Pest Control Agents Research Articles

Altitudinal variability in chemical profile and pesticidal properties of Zingiber roseum (Roxb.) Roscoe extracts

Plant extracts are considered as a promising alternative to chemical pest control agents. The chemistry of plant extracts varies with several environmental as well as geographical factors. Zingiber roseum (Roxb.) Roscoe also known as “Rosy Ginger” and “Jangli Adrak” is one of the most important aromatic and medicinal plant of family Zingiberaceae. The present study aimed to investigate the impact of altitude on the chemical composition, nematicidal and herbicidal activity of Z. roseum rhizome and seed extracts. The plants were collected from three different altitudes of Kumaun, Uttarakhand representing different environmental conditions. The extracts were prepared in acetone using cold percolation method. The compositional variation in chemical constituents of the extracts was determined by gas chromatography-mass spectrometry (GC–MS) analysis. The yield and chemical composition of extracts showed a significant altitudinal impact. Nematicidal activity of extracts was performed against Meloidogyneincognita. Results showed that the extracts exhibited significant nematode mortality irrespective of the altitudinal gradients. A significant correlation of altitudinal gradient was observed for the nematode egg hatchability reduction for the rhizome extracts. It was observed that plants growing at higher altitudes had better egg hatchability reduction (86.42 ± 2.30% at 1000 μg/mL after 96 h), compared with those growing at lower elevations. The herbicidal activity of rhizome and seed extracts was performed against radish and chicory seeds and the extracts showed different level of intensity of germination percentage, root and shoot length inhibition. In silico molecular docking was conducted to screen the nematicidal activity of major and potent compounds with the crystalline structure of Glutathione S-transferases (GSTs) of Caenorhabditis elegans and Wuchereria bancrofti, and Glutathione S-transferase-1 (GST-1) of M. incognita. Based on the current study, extract of Z. roseum may be regarded as potential nematicidal and herbicidal agents and may have potential application as botanicals.

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.

Biotic and abiotic factors shaping bat activity in Maryland soybean fields

AbstractBats are important pest control agents in agriculture. Yet, the underlying fine‐scale biotic and abiotic mechanisms that drive their foraging behaviors and responses to insect outbreaks are unclear. Herbivore‐induced plant volatiles (HIPVs) can attract both invertebrate and vertebrate natural enemies that use the chemical plant cues to locate insect prey. The ability of HIPVs to attract multiple species raises the question of whether they may also be a biotic factor influencing insectivorous bat activity. Additionally, abiotic factors, such as weather conditions, can affect bat activity in agricultural settings, but little is known about how bats respond to shifting environmental conditions on short timescales in this landscape context. Using a model crop system, soybean (Glycine max), our study asked three questions: (1) Which bat species are active in eastern Maryland soybean fields? (2) Is insectivorous bat activity affected by naturally occurring soybean HIPVs and/or synthetic soybean HIPVs (indole or farnesene)? (3) How is insectivorous bat activity affected by hourly weather conditions in this landscape? In soybean fields in eastern Maryland, we created paired treatment plots: HIPV plots (damaged plants or synthetic HIPV dispensers) and control plots (undamaged plants or empty dispensers). We measured bat activity using ultrasonic recorders, summarizing hourly and nightly activity, and detected 10 total species. The most abundant species were big brown/silver‐haired bats (Eptesicus fuscus/Lasionycteris noctivagans). Bat activity did not significantly differ between control and HIPV plots in any of the three experiments. Thus, our results do not support our expectation that bats in eastern Maryland use soybean HIPVs to locate insect prey. However, bat activity did increase with increasing average hourly temperature and wind speed. This initial study of bats and HIPVs, as well as the fine‐scale examination of weather conditions on bat activity, may serve as a guide for future research on bat–plant interactions that can support the development of new strategies for sustainable pest management.

Comparative analysis of adipokinetic hormones and their receptors in Blattodea reveals novel patterns of gene evolution.

