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Leaf curl, a whitefly-borne begomovirus disease, is the cause of frequent epidemic in chili. In the present study, transmission parameters involved in tripartite interaction are estimated to simulate disease dynamics in a population dynamics model framework. Epidemic is characterized by a rapid conversion rate of healthy host population into infectious type. Infection rate as basic reproduction number, R0 = 13.54, has indicated a high rate of virus transmission. Equilibrium population of infectious host and viruliferous vector are observed to be sensitive to the immigration parameter. A small increase in immigration rate of viruliferous vector increased the population of both infectious host and viruliferous vector. Migrant viruliferous vectors, acquisition, and transmission rates as major parameters in the model indicate leaf curl epidemic is predominantly a vector -mediated process. Based on underlying principles of temperature influence on vector population abundance and transmission parameters, spatio-temporal pattern of disease risk predicted is noted to correspond with leaf curl distribution pattern in India. Temperature in the range of 15–35 °C plays an important role in epidemic as both vector population and virus transmission are influenced by temperature. Assessment of leaf curl dynamics would be a useful guide to crop planning and evolution of efficient management strategies.

Colletotrichum spp. cause anthracnose disease in several plant species in tropical and temperate regions. In this study, a total of 30 isolates of Colletotrichum spp. were isolated from nine different fruit crops showing anthracnose symptoms. Phylogenetic analysis based on the GAPDH gene divided the population into four primary clades. All C. gloeosporioides species complex grouped together and separated from C. karstii and two different monophyletic lineages i.e. C. brevisporum, C. cliviae. C. gloeosporioides species complex was found dominant within the population containing 7 cryptic species. To study the population diversity of Colletotrichum species, the isolates were grouped into 4 geographical clusters based on their collection site i.e. Delhi, Maharashtra, West Bengal (WB), and North East (NE) states (Assam and Meghalaya). Out of 12 ISSR primers used 11 primers generated scorable polymorphic band of 100-1300 bp having average PIC value of 0.27. The intrapopulation genetic diversity was high in NE population with 78.75% polymorphism. The inter-population genetic distance was high (0.129) between Maharashtra and WB populations. The degree of genetic differentiation was 0.09 and gene flow was estimated at 2.45 within Colletotrichum population. Population stratification using UPGMA dendrogram divided the population into two main groups. Group 1 consisted of isolates from all over the four geographical region and population from NE region formed group 2. The overall result indicates admixture between isolates and homogeneous population structures from different geographical regions.

Papaya ringspot virus (PRSV) is one of the important pathogens responsible for damage of the papaya crop and causes significant yield loss of fruits and vegetable worldwide and hence a serious threat. In this study, PRSV-infected plant samples collected from different locations in North 24 Parganas districts of West Bengal, were tested with potyvirus specific ELISA and further confirmed with potyvirus group specific degenerate primers by RT PCR, TEM and sequence analysis. Our result indicates that the disease symptoms occurred in 80–100% of the plant in the field surveyed. The complete sequence of PRSV isolate WB was determined from RT-PCR products with specific primer pairs designed covering the whole genome and confirmed by next-generation sequencing. The whole genome of the PRSV was determined and submitted to GenBank as accession no. LC482263. The sequence of PRSV-WB (10,340 bp) was found to share upto 90% and 93%, identity with other PRSV isolates at the nucleotide and amino acid levels respectively. Based on phylogenetic analysis, PRSV- WB was found to be most closely related to PRSV-BD2 (MH397222) from papaya in Bangladesh (geographically close).

The cultivation of dolichos bean [Lablab purpureus (L.) Sweet] has been severely affected by dolichos yellow mosaic virus (DoYMV, Begomovirus) transmitted by whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae). We tested the transovarial transmission of DoYMV in next-generation B. tabaci by PCR, real-time PCR, Southern blot hybridization, and biological transmission. The eggs, laid by DoYMV-exposed B. tabaci, carry the virus in a unique pattern. Only the eggs laid in between 3 and 6 days post virus acquisition by a parent B. tabaci were DoYMV positive. When tested individually in real-time PCR, around 31–53% of the eggs carried the virus. The presence of DoYMV in ovaries and F1 eggs was further substantiated by the hybridization of a Cy3-conjugated nucleic acid probe complementary to the viral strand of DoYMV. Viral DNA was also detected in F1 adults and F2 eggs. B. tabaci progenies carried not only the DoYMV DNA but were also infective. The F1 adults transmitted DoYMV to all tested plants and produced strong yellow mosaic symptoms. An increase in viral copies from egg to nymphal stage indicated propagation of DoYMV in B. tabaci. However, the increase was for a short period and decreased thereafter. The present study provides the first evidence of transovarial transmission and propagation of a bipartite begomovirus in its vector, B. tabaci Asia II 1. The transovarial transmission and replication of DoYMV in B. tabaci have great epidemiological relevance as B. tabaci can serve as a major host of the virus to bridge the gap between the cropping seasons.

