Mite Density Research Articles

Survey and Population Densities of Phytophagous Mites and their Natu-ral Enemies Inhabiting Pomegranate Orchards in Assiut Governorate

Survey and Population Densities of Phytophagous Mites and their Natu-ral Enemies Inhabiting Pomegranate Orchards in Assiut Governorate

Evaluation of a 'Preventative' Strategy to Manage Spider Mites on Almond.

Simple SummaryThe almond industry in California produces approximately 80% of the world’s supply and currently consists of roughly 0.45 million bearing and non-bearing hectares. Spider mite management is a component of annual arthropod management strategies on almond. Regularly, acaricides containing the active ingredient, abamectin, are applied in spring when mites are not yet present or well below a level which justifies treatment, in other words applied to prevent rather than treat existing populations. Although other acaricides are used, those containing the active ingredient, abamectin, accounted for 68% to 95% of spring (preventative) applications between 2005 and 2017. Although the strategy is widely employed in the almond industry, there are no published studies supporting the practice. Moreover, the strategy runs contrary to sustainable, integrated pest management practices by forgoing monitoring, reliance on spider mite natural enemies, and economic threshold levels. In this study, we conducted large field trials to evaluate the effectiveness of preventative acaricide applications. Results showed that farmers can forego a preventative strategy since spider mite densities typically remain well below damaging levels through the period critical for tree growth and nut yield. Also, results showed that such a heavy reliance on abamectin has led to a low to moderate level of resistance developing in some spider mite populations in the southern and mid San Joaquin Valley.Field experiments were conducted in two commercial almond orchards located in the southern San Joaquin Valley during 2016 and 2017 to evaluate a “preventative” strategy to manage spider mites. Pacific mite, Tetranychus pacificus McGregor, was identified as the only mite species infesting the experimental sites in both years. We monitored mites weekly in 3.6-hectare plots over approximately 21 weeks in 2016 and in 2017 using guidelines developed by the University of California. In late May, prior to the detection of mites, preventative acaricide treatments, abamectin, cyflumetofen, or etoxazole were applied to the experimental plots at a field rate. In 2016 and 2017, mite densities in all the treatments increased at early-July, peaked at mid-August, and were undetectable by late August. Preventative acaricide-treated plots in 2016 tended to have significantly lower mite densities than in the untreated control plots. Although in 2017, densities in the acaricide-treated plots tended to not significantly differ from control plots. Mite feeding injury, measured as mean cumulative mite-days, did not exceed the economic threshold during the experiment. The biological control agent, sixspotted thrips, Scolothrips sexmaculatus (Pergande) likely played a role in controlling mite populations at mid and late August. Our results indicate that a preventative strategy does not play a definitive role in T. pacificus management on almond. Additionally, acaricides with the active ingredient, abamectin, are heavily relied on as preventative treatments. We assessed populations of T. pacificus from the mid and southern San Joaquin Valley and found increased tolerance to a medium level of resistance to the acaricide.

Comparison of the performance of an eriophyid mite, Aceria salsolae, on nontarget plants in the laboratory and in the field

There is increasing interest in the possibility of using eriophyid mites as biological control agents of invasive alien weeds; however their small size and our lack of knowledge about their general biology present challenges to evaluating their risk to nontarget plants. Aceria salsolae has been proposed as a candidate agent for Russian thistle (Salsola tragus) in the USA. During host specificity testing this mite could sometimes persist on five nontarget species under laboratory no-choice conditions. We conducted a series of no-choice laboratory experiments and a field experiment to try to delineate the physiological and ecological host ranges of this mite and assess its risk to nontarget plants. In the laboratory, A. salsolae increased exponentially on S. tragus, multiplying about 80 fold in 5 weeks. Low levels of reproduction were observed on some plants of Atriplex coronata, Bassia hyssopifolia, B. prostrata, Kochia scoparia and Suaeda calceoliformis in the laboratory during 5 weeks, but mean mite densities remained low (less than 6 fold increase vs. 80 fold on S. tragus). In a field experiment in which plants were inoculated with mites in June and then harvested when they began to produce seed, mites persisted on A. coronata for up to 9 weeks after inoculation, but at extremely low densities, and with no evidence of reproduction. No mites persisted on A. truncata, B. hyssopifolia, or S. calceoliformis. Mite densities were lower on all plants in the field than in the laboratory, probably due to increased mortality and the opportunity to disperse by wind. No signs of damage were observed on any of the nontarget plants in the laboratory or the field experiments. We conclude that this mite is not likely to multiply on any of these plants under field conditions, and that it is not expected to pose a risk to any nontarget plants in the contiguous USA.

Fungicide reduction favors the control of phytophagous mites under both organic and conventional viticulture

Pesticides can have detrimental effects on non-target biodiversity, especially in intensively managed agroecosystems such as vineyards. However, new fungus-resistant grape varieties can greatly reduce the need and use of fungicides. Fungicides can have direct and indirect effects on economically important predatory mites (mainly Phytoseiidae) and on phytophagous mites (Tetranychidae, Eriophyidae) on which they prey. We investigated the impact of fungicide treatments on beneficial and phytophagous mite densities in 32 vineyards of organic and conventional wineries planted with susceptible and fungus-resistant grape varieties in the Palatinate region, Germany. Organic vineyards were sprayed with different formulations of sulfur, copper and potassium bicarbonate, while conventional vineyards received mostly synthetic fungicides. Fungicide applications were reduced by 47-80 % in fungus-resistant varieties, with stronger reductions under organic than under conventional management. Regardless of organic or conventional management, predatory mites (Phytoseiidae and Tydeidae) were significantly enhanced in vineyards planted with fungus-resistant varieties. Contrastingly, phytophagous mites (Eriophyidae) were enhanced in vineyards with fungus-susceptible varieties and in those under organic management. Densities of further predatory mite families increased under organic farming (Anystidae) or showed an interactive response to farming system and grape variety (Trombidiidae). Reduced fungicide applications through cultivation of fungus-resistant varieties enhance predatory mite densities and thus contribute to higher natural pest control potential. Thus, the cultivation of fungus-resistant grape varieties is an effective approach towards more environmentally friendly viticulture.

