Suppress Pest Populations Research Articles

How population control of pests is modulated by density dependence: The perspective of genetic biocontrol.

Managing pest species relies critically on mechanisms that regulate population dynamics, particularly those factors that change with population size. These density-dependent factors can help or hinder control efforts and are especially relevant considering recent advances in genetic techniques that allow for precise manipulation of the timing and sex-specificity of a control. Despite this importance, density dependence is often poorly characterized owing to limited data and an incomplete understanding of developmental ecology. To address this issue, we construct and analyze a mathematical model of a pest population with a general control under a wide range of density dependence scenarios. Using this model, we investigate how control performance is affected by the strength of density dependence. By modifying the timing and sex-specificity of the control, we tailor our analysis to simulate different pest control strategies, including conventional and genetic biocontrol methods. We pay particular attention to the latter as case studies by extending the baseline model to include genetic dynamics. Finally, we clarify past work on the dynamics of mechanistic models with density dependence. As expected, we find substantial differences in control performance for differing strengths of density dependence, with populations exhibiting strong density dependence being most resilient to suppression. However, these results change with the size and timing of the control load, as well as the target sex. Interestingly, we also find that population invasion by certain genetic biocontrol strategies is affected by the strength of density dependence. While the model is parameterized using the life history traits of the yellow fever mosquito, Aedes aegypti , the principles developed here apply to many pest species. We conclude by discussing what this means for pest population suppression moving forward.

Deployment of tethered gene drive for confined suppression in continuous space requires avoiding drive wave interference.

Gene drives have great potential for suppression of pest populations and removal of exotic invasive species. CRISPR homing suppression drive is a powerful but unconfined drive, posing risks of uncontrolled spread. Thus, developing methods for confining a gene drive is of great significance. Tethered drive combines a confined system such as Toxin-Antidote Recessive Embryo drive with a strong drive such as a homing suppression drive. It can prevent the homing drive from spreading beyond the confined drive and can be constructed readily, giving it good prospects for future development. However, we have found that care must be taken when deploying tethered drive systems in some scenarios. Simulations of tethered drive in a panmictic population model reveal that successful deployment requires a proper release ratio between the two components, tailored to prevent the suppression drive from eliminating the confined system before it has the chance to spread. Spatial models where the population moves over a one-dimensional landscape display a more serious phenomenon of drive wave interference between the two tethered drive components. If the faster suppression drive wave catches up to the confined drive wave, success is still possible, but it is dependent on drive performance and ecological parameters. Two-dimensional simulations further restrict the parameter range for drive success. Thus, careful consideration must be given to drive performance and ecological conditions, as well as specific release proposals for potential application of tethered drive systems.

Population suppression by release of insects carrying a dominant sterile homing gene drive targeting doublesex in Drosophila

CRISPR homing gene drives can suppress pest populations by targeting female fertility genes, converting wild-type alleles into drive alleles in the germline of drive heterozygotes. fsRIDL (female-specific Release of Insects carrying a Dominant Lethal) is a self-limiting population suppression strategy involving continual release of transgenic males carrying female lethal alleles. Here, we propose an improved pest suppression system called “Release of Insects carrying a Dominant-sterile Drive” (RIDD), combining performance characteristics of homing drive and fsRIDL. We construct a split RIDD system in Drosophila melanogaster by creating a 3-gRNA drive disrupting the doublesex female exon. Drive alleles bias their inheritance in males, while drive alleles and resistance alleles formed by end-joining cause dominant female sterility. Weekly releases of RIDD males progressively suppressed and eventually eliminated cage populations. Modeling shows that RIDD is substantially stronger than SIT and fsRIDL. RIDD is also self-limiting, potentially allowing targeted population suppression.

Identification and knockout of a herbivore susceptibility gene enhances planthopper resistance and increases rice yield.

Brown planthoppers (Nilaparvata lugens) and white-backed planthoppers (Sogatella furcifera) are among the most destructive pests on rice. However, plant susceptibility genes have not yet been exploited for crop protection. Here we identified a leucine-rich repeat protein, OsLRR2, from susceptible rice varieties that facilitates infestation by brown planthopper N. lugens. Field trials showed that knockout of OsLRR2 significantly reduced BPH infestation and enhanced natural biological control by attracting natural enemies. Yield of a susceptible variety was increased by 18% in insecticide-treated plots that eliminated planthoppers and by 25% in untreated plots. These findings underscore the pivotal role of OsLRR2, offering a promising pathway for pest population suppression and rice yield increase.

