Biological Pest Control Agents Research Articles

Tritrophic Interactions Mediated by Zoophytophagous Predator-Induced Host Plant Volatiles.

The zoophytophagous mirid predator Nesidiocoris tenuis and the ectoparasitoid Stenomesius japonicus are important biological control agents for several agricultural pests including the invasive leafminer, Phthorimaea absoluta, a destructive pest of Solanaceous crops especially tomato in sub-Saharan Africa. However, little is known about how feeding by N. tenuis can influence the tritrophic interactions in the tomato plant. Here, we tested the hypothesis that N. tenuis phytophagy would influence the tritrophic olfactory interactions between the host plant tomato and pest, predator, and parasitoid. In olfactometer assays, P. absoluta females and N. tenuis adults were both attracted to constitutive volatiles released by the tomato plant. Whereas females of P. absoluta avoided volatiles released by N. tenuis-infested plants, S. japonicus females and N. tenuis adults were attracted to the induced volatiles. In coupled gas chromatography-electroantennographic detection (GC-EAD) recordings of intact and N. tenuis-infested plant volatiles, antennae of P. absoluta and S. japonicus females both detected eight components, whereas N. tenuis adults detected seven components which were identified by GC-mass spectrometry (GC-MS) as terpenes and green leaf volatiles (GLVs). Dose-response olfactometer bioassays revealed that the responses of P. absoluta, N. tenuis, and S. japonicus varied with the composition and concentration of blends and individual compounds tested from N tenuis-induced volatiles. Females of P. absoluta showed no preference for an eight-component blend formulated from the individual repellents including hexanal, (Z)-3-hexenyl butanoate, and δ-elemene identified in the volatiles. On the other hand, S. japonicus females were attracted to an eight-component blend including the attractants (E)-2-hexenal, (Z)-3-hexenol, methyl salicylate, β-phellandrene, and (E)-caryophyllene. Likewise, N. tenuis adults were attracted to a seven-component blend including the attractants β-phellandrene, δ-elemene, and (E)-caryophyllene identified in the volatiles. Our findings suggest that there is potential for the use of terpenes and GLVs to manage the insects in the tritrophic interaction.

Distribution and accumulation of Cadmium in different trophic levels affecting Serangium japonicum, the predatory beetle of whitefly Bemisia tabaci, biologically, physiologically and genetically: An experimental study

Cadmium (Cd) is a heavy metal that is of great concern in agroecosystems due to its toxicity to plants, herbivores, carnivores, and human beings. The current study evaluated the allocation and bioaccumulation of Cd from soil to cotton plants, cotton plants to herbivore pests, and herbivorous pests to a natural enemy predator. When soil was spiked with 100 mg/kg Cd, results demonstrated that cotton roots accumulated more Cd than the stems and leaves. The bioaccumulation of Cd was less in 4th instar larvae, pupa, and adults of Serangium japonicum than in Bemisia tabaci adults. The bioaccumulation in S. japonicum elongated the immature development period and reduced adult longevity, oviposition days, fertility, and total pre-oviposition duration. The net reproduction of S. japonicum was also reduced, as was female mature weight and feeding potential; as a result, Cd exposure could reduce the future population size compared to uncontaminated populations. There was decreased activity of the antioxidant enzymes (SOD, CAT, and POD) and energy-conserving lipids (glycogen, triglyceride, and total cholesterol) in Cd-contaminated S. japonicum compared to controls. The detoxifying enzyme activity of GST and P450 increased while AChE activity did not change. The qRT-PCR research showed that SOD1, CAT, POD, glycogen, and triglyceride gene expression was higher than in controls, whereas detoxification gene expression did not change. Our results indicate that Cd exposure has a physiological trade-off between its adverse effects on life history traits and elevated detoxification and antioxidation of S. japonicum, which could result from gene expression alteration. Further studies are needed to assess whether Cd exposure causes irreversible DNA damage in S. japonicum.

Predation evaluation of the green lacewing, Chrysopa pallens on the pink tea mite pest, Acaphylla theae (Watt) (Acarina: Eriophyidae).

