Insect Pest Management Research Articles

Evaluation of suitability and biodegradability of the organophosphate insecticides to mitigate insecticide pollution in onion farming

Organophosphates constitute a major class of pesticides widely employed in agriculture to manage insect pests. Their toxicity is attributed to their ability to inhibit the functioning of acetylcholinesterase (AChE), an essential enzyme for normal nerve transmission. Organophosphates, especially chlorpyrifos, have been a key component of the integrated pest management (IPM) in onions, effectively controlling onion maggot Delia antiqua, a severe pest of onions. However, the growing concerns over the use of this insecticide on human health and the environment compelled the need for an alternative organophosphate and a potential microbial agent for bioremediation to mitigate organophosphate pesticide pollution. In the present study, chloropyrifos along with five other organophosphate insecticides, phosmet, primiphos-methyl, isofenphos, iodofenphos and tribuphos, were screened against the target protein AChE of D. antiqua using molecular modeling and docking techniques. The results revealed that iodofenphos showed the best interaction, while tribuphos had the lowest interaction with the AChE based on comparative binding energy values. Further, protein-protein interaction analysis conducted using the STRING database and Cytoscap software revealed that AChE is linked with a network of 10 different proteins, suggesting that the function of AChE is disrupted through interaction with insecticides, potentially leading to disruption within the network of associated proteins. Additionally, an in silico study was conducted to predict the binding efficiency of two organophosphate degrading enzymes, organophosphohydrolase (OpdA) from Agrobacterium radiobacter and Trichoderma harzianum paraoxonase 1 like (ThPON1-like) protein from Trichoderma harzianum, with the selected insecticides. The analysis revealed their potential to degrade the pesticides, offering a promising alternative before going for cumbersome onsite remediation.

Farmer’s knowledge, perception, and practices in managing insect pests and diseases of grapevine in Morocco

An evaluation of pest and disease management practices was conducted among 181 grapevine farmers across five key viticulture regions in Morocco from 2019 to 2022. The primary objectives were to assess farmers’ knowledge, perceptions, and practices and to examine their impact on grapevine productivity. A diverse range of grape varieties was noted, with over 21 varieties yielding from 10 to 30 t/ha. Disease monitoring was reported by 97.4% of the winegrowers within their vineyards, but only 12.1% actively scouted for grapevine trunk diseases. A diverse array of over 40 active ingredients was evaluated against each reported disease. For instance, gray mold (Botrytis cinerea) was mainly treated with boscalid + pyraclostrobin (72%), mancozeb + thiophanate methyl (71%), cyprodinil (69%), and fenthion (69%). As for the downy mildew (Plasmospora viticola), seven active ingredients were significantly been highlighted including cymoxanil + mancozeb (72%), hexaconazole 5% (71%), iprodione (69%), and mancozeb (72%), while maneb (69%) was the most adopted treatment for black rot (Guignardia bidwellii) disease. Some of these treatments showed positive correlations with each other in targeting multiple pests. Identification and control of pests and diseases were often based on damage symptoms rather than on recording causal agents. Respondents were aware of the most common foliar diseases and pests. Multivariate analyses showed that there is a strong relationship between farmers’ characteristics and their overall knowledge of pests and diseases. However, farmers’ knowledge of major grapevine trunk diseases was relatively low and management practices were inadequate. The study underscores the critical role of improved practices and knowledge in mitigating the high variability in grapevine productivity experienced by Moroccan farmers.

Advancing RNAi-based Strategies for Eco-friendly and Targeted Insect Pest Management in Sustainable Agriculture

The RNA interference (RNAi) has emerged as a promising approach for targeted and eco-friendly insect pest management in sustainable agriculture. The RNAi involves the silencing of specific genes through the introduction of double-stranded RNA (dsRNA), leading to the degradation of complementary mRNA and subsequent reduction in the expression of targeted proteins. This chapter provides a comprehensive overview of the current state and future prospects of RNAi-based strategies for insect pest control. We discuss the molecular mechanisms underlying RNAi, delivery methods for dsRNA, and the design and selection of effective target genes. The application of RNAi in controlling various insect pests, including lepidopterans, coleopterans, and hemipterans is extensively reviewed. also highlight the potential challenges and limitations associated with RNAi-based pest management, such as off-target effects, variable efficacy across insect species, and the development of resistance. Strategies to overcome these challenges, including the use of nanoparticle-based delivery systems and the combination of RNAi with other pest control methods, are explored. Furthermore, discuss the environmental and ecological considerations surrounding the use of RNAi in agriculture, emphasizing the importance of assessing non-target effects and the need for appropriate risk assessment frameworks. The chapter concludes by outlining future research directions and the potential for RNAi to revolutionize insect pest management, contributing to the development of sustainable and resilient agricultural systems.

