Integrated Pest Management Strategies Research Articles

Life Table Parameters of the Tomato Leaf Miner Tuta absoluta (Lepidoptera: Gelechiidae) on Five Tomato Cultivars in China.

Tomato is the most preferred host plant for Tuta absoluta, a newly emerged devastating invasive pest in China. However, no study has evaluated the damage risk of T. absoluta on processed tomato worldwide. In the current study, the life table parameters of T. absoluta were systematically investigated on five tomato cultivars (one fresh tomato cultivar, four processed tomato cultivars) to determine their susceptibility to T. absoluta infestation. T. absoluta had a better population growth ability on the fresh tomato, "Dafen", showing shorter duration of the preadult stage, higher lifetime fecundity, and a higher intrinsic rate of increase compared to four processed tomato cultivars. Meanwhile, the life table parameters of T. absoluta among different processed tomato cultivars also showed significant differences. Th9 was the most susceptible to T. absoluta attack, while Th1902, Heinz1015, and Dimen2272 were the least suitable ones for its development and reproduction. In summary, these tomato cultivars are the most recommended for commercial tomato production to reduce the damage caused by T. absoluta and improve the integrated pest management strategy.

Integrated Pest Management Precision: Harnessing the Joint Influence of Entomopathogenic Fungi, Nematodes, and Chlorantraniliprole for Targeted Control of Fall Armyworm (Spodoptera Frugiperda)

Background: The Spodoptera frugiperda, commonly known as the fall armyworm (FAW), is a significant pest impacting agricultural productivity worldwide. Originating from tropical and subtropical regions, FAW has shown a high capacity for migration and destruction across a wide variety of crops. Integrated Pest Management (IPM) strategies offer sustainable approaches to managing pest populations, minimizing environmental impact, and reducing reliance on chemical insecticides. Objective: This study aimed to evaluate the efficacy of combining biological control agents, specifically Heterorhabditis bacteriophora (Hb) and Beauveria bassiana (Bb), with the chemical insecticide chlorantraniliprole (Ch) against third and fifth instar larvae of S. frugiperda. The study sought to determine the potential synergistic effects of these combinations on larval mortality and developmental disruption. Methods: The research encompassed laboratory bioassays, greenhouse, and field trials to assess the impact of the biocontrol agents and chlorantraniliprole, both individually and in combination, on FAW larval mortality and development. Larval populations of S. frugiperda were collected and reared under controlled conditions. Treatments applied included Hb, Bb, Ch, Hb+Bb, Hb+Ch, Bb+Ch, and Hb+Bb+Ch. Mortality rates were recorded at 3, 5, and 7 days post-treatment, while developmental parameters were assessed through pupation rates, adult emergence, and egg eclosion percentages. Results: The combined application of Hb, Bb, and Ch significantly increased mortality rates in both the third and fifth instar larvae compared to individual treatments, with the highest mortality observed in the Hb+Bb+Ch group (100% by day 7). Developmental disruptions were also noted, including reduced pupation rates, adult emergence, and egg eclosion, particularly in treatments involving the combined use of biocontrol agents and chlorantraniliprole. Statistical analysis confirmed the significance of these findings (P<0.01). Conclusion: The integration of Hb, Bb, and Ch presents a viable IPM strategy for effectively managing S. frugiperda populations. This combination not only enhances larval mortality but also disrupts developmental stages, offering a potential reduction in FAW infestation levels and associated crop damages. These results underscore the importance of adopting sustainable pest management practices that leverage synergistic effects between biological and chemical agents.

Integrated pest management goes hand-in-hand with safety

This publication is geared toward pest management specialists, certified pesticide applicators, and homeowners who are managing indoor and outdoor pests. It provides a broad definition of a pest and describes integrated pest management (IPM) and pest management strategies. As opposed to other EDIS which are specific to management areas (ex: landscape, turf, vegetable) this publication can be used as a basis for all sectors of pest management. The publication also emphasizes using IPM to reduce the development of pesticide resistance and emphasizes how each aspect of IPM contributes to personal and environmental safety.