A better understanding of predator-prey interactions is crucial for the development of biological control strategies. The green lacewing, Chrysopa pallens, is a well-known generalist predator and reportedly functions as one of the most important biological control agents of insect pests. However, information regarding C. pallens' predation on tea plant pests, particularly notorious tea mites, remains largely unknown. In this study, we focused on the predator-prey relationship between C. pallens and an important tea mite pest, Acaphylla theae. We designed species-specific primers for the detection of A. theae DNA and established a PCR-based DNA gut content analysis assay. These results demonstrated that the primers were A. theae-specific and suitable for its molecular identification. The laboratory feeding experiment showed that the detectability success (DS50) of A. theae DNA remaining in C. pallens' guts was 2.9h. We then performed a molecular detection of field predation, and achieved a 23.53% positive detection rate of A. theae DNA in the guts of field-collected C. pallens. This, for the first time, provides direct evidence that C. pallens can prey on A. theae in tea plantations. Finally, we tested the prey preference and estimated the predation ability of C. pallens on different developmental stages of A. theae. The results revealed that C. pallens had no significant preference for different developmental stages of A. theae. The functional responses of C. pallens' predation on different densities of A. theae at different developmental stages followed a Type II Holling model. The initial attack rate (a') ranged from 0.735 to 0.858 and the handling time (Th) was approximately 0.01. This study is the first to demonstrate the trophic interactions between C. pallens and A. theae and provides evidence for the development of biological control strategies against A. theae using C. pallens as a candidate predator.

The effects of temperature on pathogenicity of entomopathogenic fungi for controlling larval populations of the European grapevine moth (Lobesia botrana) (Lepidoptera: Tortricidae)

The European grapevine moth (Lobesia botrana) is currently the most damaging pest in many viticultural regions of South and Central Europe and is highly responsible for the development of secondary infections by Botrytis cinerea to both table and wine grapes. Entomopathogenic fungi (EPF) are considered as substantial biological control agents of insect pests. However, they are able to infect their hosts only under a narrow spectrum of environmental conditions. In this study, the effects of temperature on pathogenicity of EPF for the control of L. botrana are reported. Among a collection of 33 EPF isolates, six virulent isolates were selected for the experiments. The bioassays took place at controlled conditions, under the temperature regimes of 20, 22.5, 25, 27.5, 30, and 32.5 °C. A conidial concentration of 1 × 108 conidia/ml was prepared for each isolate, and fungi were applied by spraying them on third-instar larvae (L3) of L. botrana. Both factors, fungal isolate and temperature, significantly affected mortality of L. botrana. Most fungal isolates exhibited their highest larval mortality rates seven days post-treatment at the temperatures of 25 and 27.5 °C. Some isolates caused considerably high larval mortality that exceeded 90% under specific temperature conditions. Overall, EPF showed great potential as bio-control agents for controlling larval populations of L. botrana.

Host-foraging strategies of five local entomopathogenic nematode species in South Africa

Entomopathogenic nematodes (EPNs) are obligate parasites of soil-dwelling insects and are used as biological control agents for many insect pests. These nematodes have a free-living third growth stage called infective juveniles (IJs), which are responsible for foraging and infecting suitable insect hosts. Infective juveniles exhibit three host-foraging strategies: cruising, ambushing, and intermediate foraging strategies. The foraging strategy of EPNs is important for successful infection but is poorly understood. The current study investigated the host-foraging strategies of five local South African EPN species including Heterorhabditis noenieputensis, H. safricana, Steinernema fabii, S. jeffreyense, and S. yirgalemense by assessing their dispersal behavior. Of the five EPN species, H. noenieputensis, H. safricana, S. jeffreyense, and S. yirgalemense showed a positive response to the presence of the wax moth larvae, whereas S. fabii showed a negative response. The four EPN species that showed a positive response to the presence of the host also caused 100% mortality of wax moth larvae that were buried in sand at a depth of 10 cm, whereas S. fabii caused the lowest mortality of 34%. The average distance traveled by all five EPN species decreased on rough textured substrate compared with smooth textured substrate. The observed behavioral patterns suggested that H. noenieputensis, H. safricana, S. jeffreyense, and S. yirgalemense use a cruiser foraging strategy whereas S. fabii uses an ambusher foraging strategy.

