Mitigating dengue incidence through advanced Aedes larval surveillance and control: A successful experience from Pakistan.

Dengue fever is a viral disease caused by one of four dengue stereotypes (Flavivirus: Flaviviridae) that are primarily transmitted by Aedes albopictus (Skuse) and Aedes aegypti (L.). To safeguard public health, it is crucial to conduct surveys that examine the factors favouring the presence of these species. Our study surveyed 42 councils across four towns within the Bhakkar district of Punjab Province, by inspecting man-made or natural habitats containing standing water. First, door-to-door surveillance teams from the district health department were assigned to each council to surveillance Aedes species and dengue cases. Second, data collection through surveillance efforts, and validation procedures were implemented, and the verified data was uploaded onto the Dengue Tracking System by Third Party Validation teams. Third, data were analysed to identify factors influencing dengue fever cases. The findings demonstrated the following: (1) Predominantly, instances were discerned among individuals who had a documented history of having travelled beyond the confines of the province. (2) Containers associated with evaporative air coolers and tyre shops were responsible for approximately 30% of the Aedes developmental sites. (4) Variability in temperature was responsible for approximately 45% of the observed differences in the quantity of recorded Aedes mosquito developmental sites. (5) Implementation of dengue prevention initiatives precipitated a 50% reduction in Aedes-positive containers, alongside a notable 70% decline in reported cases of dengue fever during the period spanning 2019 to 2020, while the majority of reported cases were of external origin. Aedes control measures substantially curtailed mosquito populations and lowered vector-virus interactions. Notably, local dengue transmission was eliminated through advanced and effective Aedes control efforts, emphasising the need for persistent surveillance and eradication of larval habitats in affected regions.

Nanoscale and Tensile-Like Properties by an Instrumented Indentation Test on PBF-LB SS 316L Steel.

The mechanical properties of a defect-free laser melting (PBF-LB) deposit of an AISI 316L steel alloy were assessed by means of an instrumented indentation test (IIT), at both the macro- and nano-scales. The inherent non-equilibrium microstructure of the alloy was chemically homogenous and consisted of equiaxed grains and large-elongated grains (under the optical microscope) with irregular outlines composed of a much finer internal cell structure (under the scanning electron microscope). Berkovich and Vickers indenters were used to assess the indentation properties across individual grains (nano) and over multiple grains (macro), respectively. The nano-indentation over the X-Y plane revealed nearly constant indentation modulus across an individual grain but variable on average within different grains whose value depended on the relative orientation of the individual grain. The macro-indentation test was conducted to analyze the tensile-like properties of the polycrystalline SS 316L alloy over the X-Y and Y-Z planes. The macro-indentation test provided a reliable estimate of the ultimate tensile strength (UTS-like) of the alloy. Other indentation properties gave inconsistent results, and a post factum analysis was, therefore, conducted, by means of a new approach, to account for the presence of residual stresses. The already existing indentation data were supplemented with new repeated indentation tests to conduct a detailed analysis of the relaxation ability of compressive and tensile residual stresses. The developed methodology allows the effect of residual stresses and the reliability of measured macro-indentation properties to be examined as a function of a small group of indentation parameters.

Larval competition analysis and its effect on growth of Ostrinia furnacalis (Lepidoptera: Crambidae) at natural conditions in Northeast China.

The Asian corn borer (Ostrinia furnacalis, Lepidoptera, Crambidae) and Oriental armyworm (Mythimna separata, Lepidoptera, Noctuidae) are 2 major lepidopteran pests of the maize plant, especially the whorls and tassels. The aim of this study was to investigate competition between 2 lepidopteran pests of maize. Intraspecific and interspecific competition occurs when O. furnacalis and M. separata larvae interact with various stages of the maize plant. Therefore, determining whether this competition can decrease larval damage by causing adverse effects on larval growth is crucial. During the maize growing season of 2022, the interaction of these species was assessed in the experimental field of Jilin Agricultural University, China. Interspecific and intraspecific competition of larvae in different maize tissues and the influence of competition on larval development was determined in the fields. The results showed that first, probing behavior was significantly frequent in O. furnacalis larvae; intraspecific and interspecific attack was significant at 4th instar (with leaf, silk, and kernel). Interspecific defense behavior was significant at 3rd instar (without food). O. furnacalis larvae showed attack behavior toward M. separata larvae frequently. Second, competition increased the mortality rate of O. furnacalis larvae (intraspecific, 67%; interspecific, 33%) and decreased pupation emergence rate. Thus, intraspecific and interspecific competition might affect the competitive displacement of pest species sharing the same ecological niche, as well as the prevalence and population dynamics of pests, and help to develop integrated pest management strategies.