Insect Pests in Agriculture Identifying and Overcoming Challenges through IPM

Insect pests pose significant challenges to agricultural production worldwide, threatening food security and economic stability. Integrated Pest Management (IPM) offers a comprehensive approach to address these challenges sustainably. This abstract explores the principles and strategies of IPM, emphasizing its focus on minimizing environmental impacts and reducing reliance on chemical pesticides. Through biological control, cultural practices, mechanical control, and selective pesticide use, IPM aims to manage pest populations effectively while promoting biodiversity and long-term agricultural sustainability. By implementing IPM strategies, farmers can mitigate the impact of insect pests while fostering resilient and productive agricultural systems.
 Insect pests pose a significant threat to agricultural productivity worldwide. They can devastate crops, leading to substantial economic losses and threatening food security. Identifying and managing these pests effectively is crucial for sustainable agriculture. Integrated Pest Management (IPM) offers a comprehensive approach to address insect pest challenges while minimizing environmental impacts and reliance on chemical pesticides. Insect pests represent a persistent threat to agricultural productivity and food security globally. This abstract delves into the principles and practices of Integrated Pest Management (IPM) as a sustainable approach to address these challenges. IPM integrates various strategies, including biological control, cultural practices, mechanical control, and selective pesticide use, to manage pest populations effectively while minimizing environmental harm. By emphasizing monitoring, threshold levels, and selective interventions, IPM promotes the judicious use of pesticides and fosters ecosystem resilience. The abstract underscores the importance of IPM in promoting biodiversity, reducing chemical inputs, and ensuring the long-term sustainability of agricultural systems. Through the adoption of IPM principles, farmers can mitigate the impacts of insect pests while advancing environmentally conscious and economically viable agricultural practices.

Study on Biology of Fall Armyworm, Spodoptera frugiperda (J.E. Smith) on Maize, Zea mays L. in Manipur, India

Aim: To study the biology and morphometric parameters of different stages of fall armyworm, Spodoptera frugiperda.
 Study Design: Experimental study.
 Place and Duration of Study: PG laboratory, Department of Entomology, College of Agriculture, Iroisemba, CAU (Central Agricultural University), Imphal, June-August 2022.
 Methodology: The egg masses collected from maize fields were transferred to sterilized petri plates containing maize leaves and reared under laboratory conditions (25±2°C, 70±10% RH). Duration and morphometric parameters of different stages of fall armyworm were recorded regularly.
 Results: The mean incubation period of eggs was observed to be 1.90 days. The larval period of six instars were recorded to be 2-4, 2-5, 2-3, 2-3, 2-3, 2-3 and 3-6 days, respectively. The mean larval length of six instars were 1.91, 3.38, 6.15, 9.78, 18.60 and 32.30 mm, respectively. The mean larval width of six instars were 0.33, 0.74, 1.31, 2.26, 2.92 and 3.53 mm, respectively. The average larval weight of six instars were 0.0031, 0.0214, 0.0420, 0.0503, 0.0576 and 0.0652 gm, respectively. The total larval duration was observed to be 16.70 days. The male and female pupal period was found to be 7.60 and 7.10 days, respectively. The average male pupal length, width and weight were 14.79±0.18 mm, 4.54±0.14 mm and 0.17±0.01 gm, respectively. The average female pupal length, width and weight were 13.0-18.20 mm, 4.0-5.2 mm and 0.18±0.01 gm, respectively. The ovipositional period was found to be 1-6 days. Mean longevity of males and females were observed to be 8.70 and 9.00 days, respectively. The total life cycle of male and female lasted 34.90 and 35.60 days, respectively.
 Conclusion: This study clearly provides basic information about the biology of this recently invaded pest. To prevent the potential devastating occurrence, compatible integrated pest management strategies are needed at the early stages of FAW infestation.