T6SS: A Key to Pseudomonas's Success in Biocontrol?

Bacteria from the genus Pseudomonas have been extensively studied for their capacity to act as biological control agents of disease and pests and for their ability to enhance and promote crop production in agricultural systems. While initial research primarily focused on the human pathogenic bacteria Pseudomonas aeruginosa, recent studies indicate the significance of type VI secretion (T6SS) in other Pseudomonas strains for biocontrol purposes. This system possibly plays a pivotal role in restricting the biological activity of target microorganisms and may also contribute to the bolstering of the survival capabilities of the bacteria within their applied environment. The type VI secretion system is a phage-like structure used to translocate effectors into both prokaryotic and eukaryotic target cells. T6SSs are involved in a myriad of interactions, some of which have direct implications in the success of Pseudomonas as biocontrol agents. The prevalence of T6SSs in the genomes of Pseudomonas species is notably greater than the estimated 25% occurrence rate found in Gram-negative bacteria. This observation implies that T6SS likely plays a pivotal role in the survival and fitness of Pseudomonas. This review provides a brief overview of T6SS, its role in Pseudomonas with biocontrol applications, and future avenues of research within this subject matter.

Screening five local entomopathogenic nematode species for their virulence against pupae of the Eucalyptus snout beetle, Gonipterus sp. n. 2, under laboratory conditions

The Eucalyptus snout beetle, Gonipterus sp. n. 2, is an important pest of eucalypt trees in South Africa and other countries. The pest is partially controlled with a mymarid egg parasitoid, Anaphes nitens. Identifying additional biological control agents that target other developmental stages of Gonipterus sp. n. 2 is necessary to improve control. Entomopathogenic nematodes (EPNs) are used as biological control agents for numerous soil pests and thus have the potential to be used against the pupal stage of Gonipterus sp. n. 2, which occurs in the soil. In this study, five South African EPN species were screened for their virulence on uncased pupae of Gonipterus sp. n. 2. At a concentration of 200 IJs/pupa in 50 μl of sterile water, Steinernema jeffreyense, S. fabii, Heterorhabditis noenieputensis and H. safricana caused pupal mortality of less than 40 %, while S. yirgalemense caused the highest pupal mortality of 100 % two days post-inoculation. Steinernema yirgalemense was selected and applied at different concentrations, namely 0, 12, 25, 50, 100, 200, and 400 IJs/pupa to determine its lethal concentration. Probit analysis indicated that the LC50 and LC90 of S. yirgalemense were 48.29 and 260.63 IJs/pupa, respectively. The study also showed that the pupal cases do not affect the efficacy of S. yirgalemense as it caused more than 90 % mortality of cased pupae of Gonipterus sp. n. 2 in soil bioassays. In addition, pupal age did not affect the efficacy of S. yirgalemense. Based on our findings, S. yirgalemense is a potential candidate for the biological control of pupae of Gonipterus sp. n. 2.

Mining biodiversity databases establishes a global baseline of cosmopolitan Insecta mOTUs: a case study on Platygastroidea (Hymenoptera) with consequences for biological control programs

