Insecticide Sprays Research Articles

Comparative Efficacy of Insecticides Against Jassid on Cotton Crop under Field Conditions of Dera Ghazi Khan

The experiment was conducted in local field conditions of Dera Ghazi Khan during the 2021 Kharif season on three different sites. The core objective of this experiment is to manage Jassid on the cotton crop a major pest. Five different insecticides Dinotefuran, Thiamethoxam, Nitenpyram, Dimethoate and clothianidin were evaluated at recommended doses. The treatments were laid out in randomized complete block designs with three replications. Data regarding the Jassid population before a spray of insecticides and after 24-, 48-, and 72-hour’s of spray were recorded. The reduction in the Jassid population is evaluated by the Abbots formula. The results indicated that Nitenpyram was found most effective on Jassid with mean mortality of 63.47%, 65.07 and 61.86% followed by Dinotefuran with 59.22%, 59.33% and 51.45%. Other treatments thiamethoxam, Dimethoate and clothianidin were at par and did not reduce the Jassid population after 24 and 48 hours. However, thiamethoxam and clothianidin reduced the Jassid population below ETL after 72 hours of spray as compared to Dimethoate. Therefore, it is recommended that Nitenpyram and Dinotefuran should be used for Jassid control at the recommended dose.

Prevalence Rate and Associated Risk Factors of Anaemia among under Five Years Children in Ethiopia.

Background: Anaemia is a condition characterised by a decrease in the concentration of haemoglobin (Hb) in the blood. Anaemia suffers under five years children about 47.4% and 67.6% worldwide and developing countries including Ethiopia, respectively. The aim of this study was to assess the prevalence rate and the associated socio-economic, geographic and demographic factors of anaemia status of under five years children in Ethiopia. Methods: The data for this study were obtained from the 2011 Ethiopia National Malaria Indicator Survey (EMIS 2011). A sample of 4356 under five years age children was obtained from three regional states of Ethiopia. Based on haemoglobin level, child anaemia status was ordered and takes an ordinal value as no anaemia, mild anaemia, moderate anaemia and severe anaemia, respectively. Ordinal logistic regression model, specifically the proportional odds model was used by considering with and without survey design features. Results: Of the 4356 complete cases, 2190 (50.28%) were male and 1966 (49.72%) were female children under five years old. The children overall mean (SD) age was 2.68 (1.21) years. It was observed that both the mean ages and their variabilities in the regions are approximately equal to the overall mean and variability. It was also observed that in Amhara, Oromiya and SNNP regions 72.28%, 67.99% and 73.63% of the children, respectively had no anaemia; 15.93%, 13.47% and 13.56% of the children, respectively had mild anaemia; 10.99%, 15.61% and 11.33% of the children, respectively had moderate anaemia; and only 0.81%, 2.93% and 1.49% had severe anaemia, respectively. The prevalence of severe child anaemia status was higher in Oromiya region compared to Amhara and SNNP regions, respectively. Our result indicates that age, use of mosquito net, malaria RDT outcome, type of toilet facility, household wealth index, region and median altitude were significantly related to child anaemia status. However, it was observed that some covariates were model dependent, for example household wealth index and type of toilet facility were not significant when considering survey features. Conclusions: Anaemia burden remains high particularly in developing countries. Controlling the burden of anaemia necessitates the formulation of integrated interventions which prioritise the highest risk groups including children under five years. The statistical model used in this paper identified individual, household and cluster level risk factors of child anaemia. The identified risk factors for example not having improved toilet facility in the dwelling where a child lived as well as poorest household wealth index suggest the policymakers should target to focus more on children from poor community. Further, the strong association between malaria infection and anaemia suggests that malaria preventative methods such as vector control methods namely, long-lasting insecticidal nets (LLINs) and indoor residual spraying of households with insecticides and including case diagnostic testing and treatment may be the most effective ways to reduce infections associated with anaemia. Such collective assessment approach may lead to more effective public health strategies and could have important policy implications for health promotion and for the reduction of health disparities.

