Biological Control Of Insect Pests Research Articles

Epigenetic Regulation in Insect-Microbe Interactions.

Insects have evolved diverse interactions with a variety of microbes, such as pathogenic fungi, bacteria, and viruses. The immune responses of insect hosts, along with the dynamic infection process of microbes in response to the changing host environment and defenses, require rapid and fine-tuned regulation of gene expression programs. Epigenetic mechanisms, including DNA methylation, histone modifications, and noncoding RNA regulation, play important roles in regulating the expression of genes involved in insect immunity and microbial pathogenicity. This review highlights recent discoveries and insights into epigenetic regulatory mechanisms that modulate insect-microbe interactions. A deeper understanding of these regulatory mechanisms underlying insect-microbe interactions holds promise for the development of novel strategies for biological control of insect pests and mitigation of vector-borne diseases.

Glyphosate-based herbicides reduced overwintering population and reproduction of agrobiont spiders

Spiders are important in ecosystem and serve as predators in the biological control of pest insects in agroecosystem, where they encounter various harsh challenges including pesticides and low temperature in winter. Glyphosate-based herbicides (GBH) are widely and frequently applied to diminish weeds, exposing spiders a disturbed habitat, especially to overwintering spiders. We conducted a study combining field surveys and lab assays, to assess the effects of a GBH on the overwintering of the agrobiont wolf spider, Pardosa pseudoannulata. The GBH significantly reduced the overall overwintering spider population by about 69 %, and reduced the number of vulnerable juveniles by about 80 %. The survivors exhibited substantial fitness costs such as reproductive dysfunctions and enhanced oxidative stress responses. We then mimicked the overwinter process in lab. We housed spiders on soil patches with and without weeds to examine whether weeds contributed to the GBH’s sublethal effects. Spiders overwintered independent of weeds when GBH was not applied. When GBH was applied before or during overwintering, juvenile spiders overwintered in weedy habitats exhibited reduced survival and fecundity, and increased oxidative stress compared to their counterparts in weed-free habitats. Therefore, GBH-containing weeds contributed to the persistent adverse effects of GBH on overwintering spiders. The findings revealed the cross-talk among weeds, herbicides, low temperature, and non-target organisms. The study provides novel information on the environmental risk assessment of pesticides and rational scheduling of pesticide application.

Effects of Two Prey Species Combinations on Larval Development of the Predatory Ladybird Cheilomenes propinqua.

Feeding on mixed, alternating, or changing diets often favor insect development. With the aim to optimize mass rearing and use for the biological control of insect pests, we investigated the effects of various combinations of high-quality (the green peach aphid Myzus persicae) and low-quality (eggs of the grain moth Sitotroga cerealella) foods on the larval development of a predatory ladybird Cheilomenes propinqua. In the first experiment, eggs and aphids were mixed in different proportions; in the second experiment, larvae switched from feeding on aphids to feeding on eggs. Although the beneficial additive effect of mixed foods was detected in some treatments with limited diets, feeding on various combinations of eggs with aphids never resulted in higher survival, faster development, or a larger size of emerging adults than those observed for feeding on unlimited amounts of aphids. For the practice of biological control, we conclude that, if necessary (for example, in the case of temporary shortage or a lack of aphids in mass rearing facilities or in the case of preventing release of C. propinqua adults in greenhouses), C. propinqua larvae can be fed with grain moth eggs by replacing, mixing, or alternating with aphids, although this will inevitably result in a proportional decrease in pre-adult survival, rate of development, weight, and size of the emerging adults. On the other hand, even a minimal addition of aphids can have a substantial positive effect on larvae fed with grain moth eggs.

Tripartite interactions of an endophytic entomopathogenic fungus, Asian corn borer, and host maize under elevated carbon dioxide.