In the past decade, several species of platygastroid wasps were found to be adventive in North America and Europe while under evaluation in quarantine as biological control agents of invasive pests. The scope and relative risk of this phenomenon is not fully known, but it is clearly a trend with implications for classical biological control. As a means of assessing the issue and to provide a global baseline, we implemented a data-mining approach with DNA sequences in the Barcode of Life Database, yielding 201 platygastroid BINs with intercontinental and island distributions. At least fifty-five BINs displayed exact COI barcode matches across continents, with many more BINs scored as inconclusive due to sequence length variation. These intercontinental and island BINs include biocontrol agents known to be adventive, as well as many species identified only to genus with uncertain geographic origins. We provide 2,500 identifications for platygastroid BOLD BINs, 88% to genus, to encourage additional research on this distributional phenomenon. The intercontinental BOLD BINs were compared to literature records and GBIF occurrences of cosmopolitan species to identify gaps and discordance across data sources. Smaller COI barcode datasets from localities in Florida and Germany, including topotypical specimens, revealed more intercontinental matches. We analyzed COI sequences in BOLD for the entirety of Insecta and Araneae to assess this phenomenon more broadly and because these taxa contain many hosts for platygastroid wasps. This method revealed that the intercontinental distribution phenomenon is widespread with implications for assessing biological diversity, taxonomic methodology and regulatory frameworks.

The indigenous species of predatory mites (Acari: Phytoseiidae) as biological control agents of plant pests in Slovenia

Phytoseiid mites are of great importance for the biological control of spider mites, thrips, and whiteflies. In this article, we present six species of predatory mites from the family Phytoseiidae, which are included in the list of indigenous organisms for biological control in Slovenia. These species are Amblyseius andersoni, Neoseiulus californicus, N. barkeri, N. cucumeris, Euseius gallicus, and Typhlodromus pyri. Being included in the list mentioned above, these species have great potential to be used in biological control and are technically qualified sources for the management of several pest species in agricultural production in Slovenia. Detailed information about the feeding habits, food preferences, and biological control potentials of these species is presented herein.

A Study on the Evaluation of Pesticides for the Conservation of Wooden Cultural Heritages

Although no regulations specify safety and performance evaluations for biological pest control agents used on wooden cultural artifacts, the revised 2019 Cultural Heritage Repair Standards state that the agents used on cultural artifacts must be approved by the National Institute of Environmental Sciences. In addition, the performance evaluations of these agents should comply with the performance standards specified in the Korean Forestry Promotion Institute Standard Test Method, as stated in the standards. This study performed performance evaluations on one type of agent currently used for biological pest control on wooden cultural artifacts and two types of imported wood preservative products on the domestic market. For performance evaluation, we conducted tests for decay resistance, termite resistance, mold resistance, corrosion resistance, and moisture absorption, and analyzed residue levels of active ingredients through outdoor exposure tests to confirm the persistence of the biocide during natural weathering processes. The results of this study aim to summarize the testing procedures and methods for performance evaluation, identify areas for improvement, and utilize the test results as a basis for establishing standards for the evaluation of biocidal agents.

Virulence and Reproduction of Entomopathogenic Nematodes Isolated from a Single Mexican Locality

Abstract Entomopathogenic nematodes (EPNs) are important biological control agents of insect pests. Strains or isolates obtained in specific regions and utilized in situ might contribute to the success of EPNs, since they are adapted to local abiotic conditions. We isolated and identified three isolates each of Heterorhabditis bacteriophora Poinar and Steinernema carpocapsae (Weiser) from soils at Saltillo, Coahuila State, Mexico. These six isolates were bioassayed against larvae of Tenebrio molitor L., using six concentrations of infective juveniles (IJs) per larva (0, 10, 25, 50, 100, 200). EPN-induced mortality of the isolates ranged from 15.2% to 100%. The designated M5 isolate of S. carpocapsae caused 100% mortality after 72 h at concentrations ≥25 IJs/larva with a median lethal concentration of 4.99 IJs/larva. Comparison of mortality levels induced at the same concentration of the six EPN isolates indicated that the Steinernema isolates, in general, induced higher mortality levels than the Heterorhabditis isolates. IJ production in T. molitor larvae also was greatest with the M5 isolate of S. carpocapsae following exposure of larvae to a concentration of 100 IJs/larva with a mean of 17,320 IJs/larva. Based on induced mortality and IJ production, the S. carpocapsae M5 isolate appears to be a viable candidate for further study and possible development for use in insect pest management programs. This study indicates that naturally coexisting local nematode isolates possess different attributes critical for their use as biocontrol agents.