Image classification of sugarcane aphid density using deep convolutional neural networks

Sugarcane aphid, Melanaphis sacchari (Zehntner), has caused significant yield loss across the sorghum (Sorghum bicolor L. Moench) production region in the U.S. Adequate management of sugarcane aphid depends on pest monitoring and economic threshold levels to spray insecticides. However, scouting this pest under field conditions is time-consuming and inefficient. To assist pest monitoring, we propose the use of deep learning models to automatically classify sugarcane aphid infestation on leaves according to different density levels in images. We used a total of 5,048 images collected during field scouting events and evaluated the performance of four deep learning classification models: Inception v3, DenseNet 121, Resnet 50, and Xception. We trained the models to classify aphid densities into 6 classes based on established standard threshold levels for spraying: no aphids present (0 sugarcane aphids/leaf), no threat or below an action/treatment threshold (1–10, and 11–39 sugarcane aphids/leaf), and infested above an economic threshold where an insecticide should be applied (40–125, 126–500, and > 500 sugarcane aphids/leaf) to manage sugarcane aphid in field conditions. Among these models, Inception v3 and Xception performed best with an overall accuracy score of 86% and a lower number of misclassified images. Importantly, the models correctly classified aphids as above or below threshold spray density over 97% of the time. The methodology developed and the models tested in this study can be used in sampling protocols and further mobile applications or remote sensing technologies. These technologies can assist sorghum growers and researchers to scout and screen sugarcane aphid in susceptible and resistant sorghum varieties automatically and provide accurate recommendations on whether or not to apply pesticides.

EFFECT OF IPM/IRM STRATEGIES FOR PINK BOLLWORM, PECTINOPHORA GOSSYPIELLA SAUNDERS INFESTING BTCOTTON

Farmers had initiated indiscriminate use of insecticides against pink bollworm and incurred high cost of managing. Unless extension initiatives to create awareness to manage pink bollworm, the situation may further lead to yield losses, distress of cotton farmers and threat to sustainability that in turn will have a cascading effect on textile industries and economy. Keeping in view, pink bollworm management strategies comprising of timely sowing, use of refuge, recommended nutrition, monitoring through pheromone traps, release of bio-control agent, recommended insecticide sprays at ETL, field sanitation and timely termination of the crop formulated by ICAR-CICR, Nagpur were disseminated and demonstrated to 50 beneficiary farmers in irrigated tract of Valia taluka of Bharuch district. Amongst sucking pests population, aphid, thrips and leafhopper had crossed ETL once and whitefly and mealybug remained below ETL during the season in IRM-FLD plots whereas aphid, thrips and leafhopper crossed ETL 4, 1 and 5 times, respectively whereas whitefly and mealybug remain below ETL during the season in non-IRM plots. Sucking pests required average 2.90 sprays in IRM-FLDs plots whereas slightly higher 3.00 in non IRM plot. For pink bollworm management, 2.20 and 2.70 sprays were targeted by farmers under IRM and non-IRM plots condition, respectively. Seed cottonyield varied from 830 to 979 kg/acre and from 810 to 968 kg/acre under IRM and non IRM condition, respectively. The net return was found higher in IRM plots (Rs. 21,500 to 27,875/acre) than the non IRM (Rs. 18,740 to 25,663/acre). The FLDs and outreach extension activities aided in educating and percolating technology to adjacent periphery of the region.

Interception Strategies for Managing Exotic Ambrosia Beetles (Coleoptera: Curculionidae) in Nurseries

Interception Strategies for Managing Exotic Ambrosia Beetles (Coleoptera: Curculionidae) in Nurseries

Efficacy of insecticide aerial spraying programs to reduce tree mortality during a spruce budworm outbreak (1967–1992) in the province of Quebec