The new kid on the block in insect pest management: sprayable RNAi goes commercial.

The new kid on the block in insect pest management: sprayable RNAi goes commercial.

Climate-smart Pest Management Strategies: Under Changing Climatic Scenarios

In the face of changing climatic conditions, it's crucial to acknowledge their far-reaching impacts on humans, animals, and agricultural systems worldwide, where negative consequences often overshadow any positive outcomes. With global warming and climate change, previously minor insect pests are now poised to wreak havoc, leading to widespread pest outbreaks. As a result, the effectiveness of various pest control measures, including host-plant resistance, natural enemies, transgenics, bio-pesticides, and synthetic chemicals, may undergo significant shifts. Growers and researchers are actively devising Integrated Pest Management (IPM) strategies to minimize environmental harm while maximizing crop yields and economic benefits. Numerous studies highlight the necessity of reevaluating pest management practices and IPM strategies to adapt to novel environmental conditions and enhance the resilience of diverse agroecosystems to weather variability. This involves initiatives such as breeding climate-resilient crops, adjusting crop calendars, employing GIS-based risk mapping for crop pests, and exploring novel pesticides with alternative modes of action, informed by predictive modeling data. Thus, this chapter explores the potential of these techniques for climate-smart insect pest management.

Activity of insecticide detoxification enzymes in Pectinophora gossypiella (Saunders): Implications for insect pest management in cotton crops

The pink bollworm Pectinophora gossypiella is one of the most important endocarpic pests in cotton. In the management of this pest, the intensive use of synthetic insecticides has led to the reduction of its sensitivity to certain active ingredients. It is in this perspective that the study was conducted to determine the enzymes involved in the metabolism of insecticides in P. gossypiella. Insects were collected in five localities (Bouaké, Bouaflé, Vavoua, Sésuéla and Kounahiri) with high pest pressure in the southern cotton zone. The collected insects were ground for the determination of enzymes involved in insecticide metabolism. The analyses showed a significant increase in glutathione-δ-transferase activity in populations of Bouaké compared to the other localities. However, individuals from Séguéla expressed more esterase (alpha and beta) and oxidase activities. Alpha and beta esterase activities were also more expressed in Bouaflé individuals. The high enzymatic activity of esterases and oxidases in individuals from Séguéla and Bouaflé reflects a low sensitivity to insecticides in which esterases and oxidases are involved in the metabolism. On the other hand, in Bouaké, only glutathione- δtransferases are involved in the detoxification of insecticides.

Survey and Management of Major Insect Pests of Summer Paddy

Roving survey was conducted for the major insect pests of summer paddy in north eastern zone of Karnataka. At vegetative stage, the incidence of yellow stem borer Scirpophaga incertulas (Walker) was highest in Vijayanagar district (2.38%), whereas, the occurrence of brown planthopper Nilaparvata lugens (Stal) (1.61/hill), green leafhopper Nephotettix nigropictus (Stål) (1.66/ hill) and rice gall fly Orseolia oryzae (Wood-Mason) (6.10%) was maximum in Koppal. The incidence of rice leaf folder, Cnaphalocrocis medinalis (Guenee) (1.33%) was highest in Raichur. All the five insects pest of summer paddy surveyed were abudant in Koppal at reproductive stage. The efficacy of bioagents was evaluated. Bacillus thuringiensis (Berliner) formulations. Dipel was effective with least S. incertulas (1.93%) and C. medinalis damage (1.72%) whereas, azadirachtin and Dipel recorded the lowest S. incertulas (2.64% and 2.72%) and C. medinalis (1.67% and 1.71%), respectively. Similarly, azadirachtin and Metarhizium anisopliae recorded lowest N. lugens (1.90 hoppers/ hill) and N. nigropictus (0.70 hoppers/ hill) after three sprays at 15 days interval.