Predation potential and life history of three nabid species as biological control agents of pests in Canadian greenhouses

Nabids are hemipteran generalist predators commonly associated with agroecosystems. In this study, the predation rate of Nabis americoferus Carayon, N. roseipennis Reuter, and Hoplistoscelis pallescens Kerhzner on several common greenhouse pests was assessed in the laboratory, compared to the most closely related commercially available predator in North America, Dicyphus hesperus Knight (Heteroptera: Miridae). In addition, life history parameters of the nabids were determined to estimate their capacity for population increase, an important data set when considering their mass rearing and population establishment in crops. Our results showed that the three nabid species are generally more voracious predators than D. hesperus, especially when fed adult green peach aphids, adult western flower thrips and adult greenhouse whiteflies. Dicyphus hesperus preyed more on two spotted spider mites and greenhouse whitefly nymphs. Nabis americoferus consumed more western flower thrips larvae than all other species. Of the three nabids, N. americoferus also performed significantly better as a predator of western flower thrips. Additionally, N. americoferus had a significantly shorter egg to adult development time, and had a shorter pre-oviposition period than the other two species. Based on its predation capacity and favourable life history characteristics, N. americoferus was selected for further development as a new biological control agent for the North American market.

Testing a modified version of the EPPO decision-support scheme for release of classical biological control agents of plant pests using Ganaspis cf. brasiliensis and Cleruchoides noackae as case studies

The 6/04 standard of the European and Mediterranean Plant Protection Organisation (EPPO) on the safe use of biological control is a decision-support scheme (DSS) for the import and release of biological control agents in Europe. It was recently developed by the Joint EPPO/International Organisation of Biological Control (IOBC) Panel on Biological Control Agents. The DSS can be used to assess the potential environmental impacts of biological control agents. It is valid for different types of biological control: classical and augmentative biological control of invertebrates, pathogens and weeds. However, the DSS is not yet widely implemented in Europe and, during preliminary trials, it was found that its broad range of usages could lead to some confusion or misunderstandings, as well as requiring unnecessary information in some cases. Thus, the scheme was modified to specifically assess classical biological control against plant pests, i.e. the introduction of exotic natural enemies of plant pests for establishment and long-term control. The new version of the scheme was then tested on two parasitoids that are presently being released in Europe, the figitid Ganaspis cf. brasiliensis against the spotted wing drosophila Drosophila suzukii and the mymarid Cleruchoides noackae against the Eucalyptus bronze bug Thaumastocoris peregrinus. Both parasitoids were successfully assessed with the new version of the DSS. No major issues were encountered during the assessments and most questions were answered with low levels of uncertainty. Both assessments concluded that the parasitoids were safe to release in the impact assessment areas, with positive impacts exceeding negative impacts. Suggestions for potential improvements are provided.

Identification and functional characterization of eight novel tpp family genes from Bacillus thuringiensis.

Bacillus thuringiensis (Bt) and its transgenic crops are widely used as biological control agents for agricultural pests. The tpp family is a branch of Bt insecticidal genes and consists of a few members. Research on the Tpp family proteins has focused on the binary toxins Gpp34Ab/Tpp35Ab and Tpp1/Tpp2, which need to function together to achieve insecticidal activity. However, only a few tpp family genes have been reported to exert insecticidal activity independently. This study aimed to identify and characterize tpp family genes that independently perform insecticidal functions. A total of 162 nucleotide sequences homologous to the single component Bt insecticidal gene tpp78Aa were obtained from the genome data of 1368 wild-type Bt strains, and 25 new full-length tpp family genes were identified. Eight new tpp family genes were successfully cloned and expressed, and bioassays of the expressed products were performed against five different pests. Bioassay results showed that these proteins exerted high insecticidal activity only against Laodelphax striatellus, a globally important rice pest, and were named Tpp78Ab1, Tpp78Bb1, Tpp78Ca1, Tpp78Da1, Tpp80Aa3, Tpp80Ac1, Tpp80Ad1, and Tpp80Ae1. The LC50 values of Tpp78Ab1, Tpp78Bb1, Tpp78Ca1, and Tpp80Ae1 against L. striatum were 8.1, 8.6, 10.1, and 9.6 μg mL-1 , respectively. The phylogenetic tree and conserved motifs indicated that the Tpp family had a common evolutionary ancestor. During evolution, the C-terminal pore-forming domain of the Tpp family adopted a similar arrangement; however, the N-terminal conserved motif showed high variability. Twenty-five full-length tpp family genes were identified. Eight new tpp family genes were cloned successfully, which could independently achieve insecticidal activity against L. striatellus. This provides abundant genetic resources for the biological control of important rice pests. In this study, we found that the relative conservation of the Tpp family proteins in the lengthy evolutionary process and the diversity generated for adapting to the environment can lay a theoretical foundation for an in-depth analysis of the function and evolution of the Tpp family. © 2023 Society of Chemical Industry.

