Tobacco cutworm, Spodoptera litura Feb. (Lepidoptera; Noctuidae) is a notorious cosmopolitan pest of numerous crops. Frequent evolution of insecticide resistance and polyphagous nature favors the ...survival of this voracious pest. Nanotechnology offers an alternative technique to overcome the limitations of existing pest management strategies. In the present study, the silver nanoparticles were synthesized from Ocimum basilicum leaf extract and UV-spectra at 464.17 nm confirmed their synthesis while crystalline nature of nanoparticles was evaluated by X-rays diffraction (XRD) pattern and scanning electron microscopy (SEM) revealed their octagonal to spherical shape. Insecticidal potential of O. basilicum synthesized silver nanoparticles (ObAgNPs) was evaluated in comparison with some synthetic insecticides owning different mode of actions, including Coragen®, Proclaim®, Tracer® and Talstar® against S. litura. Probit analysis of 2nd, 3rd, 4th and 5th instars of S. litura showed that lethal concentrations (LCs) of tested nanoparticles and pesticides were positively correlated with older instars. All values of LC50, LC90 and LC95 were statistically different from each other with maximum on the 4th instar and minimum on 2nd instar of S. litura. Tukey’s HSD test revealed that ObAgNPs caused maximum mortality (21.67–96.67%) in 2nd instar larvae at the rate of 100–1500 mg/L followed by Coragen® (18.33–91.67%), Proclaim® (13.33–78.33%) and Talstar® (13.33–68.33%), while Tracer indicated the lowest larval mortality (11.67–66.67%) at the rate of 60–120 mg/L and a similar trend was assessed for all the successive instars of S. litura. Higher activity of carboxyl esterase and glutathione-s-transferases confirmed the development of insecticide resistance against the synthetic chemicals. Conclusively, ObAgNPs were found to be eco-friendly but the most effective biogenic compounds for the suppression of S. litura population as compared to the selected synthetic chemicals which may be hazardous for the environment as well as human health. This study will assist the pesticide industries to re-standardize the dose rates against Spodoptera litura.
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•Sliver nanoparticles (AgNPs) were synthesized with Ocimum basilicum leaf extract.•Structural and morphological characterization of ObAgNPs were investigated with XRD, SEM and EDAS.•Ocimum basilicum AgNPs were found more effective and may be used as an ecofriendly management of Spodoptera litura.•Activity of detoxification enzymes was non-significantly increased with ObAgNPs.
This paper presents a compilation of previous studies on the Stewart platform, which is a class of six degree of freedom parallel manipulators. The abstraction of a parallel manipulator is ...appropriated for the entire class of it. The paper focuses on the studies in the different fields which are closely checked to determine the direction of research and identify the solved problem areas. A significant investigation has been presented to discuss the existing methods for the analysis of the Stewart platform manipulator due to their unique applications. Studies on analysis and design of the Stewart platform manipulator using flexible joints are included. Modeling and analysis of parallel manipulators by Matlab SimMechanics environment are also highlighted.
The present study is based on the interactions caused by 340-GeV negative pions with emulsion nuclei. The main aim of this paper is to investigate some aspects of central collision events. Thus, the ...events in which the total number of charged shower particles is greater than or equal to twenty eight (
N
s
≥ 28) were chosen for the analysis. They are not exactly central collision events, but may be considered as pseudo-central collision events. The angular characteristics of relativistic charged secondaries have been studied in terms of pseudo-rapidity, and bimodality is found to be absent in the distributions. The mean pseudo-rapidity seems to be independent of grey and heavy particle multiplicities, which indicates its independence with number of collisions. Finally, the correlation between different particle multiplicities in this paper is discussed.
ABSTRACT Molecular and proteomic study was conducted on field evolved resistance of Red Palm Weevil (Rhy-nchophorus ferruginous) against Parathyroid group of insecticide (Cypermethrin). Cytochrome ...P450 genes have been associated with insecticides resistance. Field collected population of R. ferruginous from different provinces of Pakistan was investigated for insecticides resistance development against P450 gene. Insect bioassay indicated highly significant level of LC50 values among laboratory reared and field collected population against Cypermethrin. The laboratory reared resistant population, Sindh and South Punjab collected population showed high LC50 values as compared to susceptible, Baluchistan and KPK population. The expression of P450 gene through PCR showed enhanced level of P450 gene in different Instars as well as collected population. The dsRNA specific for CYP450 gene was designed and targeted through dsRNA in thoracic region of R. ferruginous through micro-injection. Gene expression and proteomic study confirmed the down regulation of P450 gene and associated protein in dsRNA treated population. The application of ds RNA specific for CYP450 also reduced insecticide resistance in R. fer-ruginous. The developmental parameters were highly affected in RPW treated with dsRNA as compared to control samples treated with water or dsGFP. These results support the RNAi application as a suitable tool for the management of insecticide resistance and control of R. ferruginous.