Effect of Pelargonium graveolens essential oil and cyantraniliprole on the feeding behavior of Bemisia tabaciMED

AbstractThe sweet potato whitefly, Bemisia tabaci MED (Gennadius) (Hemiptera: Aleyrodidae), is highly harmful to solanaceous crops. The use of essential oils (EOs) is promising for the management of several insect pests, promoting both lethal and sublethal effects. This study aimed to evaluate the effects of sublethal concentrations of Pelargonium graveolens L'Her (Geraniaceae) EO on the feeding behavior of B. tabaci MED on tomato plants (Solanum lycopersicum L., Solanaceae). For this research, the electrical penetration graph (EPG) technique was used to monitor whitefly stylet activities on their host plants. Two sets of plants were previously sprayed with two concentrations of EO (the LC25 and LC50, which were determined in a mortality test), a third set was treated with the insecticide cyantraniliprole, and a fourth set received a control treatment. Our results indicate that the insecticide cyantraniliprole and the EO could both reduce the stylet feeding activity of B. tabaci MED, as well as reduce the number and duration of phloem sap ingestion events (waveform E2), which could avoid or reduce the transmission of viruses. Thus, the application of sublethal concentrations of P. graveolens EO, as well as exposure to cyantraniliprole, negatively affected the feeding behavior of B. tabaci MED. This information may contribute to the management of this pest and the reduction of the incidence of viruses in tomato production.

A comprehensive Review on Genomic Approaches for Insect Pest Management

Genomic approaches, such as RNA interference (RNAi) and CRISPR/Cas9, have shown promise for insect pest management. RNAi techniques involve the use of double-stranded RNAs (dsRNA) to silence specific target genes in arthropod pests, which can be highly selective and safe for non-target organisms. CRISPR/Cas9 technology, on the other hand, allows for precise editing of insect genomes, offering potential strategies for controlling pests through various mechanisms such as impairing reproductive capacity or making pests susceptible to insecticides. These genomic approaches provide species-specific and environmentally friendly alternatives to chemical insecticides, which are facing challenges such as resistance and negative impacts on human health and the environment. However, there are still challenges to overcome, such as the delivery of genetic material into the germline of insects, particularly in the Hemiptera order. Further research and advancements in these genomic technologies are needed to fully realize their potential for insect pest management.

The potency of fungal entomopathogens isolated from Spodoptera frugiperda as endophytic plant-growth promoter

Previous studies have identified endophytic fungi as plant growth promoters and insect pest management. In the current study, six fungal isolates of Metarhizium anisopliae and Beauveria bassiana were isolated from larval corpses of fall armyworm (Spodoptera frugiperda) and tested for their ability to colonize leaf tissue through root and leaf applications or foliar-spray and to promote the growth of young maize (Zea mays) plants. The maize growth attributes examined were germination rate, height, dry and fresh weight, and leaf area. The research was conducted in May until June 2023 in Universitas Sriwijaya, Indonesia. The results revealed that M. anisopliae and B. bassiana were isolated from the cadavers of S. frugiperda and confirmed to be endophytic fungi. Root application was more effective to enhance the fresh weight, plant height, and leaf area of maize compared to foliar-spray. The fungi could significantly enhance the fresh weight, plant height, and leaf area of the young maize plants. The best isolate that could enhance the maize growth was the B. bassiana WTTJC260521A isolate. These findings suggest that M. anisopliae and B. bassiana isolated from fall armyworm corpses that had the potential to enhance maize plant growth through root applicaton.

Seasonal Incidence of Insect Pests and Natural Enemies in Foxtail Amaranthus and Spinach and Efficacy of Dimethoate Against Insect Pests Infesting Leafy Vegetables