Abstract Spruce budworm (Choristoneura fumiferana) is the most important pest of conifer forests in eastern North America. The main approach for protecting forests against this defoliator is aerial spraying of insecticides. Despite the crucial role of aerial insecticide applications in the global forest protection strategy, little is known about its real effects on tree mortality or the stand characteristics that may affect its long‐term efficacy. We evaluated the efficacy of the protection program that was implemented during the 1967–1992 outbreak in Quebec (Canada) in tree mortality reduction. We established 422 plots in eastern Quebec based upon the following parameters: insecticide application; stand composition; drainage quality; and stand age. Unprotected plots exhibited 18 to 44% greater tree mortality than protected plots. Insecticide efficacy was affected by drainage condition. Protected plots that established on sites with poor quality drainage exhibited 67.53% lower balsam fir (Abies balsamea) mortality than did unprotected plots. Stand age did not affect tree mortality. Insecticide application had no substantial effect on spruce mortality. Our study also found that the return on protection investment in terms of mortality reduction may decline after 7 years of aerial spraying, and that it is not necessary to achieve the target protection goal (50% foliage protection) every year to reduce host tree mortality. Our results may be useful for decision‐makers to decide where and when to apply insecticides during a spruce budworm outbreak and may help to determine the appropriateness of treating the forest on an annual basis depending upon the protection goals.

An Economic Analysis of Mentha Cultivation in Punjab

The present study was conducted for economic analysis on mentha cultivation in Punjab. The primary data were collected from fifty farmer respondents classified based on operational landholding. Cobb-Douglas production function was fitted to identify the variables influencing the yield of the mentha crop. The benefit-cost ratio was estimated to be 2.87, which highlights the profitability of the mentha crop. The major cost components of mentha cultivation were found to be human labour (39.04 per cent), followed by fertilizers (20.65 per cent) and suckers (11.82 per cent). Most farmers were growing the varieties of mentha, peppermint and koshi, a larger area devoted to the former. The highest returns over variable cost were observed in the case of large farms (`139852 per ha), followed by medium farms (`106083 per ha) and small farms (`57371 per ha). In the present study, area (ha), irrigation ( hours), and insecticide sprays (numbers) were found to be significantly affecting the yield of the mentha crop by 82 per cent.

Towards environmental detection of Chagas disease vectors and pathogen

Chagas disease vector control relies on prompt, accurate identification of houses infested with triatomine bugs for targeted insecticide spraying. However, most current detection methods are laborious, lack standardization, have substantial operational costs and limited sensitivity, especially when triatomine bug densities are low or highly focal. We evaluated the use of FTA cards or cotton-tipped swabs to develop a low-technology, non-invasive method of detecting environmental DNA (eDNA) from both triatomine bugs and Trypanosoma cruzi for use in household surveillance in eastern Colombia, an endemic region for Chagas disease. Study findings demonstrated that Rhodnius prolixus eDNA, collected on FTA cards, can be detected at temperatures between 21 and 32 °C, when deposited by individual, recently blood-fed nymphs. Additionally, cotton-tipped swabs are a feasible tool for field sampling of both T. cruzi and R. prolixus eDNA in infested households and may be preferable due to their lower cost. eDNA detection should not yet replace current surveillance tools, but instead be evaluated in parallel as a more sensitive, higher-throughput, lower cost alternative. eDNA collection requires virtually no skills or resources in situ and therefore has the potential to be implemented in endemic communities as part of citizen science initiatives to control Chagas disease transmission.

Wavelet Decomposition and Machine Learning Technique for Predicting Occurrence of Spiders in Pigeon Pea

Influence of weather variables on occurrence of spiders in pigeon pea across locations of seven agro-climatic zones of India was studied in addition to development of forecast models with their comparisons on performance. Considering the non-normal and nonlinear nature of time series data of spiders, non-parametric techniques were applied with developed algorithm based on combinations of wavelet–regression and wavelet–artificial neural network (ANN) models. Haar wavelet filter decomposed each of the series to extract the actual signal from the noisy data. Prediction accuracy of developed models, viz., multiple regression, wavelet–regression, and wavelet–ANN, tested using root mean square error (RMSE) and mean absolute percentage error (MAPE), indicated better performance of wavelet–ANN model. Diebold Mariano (DM) test also confirmed that the prediction accuracy of wavelet–ANN model, and hence its use to forecast spiders in conjunction with the values of pest–defender ratios, would not only reduce insecticidal sprays, but also add ecological and economic value to the integrated pest management of insects of pigeon pea.