Biological control of insect pests is encountering an unprecedented challenge in agricultural systems due to the ongoing rise in carbon dioxide (CO2) level. The use of entomopathogenic fungi (EPF) in these systems is gaining increased attention, and EPF as crop endophytes hold the potential for combining insect pest control and yield enhancement of crops, but the effects of increased CO2 concentration on this interaction are poorly understood. Here, the introduction of endophytic EPF was explored as an alternative sustainable management strategy benefiting crops under elevated CO2, using maize (Zea mays), Asian corn borer (Ostrinia furnacalis), and EPF (Beauveria bassiana) to test changes in damage to maize plants from O. furnacalis, and the nutritional status (content of carbon, nitrogen, phosphorus, potassium), biomass, and yield of maize. The results showed that endophytic B. bassiana could alleviate the damage caused by O. furnacalis larvae for maize plants under ambient CO2 concentration, and this effect was enhanced under higher CO2 concentration. Inoculation with B. bassiana effectively counteracted the adverse impact of elevated CO2 on maize plants by preserving the nitrogen content at its baseline level (comparable with ambient CO2 conditions without B. bassiana). Both simultaneous effects could explain the improvement of biomass and yield of maize under B. bassiana inoculation and elevated CO2. This finding provides key information about the multifaceted benefits of B. bassiana as a maize endophyte. Our results highlight the promising potential of incorporating EPF as endophytes into integrated pest management strategies, particularly under elevated CO2 concentrations. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effect of faba bean nectar on longevity and fecundity of Plutella xylostella and its parasitoid Cotesia vestalis

Intercropping faba bean with vegetables provides a possibility to promote pest control and better nutrient cycling in sustainable agriculture. Faba bean produces extrafloral nectar which supports parasitoid wasps that play a role in the biological control of pest insects. However, adult lepidopteran pests also benefit from nectar, increasing their lifespan and the number of offspring they produce. Here, a laboratory-based study was conducted to assess the role of faba bean on the components of a Brassica-based host-parasitoid system. We measured how access to faba bean affected the longevity and fecundity of the brassica pest Plutella xylostella and its parasitoid Cotesia vestalis. It was also studied if odors of flowering faba bean disrupt host finding by C. vestalis in Y-tube bioassays and volatile organic compounds were analyzed to explain the olfaction-based choices made by the parasitoids. The longevity of C. vestalis was 6.6 times longer and the number of pupae produced almost 10 times greater when they had access to faba bean. Meanwhile, the longevity of P. xylostella was 3.6 times longer and it laid 4.6 times more eggs when provided access to faba bean. In Y-tube bioassays, C. vestalis females also oriented toward host-related odors of the damaged cabbage more than intact cabbage when odors of faba bean were mixed with both of them. In conclusion, faba bean provided sustenance to both pest insects and their natural enemies that prolonged their lifespans and their reproductive capacity.

Genetic Diversity Analysis of Rhynocoris marginatus Fabricius Based on 18S Ribosomal RNA Gene (Heteroptera: Reduviidae)

The R. marginatus are essential components of ecosystem, but also important in the biological control of insect pest, infesting a varity of agro ecosystem and medicine. The present investigation was carried out in the insect molecular genetic variation of 18S Ribosomal RNA gene from R. marginatus. The study was represent by the reduviid insect R. marginatus nucleotide gene sequences were translate amino acid sequence and obtained hydropathy, Domain, Transmembranes of proteins were calculated. The multiple gene sequence alignment of in-silico translated amino acid sequence of the partial ribosomal genes protein of R. marginatus were generated and the phylogenetic relationships were observed.

Functional Response of Chrysoperla Zastrowi Sillemi (Esben-Peterson) on Lipaphis erysimi (Keltenbach)

Biological control of insect pests depends upon predating potential of natural enemies, which in turn relate to their functional response that is key to selection of a proper species for the biological control programs. The main aim of the study was to access the functional response of second instar grub of C. zastrowi sillemi (Neuroptera: Chrysopidae) on Raya (Brassica juncea) aphid Lipaphis erysimi (Keltenbach). Five different predator: prey densities of aphids (1:50, 1:100: 1:150, 1:200 and 1:250) were taken and results indicated the type-II functional curve response by logistic regression analysis of C. zastrowi sillemi on L. erysimi. Hollings Type II functional response signifies that the rate of prey consumption by a predator rises as prey density increases, but eventually remains constant in spite of increase in prey density. The aphids consumption, search rate (a`) and maximum predation rate (1/Th) was recorded less (7.36, 0.06 and 0.40) as compared (7.56, 0.068and 0.467) when grubs fed on artificial diet. However, time taken to handle a prey by second instar grub was more (2.55) on natural diet but less (2.17) on artificial diet.

Entomopathogenic pseudomonads can share an insect host with entomopathogenic nematodes and their mutualistic bacteria.