An investigation was made to study the efficacy of dimethoate against sucking and defoliator pest-infesting foxtail amaranths and spinach. The efficacy of dimethoate was evaluated at two doses, one at the recommented does of 200 g active ingredient (a.i.) ha-1 and other at double the recommended dose of 400 g a.i. ha-1 along with control and the other at double the recommended dose of 400 g a.i ha-1 along with control. The incidence of leaf webber (Hymenia recurvalis), ear-head bug (Cletus pugnator), Thrips (Thrips tabaci) and leaf miner (Liriomyza trifoli) were observed in foxtail amaranth. In spinach, leaf-eating caterpillars (Spodoptera litura), cutworm (Agrotis ipsilon) and Thrips (Thrips tabaci) were recorded. In spinach at the third leaf stage, nearly 9.20% leaf defoliation, 10.34% leaf damage and a mean thrips population of 3.48/five plants with a mean predator population of 0.32/ five plants were recorded. In the efficacy study, dimethoate was efficient in reducing the infestation of the leaf webber population with pre-mean count of 4.4± 0.87 in control and 1.2± 0.03 in X dose and 0.0± 0.0 in 2X dose after a day after treatment (DAT) in foxtail amaranths. In an efficacy study of dimethoate on thrips in spinach and foxtail amaranth, a complete reduction of thrips population was observed on 3 DAT at X dose and 2X dose with mean thrips population on control was 17.1± 2.12 in spinach and 8.5± 1.24 in foxtail amaranth 3 DAT. These findings indicate that dimethoate application has promising potential as a practical approach for managing insect pests in foxtail amaranth and spinach crops.

Survey of target site mutations linked with insecticide resistance in Italian populations of Aphis gossypii.

Aphis gossypii is a worldwide agricultural pest that causes high levels of economic losses by feeding and transmitting virus diseases. It is usually controlled by chemical insecticides, but this could lead to the selection of resistant populations. Several single nucleotide polymorphisms (SNPs) have been identified associated with insecticide resistance. Monitoring activities to detect the presence of such mutations in field populations can have an important role in insect pest management but, currently, no information on Italian strains is available. The presence of target site mutations conferring resistance to different insecticides was analysed in Italian field collected populations of A. gossypii with an allele specific approach (QSGG, Qualitative Sybr-Green Genotyping). Primers were designed to detect mutations in genes coding acetylcholinesterase (S431F), nicotinic acetylcholine receptor (R81T) and voltage-gated sodium channel (M918L and L1014F). S431F was widespread but with high variability across populations. R81T was detected for the first time in Italy but only in two populations. The L1014F mutation (kdr) was not found, while in the samples showing the M918L two different nucleotidic substitutions were detected. Mutant allele frequencies were, respectively, 0.70 (S431), 0.31 (M918) and 0.02 (R81). Further analysis on the voltage-gated sodium channel gene showed the presence of eight haplotypes and one non-synonymous mutation in the gene coding region. Multiple target-site mutations were detected within Italian populations. The combinations of genotypes observed in certain locations could affect negatively the control of this pest. Preliminary insights on the genetic structure in the Italian populations of A. gossypii were acquired. © 2024 Society of Chemical Industry.

Trade-offs between winter survival and reproduction in female insects.

In temperate environments most species of insects enter an arrested state of development, known as diapause, that enables them to survive the adverse environmental conditions associated with winter. Although diapause is restricted to a single life stage within species of insects, there are examples of insects that overwinter in the egg, larval, pupal and adult stages. Here we offer a targeted, non-systematic literature review examining how overwintering impacts subsequent reproduction in female insects. Several factors, including the lifestage at which insects overwinter, the type of energy investment strategy females use for breeding, elements of the winter environment, and contributions from male insects can influence trade-offs that female insects face between overwintering survival and post-diapause reproduction. Additionally, climate change and elements of the urban environment, including light pollution and higher temperatures in cities, can exacerbate or ameliorate trade-offs faced by reproducing female insects. Better understanding trade-offs between overwintering survival and reproduction in insects not only enhances our understanding of the underlying physiological mechanisms and ecological processes governing diapause and reproduction, but also provide opportunities to better manage insect pests and/or support beneficial insects.

Comparative resistance of wheat genotypes to aphid infestation under varied sowing dates