Efficacy of wax-based bait stations for controlling Bactrocera dorsalis (Diptera: Tephritidae).

Bactrocera dorsalis is a notorious pest and spraying of insecticides has been the major approach to controlling its damage. However, insecticide abuse has led to negative impacts on public health and insecticide resistance; hence, sustainable strategies, such as bait stations, need to be developed and taken into account for B. dorsalis management. In this study, we integrated insecticide, sugar, olfactory and visual elements into a wax matrix to formulate a long-lasting bait station. We determined its efficacy against B. dorsalis under field conditions. The optimal bait station was a wax matrix incorporated with 1% spinetoram, 1% yellow pigment, and 3% ammonium acetate, and was spherical in shape with a 6cm diameter. The longevity of this bait station was at least 10 weeks under field conditions. In a release and recapture experiment performed in Orchard 1, the bait stations were as effective as bait spray in controlling sterile fly populations, and more effective than the control. In a 2-year field trial conducted in Orchard 2, the number of female B. dorsalis and fruit infestation in the area where bait stations had been deployed was similar to the areas treated with cover spray. In Orchard 3, deployment of bait stations combined with chemical cover spray treatment decreased the population of female B. dorsalis and fruit damage more effectively than cover spray alone. Overall, wax-based bait stations can be regarded as a viable alternative to insecticides or a synergistic method for managing B. dorsalis. © 2022 Society of Chemical Industry.

Cattle-related risk factors for malaria in southwest Ethiopia: a cross-sectional study

BackgroundDespite the low to moderate intensity of malaria transmission present in Ethiopia, malaria is still a leading public health problem. Current vector control interventions, principally long-lasting insecticidal nets and indoor residual spraying, when deployed alone or in combination, are insufficient to control the dominant vector species due to their exophagic and exophilic tendencies. Zooprophylaxis presents a potential supplementary vector control method for malaria; however, supporting evidence for its efficacy has been mixed.MethodsTo identify risk factors of malaria and to estimate the association between cattle and Anopheles vector abundance as well as malaria risk, a cross-sectional study was conducted in a village near Arba Minch, Ethiopia. Epidemiological surveys (households = 95, individuals = 463), mosquito collections using CDC light traps and a census of cattle and human populations were conducted. To capture environmental conditions, land cover and water bodies were mapped using satellite imagery. Risk factor analyses were performed through logistic, Poisson, negative binomial, and spatial weighted regression models.ResultsThe only risk factor associated with self-reported malaria illness at an individual level was being a child aged 5 or under, where they had three times higher odds than adults. At the household level, variables associated with malaria vector abundance, especially those indoors, included socioeconomic status, the proportion of children in a household and cattle population density.ConclusionsStudy results are limited by the low abundance of malaria vectors found and use of self-reported malaria incidence. Environmental factors together with a household’s socioeconomic status and host availability played important roles in the risk of malaria infection in southwest Ethiopia. Cattle abundance in the form of higher cattle to human ratios may act as a protective factor against mosquito infestation and malaria risk. Humans should remain indoors to maximize potential protection against vectors and cattle kept outside of homes.