Sublethal effects of spinetoram and emamectin benzoate on key demographic parameters of fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) under laboratory conditions.

Fall armyworm (FAW) Spodoptera frugiperda, is a serious invasive pest of many crops that causes huge economic losses to agricultural commodities. Insecticides are employed for the management of S. frugiperda. In this study, we investigated the impact of sublethal concentration (LC10) and low lethal concentration (LC30) of spinetoram and emamectin benzoate on S. frugiperda using two-sex life table method. Bioassay results revealed that emamectin benzoate exhibited more toxicity on the 3rd instar of S. frugiperda (LC50 8.35 × 10-4 mgL-1) than spinetoram (LC50 2.6 × 10-2 mgL-1) after 48 h exposure. The total longevity, adult pre-ovipositional period (APOP) and total pre-ovipositional period (TPOP) were prolonged, while pre-adult survival rate and fecundity were reduced at both concentrations of spinetoram and emamectin benzoate. Moreover, the key demographic parameters, including the intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (R0), were significantly lower in insecticide treated groups as compared to untreated insects. Our findings revealed that the sublethal and low lethal concentrations of both insecticides reduce the survival and reproductive capability of S. frugiperda. These results would be useful to assess the overall effect of both insecticides on S. frugiperda and can provide important implications for the rational utilization of insecticides against S. frugiperda.

Assessment of sublethal and transgenerational effects of spirotetramat, on population growth of cabbage aphid, Brevicoryne brassicae L. (Hemiptera: Aphididae).

The cabbage aphid (Brevicoryne brassicae L.) is a devastating pest of cruciferous crops causing economic damage worldwide and notably owing to its increasing resistance to commonly used pesticides. Such resistance prompts the development of integrated pest management (IPM) programs that include novel pesticides being effective against the aphids. Spirotetramat is a novel insecticide used against sap-sucking insect pests, particularly aphids. This study evaluated the toxicity of spirotetramat to adult apterous B. brassicae after 72 h using the leaf dipping method. According to the toxicity bioassay results, the LC50 value of spirotetramat to B. brassicae was 1.304 mgL-1. However, the sublethal concentrations (LC5 and LC15) and transgenerational effects of this novel insecticide on population growth parameters were estimated using the age-stage, two-sex life table theory method. The sublethal concentrations (LC5; 0.125 mgL-1 and LC15; 0.298 mgL-1) of spirotetramat reduced the adult longevity and fecundity of the parent generation (F0). These concentrations prolonged the preadult developmental duration while decreasing preadult survival, adult longevity and reproduction of the F1 generation. The adult pre-reproductive period was also extended by spirotetramat treatment groups. Subsequently, the population growth parameters such as the intrinsic rate of increase r, finite rate of increase λ and net reproductive rate R 0 of the F1 generation were decreased in spirotetramat treatment groups whereas, the mean generation time T of the F1 generation was not affected when compared to the control. These results indicated the negative effect of sublethal concentrations of spirotetramat on the performance of B. brassicae by reducing its nymphal survival, extending the duration of some immature stages and suppressing the population growth of B. brassicae. Overall, we demonstrated that spirotetramat is a pesticide showing both sublethal activities, and transgenerational effects on cabbage aphid; it may be useful for implementation in IPM programs against this aphid pest.

A study on the role of aedes mosquitoes in arboviruses and SARS-CoV-2 infection: A new challenge.