Adipokinetic hormone (AKH) is a neuropeptide produced in the insect corpora cardiaca that plays an essential role in mobilising carbohydrates and lipids from the fat body to the haemolymph. AKH acts by binding to a rhodopsin-like G protein-coupled receptor (GPCR), the adipokinetic hormone receptor (AKHR). In this study, we tackle AKH ligand and receptor gene evolution as well as the evolutionary origins of AKH gene paralogues from the order Blattodea (termites and cockroaches). Phylogenetic analyses of AKH precursor sequences point to an ancient AKH gene duplication event in the common ancestor of Blaberoidea, yielding a new group of putative decapeptides. In total, 16 different AKH peptides from 90 species were obtained. Two octapeptides and seven putatively novel decapeptides are predicted for the first time. AKH receptor sequences from 18 species, spanning solitary cockroaches and subsocial wood roaches as well as lower and higher termites, were subsequently acquired using classical molecular methods and in silico approaches employing transcriptomic data. Aligned AKHR open reading frames revealed 7 highly conserved transmembrane regions, a typical arrangement for GPCRs. Phylogenetic analyses based on AKHR sequences support accepted relationships among termite, subsocial (Cryptocercus spp.) and solitary cockroach lineages to a large extent, while putative post-translational modification sites do not greatly differ between solitary and subsocial roaches and social termites. Our study provides important information not only for AKH and AKHR functional research but also for further analyses interested in their development as potential candidates for biorational pest control agents against invasive termites and cockroaches.

Tea green leafhopper-induced synomone attracts the egg parasitoids, mymarids to suppress the leafhopper.

The tea green leafhopper, Empoasca flavescens is the most important pest of tea plants in China. Mymarid attractants based on herbivore-induced plant volatiles (HIPVs) from leafhopper feeding and oviposition-induced plant volatiles (OIPVs) were formulated and tested as a novel pest control agent against the leafhopper in tea plantations. Results showed that two mymarid species, Stethynium empoascae and Schizophragma parvula, had a reducing effect on leafhopper populations. The HIPVs and OIPVs were identified and bioassayed to screen the key synomones showing strong attraction to the mymarids. They were formulated into different blends, of which Field Attractant 1, comprising linalool, methyl salicylate, (E)-2-hexenal, perillen and α-farnesene at ratio of 1:2:3:58:146 (20 mg/lure), showed the strongest attraction to the mymarids. In field trials with the attractant, the average parasitism rate (60.46 ± 23.71%) of tea leafhoppers by the two mymarids in the attractant-baited area was significantly higher than that (42.85 ± 19.24%) in the CK area. Also, the average leafhopper density (46 ± 30 per 80 tea shoots) in the attractant-baited area was significantly lower than that (110 ± 70 per 80 tea shoots) in the CK area. This study showed that a synthetic blend of key volatiles from HIPVs and OIPVs at an optimal ratio can be formulated into an attractant with the potential to attract and retain wild mymarid populations to suppress leafhopper populations in infested tea plantations, so as to reduce or avoid the spraying of insecticides. © 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.

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.

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.

Phytophagy of Nesidiocoris tenuis triggers the response of Trichogramma achaeae to tomato plants infested by Tuta absoluta

The generalist predator Nesidiocoris tenuis, an effective biological control agent of numerous pests of the tomato crops, can also trigger plant defence mechanisms (direct and indirect) due to its phytophagous behaviour. In southern Europe, Nesidiocoris tenuis is frequently released in tomato greenhouses to control the invasive pest Tuta absoluta, sometimes combined with another biocontrol agent, the egg parasitoid Trichogramma achaeae. In this study, using olfactometer bioassays, we showed that the modification of the volatile chemical profile induced by the plant feeding activity of the mirid made tomato plants more attractive to T. achaeae, both in the absence and in the presence of T. absoluta eggs or larvae. This result was discussed in relation to difference observed among the chemical profiles of the volatile organic compounds released by tomato plants punctured by N. tenuis, without or in combination with T. absoluta infestation. We found that a few compounds (e.g.β-pinene and myrcene) could play a role in the foraging behaviour of T. achaeae in this scenario. Overall, our data support the emerging idea of an ecological role of N. tenuis, in addition to its predatory activity, in making tomato crops more resilient against the attack of pests, including T. absoluta.