New Control Methods Against the Cabbage Stem Flea Beetle in Oilseed Rape Crops

Cabbage stem flea beetle (CSFB) is one of the most damaging pests of oilseed rape (OSR) grown in the UK. An intensive research effort is underway in the UK and throughout OSR growing regions of continental Europe to develop new control methods for this pest. In the first article of a series of three, we review this research and consider approaches to this pest problem that may be available immediately and in the short-term. Agronomic practices (sowing date, seed rate, crop defoliation, companion crops, etc) are being investigated and several of these approaches are already being used on farm. The use of physically acting biopesticides such as fatty acids, while not yet being used may also provide an effective solution and could be available in the short-term. Each of these approaches has the potential to form part of future Integrated Pest Management (IPM) programmes but importantly none should be seen as simple replacements for conventional synthetic insecticides. Solutions that may be available in the medium and longer-term will be discussed in the next articles. The cabbage stem flea beetle (CSFB), Psylliodes chrysocephala (Coleoptera: Chrysomelidae) is one of the most important pests of winter OSR crops in central and northern European countries. The adult beetle causes 'shot holing' feeding damage on cotyledons and true leaves of young winter OSR plants in late summer-early autumn. The larvae feed inside petioles and stems of the plants, causing additional damage. The focus on making food production more environmentally friendly means reduced chemical inputs, protecting nontarget species and overall biodiversity. This led to the withdrawal of systemic synthetic neonicotinoid pesticide seed treatments in many crops (oilseed rape included) in 2013. Since the withdrawal of neonicotinoid seed treatments, there has been a reliance on pyrethroid insecticides. This has been seen with a shift in the use of insecticides in oilseed rape, with CSFB the target for 28% of insecticide applications in 2012 (before neonicotinoid seed treatments were withdrawn) to 75% in 2020. The result of this shift has been the development of resistance to this group of insecticides in CSFB population. This situation has become so severe that some UK populations of CSFB are now 100% resistant to the pyrethroid insecticide lambda-cyhalothrin. These changes have led to the area of oilseed rape grown in the UK being halved (756,000 hectares in 2012 versus 307,000 hectares in 2021), with growers citing CSFB as one of the main reasons for this decrease. At the same time, the number of insecticide spray rounds has increased from two to three between 2012 and 2020, with these applications dominated by the use of pyrethroids. The most widely used pyrethroid insecticide, lambda-cyhalothrin, has also increased as a proportion of the insecticide-treated area from 32% in 2012 to 76% in 2020. Additional surveys by Fera, completed as part of the CropMonitor information service, between 2009 and 2020 show that the number of CSFB larvae per plant increased from an average of 0.5 larvae per plant in the years before the withdrawal of neonicotinoids, to more than 2 larvae per plant the following year in 2014 in East England, and almost 5 larvae per plant in 2019 in the South West of England. Here we present solutions that are currently available or that could be made available in the short-term. We consider how each of these approaches could be used in Integrated Pest Management (IPM) programmes.

Identification, Microhabitat, and Ecological Niche Prediction of Two Promising Native Parasitoids of Tuta absoluta in Kenya.

Simple SummarySince the arrival of Tuta absoluta, a multivoltine insect species whose larvae develop in leaves, fruits, flowers, buds, and stems of tomatoes, producers are facing one of its biggest production challenges. The pest continues to invade new areas, causing heavy losses in the tomato value chain. Sprays of synthetic insecticides have shown very low efficacy on this pest because of its inclination to develop resistance to various insecticide-active ingredients. Biological control is one of the most promising solutions for the management of this pest. In this work, we investigated the most efficient indigenous parasitoids associated with T. absoluta in Kenya and their preferable habitat and ecological niche suitability. We identified two species, Stenomesius sp. near japonicus and Bracon nigricans, with up to 17% and 21% parasitism respectively. Stenomesius sp. near japonicus was more abundant in greenhouses and non-insecticide-treated tomatoes while B. nigricans was more abundant in the field tomatoes with a low abundance of Nesidiocoris tenuis. The ecological niche of these two species showed that B. nigricans was suitable for establishment in sub-Saharan Africa, a big part of South America, and Australia in both current and future scenarios.Associations between the South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), and its native parasitoids need to be updated to increase the implementation of pest control strategies. In this study, T. absoluta-infested tomato plants were collected from three regions in Kenya. The emerged parasitoids were identified, and their abundance was correlated with agroecological parameters, viz. cropping systems, and the abundance of the predator Nesidiocoris tenuis Reuter (Hemiptera: Miridae). The study further conducted a habitat suitability prediction for the identified parasitoids. Two parasitoid species, Bracon nigricans (Szépligeti) (Hymenoptera: Braconidae) and Stenomesius sp. near japonicus (Ashmead) (Hymenoptera: Eulophidae) emerged from T. absoluta immature stages, with parasitism rates ranging from 0 to 21% and 0 to 17% respectively. Insecticide application and open field cropping negatively influenced the parasitism by S. sp. nr japonicus. Low occurrence of N. tenuis positively affected B. nigricans parasitism. The predicted occurrence of parasitoid species indicated vast suitable areas for B. nigricans in sub-Saharan Africa, Australia, and South America. Low suitability was observed for S. sp. nr japonicus in Africa. Therefore, native parasitoids, especially B. nigricans could be considered for implementation as a biocontrol agent in the Integrated Pest Management program of T. absoluta.