Aberrant splicing of a nicotinic acetylcholine receptor alpha 6 subunit is associated with spinosad tolerance in the thrips predator Orius laevigatus

Susceptibility to insecticides is one of the limiting factors preventing wider adoption of natural enemies to control insect pest populations. Identification and selective breeding of insecticide tolerant strains of commercially used biological control agents (BCAs) is one of the approaches to overcome this constraint. Although a number of beneficial insects have been selected for increased tolerance to insecticides the molecular mechanisms underpinning these shifts in tolerance are not well characterised. Here we investigated the molecular mechanisms of enhanced tolerance of a lab selected strain of Orius laevigatus (Fieber) to the commonly used biopesticide spinosad. Transcriptomic analysis showed that spinosad tolerance is not a result of overexpressed detoxification genes. Molecular analysis of the target site for spinosyns, the nicotinic acetylcholine receptor (nAChR), revealed increased expression of truncated transcripts of the nAChR α6 subunit in the spinosad selected strain, a mechanism of resistance which was described previously in insect pest species. Collectively, our results demonstrate the mechanisms by which some beneficial biological control agents can evolve insecticide tolerance and will inform the development and deployment of insecticide-tolerant natural enemies in integrated pest management strategies.

Gathering a bountiful harvest: the impacts of cultural ecosystem service experiences on management practices and agrobiodiversity in urban community gardens

ABSTRACT In addition to their food security and ecological benefits, urban community gardens support human well-being in numerous non-material ways. In this paper, we investigate whether experience of these cultural ecosystem services (CES) shapes how gardeners choose to manage the garden ecosystem, which may influence the ability of these multifunctional green spaces to provide other local ecosystem services (ES). Using questionnaires, in-depth interviews, and plant community analysis, we assess the relationship between perception of CES by community gardeners, the management practices they utilize, and the agroecological characteristics of their garden plots, such as presence and prevalence of species that provide regulating and supporting ES. We find that while almost all survey participants report sociocultural benefits of gardening, experience of these CES varies significantly between gardeners, with garden structure influencing which group of benefits is most perceived. Experience of some CES was also correlated with local ecological knowledge and use of certain sustainable garden management practices, such as utilizing integrated pest management strategies and planting a wide variety of species, but not with observed non-provisioning plant agrobiodiversity. These results provide important insights into the complex role that CES play in encouraging environmental stewardship and shaping ecological outcomes in collectively managed urban green spaces.

Main Parasites of Crops

The article talks about the characteristics of main parasites of crops, their characteristics. Efforts to control these plant parasites involve integrated pest management strategies, including sustainable crop varieties, cultural practices, biological control, and judicious use of chemical interventions. Continued monitoring and research is critical to developing sustainable solutions to reduce the impact of these pests on global agriculture.

Effect of the mycotoxins enniatin B and deoxynivalenol on the wheat aphid Sitobion avenae and on the predatory lacewing Chrysoperla carnea.

Fusarium species are responsible for Fusarium head blight (FHB) in wheat, resulting in yield losses and mycotoxin contamination. Deoxynivalenol (DON) and enniatins (ENNs) are common mycotoxins produced by Fusarium, affecting plant, animal and human health. Although DON's effects have been widely studied, limited research has explored the impact of ENNs on insects. This study examines the influence of DON and enniatin B (ENB), both singularly and in combination, on the wheat aphid Sitobion avenae and one of its predators, the lacewing Chrysoperla carnea. When exposed to DON (100 mg L-1) or DON + ENB (100 mg L-1), S. avenae exhibited significantly increased mortality compared to the negative control. ENB (100 mg L-1) had no significant effect on aphid mortality. DON-treated aphids showed increasing mortality from 48 to 96 h. A dose-response relationship with DON revealed significant cumulative mortality starting at 25 mg L-1. By contrast, C. carnea larvae exposed to mycotoxins via cuticular application did not show significant differences in mortality when mycotoxins were dissolved in water but exhibited increased mortality with acetone-solubilized DON + ENB (100 mg L-1). Feeding C. carnea with aphids exposed to mycotoxins (indirect exposure) did not impact their survival or predatory activity. Additionally, the impact of mycotoxins on C. carnea was observed only with acetone-solubilized DON + ENB. These findings shed light on the complex interactions involving mycotoxins, aphids and their predators, offering valuable insights for integrated pest management strategies. Further research should explore broader ecological consequences of mycotoxin contamination in agroecosystems. © 2024 Society of Chemical Industry.

