suggests that they followed a different migration pathway, or that they are better adapted to Asian conditions than to those elsewhere in the world.

Transparent conducting undoped and Al impurity doped ZnO films were deposited on glass substrate by spin coat technique using 24 days aged ZnO precursor solution with solution of ethanol and diethanolamine. The films were characterized by UV-Visible spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), electrical resistivity (ρ), carrier concentration (n), and hall mobility (µ) measurements. XRD data show that the deposited film shows polycrystalline nature with hexagonal wurtzite structure with preferential orientation along (002) crystal plane. The SEM images show that surface morphology, porosity and grain sizes are affected by doping concentration. The Al doped samples show high transmittance and better resistivity. With increasing Al concentration only mild change in optical band gap is observed. Optical properties are not affected by aging of parent solution. A lowest resistivity (8.5 × 10 -2 ohm cm) is observed at 2 atomic percent (at.%) Al. With further increase in Al concentration, the resistivity started to increase significantly. The decrease resistivity with increasing Al concentration can be attributed to increase in both carrier concentration and hall mobility.