Chikungunya, Zika, Dengue Viruses, and now Novel Coronavirus are global health challenges that cause human diseases ranging from febrile illnesses to death. Most of these viruses are mainly vectored by Aedes mosquitoes worldwide. Molecular detection of arboviruses was made in female Aedes mosquito pools caught from all the seven districts by using a reliable molecular technique, "RT-PCR." From 216 collections of Aedes species, arboviruses were detected in 27, including only Alphavirus genus to determine mosquito abundance and evaluate the potential role of Aedes aegypti and Ae. albopictus mosquitoes in arboviruses and nvel Coronavirus transmission. 5322 mosquitoes were collected using aspirators; 35.31% (n = 2049) were identified as female Aedes using morphological keys, pooled into 216 pools, and tested for arboviruses and coronaviruses by using RT-PCR with the help of specific primers. Novel Coronavirus was not detected in this study. Only the Flavivirus genus was detected in twenty-seven pools giving an infection rate of 62.96% (n = 17) for DENV2, while DENV3 was 37.03% (n = 10). Furthermore, our results indicated no role of mosquitoes in the spread of Covid-19. Results showed a higher infection rate in urban sites than in rural ones. The detection of arboviruses indicates possible human health risk due to active role of these mosquitoes in spreading of arbovirus in the study area.

Prevalence and management of aphids (Hemiptera: Aphididae) in different wheat genotypes and their impact on yield and related traits.

Wheat (Triticum aestivum L.) production is significantly altered by the infestation of sucking insects, particularly aphids. Chemical sprays are not recommended for the management of aphids as wheat grains are consumed soon after crop harvests. Therefore, determining the susceptibility of different wheat genotypes and selecting the most tolerant genotype could significantly lower aphid infestation. This study evaluated the susceptibility of six different wheat genotypes ('Sehar-2006', 'Shafaq-2006', 'Faisalabad-2008', 'Lasani-2008', 'Millat-2011' and 'Punjab-2011') to three aphid species (Rhopalosiphum padi Linnaeus, Schizaphis graminum Rondani, Sitobion avenae Fabricius) at various growth stages. Seed dressing with insecticides and plant extracts were also evaluated for their efficacy to reduce the incidence of these aphid species. Afterwards, an economic analysis was performed to compute cost-benefit ratio and assess the economic feasibility for the use of insecticides and plant extracts. Aphids' infestation was recorded from the seedling stage and their population gradually increased as growth progressed towards tillering, stem elongation, heading, dough and ripening stages. The most susceptible growth stage was heading with 21.89 aphids/tiller followed by stem elongation (14.89 aphids/tiller) and dough stage (13.56 aphids/tiller). The genotype 'Punjab-2011' recorded the lower aphid infestation than 'Faisalabad-2008', 'Sehar-2006', 'Lasani-2008' and 'Shafaq-2006'. Rhopalosiphum padi appeared during mid-February, whereas S. graminum and S. avenae appeared during first week of March. Significant differences were recorded for losses in number of grains/spike and 1000-grain weight among tested wheat genotypes. The aphid population had non-significant correlation with yield-related traits. Hicap proved the most effective for the management of aphid species followed by Hombre and Husk among tested seed dressers, while Citrullus colocynthis L. and Moringa oleifera Lam. plant extracts exhibited the highest efficacy among different plant extracts used in the study. Economic analysis depicted that use of Hombre and Hicap resulted in the highest income and benefit cost ratio. Therefore, use of genotype Punjab-2011' and seed dressing with Hombre and Hicap can be successfully used to lower aphid infestation and get higher economic returns for wheat crop.

Laboratory induced selection of pyriproxyfen resistance in Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae): Cross-resistance potential, realized heritability, and fitness costs determination using age-stage, two-sex life table.

Pyriproxyfen is a biorational insecticide from IGR family, used worldwide against several economic pests. To evaluate the risk of pyriproxyfen resistance in dusky cotton bug, Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae), a major concern for cotton producers, and to formulate strategies effective to tackle resistance, a field collected population was selected with pyriproxyfen under laboratory conditions using seed-dip method. A resistant strain designated as Pyr-SEL (G18) was developed after repeatedly selecting O. hyalinipennis with pyriproxyfen over eighteen generations. Thereafter, fitness costs, realized heritability (h2) and cross-resistance were investigated. As a result of selection, Pyr-SEL (G18) developed a very high level of resistance (resistance ratio = 464.23-fold) compared with the susceptible strain unselected over twenty generations Un-SEL (G20). The Pyr-SEL (G18) conferred strong cross-resistance to bifenthrin (146.59-fold), lambda-cyhalothrin (132.96-fold) and fenoxycarb (91.06-fold), whereas showed moderate cross-resistance to diafenthiuron (28.86-fold) and fipronil (22.73-fold). The h2 estimate was 0.16 in Pyr-SEL (G18). The developmental duration of O. hyalinipennis pre-adult prolonged, but traits of λ, r and R0 reduced in Pyr-SEL (G18) compared with the Un-SEL (G20). Also, the population projection obtained lower population size for Pyr-SEL (G18) than Un-SEL (G20). Fitness studies revealed that high resistance development to pyriproxyfen lowered the relative fitness of Pyr-SEL (G18) (Rf = 0.38) compared with the Un-SEL (G20). These findings may be practically valuable in tackling O. hyalinipennis resistance for better pest management.