ABSTRACT Plutella xylostella (Lepidoptera: Plutellidae) is a cosmopolitan pest, infesting the cruciferous crops worldwide. It has developed resistance against chemical insecticides. To overcome this ...problem there is dire need to explore alternative control measures which are safer to the environment and compatible with human health. The present study was conducted to investigate the insecticidal properties of native isolated Plutella xylostella granulovirus (PxGV) and Azadirachta indica (AZA) on mortality and development of P. xylostella under laboratory conditions. Both AZA and PxGV were applied alone and in integrated manners at LC20 and LC50 dose rates. The combination of 349.3 parts per million of AZA and 4.8×10 4 occlusion bodies per millimeter of PxGV, resulted in synergistic interaction after 3 rd, 5 th and 8 th days post application while the additive effect was observed only after 1 day post-treatment. Moreover, combined application of PxGV and AZA at sub-lethal doses exhibited increased larval, pupal and adult longevity and decreased larval and adult weight. In conclusion, combination of PxGV and AZA at low dose rate is a viable option to control diamondback moth.
In the Brassicaceae family, a glucosinolate-myrosinase-based system exists against herbivory Glucosinolate-Myrosinase system is differentially compartmentalized but substrate glucosinolate enter in ...contact with the enzyme myrosinase when plant tissues are attacked by insects. The glucosinolate breakdown into a variety of biologically active toxins further deterrenting the herbivory of different chewing and sucking insect pests. The myrosinase enzyme present is in myrosin cells were genetically removed from
B. napus
plant during the seed development. These genetically modified myrosin cells free plants are known as
MINELESS
plant. Genetically modified oilseed rape (
Brassica napus
) was produced by removing toxic mines. Here, we evaluauted the tritrophic interaction between
Brassica napus
wildtype and genetically modified and polyphagous pest
Spodoptera
. In force feeding experiment, larval growth of
S. exigua
was slow and gained less weight on
MINELESS
seedlings as compared to wild-type seedling. Additionally, highest amount of total glucosinolate was found in
MINELESS
control than that of wild type control. Myrosinase activity was not affected by the
S. exigua
feeding on the
MINELESS
plants. However, reduced activity of myrosinase was observed in the wild-type seedlings. Moreover, the
S. exigua
induced the concentration of tryptophan derived glucosinolate (indol-3-yl-methyl, 1-methoxy-indol-3-yl-methyl) that was found slightly higher in
MINELESS
seedlings than on wild-type seedling. Feeding of
S. exigua
deregulated the level of glucosinolate hydrolysis products in both types of plants. Transcriptional data after
S. exigua
feeding on wildtype and
MINELESS
showed differential response of methyl jasmonate and glucosinolate responsive genes were observed. We also observed that after methyl jasmonate treatment, methyl jasmonate and glucosinolate responsive genes were incease in the wild-type and
MINELESS
seedlings showing their negative effect on the growth of
S. exigua
. Overall, generalist insect results are interesting by considering the function of myrosin cells and binary defense system. Further, same experiment should be performed against generalist and specialist insect herbivores of above- and below-ground.
This research aims to evaluate Al-Al joints fabricated by overcasting liquid 2024 Al alloy onto Zn-electroplated 2024 Al alloy solid inserts followed by solidification under pressure. The effects of ...three most influencing process parameters including squeeze pressure, die temperature and melt temperature on the mechanical properties of as-casted and aged overcast joints were investigated. Response surface methodology with central composite design was employed for experimental design and development of empirical models. The observed responses in this research include ultimate tensile strength and hardness. Adequacy and validity of the developed models were verified through ANOVA and confirmation experiments, respectively. For both as-casted and aged overcasting conditions, the results revealed melt temperature as the most significant process parameter affecting ultimate tensile strength and hardness followed by die temperature and squeeze pressure. The comparative analysis of the two conditions suggested aged overcasting as the better alternative which resulted in 5.7~9.8 and 3.6~12.4% improvement in ultimate tensile strength and hardness, respectively.
Nepeta paulsenii is a less explored plant found in the South-Eastern hilly region of Pakistan. Local people consider it a medicinal plant. The protective effect of methanol extract of N. paulsenii ...leaves on carbon-tetrachloride (CCl4) tempted liver damage in male rats was assessed. Forty-eight rats were equally divided into 8 groups and various concentrations of extract + CCl4 were induced for 30 days. Crude methanolic extract of N. paulsenii plant was examined through phytochemical analyses and gas chromatograph coupled with mass spectrometre (GC–MS) before biological testing on albino rats. Phytochemical analysis of extract showed coumarins, flavonoids, terpenoids, saponins and betacyanins, while GC–MS results revealed the existence of several compounds belonging to diverse classes, responsible for the hepatoprotective attribute of N.paulsenii. CCl4 exposure substantially decreased the antioxidant enzymes activity while increased the thiobarbituric acid reactive substances and reactive oxygen species levels. A remarkable increase in the aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase levels was observed in CCl4 treated rats. Comet-parameters were observed after CCl4 administration. N. paulsenii extract administration substantially improved the antioxidant enzyme activity, hepatic markers as well as comet parameters and reversed the CCl4 induced histopathological damages. The results revealed that N. paulsenii has therapeutic effects against CCl4-induced liver damages.
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