Carica papaya (papaya) is a fruit crop that is cultivated mostly in kitchen gardens throughout Nepal. Leaf samples of C. papaya plants with leaf curling, vein darkening, vein thickening, and a reduction in leaf size were collected from a garden in Darai village, Rampur, Nepal in 2010. Full-length clones of a monopartite Begomovirus, a betasatellite and an alphasatellite were isolated. The complete nucleotide sequence of the Begomovirus showed the arrangement of genes typical of Old World begomoviruses with the highest nucleotide sequence identity (>99 %) to an isolate of Ageratum yellow vein virus (AYVV), confirming it as an isolate of AYVV. The complete nucleotide sequence of betasatellite showed greater than 89 % nucleotide sequence identity to an isolate of Tomato leaf curl Java betasatellite originating from Indonesian. The sequence of the alphasatellite displayed 92 % nucleotide sequence identity to Sida yellow vein China alphasatellite. This is the first identification of these components in Nepal and the first time they have been identified in papaya.

A semi-selective medium for isolation of Xanthomonas axonopodis pv. vignicola from cowpea (Vigna unguiculata) plant and soil samples was developed. Twelve carbon and five nitrogen sources were tested with four strains of X. axonopodis pv. vignicola, and 25 antibiotics were screened against saprophytes. D D -cellobiose (10 g) was selected as the optimal carbon source. Among the antibiotics, cefazoline inhibited growth of most of the saprophytes with little effect on strains of the pathogen. D D ,L L -methionine enhanced growth of X. axonopodis pv. vignicola. Boric acid along with ammonium chloride suppressed growth of Pseudomonas fluorescens. The semi-selective medium designated as cefazoline-cellobiose-methionine (CCM) medium contained K 2 HPO 4 1.34 g, KH 2 PO 4 0.4 g, MgSO 4 0.3 g, H 3 BO 3 0.2 g, NH 4 Cl 1.0 g, D D -cellobiose 10 g, cycloheximide 0.2 g, D D ,L L -methionine 1.0 g, cefazoline 10 mg and agar 14 g per l of water (pH 7.2). Colonies of X. axonopodis pv. vignicola on CCM medium were whitish, round, raised and 0.2-1.8 mm in diameter 96 h after incubation. CCM medium generally inhibited growth of Pantoea agglomerans, Bacillus subtilis and saprophytes isolated from cowpea leaves. Colonies of Pseudomonas fluorescens and a saprophytic bacterium, which were not completely suppressed by CCM, could be differentiated from X. axonopodis pv. vignicola by their smaller size and different color. The CCM medium proved useful for isolation of X. axonopodis pv. vignicola from cowpea plant and soil samples. This is the first report of a semi-selective medium developed for detection of X. axonopodis pv. vignicola.

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Forty seed sample of wheat (Triticum aestivum) were collected from four locations viz. Chitwan, Kaski, Banke and Lalitpur and tested by blotter method at laboratory during 2013 for determining fungal pathogens associated with wheat seeds in Nepal. Eighteen species representing thirteen genera of fungi were recovered from the seed. Alternaria alternata and Bipolaris sorokiniana were predominant in all the varieties/genotypes from all the locations, where B. sorokiniana was strongly pathogenic in wheat crop. Percentage frequency and type of fungi detected varied with variety and locations. Bipolaris sorokiniana was highest (64.40%) in Banke than remaining three locations. Seeds of Chitwan had lowest percentage (5.50%) of seed infection as compared to other locations. Relative abundance of Alternaria alternata (55.10%) was highest as it was the most prevalent component of seed borne mycoflora, followed by Bipolaris sorokiniana (34.69%) and Cladosporium herbarum (7.19%). Differences in quantity of precipitation and relative humidity might be the possible reason for variation in frequency and type of fungi detected in wheat seeds of four locations.

Pea (Pisum sativum) plants exhibiting leaf distortion, yellowing, stunted growth and reduction in leaf size from Rampur, Nepal were shown to be infected by a begomovirus in association with betasatellites and alphasatellites. The begomovirus associated with the disease showed only low levels of nucleotide sequence identity (<91%) to previously characterized begomoviruses. This finding indicates that the pea samples were infected with an as yet undescribed begomovirus for which the name Pea leaf distortion virus (PLDV) is proposed. Two species of betasatellite were identified in association with PLDV. One group of sequences had high (>78%) nucleotide sequence identity to isolates of Ludwigia leaf distortion betasatellite (LuLDB), and the second group had less than 78% to all other betasatellite sequences. This showed PLDV to be associated with either LuLDB or a previously undescribed betasatellite for which the name Pea leaf distortion betasatellite is proposed. Two types of alphasatellites were identified in the PLDV-infected pea plants. The first type showed high levels of sequence identity to Ageratum yellow vein alphasatellite, and the second type showed high levels of identity to isolates of Sida yellow vein China alphasatellite. These are the first begomovirus, betasatellites and alphasatellites isolated from pea.