Host range of a parasitoid wasp is linked to host susceptibility to its mutualistic viral symbiont.

Parasitoid wasps are one of the most species-rich groups of animals on Earth, due to their ability to successfully develop as parasites of nearly all types of insects. Unlike most known parasitoid wasps that specialize towards one or a few host species, Diachasmimorpha longicaudata is a generalist that can survive within multiple genera of tephritid fruit fly hosts, including many globally important pest species. Diachasmimorpha longicaudata has therefore been widely released to suppress pest populations as part of biological control efforts in tropical and subtropical agricultural ecosystems. In this study, we investigated the role of a mutualistic poxvirus in shaping the host range of D. longicaudata across three genera of agricultural pest species: two of which are permissive hosts for D. longicaudata parasitism and one that is a nonpermissive host. We found that permissive hosts Ceratitis capitata and Bactrocera dorsalis were highly susceptible to manual virus injection, displaying rapid virus replication and abundant fly mortality. However, the nonpermissive host Zeugodacus cucurbitae largely overcame virus infection, exhibiting substantially lower mortality and no virus replication. Investigation of transcriptional dynamics during virus infection demonstrated hindered viral gene expression and limited changes in fly gene expression within the nonpermissive host compared with the permissive species, indicating that the host range of the viral symbiont may influence the host range of D. longicaudata wasps. These findings also reveal that viral symbiont activity may be a major contributor to the success of D. longicaudata as a generalist parasitoid species and a globally successful biological control agent.

Susceptibility of Orius insidiosus to Beauveria bassiana, Akanthomyces muscarius, and Cordyceps fumosorosea and their effects on predator behavior

AbstractThe use of pathogens and other natural enemies to suppress pest populations is a key component of integrated pest management (IPM) strategies. As biocontrol agents may interact synergistically, additively, or antagonistically, it is crucial to assess their interactions for effective pest management. In this study, we investigated the effect of three entomopathogenic fungus (EPF) species—Beauveria bassiana (Bals.‐Criv.) Vuill. CEP 091, Akanthomyces muscarius (Petch) Spatafora, Kepler & B. Shrestha CEP 182, and Cordyceps fumosorosea (Wize) Kepler, B. Shrestha & Spatafora CEP 315 (all Hypocreales)—on the survival, fecundity, and searching behavior of Orius insidiosus (Say) (Hemiptera: Anthocoridae). All three EPF species were found to be pathogenic to O. insidiosus, resulting in a significant decrease in survival compared with the control group. Fecundity remained unaffected by the fungal treatments. No effect of EPF on searching behavior of the predator was found. In relation to the searching behavior, individuals of 2 days post‐infections remained in the food patch longer than individuals of 7 days post‐infections, regardless of treatment. These findings provide valuable insights into the compatibility of EPF and O. insidiosus as combined biocontrol agents for managing whiteflies, aphids, and thrips. Understanding the interactions between EPF and predatory insects is crucial for developing IPM strategies that maximize pest control efficacy. Further studies should explore the long‐term effects of EPF on O. insidiosus populations and their overall impact on pest management in agricultural systems.

Eksplorasi dan Deskripsi dan Kunci Determinasi Musuh Alami Hama Kutu Kepik (Vatiga illudens Drake 1922) (Hemiptera: Tingidae) dari Pertanaman Singkong (Manihot esculenta) di Kabupaten Banyumas, Provinsi Jawa Tengah

The invasion of the ladybug (Vatiga illudens) has started a new chapter in Indonesia, with the first report of this pest in East Java Province in 2021. As a pest that attacks cassava plants, this pest is a threat to cassava plantations, one of which is in Banyumas District, Central Java Province. It is necessary to identify potential natural enemies that can become biological agents that suppress pest populations in the field and insects associated with cassava cultivations to control the pest and anticipate losses due to decreased production of cassava plants in the Banyumas District. This study aimed to explore and describe the natural enemies of ladybug pests and insects associated with cassava cultivations in the Banyumas District. The research was conducted in September 2022-January 2023 in seven cassava cultivation locations in Banyumas District. Samples of pests and or natural enemies were collected using a purposive random sampling method. The results showed a community of potential natural enemies of V. illudens and insects associated with cassava cultivations from the Orders Hemiptera, Diptera, Orthoptera, Coleoptera, and Araneae. The Results showed that 15 species act as potential natural enemies, eight species as pests, and two species as none of them (neutral).