INSECT PESTS OF RICE IN PAKISTAN: A COMPREHENSIVE REVIEW OF BIOLOGY, DAMAGE, AND MANAGEMENT

Rice is one of the most significant food crops in the world. It is predominantly a subsistence crop because half of it is consumed where it is grown. The main insect pests of rice in Pakistan include Stem borers, Plant-hoppers, Leafhoppers, rice grass-hopper, leaf-folder, African pink borers, and many others. There have been noticeable changes in Pakistan’s insect pest complex with the introduction of high-yielding cultivars. Many species that work earlier thought to be minor pests are now regarded as serious pests in Pakistan. In traditional Basmati growing regions, stem borers remain a serious issue. From ancient times, the Pakistani farming community used different management strategies to deal with the insect pests of rice. The management strategies involved are cultural, biological, physical, and chemical. Cultural practices have changed, such as the use of greater fertilizers rates in high-yielding varieties, and the leaf folder complex. Rice growers throughout Pakistan are strongly reliant upon traditional cultural practices. But this tendency has slowly changed towards chemical methods. Chemical pesticides are now used more frequently as a primary method of control in Pakistan. Biological control or the use of living organisms as pest control agents is a common natural process in which insects population in crops are continuously decreased by predators, parasites, and pathogens of the pests. Pakistan now has a problem with insect pests, thus utilizing an integrated pest management (IPM) strategy that is effective, affordable, and safe for the environment. Other techniques for pest control include the use of pheromones as attractants, insect growth regulators, insect growth inhibitors, repellents, and sterile insect release systems.

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.

2D finger-printing and molecular docking studies identified potent mosquito repellents targeting odorant binding protein 1

Personal protection measures against the mosquitoes like the use of repellents constitute valuable tools in the effort to prevent the transmission of vector-borne diseases. Therefore, the discovery of novel repellent molecules which will be effective at lower concentrations and provide a longer duration of protection remains an urgent need.Mosquito Odorant-Binding Proteins (OBPs) involved in the initial steps of the olfactory signal transduction cascade have been recognized not only as passive carriers of odors and pheromones but also as the first molecular filter to discriminate semiochemicals, hence serving as molecular targets for the design of novel pest control agents. Among the three-dimensional structures of mosquito OBPs solved in the last decades, the OBP1 complexes with known repellents have been widely used as reference structures in docking analysis and molecular dynamics simulation studies for the structure-based discovery of new molecules with repellent activity.Herein, ten compounds known to be active against mosquitoes and/or displaying a binding affinity for Anopheles gambiae AgamOBP1 were used as queries in an in silico screening of over 96 million chemical samples in order to detect molecules with structural similarity. Further filtering of the acquired hits on the basis of toxicity, vapor pressure, and commercial availability resulted in 120 unique molecules that were subjected to molecular docking studies against OBP1. For seventeen potential OBP1-binders, the free energy of binding (FEB) and mode of interaction with the protein were further estimated by molecular docking simulations leading to the selection of eight molecules exhibiting the highest similarity with their parental compounds and favorable energy values. The in vitro determination of their binding affinity to AgamOBP1 and the evaluation of their repellent activity against female Aedes albopictus mosquitoes revealed that our combined ligand similarity screening and OBP1 structure-based molecular docking successfully detected three molecules with enhanced repellent properties. A novel DEET-like repellent with lower volatility (8.55 × 10−4 mmHg) but a higher binding affinity for OBP1 than DEET (1.35 × 10−3 mmHg). A highly active repellent molecule that is predicted to bind to the secondary Icaridin (sIC)-binding site of OBP1 with higher affinity than to the DEET-site and, therefore, represents a new scaffold to be exploited for the discovery of binders targeting multiple OBP sites. Finally, a third potent repellent exhibiting a high degree of volatility was found to be a strong DEET-site binder of OBP1 that could be used in slow-release formulations.

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>

When a pest-control species becomes a pest: A shift in the foraging habitat of cattle egret (Bubulcus ibis) and the threat to grazed natural ecosystems

Ecosystem services such as natural pest control and pollination may benefit agriculture, but may also adversely affect adjacent ecosystems. Here, we explored the cosmopolitan cattle egret (Bubulcus ibis), a commensal insectivorous large bird which has been expanding worldwide and is often considered as a pest control agent. We assessed the changes in the distribution of this new resident and its nesting and foraging habitat preferences in Mediterranean agroecosystems in northern Israel over the last few decades. We evaluated the relative importance of reptile, amphibian and arthropod prey in its diet by analysing regurgitated food in nesting colonies, and modelled the effect of land-use on reptile prey composition. We found that a recent expansion of B. ibis has been facilitated by the introduction of cattle grazing to natural habitats, and by augmentation of human-dominated landscapes and crop fields. Arthropods have dominated the egret diet (73.75 %), but the overwhelming proportion of reptile species (19.67 %) comprises predominantly maquis dwellers, indicating high predation pressure in natural rangelands. Although B. ibis acts as an agricultural pest control agent in croplands, its function as a harmful predator in grazed natural habitats seems to be substantial. Such intrusion of a novel predator into natural ecosystems may have catastrophic implications for native fauna, particularly in human-dominated and fragmented landscapes. Our findings underscore the potential adverse effects of a naturally thriving predator on local fauna and the importance of further research to understand its actual impact on both agricultural pests and non-pest prey communities in the wild.