Aphid infestations pose a significant threat to wheat production worldwide, leading to substantial yield losses. Understanding the variation in wheat genotype response to aphids’ infestation across different sowing dates is crucial for effective insect pest management approaches. In this study, we investigated the relative resistance of various wheat genotypes to aphid infestations under varying sowing dates over multiple growing seasons 2019–20 and 2020–21 at Cereal Crops Research Institute, Pirsabak, Nowshera, Pakistan. The objectives were to assess the impact of sowing date on aphid infestations and to identify wheat genotypes that exhibit consistent resistance to aphids. The results revealed significant variations in aphid infestations across different sowing dates, with early-sown (October) wheat genotypes; Khaista-17 and PR-123 having 5.53 and 5.22 aphids/tiller, respectively, experiencing higher aphid pressure among all sowing dates, while lower aphid infestation 1.91 and 2.30 aphids/tiller observed on PR-125 and PR-127 respectively in late-sown (January). In contrast, Khaista-17 and PR-126 sown in October attained higher yield (4041 and 3639 kg ha−1), while the same genotypes attained 448 and 441 kg ha−1 respectively, that late-sown at January 2019–20. Similarly, these genotypes, Khaista-17 and PR-131 with 4.44 and 4.31 aphids/tiller not only sustained lower aphid populations but also demonstrated minimal yield loss due to aphid damage during 2020–21. This research highlights the importance of considering sowing date as a critical factor in wheat-aphid interactions. Furthermore, this study offers valuable insights for pest management strategies aimed at mitigating aphid-related yield losses and improve overall wheat production sustainability.

Unmanned Aerial Vehicle (UAVs): A Novel Spraying Technique for Management of Sucking Insect Pests in Cotton Ecosystem

Unmanned Aerial Vehicle (UAVs): A Novel Spraying Technique for Management of Sucking Insect Pests in Cotton Ecosystem

ENTOMOPATHOGENIC FUNGI AS MYCO-BIOCONTROL AGENT OF STORED GRAIN INSECT PESTS

Chemical insecticides have been a fairly successful means of controlling pests that cause harm to stored agricultural commodities. However, there are risks, involved in applying these pesticides continuously; these risks are fast becoming problem of global proportion. The overuse and misuse of chemical pesticides by agricultural value chain actors has made the development of new and lower-risk, benign methods for managing insect pests necessary. One lower risk method of managing insect pest that is gaining traction in terms of utilization is myco-biocontrol, one of which is entomopathogenic fungi (EPF) with a biological origin. Entomopathogenic fungi are pathogenic to insects, and based on their widespread presence in natural environments are purported as less harmful to the environment. Toxicologically, EPF are considered benign to man, making them desirable in the context of the new integrated pest management (IPM) framework. Fundamentally, this review covers the current state of knowledge regarding EPF fungi and their use for biological pest management as well as recent developments in the bio-control of stored-grain insects using formulated and unformulated strains. It also covers the mode of application, mechanism of action, and environmental factors necessary for the germination and growth of conidia.

Larval density-dependent mortality of western corn rootworm (Coleoptera: Chrysomelidae) in Bt and non-Bt maize and implications on dose calculations†.

Transgenic crops producing insecticidal toxins from the bacterium Bacillus thuringiensis (Bt) have been used to manage insect pests for nearly 30 years. Dose of a Bt crop is key to assessing the risk of resistance evolution because it affects the heritability of resistance traits. Western corn rootworm (Diabrotica virgifera virgifera, LeConte), a major pest of maize, has evolved resistance to all commercially available Bt traits targeting it, and threatens resistance to future transgenic traits. Past research shows the dose of Bt maize targeting western corn rootworm can be confounded by larval density-dependent mortality. We conducted a 2-year field study at two locations to quantify larval density-dependent mortality in Bt and non-Bt maize. We used these results to calculate dose for our method and compared it to three previously published methods. Additionally, adult emergence and root injury were analyzed for predicting initial egg density. Increased pest density caused greater proportions of larvae to die in Bt maize than in non-Bt maize. All methods for calculating dose produced values less than high-dose, and stochastic variation had the greatest impact on dose at high and low pest densities. Our method for calculating dose did not produce values positively correlated with pest density while the three other methods did. To achieve the most accurate calculation of dose for transgenic maize targeting western corn rootworm, density-dependent mortality should be taken into account for both transgenic and non-transgenic maize and assessed at moderate pest densities. © 2024 Society of Chemical Industry.