Deleterious effects of the endosymbiont Rickettsiella viridis in Myzus persicae are environmentally dependent

AbstractEndosymbionts living within insect cells can modify host fitness and could provide new tools for pest control. The endosymbiont Rickettsiella viridis has been transferred experimentally into the green peach aphid, Myzus persicae, a globally important agricultural pest. This Rickettsiella spreads via vertical and horizontal transmission and induces host fitness costs which could potentially suppress pest populations. Endosymbiont prevalence can fluctuate in natural populations, and it is important to identify factors that contribute to their spread or loss. Here, we explore the effects of Rickettsiella infection when aphids are reared on eight different host plants or exposed to thermal, starvation and desiccation stresses. Rickettsiella infection reduced M. persicae fecundity and longevity across all host plants, but the magnitude of costs varied among host plants and generations. Rickettsiella was horizontally transmitted and spread in caged populations at initial ratios of 1:2 Rickettsiella (+): Rickettsiella (−) on all host plants, but with limited long-term persistence under cycling 20–30 °C. We also identified temperature-dependent costs of Rickettsiella infection on heat knockdown time, chill coma recovery, and starvation tolerance. Finally, we present evidence that Rickettsiella infection reduces host activity levels under heat stress. Our results suggest that Rickettsiella infections induce a variety of deleterious effects but with complex environment-dependent interactions. This work helps understand ecological conditions that enhance or limit the spread of these endosymbionts in aphid populations.

Role of integrated pest management in agriculture

Agriculture in India has a pivotal role in promoting food security, livelihoods and sustainable development, especially for the rural poor. However, it is increasingly affected by issues such as degradation of natural resources, increased frequency of extreme weather events and change in rainfall patterns that are linked to climate change. The population is also growing fast, affecting the demand for food and other agricultural products. Due to these factors and given the limited availability of agricultural land, the burden on the farming sector has increased manifold. The various crop plants are greatly affected by multifarious types of pests which not only result in reduced productivity figures but also distress the farmers as they get less revenue due to crop losses to these pests. Pest attack coupled with disease breakout sometimes results in suicidal situations as has been witnessed in our country. As such strong measures have to be taken up for bringing the pest attack to halt forthwith and reduce the incidence of pests. According to estimates by the Food and Agriculture Organization of the United Nations (FAO), East Asia (including China) and South Asia together account for more than half of pesticide use in developing countries in the world. Moreover, farmers often apply large quantities of highly toxic pesticide or even use banned or spurious ones, instead of less toxic alternatives. In order to overcome these negative effects Integrated Pest Management (IPM) offers an alternative that is safer for human and environmental health. Integrated pest management (IPM), also known as integrated pest control (IPC) is a broad-based approach that integrates practices for economic control of pests. IPM is the best combination of cultural, biological and chemical measures to manage diseases, insects, weeds and other pests. As the global population is on the rise the demand of growing world population for food and fiber require farmers to produce more crops on existing farm land. IPM is a big part of the solution. Increasingly it is being adopted in both developed and developing countries for long-term, sustainable agriculture that achieves adequate, safe and quality food production. IPM does not, however, consist of any absolute or rigid criteria. As it is a flexible system that makes good use of local resources and the latest research, technology, knowledge and experience. The main of the IPM aims to suppress pest populations below the economic injury level (EIL).

Annotated checklist of ladybugs (Coleoptera: Coccinellidae) with nine new country records from Cambodia

Ladybugs (Coccinellidae) are commonly known for their beneficial roles in insect pest population suppression. Despite their importance and the limited scientific research conducted in Cambodia, the ladybug fauna needs to be documented in the country. Therefore, this study aims to establish the first checklist of Cambodian ladybug fauna including a brief taxonomic description and distribution for each species. We identified a total of 13 species based on the specimens deposited in the collection of Cambodian Entomology Initiatives. 9 of all species are newly recorded for Cambodia. Within this addition and six previously recorded species, ladybugs reached 15 species recorded from Cambodia. However, many new species are under-discovered in the country. The study provided a valuable baseline checklist for the taxonomy, diversity and ecology of ladybugs in Cambodia.