A promising strategy to overcome limitations in biological control of insect pests is the combined application of entomopathogenic pseudomonads (EPPs) and nematodes (EPNs) associated with mutualistic bacteria (NABs). Yet, little is known about interspecies interactions such as competition, coexistence, or even cooperation between these entomopathogens when they infect the same insect host. We investigated the dynamics of bacteria-bacteria interactions between the EPP Pseudomonas protegens CHA0 and the NAB Xenorhabdus bovienii SM5 isolated from the EPN Steinernema feltiae RS5. Bacterial populations were assessed over time in experimental systems of increasing complexity. In vitro, SM5 was outcompeted when CHA0 reached a certain cell density, resulting in the collapse of the SM5 population. In contrast, both bacteria were able to coexist upon haemolymph-injection into Galleria mellonella larvae, as found for three further EPP-NAB combinations. Finally, both bacteria were administered by natural infection routes i.e. orally for CHA0 and nematode-vectored for SM5 resulting in the addition of RS5 to the system. This did not alter bacterial coexistence nor did the presence of the EPP affect nematode reproductive success or progeny virulence. CHA0 benefited from RS5, probably by exploiting access routes formed by the nematodes penetrating the larval gut epithelium. Our results indicate that EPPs are able to share an insect host with EPNs and their mutualistic bacteria without major negative effects on the reproduction of any of the three entomopathogens or the fitness of the nematodes. This suggests that their combination is a promising strategy for biological insect pest control.

A parasitoid regulates 20E synthesis and antibacterial activity of the host for development by inducing host nitric oxide production.

Parasitoids are important components of the natural enemy guild in the biological control of insect pests. They depend on host resources to complete the development of a specific stage or whole life cycle and thus have evolved towards optimal host exploitation strategies. In the present study, we report a specific survival strategy of a fly parasitoid Exorista sorbillans (Diptera: Tachinidae), which is a potential biological control agent for agricultural pests and a pest in sericulture. We found that the expression levels of nitric oxide synthase (NOS) and nitric oxide (NO) production in host Bombyx mori (Lepidoptera: Bombycidae) were increased after E. sorbillans infection. Reducing NOS expression and NO production with an NOS inhibitor (NG-nitro-L-arginine methyl ester hydrochloride) in infected B. mori significantly impeded the growth of E. sorbillans larvae. Moreover, the biosynthesis of 20-hydroxyecdysone (20E) in infected hosts was elevated with increasing NO production, and inhibiting NOS expression lowered 20E biosynthesis. More importantly, induced NO synthesis was required to eliminate intracellular bacterial pathogens that presumably competed for shared host resources. Inhibiting NOS expression down-regulated the transcription of antimicrobial peptide genes and increased the number of bacteria in parasitized hosts. Collectively, this study revealed a new perspective on the role of NO in host-parasitoid interactions and a novel mechanism for parasitoid regulation of host physiology to support its development.

Constraints in Adopting Biological Based Pest Management Strategies

Biological control of insect pests is a “viable alternative” to insecticides with an aim to suppress the pest populations below economic injury levels and is the need of the hour. The key biological based management strategies include erection of pheromone traps for mass trapping/monitoring the incidence of moths (adults) of insect pests; conservation of natural enemies like predators/parasitoids in crop ecosystem; augmentation and inundative release of bio-agents like parasitoids and predators against the targeted pests; and application of bio-rational or “reduced risk” insecticides that effectively controls the insect pests and non toxic to other organisms with meager environment risk. Many research findings had strongly witnessed the biological pest management as superior method in suppressing the pest infestation levels in almost all crops, but the success rate is not substantial at farmer’s level. In order to assess the constraints in adopting biological methods and restraints in low success rate of these methods in suppressing the insect pests an explorative research study was conducted for a period of two successive years i.e., 2020-2021 and 2021-22. A total of ten mandals in Krishna district of Andhra Pradesh was selected for the study wherein biological based management strategies are being practiced by the farmers. From each mandal three villages were randomly selected and from each mandal ten farmers were chosen for personal interview to document the constrains in adopting bio-control methods. The methodologies being practiced by farmers were also recorded. The results inferred that among the various restraints, non availability of bio-control agents/materials at market level (63%), adopting the methods at improper time (59%) and lack of knowledge on pest behavior/ecology (55%) are the major influencing factors for low success rate of biological control at farmer’s level. It can be accomplished from the present study that adoption levels of biological pest management strategies at farmers are to be strengthened by conducting regular training programmes, result demonstrations, front line demonstrations and also by encouraging farmers through some incentives and certifications of the harvested organic produce.