During a survey from March 2013 to October 2015, in Barasat, West Bengal, India, symptoms suggestive of begomovirus infection were observed in Malachra capitata. The occurrence of begomovirus on M. capitata was confirmed by symptomatology, polymerase chain reaction (PCR), Southern blot analysis and nucleotide analysis of the whole genome sequence. Sequence analysis showed that the virus had 90.6% identity with available sequences of Tomato leaf curl New Delhi virus (ToLCNDV). We propose that the new begomovirus be named Malachra yellow mosaic virus (MalYMV). To the best of our knowledge, this is the first time the complete genome of the MalYMV, infecting M. capitata in West Bengal, India, has been sequenced.

In the present study vegetable oil-based, highly branched polyester modified hyperbranched epoxy nanocomposites were prepared with organically modified montmorillonite clay at different wt.% of clay loadings. X-ray diffraction patterns and transmission electron microscopy revealed the partially exfoliated structure of the nanocomposites. Cured nanocomposites exhibited improved properties such as gloss (80 – 95°), scratch hardness (3 – 5 kg), impact strength (60 – 100 cm), tensile strength (8 – 13 MPa), adhesive strength (0.9 – 1.4 × 1010 N m−1), flexibility (< 5 – 3 mm), chemical resistance etc. compared to the pristine system. The nanocomposites exhibited enhanced thermosatbility and antimicrobial activity against different bacterial, fungal and algal strains. The nanocomposites were also found to be biodegradable. The study showed that the nanocomposites have potential to be used as biodegradable antimicrobial thin film materials.

Silver-embedded modified hyperbranched epoxy/clay nanocomposites were prepared at different wt.% of octadecyl amine-modified montmorillonite at a constant silver concentration (1 wt.%). UV-visible, XRD and TEM studies confirmed the formation of silver nanoparticles. Compared to the system without silver and clay, the gloss from 70° to 94°, scratch hardness from 4 to 5.8 kg, impact strength from 60 to 90 cm, tensile strength from 8.5 to 15.5 MPa, adhesive strength from 5 to 7.1 × 10(9)N/m, flexibility from >6 to

A hyperbranched epoxy resin has been synthesized by using epichlorohydrin, bisphenol-A, and hyperbranched polyether polyol by a low-temperature polycondensation technique in the presence of a base. The reaction parameters of this polycondensation reaction were optimized, and 5 N aqueous sodium hydroxide solution, (54 ± 1) °C reaction temperature and 3 h reaction time were found to be the best. The degree of branching of the resin was found to be 0.57 as determined from 13C nuclear magnetic resonance spectroscopy (Fig. 3). This hyperbranched epoxy resin was cured with poly(amido amine) hardener at 120 °C for a specified period of time. The resin exhibits very good crosscut adhesive strength (100%). The cured films showed moderate impact strength (60 cm), good scratch resistance (5.5 kg), good gloss (82 at 60°), thermostability up to 270 °C, and good chemical resistance in various chemical media. All these results indicate its suitability to be used as an advanced surface coating material.

Modification of existing polymers by physico-chemical technique is not only interesting and useful to the academic community but the resulted product is attractive to industrial application too. In this investigation, hyperbranched epoxy was modified by vegetable oil-based highly branched polyester resin at different weight percentages and properties of the cured systems were evaluated in order to justify them as advanced thin film materials with high adhesive strength. Modified systems were studied using FTIR, XRD, TGA and SEM analyses. Curing reaction was confirmed by FTIR study and swelling test. Performance characteristics like tensile strength, impact strength, adhesive strength, flexibility, scratch hardness, gloss and chemical resistance of cured films have also been studied. Modified systems showed improved properties over pristine epoxy. Comparison study of modified systems showed that hyperbranched epoxy with 30 wt% polyester content is the best composition w.r.t performance and might be utilized in advanced thin film application.

A series of s-triazine-based hyperbranched polyethers (HBPE) have been synthesized to obtain thermostability but flexible polymers by an interfacial polycondensation of different diols as A2 and cyanuric chloride as B3 monomers using A2 + B3 approach in the presence of a phase transfer catalyst. The polymerization reaction parameters are optimized, and the results indicate that the optimum conditions for the interfacial polycondensation are a 2:3 mole ratio of cyanuric chloride to diol using butanediol, benzyldimethylhexadecyl ammonium chloride as the catalyst, dichloromethane as the organic solvent, and a three-step procedure with keeping the reaction mixture at different low temperatures for 2h/2h/5h. Other techniques such as high-temperature solution, one-step polycondensation, and transesterification were also carried out to synthesize the HBPE but proved to be not suitable due to large number of side reactions. The synthesized polymers were characterized by FTIR, 1H NMR, and 13C NMR spectroscopy, hydroxyl number determination, solution viscosity measurements, and GPC analysis. The thermal behavior of the hyperbranched polymer was investigated by thermogravimetric analysis and differential scanning calorimetry. All the results were compared with those from an analogous linear polyether, obtained from 2-methoxy-4,6-dichloro-s-triazine and butanediol by using the same polymerization technique. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3994–4004, 2010