Supervising in the Implementation of Integrated Pest Management (IPM) in good Horticultural Practices in the Sembalun agrotourism area

The use of natural enemies as pest control has long been known, but has been largely replaced by the rapid development of chemical pesticide industry technology, especially since the green revolution. One alternative pest control technology that is quite promising to be developed is the use of biological agents (predators or parasotoids) that have more natural characteristics than chemical characteristics. With the presence of natural enemies which are then used to suppress pest populations, it will be safe for human health and the environment. It can be hoped that the agricultural products produced will be acceptable and highly competitive on the global market. Considering the Sembalun area as a tourism destination, it will be very relevant if the local community understands good horticultural practices. The intervention of using technology for farmers as an alternative in good Horticultural Cultivation is highly expected by farmers in the Sembalun area. Therefore, assistance is needed to implement integrated Pest Management in good Horticultural practices. The method used in this activity is the Action Research Method by applying a Participatory Action Program approach from participants through discussion and group work in all activities. The result is that farmers are very interested in implementing good horticultural cultivation, especially with habitat management approaches such as using refugia plants to control pests. Participating farmers increase their knowledge and skills to recognize differences in pests and natural enemies (predators and parasitoids) found on potato plants that are integrated with refugia plants. The target group has increased knowledge and understanding of the importance of implementing Integrated Pest Management (IPM) practices in horticultural cultivation. It is hoped that training and assistance activities for healthy horticultural cultivation efforts will continue both by the university team and related agencies. This kind of activity needs to be continued by the participating group and spread to other groups nearby. There is a need for assistance in applying for Prima 3 and Prima 2 food safety certification to farmer groups in the Sembalun Agrotourism Area, so that the number of products from certified horticultural business actors will increase. Activities to implement Integrated Pest Management in horticultural farming business groups in the Sembalun Tourism Area need to continue

Advancements in variable rate spraying for precise spray requirements in precision agriculture using Unmanned aerial spraying Systems: A review

Pesticides suppress pest populations and maintain agricultural yield; however, their overuse causes ecological damage. To mitigate the ecological damage caused by the overuse of pesticides, this paper explores the application of a precise and adaptable technique known as unmanned aerial spraying system (UASS)-based variable rate spraying (VRS). Herein, the current state of precision agriculture is examined, and the application of UASS in variable rate spraying is discussed. Then, the role of advanced sensors, including multispectral and hyperspectral technologies, in optimizing UASS-based VRS missions is studied, followed by the challenges in UASS-based spraying, ranging from technical intricacies to regulatory considerations, and related solutions. In addition to delving into pesticides, the paper explores alternative solutions such as herbicides, encompassing an integrated approach that aligns with sustainable farming practices for more effective pest management. VRS has advantages, including increased yields, reduced resource usage, and environmental sustainability. This paper concludes by delineating current challenges and envisioning future innovations, spotlighting ongoing studies on sensor technology and AI-driven flow rate optimization. This review provides insights into UASS-based VRS for precision agriculture.

Acetylcholine esterase of Drosophila melanogaster: a laboratory model to explore insecticide susceptibility gene drives.

One of the proposed applications of gene drives has been to revert pesticide resistant mutations back to the ancestral susceptible state. Insecticides that have become ineffective because of the rise of resistance could have reinvigorated utility and be used to suppress pest populations again, perhaps at lower application doses. We have created a laboratory model for susceptibility gene drives that replaces field-selected resistant variants of the acetylcholine esterase (Ace) locus of Drosophila melanogaster with ancestral susceptible variants. We constructed a CRISPR/Cas9 homing drive and found that homing occurred in many genetic backgrounds with varying efficiencies. While the drive itself could not be homozygous, it converted resistant alleles into susceptible ones and produced recessive lethal alleles that could suppress populations. Our studies provided evidence for two distinct classes of gene drive resistance (GDR): rather than being mediated by the conventional non-homologous end-joining (NHEJ) pathway, one seemed to involve short homologous repair and the other was defined by genetic background. Additionally, we used simulations to explore a distinct application of susceptibility drives; the use of chemicals to prevent the spread of synthetic gene drives into protected areas. Insecticide susceptibility gene drives could be useful tools to control pest insects however problems with particularities of target loci and GDR will need to be overcome for them to be effective. Furthermore, realistic patterns of pest dispersal and high insecticide exposure rates would be required if susceptibility were to be useful as a 'safety-switch' to prevent the unwanted spread of gene drives. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Buckwheat (Fagopyrum esculentum) floral strips support natural enemies and maintain yields in organic green bean (Phaseolus vulgaris) crops