Diversity of endosymbionts in camellia spiny whitefly, Aleurocanthus camelliae (Hemiptera: Aleyrodidae), estimated by 16S rRNA analysis and their biological implications.

Camellia spiny whitefly, Aleurocanthus camelliae (Hemiptera: Aleyrodidae), is a major pest in tea, which poses a serious threat to tea production. Similar to many insects, various bacterial symbioses inside A. camelliae may participate in the reproduction, metabolism, and detoxification of the host. However, few reports included research on the microbial composition and influence on A. camelliae growth. We first applied high-throughput sequencing of the V4 region in the 16S rRNA of symbiotic bacteria to study its component and effect on the biological trait of A. camelliae by comparing it with the antibiotic treatment group. The population parameters, survival rate, and fecundity rate of A. camelliae were also analyzed using the age-stage two-sex life table. Our results demonstrated that phylum Proteobacteria (higher than 96.15%) dominated the whole life cycle of A. camelliae. It unveiled the presence of Candidatus Portiera (primary endosymbiont) (67.15-73.33%), Arsenophonus (5.58-22.89%), Wolbachia (4.53-11.58%), Rickettsia (0.75-2.59%), and Pseudomonas (0.99-1.88%) genus. Antibiotic treatment caused a significant decrease in the endosymbiont, which negatively affected the host's biological properties and life process. For example, 1.5% rifampicin treatment caused a longer preadult stage in the offspring generation (55.92 d) compared to the control (49.75d) and a lower survival rate (0.36) than the control (0.60). The decreased intrinsic rate of increase (r), net reproductive rate (R 0), and prolonged mean generation time (T) were signs of all disadvantageous effects associated with symbiotic reduction. Our findings confirmed the composition and richness of symbiotic bacteria in larva and adult of A. camelliae by an Illumina NovaSeq 6000 analysis and their influence on the development of the host by demographic research. Together, the results suggested that symbiotic bacteria play an important role in manipulating the biological development of their hosts, which might help us for developing new pest control agents and technologies for better management of A. camelliae.

Why losing Australia's biodiversity matters for human health: insights from the latest State of the Environment assessment.

Why losing Australia's biodiversity matters for human health: insights from the latest State of the Environment assessment.

Management intensity affects insect pests and natural pest control on Arabica coffee in its native range

Abstract Agroforestry systems provide opportunities to reduce the trade‐off between agricultural production and biodiversity, for example by enhancing a diverse community of species potentially acting as natural pest control agents. While management of agroforestry systems is intensifying across the globe, we lack insights into the impact of management intensity on pest levels and natural pest control, especially along broad management gradients and as compared with natural forests. We assessed the impact of management intensity on major insect pests (the coffee blotch miner, the serpentine leaf miner, the coffee leaf skeletonizer and damage by other free‐feeding herbivores) and natural pest control by parasitoid wasps across sixty sites in the centre of origin of Arabica coffee in southwestern Ethiopia. Within this region, coffee is growing along a broad management gradient ranging from little or no management in the natural forest to intensively managed commercial plantations. In the wet season, pest levels were largely similar in the natural forest, semi‐forest and semi‐plantation systems, whereas pests reached outbreak densities in the most intensively managed plantation system. In contrast, management intensity did not significantly affect pest levels in the dry season. The insect pests differed in their seasonal dynamics, consistently declined with elevation and were largely unaffected by shade levels. Parasitism rate of the coffee blotch miner was lower, and the parasitoid community was distinct, in the most intensively managed plantation system. Synthesis and applications : Our findings support the hypothesis that the weaker top‐down control by parasitoids in the intensively managed plantation sites leads to higher pest levels, and that—at least for some pest species—there is a threshold in the effect of management intensity on pest levels and natural pest control. It is important to consider such non‐linear relationships to maintain or enhance the sustainability of agroforestry systems during management intensification. Overall, our findings highlight that ecological knowledge of natural pest control can be used to intensify production to improve the livelihood of smallholder farmers without jeopardizing natural pest control but only up to a certain point where it starts to deteriorate.