Pea leaf weevil, Sitona lineatus (L.) (Coleoptera: Curculionidae), adult feeding preference and larval development on pulse crop varieties in Montana.

Montana accounts for approximately 45% of US dry pea production and the pea leaf weevil (PLW; Sitona lineatus (L.)) is the most common insect pest in this region. After crop emergence adult PLW feed on the foliage to mature and subsequently mate, and the soil-dwelling larvae feed and develop on the nitrogen-fixing root nodules. Producers commonly apply prophylactic insecticide treatments to the seed at planting as well as one or two post-emergent insecticide sprays to control PLW damage. To develop alternative management strategies based on integrated pest management (IPM), this field study evaluated pulse crops grown in Montana for adult feeding preference and larval development. Ten different field pea varieties, along with two faba bean, lentil and chickpea varieties, were evaluated during the 2020 and 2021 field seasons at the Montana State University Arthur H. Post Agronomy Farm. Significant PLW pest pressure was observed within the research plots during both experimental years. Field pea and faba bean were preferred by the foliage feeding adult stage, with all but one variety averaging 39.2 to 86.3 average notches per plant. The pea variety Lifter was significantly preferred over all other comparisons, averaging 142.4 and 95.0 notches per plant in 2020 and 2021, respectively. Adult PLW feeding on lentil and chickpea was minimal, averaging 3.3 to 8.2 and 0.5 to 1.6 notches per plant, respectively. Numbers of larvae were highest on the roots of pea varieties, a known reproductive host, and almost nil on lentil and chickpea roots. Faba bean is also known as reproductive host, but, unexpectedly, larval populations were also low on the two faba bean varieties. The results from this study provide some limited evidence for alternative IPM strategies for field peas based on host plant tolerance or resistance within the range of varieties tested. Adult preference and larval development of PLW varied between the different pulse crops with field peas and faba beans being the most susceptible and lentils and chickpeas being the least susceptible. Host plant resistance against PLW could provide more sustainable IPM approaches in the future. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Integrated Pest Management Strategies to Control Varroa Mites and Their Effect on Viral Loads in Honey Bee Colonies.

Honey bee viruses in combination with varroa mite are very damaging for honey bee colonies worldwide. There are no effective methods to control the viral load in honey bee colonies except regular and effective control of mites. Integrated Pest Management strategies are required to effectively control mites with veterinary medicines based on organic compounds. We evaluated the effect of two brood interruption techniques, queen caging (QC) and trapping comb (TC), followed by an oxalic acid treatment, on the mite fall, colony strength, and viral load of Deformed Wing Virus (DWV) and Acute Bee Paralysis Virus (ABPV). In this paper, we report the data obtained in two experimental sites, in Slovenia and Italy, in terms of the varroacide efficacy, colony strength, and viral load. The number of adult bees after the adoption of the two techniques showed similar decreasing trends in both locations. The viral load of Acute Bee Paralysis Virus did not show any significant reduction after 25 days, reported as the number of Real-Time PCR cycles needed to detect the virus. The viral load of DWV also did not show a significant reduction after 25 days. The acaricidal efficacy of the applied protocols was high in both experimental groups and in both apiaries. Both the queen caging and trapping comb techniques, followed by an oxalic acid treatment, can be considered effective varroa treatment strategies, but further studies should be carried out to evaluate the long-term effects on viral loads to plan the Integrated Pest Management strategy with the right timing before wintering.

Evaluation of Cotton (Gossypium hirsutum L.) Varieties/Genotypes for Jassid, Amrasca biguttula biguttula (Ishida) Resistance under Rainfed Conditions