Entomopathogenic Fungi: Nature's Secret Weapon Against Agricultural Pests

Insect pests pose significant challenges to agricultural productivity and crop yield worldwide. Conventional pest control methods, such as chemical pesticides, have limitations and adverse environmental effects. Therefore, there is a growing need for sustainable and eco-friendly alternatives in pest management. This review explores the potential of entomopathogenic fungi as a promising biological control agent for insect pests in agriculture. The review begins by providing an overview of entomopathogenic fungi and their significancce. These fungi possess unique mechanisms to infect and kill insect pests. The mode of action involves attachment of fungal spores to the insect's cuticle, followed by penetration, colonization, and release of toxic metabolites within the host. Various factors influence the efficacy of entomopathogenic fungi, including environmental conditions, insect host susceptibility, and formulation/application methods. The benefits of entomopathogenic fungi as biological control agents are discussed, including their compatibility with integrated pest management (IPM) strategies and minimal impact on non-target organisms. However, challenges exist in scaling up their commercial application. The review presents case studies showcasing successful field applications of entomopathogenic fungi in pest management. Future prospects and research directions are identified, emphasizing the importance of continued advancements in understanding the interactions between entomopathogenic fungi and insect pests. Regulatory frameworks and public acceptance are crucial for the widespread adoption of these fungi in agriculture. In conclusion, entomopathogenic fungi offer immense potential as sustainable and effective tools for biological control of insect pests in agriculture. Their ability to target specific pests, compatibility with IPM, and minimal environmental impact make them a viable alternative to chemical pesticides. Further research, collaboration, and implementation are necessary to fully harness the potential of entomopathogenic fungi in integrated pest management strategies.

Effect of spontaneous vegetation on beneficial arthropods in Mediterranean vineyards

Habitat destruction and land use intensification are major causes of arthropod decline in agroecosystems. Arthropods are key organisms that are linked to many ecosystem functions and sustainability of agriculture. Using 37 vineyards in Southern France as a model system, we analysed which characteristics of spontaneous inter-row vegetation positively influence beneficial arthropods and pest insect predation. We specifically studied the effects of flower cover, grass cover, the ratio of perennials to annuals, plant species richness and extrafloral nectar on beneficial arthropod communities in vineyards. We used direct observation and net hunting to evaluate arthropod abundance. Sentinel cards with Lucilia sp. larvae were placed on grapevine plants to analyse caterpillar predation. We found that most groups of tested beneficial arthropods were positively influenced by flower cover and plant species richness. In particular, the abundance of predators such as ladybirds (adults and larvae) and crab spiders and the abundance of parasitic wasps were positively correlated to flower cover in vineyard inter-row vegetation. The abundance of ladybirds, hoverflies and crab spiders was also positively related to plant species richness. Our results demonstrated the importance of floral resources and plant diversity for beneficial arthropods and caterpillar predation confirming their key role in biological control of pest insects.

What Is More Important to Host-Seeking Entomopathogenic Nematodes, Innate or Learned Preference?

Entomopathogenic nematodes (EPNs), small soil-dwelling non-segmented roundworms, are obligate parasites of insects and commonly used in agriculture for biological control of insect pests. For successful reproduction, EPNs must identify, move towards, and successfully infect a suitable insect host in a chemically complex soil environment. EPNs can have innate host insect preferences and can be attracted to semiochemicals associated with that host. They can also develop strong learned preferences for chemical signals associated with the presence of a host, such as herbivory-induced volatiles. We hypothesized that simultaneous manipulation of innate and learned preferences could result in increased biological control services of EPNs in agriculture. Separate cohorts of the EPN Steinernema diaprepesi were raised on two insect hosts, Galleria mellonella and Tenebrio molitor, for multiple generations until the nematodes in a dual-choice olfactometer exhibited preference for the host they were reared on. Subsequently, the two strains of nematodes were imprinted on three plant-produced terpenoids of agricultural significance: pregeijerene, β-caryophyllene, and α-pinene. After exposure to one of the plant compounds, the behavior of the EPNs was assayed in an olfactometer where the two host insects were presented with and without the plant compounds. We found that plant volatile exposure increased the infection rate of the nematodes, and some host–compound combinations proved to be attractive, but other combinations appeared to become repellent. These results indicate that learned preference is neither subordinate nor superior to innate preference, and that infection efficiency can vary with compound exposure and insect host.