New records of phytoseiid mites (Acari: Phytoseiidae) on solanaceous plants in the Syrian coastal region

Phytoseiid mites have been considered the most promising predators for the control of pest mites and small insects. Their use in solanaceous crops for the biological control of major mite pests represents an important challenge and requires continued research. This study aimed at investigating the phytoseiid species and their associated phytophagous mites on eggplant (Solanum melongena), tomato (Solanum lycopersicum) and black nightshade (Solanum nigrum) in the Syrian coastal region between 2018 and 2020, at 40 sites. A total of 12 species of the three subfamilies (Amblyseiinae Muma, Phytoseiinae Berlese, and Typhlodrominae Scheuten) were collected, with Amblysiinae being the most represented. Among them, Amblyseius andersoni (Chant) is a new record for the Syrian fauna. Phytoseiulus persimilis Athias-Henriot was the most abundant (223 specimens; 47.3%) and frequent (found in 22 out of 40 sites) species collected on all plant species surveyed and the only common phytoseiid species in greenhouses. The second most abundant species was Neoseiulus californicus (McGregor) (83 specimens: 17.6%), while the second most frequent was Phytoseius finitimus Ribaga (8 sites). Species found in this study should be considered in future research on phytoseiid mites as biological control agents of pests of tomato and eggplant cultivated in greenhouses and open fields in this region.

Barn Owls Can Decrease Pesticide Use

Rodents are a danger to farmers because they damage farm crops. For the last 100 years, chemical pesticides have been used to kill rodents, but these chemicals harm the ecosystem, humans, and all sorts of wildlife, including migratory birds. Barn owls may be a solution! These nocturnal birds of prey are common over most of the world and can act as biological pest-control agents. Barn owls nest near and in farm fields and specialize in hunting rodents—a pair of barn owls eliminates 2,000–6,000 rodents per year. A project using barn owls for rodent control began in Israel in 1983, with the placement of 14 nesting boxes. Today, there are about 5,000 nesting boxes throughout Israel, and the use of harmful pesticides has decreased by more than 50%. Several other countries have also joined, or plan to join, the project. This project is a unique method that promotes a healthier environment and can connect nations, farmers, researchers, and conservationists.

Two-Sex Life Table Analysis of the Predator Arma chinensis (Hemiptera: Pentatomidae) and the Prediction of Its Ability to Suppress Populations of Scopula subpunctaria (Lepidoptera: Geometridae)