Host plant resistance is an important component of integrated pest management strategy for jassid resistance. Evaluation of germplasm to identify the stable source of resistance is a predominant step in any resistance breeding programme. In this study, screening of Gossypium hirsutum cotton varieties/genotypes against jassid, Amrasca biguttula biguttula (Ishida) was carried out under rainfed conditions during kharif seasons of 2016-17, 2018-19 and 2019-20 at Regional Cotton Research Station, Navsari Agricultural University, Maktampur farm, Bharuch, Gujarat. Among thirteen cotton varieties/genotypes screened, none of variety/genotype was categorized as resistant by considering jassid population as well as Jassid Resistance Index. Six cotton varieties/genotypes viz., NH-615, GBHV-201, GBHV-209, GBHV-204, G.N.Cot-26, GBHV-206 and two checks i.e. DHY-286 and NDLH-1938 were categorized as moderately resistant based on maximum jassid population ranged from 4.40 to 7.40 jassids/3 leaves. Three cotton varieties/genotypes viz., Suraj, Bunny BG II and Bunny Non Bt were categorized as susceptible with population of 12.50 to 13.70 jassids/3 leaves. The cotton variety G.Cot-16 (16.70 jassids/3 leaves) and check DCH-32 (24.60 jassids/3 leaves) were categorized as highly susceptible to jassids. Five cotton varieties/genotypes viz., NH-615, GBHV-201, GBHV-204, GBHV-209, G.N.Cot-26 and two checks i.e. DHY-286 and NDLH-1938 were categorized as moderately resistant based on maximum Jassid Resistance Index in range of 1.10 to 2.00. Only the genotype GBHV-206 was found susceptible with 2.20 JRI. Four cotton varieties/genotypes viz., G.Cot-16, Bunny BG II, Suraj, Bunny Non Bt and check DCH-32 were categorized as highly susceptible to jassid based on maximum JRI of 3.10 to 4.00. Overall five varieties/genotypes of G. hirsutum cotton viz., NH-615, GBHV-201, GBHV-209, GBHV-204 and G.N.Cot-26 were found moderately resistant to jassids under rainfed conditions.

Characterization of Fusarium oxysporum f. sp. pisi Associated with Root Rot of Field Pea in North Dakota and the Effects of Temperature on Aggressiveness.

Fusarium root rot is an important disease of field pea (Pisum sativum var. sativum L.) that occurs everywhere pea is grown, causing yield loss of up to 75%. Fusarium root rot is caused by a complex of Fusarium species, most notably Fusarium solani in the Pacific Northwest of the United States and F. avenaceum in the northern Great Plains of the United States and Canada. F. oxysporum f. sp. pisi (Fop) was frequently isolated from peas exhibiting root rot symptoms in North Dakota during recent surveys. Fop causes wilt (races 1, 5, and 6) and near wilt (race 2) on pea. However, its contribution to pea root rot remains unclear. Fop race was determined for isolates from North Dakota pea root rot surveys. ND Fop isolates were evaluated for root rot pathogenicity and aggressiveness at standard and elevated temperatures. Results from greenhouse wilt assays indicated that all Fop races exist in North Dakota, with race 2 most prevalent among the 25 North Dakota isolates evaluated. Root rot evaluations conducted at 21/18°C and 25/19°C day/night temperatures demonstrated that most Fop isolates were as aggressive or more aggressive than F. solani and F. avenaceum under both temperature regimes. Aggressiveness of Fop isolates tended to increase at elevated assay temperatures. Results from these experiments indicate that Fop may be an important contributor to the root rot complex of field pea in North Dakota and should be considered in integrated pest management strategies, including pea breeding efforts to improve resistance to Fusarium root rot.[Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

The explosion of pests and diseases due to climate change

Climate change has been felt over the last few decades in Indonesia, especially in Aceh. Uncertain climatic conditions can affect crop production and food distribution. Insect pests and plant pathogens respond differently to various causes of climate change. An increase in temperature causes changes in the behavior of pests and diseases in terms of their ability to attack. This review discusses the impact of rising temperatures and CO2 levels in the atmosphere on the ability to attack insect pests and pathogens on crops. Global climate warming is expected to trigger an expansion of pests and disease geographic distribution from lowland to highland, increase their survival, and increase the number of new host plants. The survey carried out in Central Aceh on an Arabica coffee plantation showed that leaf spots caused by Hemiliea vastatrix can attack a coffee plantation at an altitude of 1.400 meters, while the same case is also found at the same altitude where coffee berry borer pest (Hyphothenemus hampei) and coffee leaf miner (Leucoptera coffeella) can attack arabica coffee plantation. A comprehensive assessment of the impact of climate change on pests and plant diseases needs to be carried out to get an integrated pest management strategy.