Comparative Efficacy of Superheated Dry Steam Application and Insecticide Spray Against Common Bed Bugs Under Simulated Field Conditions.

The common bed bug, Cimex lectularius L., is a difficult urban pest to control. A simulated field study was conducted to compare the efficacy of steam application and an insecticide mixture spray (0.05% acetamiprid and 0.06% bifenthrin mixture) against C. lectularius. Three types of furniture (desk chair, upholstered armchair, and wooden table) were treated in the laboratory. The efficacy of the treatments was evaluated by visual inspection and placement of interceptor traps under the legs of the furniture. One hundred mixed stages of an insecticide-resistant population of C. lectularius were released onto each furniture item. After a 10-day acclimation period, each furniture item received steam treatment, insecticide spray, or no treatment. The second application of treatment was conducted 14 d later. Bed bug counts from interceptors and visual inspections were recorded at 13 d and 28 d after the initial treatment. At 28 d, the mean (± SE) live bed bug count in the steam, spray, and control group was 1 ± 0, 2 ± 1, and 83 ± 10, respectively. Both treatment methods were highly effective in controlling bed bugs on furniture. The mean bed bug count from interceptors in the steam, spray, and control groups were 0.3 ± 0.2, 11 ± 7, and 47 ± 9, respectively. There was no significant difference in the efficacy between steam and spray treatments based on either visual inspection or bed bug counts from interceptors. However, based on interceptor counts, the steam treatment caused faster bed bug population reduction than insecticide sprays.

Prediction of mungbean yellow mosaic virus disease using multiple regression models

BackgroundThe main cause for low mungbean [Vigna radiata (L.) R. Wilczek] productivity is mungbean yellow mosaic virus (MYMV). Generally, the management of MYMV relies upon frequent insecticide sprays to control its vector (whitefly) and genetic resistance. However, disease forecast models can help to economize the pesticide sprays. Hence current study was designed to identifying environmental factor that promote disease development and developing a disease prediction model. MethodsOne hundred and twenty-seven mungbean accessions were planted for two years (2012 and 2013) and infection was dependent on natural inoculum. Weekly and daily data on disease incidence and environmental variables were collected and analyzed using correlation and stepwise regression analysis. ResultsWind velocity and high temperature had a negative relation with disease occurrence during both years, whereas low temperature, rainfall, and relative humidity, had positive relationship based on linear regression. The environmental conditions responsible for the highest disease incidence were, maximum temperature (32–34 °C), relative humidity (72–75 %), minimum temperature (27–29 °C), rainfall (1.8–2.1 mm) and wind velocity (3–4.5 km/hr) during both growing seasons Overall, five environmental variable multiple regression model encompassing relative humidity, wind speed, rainfall, suboptimum temperature, and optimum temperatures accommodate the data rightly explaining 83 % variation in disease outgrowth. ConclusionThe observed MYMV disease occurrence values for most of the mungbean genotypes, and those predicted by the model were very close. This multi-environmental variable model can be utilized to provide early warning forecasts for the management of MYMV in Pakistan.

Efficacy of New Generation Insecticides in Comparison with Biopesticides and their Economics against Chickpea Pod Borer (Helicoverpa armigera Hub.)