Biodiversity of hymenopteran parasitoids

Parasitoid wasps are the most successful group of insect parasitoids, comprising more than half the known diversity of Hymenoptera and probably most of the unknown diversity. This lifestyle has enabled them to be used as pest control agents conferring substantial economic benefits to global agriculture. Major lineages of parasitoid wasps include Ichneumonoidea, Ceraphronoidea, Proctotrupomorpha, and a number of aculeate families. The parasitoid lifestyle arose only once among basal Hymenoptera, in the common ancestor of the Orussidae and Apocrita some 200+ Ma ago. The ancestral parasitoid wasp was probably an idiobiont on wood-living beetle larvae. From this comparatively simple biology, Hymenoptera radiated into an incredible diversity of hosts and parasitoid lifestyles, including hyperparasitoidism, kleptoparasitoidism, egg parasitoidism, and polyembryony, in several instances co-opting viruses to subdue their hosts. Many lineages evolved beyond the parasitoid niche, becoming secondarily herbivorous or predatory nest provisioners and eventually giving rise to most instances of insect societies.

Development of a Multicomponent Microbiological Soil Inoculant and Its Performance in Sweet Potato Cultivation.

The cultivation and consumption of sweet potato (Ipomoea batatas) are increasing globally. As the usage of chemical fertilizers and pest control agents during its cultivation may lead to soil, water and air pollution, there is an emerging need for environment-friendly, biological solutions enabling increased amounts of healthy crop and efficient disease management. Microbiological agents for agricultural purposes gained increasing importance in the past few decades. Our goal was to develop an agricultural soil inoculant from multiple microorganisms and test its application potential in sweet potato cultivation. Two Trichoderma strains were selected: Trichoderma ghanense strain SZMC 25217 based on its extracellular enzyme activities for the biodegradation of plant residues, and Trichoderma afroharzianum strain SZMC 25231 for biocontrol purposes against fungal plant pathogens. The Bacillus velezensis strain SZMC 24986 proved to be the best growth inhibitor of most of the nine tested strains of fungal species known as plant pathogens, therefore it was also selected for biocontrol purposes against fungal plant pathogens. Arthrobacter globiformis strain SZMC 25081, showing the fastest growth on nitrogen-free medium, was selected as a component with possible nitrogen-fixing potential. A Pseudomonas resinovorans strain, SZMC 25872, was selected for its ability to produce indole-3-acetic acid, which is among the important traits of potential plant growth-promoting rhizobacteria (PGPR). A series of experiments were performed to test the selected strains for their tolerance to abiotic stress factors such as pH, temperature, water activity and fungicides, influencing the survivability in agricultural environments. The selected strains were used to treat sweet potato in two separate field experiments. Yield increase was observed for the plants treated with the selected microbial consortium (synthetic community) in comparison with the control group in both cases. Our results suggest that the developed microbial inoculant has the potential to be used in sweet potato plantations. To the best of our knowledge, this is the first report about the successful application of a fungal-bacterial consortium in sweet potato cultivation.

Larvicide effects of Bacillus sp isolated from soil against fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae)

Prolonged use of pesticides was known to have a negative impact on the environment, health, and living organisms. Therefore alternative pest control techniques need to be developed continuously. One pest eradication techniques that is believed to be safe for the environment is biological control. This study intended to evaluate the toxicity properties of 7 different isolates suspension of Bacillus sp. isolated from soil in a botanical garden in West Lampung against Spodoptera frugiperda larvae. Morphological characterization of protein crystals which are toxic to insects contained in the suspension was carried out microscopically at a magnification of 1000x. Then, each isolate suspension was tested for its toxicity properties on the 3rd instar larvae of S. frugiverda. The protein crystal morphology of the Bacillus sp isolate coded TB7 was similar to that of L. sphaericus. While the other six isolates (TMA 26, TBA 4, TBA 7, TB 5, BP 14, and TSR 6) had morphological characteristics similar to that found in the B. thuringiensis. The results of larvicide test showed that Bacillus sp isolates coded TMA 26, TBA 7, BP 14 and TB 5 caused mortality on day 3. TBA 4 isolates killed larvae on day 4, while isolates coded TSR 6 and TB 7 killed larvae on day 5. In conclusion, Bacillus sp isolate isolated from soil has toxic properties to the larvae of S frugiperda. So it is suggested that the bacterial isolate Bacillus sp can be used as a biological control agent for insect pests.