Correction to: Sublethal effects of a juvenile hormone analog, Pyriproxyfen demographic parameters of non-target predator, Hippodamia convergens Guerin-Meneville (Coleoptera: Coccinellidae).

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Modelling the Mechanical Attributes (Roughness, Strength, and Hardness) of Al-alloy A356 during Sand Casting.

Sand-casting is a well established primary process for manufacturing various parts of A356 alloy. However, the quality of the casting is adversely affected by the change in the magnitude of the control variables. For instance, a larger magnitude of pouring velocity induces a drop effect and a lower velocity increases the likelihood of cold-shut and mis-run types of defects. Similarly, a high pouring temperature causes the formation of hot tears, whereas a low temperature is a source of premature solidification. Likewise, a higher moisture content yields microcracks (due to gas shrinkages) in the casting and a lower moisture content results in the poor strength of the mold. Therefore, the appropriate selection of control variables is essential to ensure quality manufactured products. The empirical relations could provide valuable guidance in this regard. Additionally, although the casting process was optimized for A356 alloy, it was mostly done for a single response. Therefore, this paper aimed to formulate empirical relations for the contradictory responses, i.e., hardness, ultimate tensile strength and surface roughness, using the response surface methodology. The experimental results were comprehensively analyzed using statistical and scanning electron microscopic analyses. Optimized parameters were proposed and validated to achieve castings with high hardness (84.5 HB) and strength (153.5 MPa) with minimum roughness (5.8 µm).

Sublethal effects of a juvenile hormone analog, Pyriproxyfen on demographic parameters of non-target predator, Hippodamia convergens Guerin-Meneville (Coleoptera: Coccinellidae).

Insect predators, in general, play an important role in regulating pest populations in agricultural systems, but may be negatively affected by pesticides used in pest management. Convergent lady beetle, Hippodamia convergens Guerin-Meneville (Coleoptera: Coccinellidae) is known as an important biological control agent of soft-bodied insect pests. The development of Integrated Pest Management (IPM) program against insect pests requires an assessment of the side effect of insecticides on biological control agents. In the present work, we assessed the sublethal effects of an insect growth regulator, Pyriproxyfen (juvenile hormone mimic) on a common aphidophagous beetle, H. convergens by computing its demographic parameters through age-stage, two-sex life table theory. Present results showed that sublethal (LC10 and LC30) concentrations of tested insecticide prolonged the pre-adult developmental duration while adult longevity, fecundity and fertility were reduced following treatment compared with control. However, total pre-ovipositional period (TPOP) was declined with the increasing trend of insecticide concentration. In additions, population growth parameters such as intrinsic rate of increase r, finite rate of increase λ and net reproductive rate R0 were dramatically reduced in H. convergens population when they treated with sublethal concentrations pyriproxyfen. Therefore, the results obtained through this study reflected that pyriproxyfen impairs the population growth parameters and could reduce the biological services provided by H. convergens. Thus, more attention should be paid to the use of this insecticide in IPM program.

Mitochondrial gene cytochrome c oxidase I (CO1) used for molecular identification of Bactrocera zonata in Pakistan.

Bactrocera zonata is fruit pest mostly attacked on peach and cause heavy destruction in production of peach fruits by sucking their juice. For their management, we start to detect them on basis of their molecular characterization. As mitochondrial genome encodes a gene COI used as biomarker for identification of eukaryotes including insects. In present study, we amplified COI gene and cloned into pTZ57R/T vector (Fermentas). Cloned gene was confirmed through restriction analysis and sequenced through its entirety on both strands from Macrogen (South Korea) by Sanger sequencing method. Different computational tools were utilized for comparative analysis of sequence with other related sequences retrieved from databases. Related species were identified through phylogenetic analysis using Mega 7 tool. Pairwise sequence alignment showed the sequence identity about 96% with Bactrocera zonata. By identifying the pests with more authentic molecular biomarker may help the research to control them more effectively in future.