Hydroponic Trough Systems for Maximising Cucumber Production

Abstract: Hydroponics is a promising solution to address the increasing demand for food caused by limited arable land and a growing global population. This article focuses on the use of hydroponics in cucumber cultivation, specifically highlighting the adaptability of hydroponic trough system. It explains the design elements of the trough system in detail, including configuration, growing medium, nutrient solution, and support structures. The article emphasises the advantages of hydroponic trough systems in cucumber cultivation, such as precise nutrient dispensation, space efficiency, water conservation, and potential for automation. It discusses strategies for optimal cucumber production within these systems, including temperature control, pollination techniques, pruning, and pH monitoring. The article also addresses the challenges of insect and pest attacks, introducing common pests and presenting integrated pest management strategies for effective control. It explores diseases that can affect cucumber crops in hydroponic systems, such as powdery mildew, downy mildew, Pythium root rot, and Fusarium wilt. It discusses strategies to prevent these diseases, including preventive measures, disease-resistant cucumber varieties, cultural practices, and bio methods. By considering all these aspects, a comprehensive approach to disease management can be established. Overall, adopting hydroponic trough systems in cucumber cultivation offers a sustainable and efficient solution to traditional farming challenges. By incorporating preventive measures, disease-resistant cultivars, and organic remedies, farmers can ensure a thriving cucumber harvest and contribute to a productive and sustainable agricultural future.

Integrated pest management in beetroot cultivation: A systematic revie

This systematic review delves into the realm of Integrated Pest Management (IPM) within the context of beetroot cultivation, scrutinizing both the application and efficacy of diverse strategies. Through a meticulous synthesis of existing literature, the study evaluates key IPM approaches—ranging from biological control and cultural practices to chemical interventions—specifically tailored to address pest management challenges in beetroot farming. The review systematically identifies and examines prevailing trends, challenges, and successes in the implementation of these IPM strategies, providing a comprehensive overview intended for a diverse audience including researchers, practitioners, and policymakers engaged in beetroot agriculture. By comprehensively analysing a spectrum of studies, this review significantly contributes to the broader comprehension of sustainable pest management practices, furnishing valuable insights that can be harnessed for optimizing IPM strategies in beetroot cultivation, thereby fostering more effective and environmentally conscious pest control measures.

Biological Control of Pests in Major Tropical Vegetable Crops: A Review

India stands as a global agricultural powerhouse, employing over 60% of its population in farming and related sectors. Agriculture forms a significant pillar of the nation’s GDP, with vegetables being a cornerstone of its horticultural output. Despite advancements in vegetable production, the sector faces myriad challenges, including insect infestations, diseases and other biotic and abiotic factors that compromise yield and quality. This review article delves into the biological control of pests in key tropical vegetable crops like brinjal, tomato, chili, okra and cucurbits. It explores the use of biological control agents such as predators, parasitoids and pathogens as part of integrated pest management strategies aimed at reducing the dependency on synthetic pesticides. It provides an in-depth analysis of common pests such as whiteflies, aphids, mealybugs and thrips, as well as crop-specific pests like brinjal and bhendi shoot and fruit borers. The paper underscores the advantages of biological control, including its environmental sustainability and reduced risk of pest resistance, while also acknowledging its limitations such as slower pest elimination rates and higher costs. It calls for concerted efforts from governmental bodies, NGOs and agricultural institutes to promote awareness and training in biological control methods. The focus of the review is to advocate for a paradigm shift towards sustainable and effective pest management practices in India’s vegetable farming sector.