Host stage affects oviposition-related behaviours, development progression and reproductive output in a native hyperparasitoid of the solenopsis mealybug invading Asian regions

ABSTRACT Native hyperparasitoids may readily expand their host range by including non-native parasitoids that are introduced in classical biological control of pest insects. Here we report our observation on biology of Cheiloneurus nankingensis (Hymenoptera: Encyrtidae), an obligate hyperparasitoid attacking non-native parasitoid Aenasius arizonensis residing in Phenacoccus solenopsis mealybugs that have invaded into Asian regions. We measured durations of antennae-tapping, ovipositor-drilling and ovipositor-probing/ovipositing behaviours by C. nankingensis wasps on parasitised mealybugs with the host at either larval or pupal stage and on the unparasitised mealybug as the control. The ovipositor-probing/ovipositing duration was much longer on a pupal host than on the larval while shortest on the control. We then observed offspring development progression of C. nankingensis at attacking either egg, larva or pupa of its host by daily dissecting hyperparasitised mealybugs. The development was faster in a larval or pupal host than in the egg. Finally, our measurements of the reproductive output showed that C. nankingensis wasps during 14 days after the emergence attacked more parasitised mealybugs and produced more offspring reaching adulthood when ovipositing in the mealybug with a host larva than with a pupa. Our results from this study suggest that C. nankingensis may employ the ovipositor to probe for the host within a mealybug and the host at the larval stage is of high quality for the reproduction.

Positive Chemotaxis of the Entomopathogenic Nematode Steinernema australe (Panagrolaimorpha: Steinenematidae) towards High-Bush Blueberry (Vaccinium corymbosum) Root Volatiles

The foraging behavior of the infective juveniles (IJs) of entomopathogenic nematodes (EPNs) relies on host-derived compounds, but in a tri-trophic context, herbivore-induced root volatiles act as signals enhancing the biological control of insect pests by recruiting EPNs. In southern Chile, the EPN Steinernema australe exhibits the potential to control the raspberry weevil, Aegorhinus superciliosus, a key pest of blueberry Vaccinium corymbosum. However, there is no information on the quality of the blueberry root volatile plume or the S. australe response to these chemicals as putative attractants. Here, we describe the root volatile profile of blueberries and the chemotaxis behavior of S. australe towards the volatiles identified from Vaccinium corymbosum roots, infested or uninfested with A. superciliosus larvae. Among others, we found linalool, α-terpineol, limonene, eucalyptol, 2-carene, 1-nonine, 10-undecyn-1-ol, and methyl salicylate in root volatiles and, depending on the level of the emissions, they were selected for bioassays. In the dose–response tests, S. australe was attracted to all five tested concentrations of methyl salicylate, 1-nonine, α-terpineol, and 2-carene, as well as to 100 µg mL−1 of 10-undecyn-1-ol, 0.1 and 100 µg mL−1 of linalool, and 100 µg mL−1 of limonene, whereas eucalyptol elicited no attraction or repellency. These results suggest that some volatiles released from damaged roots attract S. australe and may have implications for the biocontrol of subterranean pests.

Insects as food and medicine: a sustainable solution for global health and environmental challenges.

Insects are a significant source of food for millions of people worldwide. Since ancient times, insects in medicine have been contributing to the treatment of diseases in humans and animals. Compared to conventional animal farming, the production of insects for food and feed generates significantly less greenhouse gas emissions and uses considerably less land. Edible insects provide many ecosystem services, including pollination, environmental health monitoring, and the decomposition of organic waste materials. Some wild edible insects are pests of cash crops. Thus, harvesting and consuming edible insect pests as food and utilizing them for therapeutic purposes could be a significant progress in the biological control of insect pests. Our review discusses the contribution of edible insects to food and nutritional security. It highlights therapeutic uses of insects and recommends ways to ensure a sustainable insect diet. We stress that the design and implementation of guidelines for producing, harvesting, processing, and consuming edible insects must be prioritized to ensure safe and sustainable use.

Laboratory assessment on compatibility of entomopathogenic fungus, <i>Beauveria bassiana</i> Balsamo-vuillemin with imidacloprid 48% FS for bhendi (<i>Abelmoschus esculentus</i> L. moench) seed treatment

Beauveria bassiana (Balsamo-Vuillemin), an effective entomopathogenic fungi is well positioned in the biological control of insect pests for more than ten decades around the world. Its potential can be attributed to the fungus’s entry through several parts of the insect and its mode of action. But sometimes a virulent strain of B. bassiana may become ineffective because of xenobiotics and environmental factors. To enhance the efficacy of B. bassiana, which is necessary for placing it in Integrated Pest Management, the Colony Forming Unit (CFU) of B. bassiana should be compatible with xenobiotics used in crop production. The compatible concentrations of imidacloprid 48% FS (500 ppm) for B. bassiana was studied in the laboratory condition and results revealed low per cent growth inhibition (21.25%) and maximum radial growth (1.46 cm) at 15 Days After Inoculation (DAI). The inhibition of colony growth was reduced by treating the bhendi seeds with B. bassiana and imidacloprid 48 % FS at a time interval of four hours which showed high mean colony growth (51.12).