Demographic Parameters of Lipaphis erysimi (Hemiptera: Aphididae) on Different Cultivars of Brassica Vegetables.

Demographic parameters of the turnip aphid, Lipaphis erysimi (Kaltenbach) (Hemiptera: Aphididae), which is a serious pest of Brassica crops worldwide, were evaluated on five major Brassica vegetables (three varieties of Brassica oleraceae (Linnaeus) (Brassicaceae: Brassicales); kohlrabi, cabbage and ornamental cabbage, and two subspecies of Brassica rapa (Linnaeus) (Brassicaceae: Brassicales); Chinese cabbage and bak choi). The study was carried out under laboratory conditions at 25 ± 1°C, 70 ± 5% RH and 16:8 (L:D) h. Preadult developmental time, survival rate, female longevity, reproduction, and life table parameters were evaluated according to the age-stage specific life table method. The highest population growth parameters, i.e., net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ) were recorded on kohlrabi (R0 = 30.45 offspring, r = 0.2174 d-1, λ = 1.2429 d-1). These parameters were the lowest on Chinese cabbage (R0 = 13.00 offspring, r = 0.1503 d-1, and λ = 1.1621 d-1) and bak choi (R0 = 16.30 offspring, r = 0.1614 d-1, λ = 1.1752 d-1). The results attained from population growth parameters, together with population projection estimation based on the age-stage, two-sex life table theory, indicated that both Chinese cabbage and bak choi were less suitable hosts for turnip aphids and should be considered as a possible source for developing resistance in breeding programs and integrated pest management strategies.

Toxicity and resistance of field collected Musca domestica (Diptera: Muscidae) against insect growth regulator insecticides.

The house fly, Musca domestica, is a serious pest of public health importance with the ability to develop insecticide resistance. The focus of the present study was to evaluate toxicity and resistance of the field collected house flies from Punjab, Pakistan, against insect growth regulator (IGR) insecticides. House flies collected from six different localities exhibited very low levels of resistance to cyromazine, triflumuron, and methoxyfenozide compared with the Lab-susceptible reference strain, with resistance ratios (RRs) ranging between 3.56- to 8.19-fold, 1.45- to 3.68-fold, and 2.20- to 8.60-fold, respectively. However, very low to low levels of resistance were observed for pyriproxyfen and very low to moderate levels for lufenuron with RRs ranged from 4.13- to 11.63-fold to 8.57- to 22.75-fold, respectively. There was a significant correlation between RRs of cyromazine and triflumuron (r = 0.976, p < 0.001), suggesting the possibility for cross-resistance. Susceptibility status of different IGRs in Pakistani strains of house flies is reported here for the first time. The trend observed in decreasing susceptibility towards different IGR insecticides tested will continue unless resistance management practices are followed.

Mosquito larvicidal activity of citrus limonoids against Aedes albopictus.

Citrus limonoids, nomilin and limonin, were used for larvicidal assay against Aedes albopictus utilizing WHO methodology. LC(50s) were 305.83, 176.08, and 136.07 µM for nomilin and 850.09, 600.72, and 407.09 µM for limonin after 24, 48, and 72 h, respectively. LT(50) assays exhibited that Savage citrange oil was the best at all concentrations (400, 500, 600, and 700 ppm) while Fairchild and Cassa grande were the weakest oils at 400 ppm, but at 500, 600, and 700 ppm, Carrizo citrange remained at the bottom with highest LT(50) values. Results exhibited that nomilin was more toxic than limonin and therefore provided a clear indication that limonoids in sample oils influenced the potential of respective oil. Out of the 10 tested citrus seed oils, Savage citrange (Citrus sinensis) comprised the maximum amount of limonin (2823.59 µg/ml) followed by grapefruit, Sacaton citrumelo, and Jaffa. When this oil (Savage citrange) was evaluated for bioassay against larvae of Ae. albopictus, it reflected complete dominance (LC(50) and LT(50)) as compared to rest of the oils. Although Jaffa (Citrus paradisi) was found to contain nomilin and limonin, it was found less effective as compared to Savage citrange. The oils from Minneola and Chinese lime did not contain limonin and nomilin, and were therefore weak in terms of LC(50) values. Presence of limonin and nomilin in plant products is therefore a significant indicator of the pest control that needs to be exploited in other plants as well.