Arthropod natural enemies can contribute to pest management by consuming crop pests, but populations of these natural enemies may be low within crops due to a lack of resources. Floral strips can provide these resources and support natural enemy communities, which in turn can suppress pest populations and thereby improve crop yields. Buckwheat (Fagopyrum esculentum Moench) floral strips were added to experimental plots of organic green beans (Phaseolus vulgaris L.) and paired with control plots, without floral strips, to determine their impact on arthropod communities, crop yields, and pest control costs. Crop yields were maintained, but costs of pest control significantly lower (16%) in plots with floral strips. This was not explained by an increased abundance or diversity of natural enemies or a decrease of pests (i.e. all herbivores). Instead, the composition of arthropod natural enemy communities were similar between buckwheat floral strips and the crop, suggesting that the floral strips support natural enemies already present within crops. Semi-natural edge habitat in control plots, had a unique community of natural enemies, which had little spillover into the crop and therefore may have little impact on biological control. These results suggest that higher crop yields can be achieved with reduced inputs, such as insecticides, by adding floral strips to crops as they may support the natural enemies present within crops. Future studies should consider the impacts of specific natural enemies, rather than diversity, and direct measurements of biological control to connect the impact of floral strips to crop yields.

Predator densities alter the influence of non‐consumptive effects on the population dynamics of an agricultural pest

Abstract Augmentative release of predators is used in agriculture to suppress pest populations and minimise crop damage. However, predators affect prey populations not only through consumption but by inducing changes to prey morphology, physiology, behaviour and life history. These risk‐induced trait responses can increase prey fitness, potentially reducing the efficacy of certain predators as biocontrol agents. We investigated how non‐consumptive effects contribute to the overall influence of predators by modelling the effect of the predator Podisus maculiventris on the population dynamics of a major agricultural pest, the Colorado potato beetle (Leptinotarsa decemlineata). We developed a demographic model incorporating both consumption and non‐consumptive Podisus‐induced shifts in beetle reproductive strategy. Our model combines data from multiple mechanistic experiments showing that predator‐exposed beetles produce fewer offspring but increase offspring provisioning, and that provisioned larvae have increased survival when predators are present. We simulated beetle densities across multiple beetle generations and a range of predator densities. The influence of non‐consumptive effects depended on predator density. At low predator densities, non‐consumptive effects strengthened the negative effect of predators by up to 45%, and risk‐induced changes to offspring provisioning had a stronger effect on prey densities than reduced offspring quantity. In contrast, at high predator densities, non‐consumptive effects changed the effect of predators by <5%, likely because beetle densities were very low both with and without non‐consumptive effects. Our results suggest that even adaptive responses to predation risk by prey do not necessarily reduce the ability of predators to suppress pest populations.

Non-additive effects of multiple predators alter the biological control of the coffee leaf miner (Leucoptera coffeella)

Although most prey are attacked by multiple predators, much of the ecological theory on prey suppression focuses on the effects of a single predator. The presence of multiple predators can lead to complex interactions such as trait-mediated interactions (TMIIs) and intraguild predation which can influence the suppression of pest populations. Here we explore the effect of two predators, a native anole lizard species Anolis cristatellus (Squamata: Dactyloidae) and a non-native ant species Wasmannia auropunctata (Hymenoptera: Formicidae), on the coffee leaf miner, Leucoptera coffeella (Lepidoptera: Lyonetiidae) (CLM). In a laboratory experiment we examined the effects of these two predators in isolation and when co-occurring. Our results show that when each predator is alone, they are able to consume the CLM in a comparable way. However, when they are together, their effect is not greater than when alone. This indicates that there is a negative effect when both predators co-occur. The results from this experiment have practical implications since both predators are present in coffee agroecosystems in Puerto Rico, where the CLM is considered the main insect pest. Furthermore, these results demonstrate the potential dynamics among several predators in agroecosystems and the potential implications for herbivore regulation.

Diversity and abundance of parasitoid fauna associated with the pests of certain medicinal plants of West Bengal

A preliminary study was conducted from 2021 to 2022 to explore the parasitoid fauna associated with insect pests and their per cent parasitism levels in the field as well as to understand the diversity of parasitoids in the medicinal plants ecosystem under northern tracts of West Bengal. In course of the study, a total of ten parasitoid species belonging to 5 families from 2 orders were observed in this ecosystem. Hymenopteran parasitoids were dominant, i.e., more than 90% and only one fly parasitoid species from Diptera belonging to the family Tachinidae was observed. Amongst the hymenopteran parasitoids, braconids were the prime species, found parasitizing various insect pests. All these parasitoids were observed attacking lepidopteran caterpillars which were predominant defoliators on various medicinal plants. The per cent parasitism by Copidosoma sp. on Helcystogramma hibisci was 38% which was the highest and found effective in the suppression of pest population.