Scopula subpunctaria (Herrich-Schaeffer) (Lepidoptera: Geometridae) is a leaf-eating pest in tea plantations that often causes serious economic losses. Arma chinensis (Fallou) (Hemiptera: Pentatomidae) as a polyphagous insect has become one of the main biological control agents for tea plantation pests due to its wide feeding habit, predatory ability, and adaptability. However, studies related to the predation using A. chinensis on the third instar S. subpunctaria have not been reported. In this study, we used the age-stage, two-sex life table method to analyze the developmental duration and fecundity of S. subpunctaria fed on tea, and A. chinensis fed on third instar S. subpunctaria larvae, under a 25 °C regime. The growth, development, survival, fecundity, and predation rates of the insect populations were investigated. The results showed that the predator and the prey can complete their respective life histories, but the developmental durations at each stage were different, and the developmental stages overlapped significantly. In addition, we used the computer program TIMING-MSChart to project the stage structure and the total population size of A. chinensis and S. subpunctaria. We also simulated the population changes of S. subpunctaria using an A. chinensis intervention. These results showed that S. subpunctaria can support A. chinensis to finish its life history and A. chinensis has great potential to control S. subpunctaria. This study contributes to the understanding of the biological characteristics of S. subpunctaria and provides a theoretical basis for releasing A. chinensis in the field to suppress S. subpunctaria.

Activation of MAPK signaling pathway genes leads to promoted thermotolerance in a high-temperature adapted predatory mite Neoseiulus barkeri (Hughes)

Predatory mites are important biological control agents for phytophagous mites and several small insect pests on vegetables, while the control efficiency is often limited by the changeable or fluctuating environment, especially under the threat of global warming. To mitigate the undesired impacts of high temperature environment, a high-temperature adapted strain (HTAS) of the predatory mite Neoseiulus barkeri (Hughes) was screened from a conventional strain (CS) by long-term heat acclimation (35°C) and regular heat hardenings (45°C). In this study, to investigate the molecular mechanisms of enhanced thermotolerance in HTAS N. barkeri, four mitogen-activated protein kinase (MAPK) pathway genes were identified from the predatory mite N. barkeri. The expression levels at different developmental stages showed four MAPK pathway genes were highest at adults and lowest at eggs or nymphs in both strains. Under 42℃ high temperature stress, the expression levels of four identified MAPK pathway genes increased rapidly at a short time in both N. barkeri strains and the magnitude of expression increase in HTAS N. barkeri was even more evident. In addition, the MAPK pathway genes expression in CS N. barkeri sharply decreased following longer exposure periods at 4 h, whereas the expression in HTAS N. barkeri remained elevated after 4 h. These results suggested that MAPK signaling pathway participated in the formation of thermotolerance in predatory phytoseiid mites, which provided new insights in promoting the biological control efficiency of predatory mites under changeable environment.

PRESENCIA DE HONGOS ENTOMOPATÓGENOS ASOCIADOS A SUELOS CULTIVADOS CON AGUACATE (Persea americana Mill.) EN COLIMA, MÉXICO

<p><strong>Background: </strong>Entomopathogenic fungi (EF) play a key role in the regulation of arthropod populations and biotransformation in natural systems, as well as biological pest control agents in different agroecosystems, including avocado cultivation (<em>Persea americana</em> Mill.), where Mexico is a leader in production and export worldwide.<strong> Objective</strong>: Determine the presence of EF in soil in commercial avocado orchards in the state of Colima, Mexico. <strong>Methodology</strong>: Sampling was carried out in three avocado orchards (Piedra rajada, El Guardián, and Montitlán) located in Comala and Cuauhtémoc in the state of Colima, Mexico, from July 2016 to June 2017. Soil samples were collected around avocado trees. Isolation of entomopathogenic fungi was performed using the <em>Galleria mellonella</em> Linnaeus insect trap technique. The isolates were identified considering their micro- and macroscopic characteristics with the taxonomic keys of Humber (2012). <strong>Results</strong>: A total of 108 samples were collected, of those, 120 isolates were obtained, of which 112 belong to the genus <em>Metarhizium</em> and eight to <em>Beauveria</em>. <strong>Implications</strong>: The recovered fungi have a great value for the avocado-growing areas of the state of Colima, either for the conservation of natural enemies of soil pests or for their potential use as an alternative to synthetic insecticides. <strong>Conclusion</strong>: Knowing the native micro-biota of the soil should be considered within biological pest control strategies, since it allows selecting the best adapted species, and including sustainable alternatives for the environment. </p>

Half a century of evolutionary games: a synthesis of theory, application and future directions.

Half a century of evolutionary games: a synthesis of theory, application and future directions.