Neem oil (Azadirachta indica) nanoemulsion--a potent larvicidal agent against Culex quinquefasciatus

BACKGROUND: Nanoemulsion composed of neem oil and non‐ionic surfactant Tween 20, with a mean droplet size ranging from 31.03 to 251.43 nm, was formulated for various concentrations of the oil and surfactant. The larvicidal effect of the formulated neem oil nanoemulsion was checked against Culex quinquefasciatus. RESULTS: O/W emulsion was prepared using neem oil, Tween 20 and water. Nanoemulsion of 31.03 nm size was obtained at a 1:3 ratio of oil and surfactant, and it was found to be stable. The larger droplet size (251.43 nm) shifted to a smaller size of 31.03 nm with increase in the concentration of Tween 20. The viscosity of the nanoemulsion increased with increasing concentration of Tween 20. The lethal concentration (LC₅₀) of the nanoemulsion against Cx. quinquefasciatus was checked for 1:0.30, 1:1.5 and 1:3 ratios of oil and surfactant respectively. The LC₅₀ decreased with droplet size. The LC₅₀ for the ratio 1:3 nanoemulsions was 11.75 mg L^?1. CONCLUSION: The formulated nanoemulsion of 31.03 nm size was found to be an effective larvicidal agent. This is the first time that a neem oil nanoemulsion of this droplet size has been reported. It may be a good choice as a potent and selective larvicide for Cx. quinquefasciatus. Copyright © 2011 Society of Chemical Industry     

Genetic analysis of adult plant leaf rust resistance in three bread wheat (Triticum aestivum L.) cultivars

Genetic basis of adult plant leaf rust resistance in three released Indian wheat cultivars viz. DWR195, RAJ3765 and HP1731 was investigated through detailed inheritance study under controlled polythene house condition at Flowerdale, India. The F₂, F_3, F₄ and F₅ generations were analyzed with the most frequent and virulent Indian leaf rust pathotype 121R63-1. Two complementary recessive genes imparted resistance in DWR195, two complementary dominant genes governed the resistance of RAJ3765 whereas two independent dominant genes were involved in the resistance of HP1731. The genes responsible for adult plant resistance in the three cultivars were not allelic. The two complementary genes of DWR195 and two independent dominant genes of HP1731 have been isolated as single gene lines. Utilization of resistance from HP1731, which carries two independent dominant genes, will be easy as compared to DWR195 and RAJ3765.     

Assessment of the efficacy of various mulch materials on improving the growth and yield of ginger (Zingiber officinale) under bamboo-based agroforestry system in NW-Himalaya

Agroforestry Systems - Agroforestry as a smart agriculture practice has started to get global attention nowadays. The present investigation is based on bamboo-ginger intercropping research carried...     

Detection and characterization of <Emphasis Type="Italic">Ageratum enation virus</Emphasis> and a nanovirus-like satellite DNA1 from zinnia causing leaf curl symptoms in India

Leaf curl in Zinnia elegans was observed in a subtemperate region in northern India, and the causal organism was identified as Ageratum enation virus (AEV). The virus appeared to be monopartite and associated with nanovirus-like satellite DNA1. The whole genome was amplified by rolling circle amplification, cloned, and sequenced using a primer walking strategy. The genome (FN543099) was composed of 2753 nucleotides (nt) and that of DNA1 (FN543100) of 1374 nt. DNA-β was not detected from any of the infected samples. The study presents the first report of a begomovirus from Zinnia spp. in India and the complete nucleotide sequence characterization of AEV associated with nanovirus-like satellite DNA1.     

Heat shock protein 70, oxidative stress, and antioxidant status in periparturient crossbred cows supplemented with α-tocopherol acetate

The study was conducted to investigating the effect of α-tocopherol acetate on heat shock protein 70 (Hsp70), oxidative stress, and antioxidant status during periparturient period in medium body condition score crossbred cows. Twenty crossbred Karan Fries cows with confirmed pregnancy were selected 2 months before expected date of calving. The cows were randomly distributed in to two groups: 10 cows were kept as control and 10 were supplemented with α-tocopherol acetate during dry period for 2 months. Blood samples were collected at ?20, ?10, ?5, 0, 5, 10, and 20 days in relation to the expected date of calving. Superoxide dismutase, catalase, and total immunoglobulin were significantly higher (P?<?0.01) in treatment as compared to control cows. Heat shock protein 70 and thiobarbituric acid reactive substance levels were significantly lower (P?<?0.01) in the treatment cows than their counterpart. Treatment with α-tocopherol acetate during dry period resulted in reduced oxidative stress, heat shock protein Hsp70 levels, improved antioxidant, and improved immunity status indicating beneficial effect of α-tocopherol acetate treatment.     