Ecological Interactions of Predatory Mites, Cheyletus eruditus (Schrank) (Trombidiformes: Cheyletidae) and Cheyletus malaccensis Oudemans, and Prey, Liposcelis decolor (Pearman) (Psocodea: Liposcelididae), under Different Thermo-Hygrometric Regimes.

Predator-prey interactions are linked through trophic relationships, and individual population dynamics are a function of multiple interactions among many ecological factors. The present study considered the efficacy of the predatory mites Cheyletus eruditus (Schrank) (Trombidiformes: Cheyletidae) and Cheyletus malaccensis Oudemans to manage Liposcelis decolor (Pearman) (Psocodea: Liposcelididae). Prey population suppression and progeny replacement efficiency of the predators were assessed under different predator-prey ratios (0:20, 1:20, 2:20, 4:20, and 10:20), temperatures (20, 24, 28, and 32 °C), and relative humidities (RH) (63, 75, and 85%) over 40 days under laboratory conditions of 0:24 (L:D) photoperiod. Suppression of L. decolor population when C. eruditus-related predator-to-prey ratios of 1:20, 2:20, 4:20, and 10:20 were used was ~61.7, 79.7, 85.1, and 87.5%, respectively, relative to the Control ratio (0:20). In the case of C. malaccensis, suppression of 70, 82.1, 92.9, and 96.5%, respectively, was achieved. Although the low 63% RH limited efficacy of these cheyletid mites, both predatory mites caused pest population suppression of ~67.1-97.2% and increased their progeny by ~96.7-844.4% fold for the predator-prey ratios of 1:20, 2:20, 4:20, and 10:20, temperatures of 20, 24, 28, and 32 °C, and RH levels of 63, 75, and 85%. The levels of psocid population suppression achieved indicate the potential of both predatory mites for psocid management.

Natural-Enemy-Based Biocontrol of Tobacco Arthropod Pests in China

The devastating impact of chemical pesticides has prompted a shift towards sustainable agricultural pest management, such as biological control with natural enemies. In recent years, commercialization advancements have enabled the suppression of pest populations through augmentative releases of biological control agents, with natural enemies being a major tactic. China has successfully implemented natural-enemy-based biocontrol strategies, particularly for controlling aphids and lepidopterans. This article provides a comprehensive overview of the state-of-the-art natural-enemy-based biocontrol against arthropod pests in tobacco in China, including practical achievements in mass-rearing methods, augmentative release strategies, and the wide-scale use of natural enemies. Current and potential future challenges for natural-enemy-based biocontrol in China are also discussed.

Numerical responses of the predatory mites, Cheyletus eruditus (Trombidiformes: Cheyletidae) and Cheyletus malaccensis, to Liposcelis decolor (Psocodea: Liposcelididae).

Predatory mites display diverse ecological mechanisms to suppress pest population density below certain thresholds known to cause economic loss. The current study explored the numerical responses of the predatory mites, Cheyletus eruditus (Schrank) (Trombidiformes: Cheyletidae) and Cheyletus malaccensis Oudemans, to Liposcelis decolor (Pearman) (Psocodea: Liposcelididae). The numerical responses of these 2 cheyletid mites to nymphs, adult males, and adult females of L. decolor were determined under laboratory conditions at 24 ± 1 °C, 85 ± 5 RH, and 0:24 (L:D) photoperiod. Oviposition rate, oviposition efficiency, and efficiency of conversion of ingested (ECI) food resources were the key numerical response parameters assessed. The present study revealed a general trend of a strong negative and positive correlation between oviposition rates and increase in prey densities (number of prey per 16.98 cm2) for C. eruditus and C. malaccensis, respectively. The oviposition efficiency was mostly similar for both predatory mites and was inversely related to prey density. Generally, ECI (%) decreased considerably with increasing prey density across different prey types for both predators, however, C. malaccensis was more efficient than C. eruditus in utilizing prey biomass. Given the relatively weak numerical responses, we recommended further assessment of these predatory mites before recommending their use for managing stored-product insect pests in the United States.