Variety mixtures of winter wheat: a general status and national case study

Food and feed production worldwide heavily relies on wheat (Triticum aestivum). However, current agricultural practices face numerous challenges including a shortage of land for cultivation, a desire to reduce the use of chemical pesticides and fertilizers, and the development of resistance towards employed pesticides and virulence towards host resistance in the most widely grown varieties. In this paper, we demonstrate based on the literature that cultivating wheat variety mixtures generally leads to increased yield and yield stability across years and environments, reduced severity of multiple diseases, and a decreased risk of lodging before harvest compared to the cultivation of pure stands. Moreover, mixtures may delay fungicide resistance development and increase genetic diversity, ultimately prolonging the durability of resistance genes. Furthermore, growing mixtures may lower the risk of crop failure due to more extreme weather events and lead to better utilization of water and nutrients. We discuss a Danish case study advocating the cropping of wheat varieties in mixtures as an example of how variety mixtures can be utilized in integrated pest management strategies. The study shows that if all involved stakeholder groups promote the adoption of variety mixtures, a major uptake by farmers can be reached, potentially reducing the dependency on pesticides in current cropping schemes.

Gregariousness in lepidopteran larvae.

The gregarious lifestyle of lepidopteran larvae is diverse and shaped by a complex interplay of ecological and evolutionary factors. Our review showed that the larval-aggregation behavior has been reported in 23 lepidopteran families, indicating multiple evolution of this behavior. Some larvae live in sibling groups throughout all larval instars and even pupation stages, which may result from the kin-selection. In contrast, group fusion may occur among different sibling or foraging groups of larvae and form larger aggregates, and the gregariousness of these species might be driven by the group-selection. While group size and foraging patterns vary greatly across species, it is generally associated with improved larval survivorship and accelerated development. However, the advantages of group living, such as facilitating feeding activities, adjusting the temperature, and defending natural enemies, may diminish along with development, with strong intraspecific competition occurring at later instars, even when food is abundant. Therefore, the group sizes and fission-fusion dynamics of certain gregarious lepidopteran larvae may be a consequence of their cost-benefit balance depending on various biotic and abiotic factors. Trail and aggregation pheromones, silk trails, or body contact contribute to collective movement and group cohesion of gregarious lepidopteran larvae. However, frequent contact among group members may cause the horizontal transmission of pathogens and pesticides, which may bring an integrated pest management strategy controlling gregarious lepidopteran pests.

Phytochemical characterization by HS-SPME-GC-MS and exploration of the antifungal, insecticidal and repellent activity of Ptychotis verticillata essential oil

The objective of this investigation was to assess the chemical makeup of essential oil derived from Ptychotis verticillata (PVEO), and to examine its antifungal, insecticidal, and repellent properties. PVEO was extracted through hydrodistillation, and its volatile constituents were analyzed using Headspace Solid-Phase Microextraction Gas Chromatography-Mass Spectrometry. Qualitative and quantitative evaluation of antifungal activity was carried out using the agar diffusion method and the minimum inhibitory concentration (MIC) test against Candida glabrata, Saccharomyces cerevisiae, Aspergillus niger and Penicillium digitatum. We evaluated the repellent potential, as well as the contact and inhalation toxicity of PVEO against Callosobruchus maculatus. The results of the study indicated that the essential oil of P. verticillata was composed mainly of γ-Terpinen (25.86%), β-Cymene (18.70%) O-Cymen-5-ol (16.78) and α-Pinene (12.13%). PVEO showed potent antifungal activity against all strains tested. The results of insecticidal activity of this essential oil were promising in adult C. maculatus. At a dose of 20 ml · dm–3 of air, EO caused maximum mortality with an LC50 value of 5.64 ml · dm–3 for the inhalation test and 3.4 ml · dm–3 for the contact test. In addition, a significant decrease in the number of eggs laid and adult emergence was observed as EO doses increased, reaching a reduction of around 95% at a dose of 20 ml · dm–3 of air. In terms of repellent activity, PVEO also showed encouraging results. It demonstrated an average repellent activity of around 92 ± 10.95%. Furthermore, molecular docking simulations corroborated the in vitro results and demonstrated that specific p-Menthen-3-one compounds formed more robust hydrogen bonding interactions with the target receptors. These experiments underscore PVEO’s effectiveness as a fungicide against the tested fungal strains, demonstrating its role as a bio-insecticide against C. maculatus adults, and its potential as an appealing repellent. This suggests that PVEO could serve as a valuable alternative within integrated pest management strategies.