Background: Chickpea (Cicer arietinum L.) is one of the most important pulses. Helicoverpa armigera [Hubner] is the most devastating chickpea pest responsible for substantial yield loss. Chickpea crop is damaged by a large number of insect species, both under field conditions and in storage. Productivity losses by gram pod borer range from 20 to 90 per cent depending upon the severity of insect attack. Among the biotic factors responsible for low yield the, damage due to insect pests is the major limiting factor. Keeping the above facts in view, the present investigation was planned and carried out to establish a new generation molecules are comparatively safer to natural enemies, honeybees and other pollinators than old generation molecules play an important role in reducing the pest populations. Methods: Field experiment was during Rabi season 2018-19 on chickpea in district Rewa. The field was prepared following the recommended package of practices. The incidence of H. armigera was observed from five randomly selected plants from four middle rows of each plot at weekly interval. The spray of insecticides was applied as soon as the pest incidence is noted. The first spray was done at 50% flowering stage of the crop and repeated after 15 days. Pre-treatment observation on pest population was undertaken one day before the application of the first spray by direct counting of H. armigera larvae per five randomly pre-selected plants in each plot. Similar procedure was followed for post-treatment observation which was recorded at 1, 3, 7, 10, 15 days after both the spray operations. Result: The experiment was laid out in randomized block design with 09 treatments (Chlorantraniliprole 18.5 SC @ 37 g a.i./ha, Fipronil 5% SC @ 50 g a.i./ha, Indoxacarb 15.8 EC @ 79 g a.i./ha, Spinosad 45 SC @ 90 g a.i./ha, Novaluron 10 EC @ 100 g a.i./ha, Emamectine benzoate 5 SG @ 10 g a.i./ha, Neem oil 0.15% , Bt.K. 3.5% and untreated check. First spray of insecticides over all mean analysis indicated that all the insecticidal treatments were significantly effective in reducing the larval population of Helicoverpa armigera Hub. as compared to untreated plots (1.56 larvae/plant) in the first and second spray (0.92 larva/plant) of insecticides over all mean larval population Indoxacarb 15.8 EC @ 79 g a.i./ha was effective in controlling the incidence of gram pod borer due to the first spray (0.59 larva/plant) and also the second spray (0.27 larva/plant) among all treatments. Resulting in the seed yield 1989.00 kg/ha with the highest cost: benefit ratio of 1:12.3, which was followed by the treatment of Emamectin benzoate 5 SG @ 10 g a.i./ha with cost benefit ratio of 1:10.83.

Diurnal biting of malaria mosquitoes in the Central African Republic indicates residual transmission may be “out of control”

Malaria control interventions target nocturnal feeding of the Anopheles vectors indoors to reduce parasite transmission. Mass deployment of insecticidal bed nets and indoor residual spraying with insecticides, however, may induce mosquitoes to blood-feed at places and at times when humans are not protected. These changes can set a ceiling to the efficacy of these control interventions, resulting in residual malaria transmission. Despite its relevance for disease transmission, the daily rhythmicity of Anopheles biting behavior is poorly documented, most investigations focusing on crepuscular hours and nighttime. By performing mosquito collections 48-h around the clock, both indoors and outdoors, and by modeling biting events using circular statistics, we evaluated the full daily rhythmicity of biting in urban Bangui, Central African Republic. While the bulk of biting by Anopheles gambiae, Anopheles coluzzii, Anopheles funestus, and Anopheles pharoensis occurred from sunset to sunrise outdoors, unexpectedly ∼20 to 30% of indoor biting occurred during daytime. As biting events did not fully conform to any family of circular distributions, we fitted mixtures of von Mises distributions and found that observations were consistent with three compartments, corresponding indoors to populations of early-night, late-night, and daytime-biting events. It is not known whether these populations of biting events correspond to spatiotemporal heterogeneities or also to distinct mosquito genotypes/phenotypes belonging consistently to each compartment. Prevalence of Plasmodium falciparum in nighttime- and daytime-biting mosquitoes was the same. As >50% of biting occurs in Bangui when people are unprotected, malaria control interventions outside the domiciliary environment should be envisaged.