Selectivity of Bacillus thuringiensis (Bacillales: Bacillaceae) to the polyphagous predator Ceraeochrysa claveri (Navás, 1911) (Neuroptera: Chrysopidae)

AbstractBioinsecticides based on Bacillus thuringiensis (Bt) are widely used to control agricultural pests. However, there are concerns about their impact on non‐target organisms, with for example, the green lacewing Ceraeochrysa claveri, a polyphagous predator with important value in the biological control of insect pests in agroecosystems. This study aimed to analyse the effects of Agree® bioinsecticide (containing Bt serovar aizawai GC‐91) on the post‐embryonic development of C. claveri. For this, neonate larvae of C. claveri were fed with Diatraea saccharalis eggs contaminated with different concentrations of Agree® (0.62, 1.25, 2.50 and 5.00 g L−1) until their pupation. Samples of the midgut of larvae were collected for histological and ultrastructural analysis. The larval and pupal inviability data were collected at the end of the respective developmental stages. After the emergence of adult insects, were considered inviable those with morphological alterations. To evaluate the reproduction, adult insect couples were formed, and the oviposition was collected. No significant differences in the viability of eggs, larvae, pupae and adults of C. claveri contaminated with Agree® were reported. Midgut analyses did not reveal cellular damage in the epithelium, indicating a possible lack of insecticidal proteins receptors. The oviposition and their viability were similar between treated and control groups. Our results demonstrated that Agree® bioinsecticide did not affect the post‐embryonic development of C. claveri. This illustrates that the combined use of Bt and C. claveri for the biological control of arthropod pests can be a sustainable strategy for integrated pest management.

Structural changes upon membrane insertion of the insecticidal pore-forming toxins produced by Bacillus thuringiensis.

Different Bacillus thuringiensis (Bt) strains produce a broad variety of pore-forming toxins (PFTs) that show toxicity against insects and other invertebrates. Some of these insecticidal PFT proteins have been used successfully worldwide to control diverse insect crop pests. There are several studies focused on describing the mechanism of action of these toxins that have helped to improve their performance and to cope with the resistance evolved by different insects against some of these proteins. However, crucial information that is still missing is the structure of pores formed by some of these PFTs, such as the three-domain crystal (Cry) proteins, which are the most commercially used Bt toxins in the biological control of insect pests. In recent years, progress has been made on the identification of the structural changes that certain Bt insecticidal PFT proteins undergo upon membrane insertion. In this review, we describe the models that have been proposed for the membrane insertion of Cry toxins. We also review the recently published structures of the vegetative insecticidal proteins (Vips; e.g. Vip3) and the insecticidal toxin complex (Tc) in the membrane-inserted state. Although different Bt PFTs show different primary sequences, there are some similarities in the three-dimensional structures of Vips and Cry proteins. In addition, all PFTs described here must undergo major structural rearrangements to pass from a soluble form to a membrane-inserted state. It is proposed that, despite their structural differences, all PFTs undergo major structural rearrangements producing an extended α-helix, which plays a fundamental role in perforating their target membrane, resulting in the formation of the membrane pore required for their insecticidal activity.

Diversidad de Insectos en Maíz en la Comarca Lagunera, México

Maize, Zea mays L., is of great economic, social, and cultural importance in Mexico. Its agroecosystem has phytophagous and entomophagous insects. Diversity in the Comarca Lagunera was studied in 2020 and 2021. Thirty-eight species of predators and parasitoids were found, with most common being Bariscapus sp., Orius leavigatus, Tetrastichus sp., Hippodamia convergens, Chrysoperla sp., and Collops vittatus. This complex of entomophagous insects is important for natural biological control of pest insects. Twenty-six species of phytophagous insects were also found, the most common being Chaetocnema ectypa, Diabrotica balteata, Rhopalosiphum maidis, and Dalbulus maidis. This complex of phytophagous insects may be important as a limiting factor of maize productivity or be potential pests. Based on values of the diversity indices of Margalef, Simpson and Shannon-Wiener, diversity of entomophagous insects was more at the beginning of the crop-growing season, while diversity of phytophagous insects was greater mid to late; diversity of entomofauna in maize was intermediate.