Effect of conjoint application of indigenous PGPR and chemical fertilizers on productivity of maize (Zea mays L.) under mid hills of Himachal Pradesh

The present study was conducted to work out the conjoint application of indigenous PGPR (plant growth promoting rhizobacteria) and chemical fertilizers levels on the productivity of maize (Zea mays L.). Three best PGPR isolates (B1N1, MAT1 and DHK) having maximum PGP (plant growth promoting) traits were screened at different recommended doses (80%, 60% and 40%) of NP (Nitrogen and Phosphorous) under net house conditions, and finally two isolates (B1N1 and MAT1) along with optimum dose i.e. 80% of NP were selected for field experimentation, which was performed for two years consecutively i.e. 2013–2015 under random block design (RBD). Conjoint application of 80% recommended doses of NP with PGPR (B1N1) significantly increased maize yield (11.7%), plant height (12.9%) and biomass (17.9%), over control (100% recommend dose of fertilizer (RDF) of chemical fertilizer). Therefore, the results revealed the potential of indigenous PGPR isolates to supplement about 20% NP fertilizers without hampering the productivity of maize.     

Changes in soil hydraulic conductivity, runoff, and soil loss due to irrigation with different types of saline–sodic water

Irrigation with saline–sodic water causes sodic conditions in the soil which reduces soil productivity. We evaluated the changes in a number of important indices related to soil structural stability when treated wastewater (TWW), albeit with higher loads of organic matter and suspended solids, was used instead of more saline–sodic irrigation water, under different degrees of aggregate slaking. We studied soil saturated hydraulic conductivity (HC) using disturbed samples packed in columns, and soil infiltration rate, runoff and erosion under simulated rainfall. Aggregate slaking was manipulated by wetting the samples prior to all tests at either a slow (1–2 mm h^− 1) or a fast (50 mm h^− 1) rate. Samples of a calcareous silty clay (Typic Calciorthids) from the Bet She'an Valley, Israel, were taken from plots irrigated for three years with either TWW, saline–sodic Jordan River water (JRW), or moderately saline–sodic spring water (SPW), and also from a non-cultivated area (control). With little or no aggregate slaking (use of slow wetting), higher HC values and lower amounts of total runoff and soil loss were measured compared to when more severe aggregate slaking was induced (use of fast wetting). The HC values for the TWW treatment were similar to, or lower than, those for the control and significantly higher than those for the JRW treatment. For the runoff and soil loss data, differences among the water quality treatments were, generally, more pronounced when aggregate slaking was substantially reduced, and were related to soil sodicity. Under the latter condition, runoff and soil loss from the TWW treatment were comparable with those from the control and significantly lower than those from the JRW treatment. Our results suggested that replacing saline–sodic irrigation water with TWW could have favorable effects on soil structural stability, especially under conditions where aggregate slaking can be reduced (e.g., in regions with low to moderate rain intensities; and/or use of low intensity irrigation systems).     

Inheritance of temperature-sensitive leaf rust resistance and adult plant stripe rust resistance in common wheat cultivar PBW343

Genetic analysis of common wheat cultivar PBW343 confirmed temperature-sensitive leaf rust resistance and adult plant stripe rust resistance. At low temperatures, PBW343 was resistant to P. triticina (Ptr) pathotype (pt.) 121R63-1, and at high temperature it was resistant to Ptr pt. 121R127. The low temperature resistance to pt. 121R63-1 was attributed to interaction between dominant and recessive genes. The dominant gene involved in low-temperature resistance to pt. 121R63-1 also conferred resistance to pt. 45R35. The high-temperature resistance to Ptr pt. 121R127 was governed by a different single partially dominant gene. Agra Local (a commonly used susceptible check) and IWP94 (a leaf rust differential used in India) are also resistant to pt. 121R127 at high temperatures. An allelism test indicated that PBW343 and IWP94 possessed a common gene for high temperature resistance to this pathotype. The adult plant stripe rust resistance against P. striiformis (Pst) was possibly conferred by one gene in addition to Yr27.     

The ability of indigenous micro-organisms to degrade isoproturon, atrazine and mecoprop within aerobic UK aquifer systems

The potential for the herbicides isoproturon, atrazine and mecoprop to degrade in the major UK aquifers of chalk, sandstone and limestone was studied using laboratory microcosms spiked at 100 microg litre(-1). Significant mecoprop degradation was only observed in sandstone groundwater samples. Atrazine transformation, based on the formation of metabolites, did occur in most groundwater samples, but only at a rate of 1-3% per year. A potential to degrade isoproturon was observed in groundwater samples from each of the aquifer types, with the most rapid and consistent degradation occurring at the sandstone field site. Biodegradation was confirmed by the formation of monodesmethyl- and didesmethyl-isoproturon. Isoproturon degradation potential rates obtained from the groundwater microcosms could not be correlated with either dissolved organic carbon or numbers of bacteria in the groundwater. It was noted that the ability of the groundwater at a field site to degrade a pesticide was not related to performance of the soil above.