The causes and consequences of pest population variability in agricultural landscapes

Variability in population densities is key to the ecology of natural systems but also has great implications for agriculture. Farmers' decisions are heavily influenced by their risk aversion to pest outbreaks that result in major yield losses. However, the need for long-term pest population data across many farms has prevented researchers from exploring the drivers and implications of pest population variability (PV). Here, we demonstrate the critical importance of PV for sustainable farming by analyzing 13 years of pest densities across >1300 Spanish olive groves and vineyards. Variable populations were more likely to cause major yield losses, but also occasionally created temporal windows when densities fell below insecticide spray thresholds. Importantly, environmental factors regulating pest variability were very distinct from factors regulating mean density, suggesting variability needs to be uniquely managed. Finally, we found diversifying landscapes may be a win-win situation for conservation and farmers, as diversified landscapes promote less abundant and less variable pest populations. Therefore, we encourage agricultural stakeholders to increase the complexity of the landscapes surrounding their farms through conserving/restoring natural habitat and/or diversifying crops.

Biotechnological Initiative for Management of Mungbean Yellow Mosaic Virus in Mungbean (Vigna radiate L.)

Mungbean (Vigna radiate L.) is one of the most important legume crops of Asiatic region. The average yield of mungbean is quite low due to its susceptibility against mungbean yellow mosaic virus (MYMV). Mungbean yellow mosaic virus disease (MYMD) is caused by MYMV, which is transmitted through whitefly (Bemisia tabaci). The controlling of this devastating disease is mainly depends upon spraying of insecticides, which cause serious ill effect on humans and soil health. Breeding for its resistance is one of the best strategies for developing MYMV resistant genotypes in mungbean. Several types of molecular markers have been used in marker assisted breeding (MAB) in mungbean. Among them SSR markers are widely used and a plethora of scientific advocate the use of the SSR marker in developing MYMV resistance in mungbean. Recent advancements in functional genomics and gene editing technologies can further enhance our understanding of the molecular mechanisms underlying resistance to MYMV and hence facilitate the development of MYMV resistant mungbean genotypes.

The combined impact of LLINs, house screening, and pull-push technology for improved malaria control and livelihoods in rural Ethiopia: study protocol for household randomised controlled trial

BackgroundThe combined application of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are commonly used malaria interventions that target indoor Anopheles vectors. Recent studies on the effects of house screening (HS) and LLINs have demonstrated a reduction in indoor vector densities and malaria when the interventions are combined. In addition, complementary interventions are needed to curb co-occurring pest populations which pose menace to agricultural crop productivity and food security. However, interventions that impact malaria mainly centre on public health strategies, overlooking subtle but important component of agricultural measures. Addressing the coexisting risks of malaria and crop pests could contribute to improved livelihood of communities.MethodsA four-armed household, cluster-randomized, controlled study will be conducted to assess the combined impact of HS, LLINs and push-pull agricultural technology (PPT) against clinical malaria in children in Ethiopia. The unit of randomization will be the household, which includes a house and its occupants. A total of 838 households will be enrolled in this study. In this trial 246 households will receive LLINs and HS, 250 will receive LLINs, HS and PPT, 175 households will receive LLINs and PPT. The remaining 167 houses which receive LLINs only will be used as control. One child aged ≤14 years will be enrolled per household in each treatment and followed for clinical malaria using active case detection to estimate malaria incidence for two malaria transmission seasons.DiscussionEpisodes of clinical malaria, density of indoor biting malaria vectors, sporozoite infection rate, improved crop infestation rate, crop yield gain, livestock productivity and cost effectiveness analysis will be the end points of this study. Socio-economic, social demographic, cost-effectiveness analysis will be conducted using qualitative and participatory methods to explore the acceptability of HS and PPT. Documenting the combined impact of LLINs, HS and PPT on the prevalence of clinical malaria and crop pest damage will be the first of its kind.Trial registrationPan African Clinical Trials Registry, PACTR202006878245287. 24/06/2020. https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=11101.