Evaluating the efficiency of silver nanoparticles prepared using <i>Pseudomonas fluorescens</i> and <i>Bacillus thuringiensis</i> subsp. <i>tenebrionis</i> in controlling eggs and adults of <i>Callosobruchus maculatus</i> (F.) (Coleoptera: Bruchidae)

This study aimed to evaluate the efficiency of silver nanoparticles (AgNPs) which are prepared biologically by two bacterial species, Bacillus thuringiensis tenebrionis (Btt) and Pseudomonas fluorescens (P.f) to control southern cowpea beetle insect, Callosobruchus maculatus. Many features of the prepared nanoparticles were examined, and the results obtained showed that the highest absorption value of AgNPs was at 262 nm. Whereas the results of FTIR analysis showed that several compounds played a role in the silver ions reduction process, which included alcohol, alkane, primary amine, and amine group. The scanning electronic microscopic images showed that the average diameter of nanoparticles which was created by P.f was 48.52 nm, while it was 56.08 nm for the nanoparticles prepared by Btt. The study showed no significant differences between the activity of both AgNP types against C. maculatus eggs, while a significant preference was recorded for the activity of Btt AgNPs against the C. maculatus adults. The highest percentage of unhitched eggs was 53.8% recorded at 3000 ppm concentration, while Btt AgNPs gave 59.6% at 3000 ppm. The highest mortality rate of the adults who were treated by Btt AgNPs was 58.8 % at 3000 ppm concentration, while it was recorded 50% at 3000 ppm with P.f AgNPs treatment. The current study demonstrates the efficiency of biologically prepared AgNPs in controlling C. maculatus insect life stages, which encourages using of these nanoparticles as a modern strategy in management of insect pests.

Entomopathogens and their role in insect pest management

Agricultural production faces significant challenges due to the loss of crop yields, highlighting the need for improvements in pest management methods to enhance productivity. Crop growers are increasingly pressured to minimize the use of chemical pesticides without compromising yields. However, managing pests has become more challenging due to pesticide resistance and limited product availability. Consequently, there is an urgent requirement for alternative approaches. Entomopathogens such as fungi, bacteria, viruses, and nematodes emerge as promising alternatives to broad-spectrum chemical insecticides. They have been widely employed to control insect pests in cultivated crops, employing successful strategies such as augmentation and classical biological control. These methods involve applying or introducing bacteria, baculoviruses, fungi, and nematodes. Utilizing entomopathogens offers numerous benefits beyond their effectiveness. These advantages encompass the capacity to treat expansive areas with a sole application, ensuring safety for both humans and non-target organisms. Additionally, their use leads to decreased pesticide residues in food, the conservation of natural enemies, and a boost in biodiversity within managed ecosystems. Entomopathogens present a viable solution by offering effective pest control while addressing environmental, human health, and ecosystem sustainability concerns. The primary emphasis of this review is on the present condition of bio-formulations, the pathogenicity associated with entomopathogens, their mode of action, and the possible implementation of diverse microbial formulations aimed at achieving sustainable pest management.

Functional transgenes in Mexican maize: benefits and risks for insect pest management in Mexico and the United States

Abstract Corn earworm (Helicoverpa zea) and fall armyworm (Spodoptera frugiperda) are major migratory pests of maize (Zea mays) in the United States and Mexico. They are primarily controlled in the United States with genetically engineered (GE) maize, while the 25-yr moratorium on cultivating GE maize in Mexico has forced growers to control these pests with insecticides, where maize productivity remains 35% below the world’s average. The United States annually exports 5% of its maize grain to Mexico, where it provides human food and animal feed. This seed is often sown by smallholder growers, leading to plantings of GE transgene-expressing maize and potential hybridization with local landraces. As a result, transgenes are now present in Mexican maize products and landraces. In this study, we examined the F1 offspring of GE maize to better understand the frequency of different transgenes expressed in maize seeds exported to Mexico. We show that exported seed contains numerous transgenes, including an estimated ~68% epsps expressing resistance to the herbicide glyphosate; ~80% pat and bar expressing resistance to the herbicide glufosinate; and ~82% Bacillus thuringiensis (Bt) genes that effectively protect maize plants from several insect pests. We tested 134 samples, including landraces from 10 Mexican states, and found that 35% expressed resistance to glyphosate and 33% to glufosinate. Many samples containing herbicide resistance also expressed 11%–100% functional Bt transgenes, which can effectively reduce the refuge area provided by Mexican maize and increase the Bt-resistant allele frequency. We discuss ways that the introgression of transgenes could provide pest management benefits to Mexican growers but, at the same time, accelerate the development of Bt-resistance in corn earworm and fall armyworm. Our cost-effective screening methods can be used to determine the introgression of functional herbicide resistance and Bt transgenes in maize.