Population abundance of Varroa destructor and its effects on Apis mellifera scutellata colonies in Kenya.

The devastating effects of Varroa destructor Anderson and Trueman on Western honeybee colonies (Apis mellifera L.) have been well documented. Not only do these mites cause physical damage to parasitized individuals when they feed on them, but they also transmit viruses and other pathogens, weaken colonies and ultimately may cause their death. Unlike the subspecies of European origin, the honeybees of African origin suffer less from mite infestations. Absconding is one of the factors contributing to low V. destructor population in honeybee colonies as it creates a brood-free period. For a long time, researchers hypothesized that absconding was the main mechanism to control the parasite. The effects of V. destructor are well documented under temperate climatic conditions with a break during winter. Therefore, our study aimed at investigating the impact of V. destructor population growth on colony size, absconding and productivity under natural infestation levels of a tropical/subtropical climate with continuous brood production. We measured several characteristics related to the mite populations, the bee colonies and the resources of the bee colonies for a period of 8 months. The seven colonies that absconded during the study period were not influenced by densities of V. destructor. Absconding of the colonies occurred as a result of low numbers of capped brood. Mite densities were generally low throughout the study period (ranged between 26.9 and 59.8 mites per month) but were positively associated with adult bee densities. The amount of open and capped brood was positively associated with densities of V. destructor in the brood and negatively associated with denisities of V. destructor on screen boards, which appeared as extremely important factors that should be monitored regularly alongside colony stores and availability of pollen.

Preventive insecticide use affects arthropod decomposers and decomposition in field crops

Insecticides use in field crops has grown increasingly prophylactic, which poses a potentially unnecessary risk to arthropod decomposers. These decomposers — including millipedes (Diplopoda), soil mites (Acari, mostly Oribatida), and Collembola — act as alternative prey for generalist predators, facilitate crop-residue breakdown, and can influence nutrient cycling. However, the abundance and activity of arthropod decomposers may be reduced by extensive prophylactic pesticide use. We conducted a three-year field experiment in no-till corn and soybean fields to assess how neonicotinoid seed coatings or broadcast applications of a pyrethroid insecticide affect arthropod decomposers and litter decomposition. Both insecticides reduced densities of arthropod decomposers and reduced decomposition of plant litter by over 10%. Neonicotinoid seed coatings reduced collembolan densities by 34% and millipede densities by 52%, while the pyrethroid significantly reduced oribatid mite densities by 24% and millipede densities by 82%. Lower mite and millipede densities correlated with slower litter loss, and decomposition was slower under neonicotinoid seed coatings and broadcast pyrethroid applications. These results indicate that perennial, widespread use of prophylactic insecticides is likely to have concerning negative effects on the availability of alternative prey, plant residue breakdown, and nutrient cycling in field crops.

Relationship Between the Population Density of Phytophagous and Predaceous Mites Associated with three Mango Varieties at Assiut and Sohag Governorates

Relationship Between the Population Density of Phytophagous and Predaceous Mites Associated with three Mango Varieties at Assiut and Sohag Governorates

Evaluation of different control strategies for the management of redberry disease associated with Acalitus orthomera (Eriophyoidea: Eriophyidae) in commercial blackberry crops

In Mexico, redberry disease in blackberry (Rubus sp.) was first observed in Tacambaro, Michoacan, in 2011, causing losses greater than 70%. In this study, the eriophyid mite species associated with buds and berries and its association with redberry disease were identified. Based on morphology, the specimens of mites collected from the buds and fruits were identified as Acalitus orthomera (Keifer in Bull Dept Agric State Calif XL(3):93–104, 1951) (Acari: Eriophyidae). The eriophyid mite densities in the buds of fruiting laterals were moderately to highly positively correlated (ρ = 0.6–0.95) with redberry disease incidence at harvest. In the second part of this study, the effects of different management strategies on the density of A. orthomera in fruiting lateral buds and redberry disease incidence were evaluated. Two IPM and organic experimental plots were established during the 2014 and 2016 seasons. Treatments were based on sequential or alternating applications of lime sulfur, plant extracts, soybean oil, the entomopathogenic fungus Hirsutella thompsonii, and acequinocyl, abamectin, and hexythiazox. Treatments were applied either from budbreak or the start of the blooming period. Management programs based on the application of lime sulfur alone or in blocks or alternating with acequinocyl, abamectin, or neem extracts were effective in reducing A. orthomera densities in buds and the incidence of redberry disease when applied either after budbreak or at the beginning of the blooming period; some of these treatment schemes are feasible for use in organic systems. These results will contribute to optimizing the management of redberry disease in blackberry in the context of integrated pest management.

Metabarcoding mites: Three years of elevated CO2 has no effect on oribatid assemblages in a Eucalyptus woodland

Elevated atmospheric carbon dioxide concentrations (eCO2) are known to significantly impact aboveground vegetation, with cascading effects on belowground systems. However, the effects of altered biogeochemical and hydrological cycles on belowground faunal assemblages remain unclear. Oribatid mites are abundant and hyperdiverse litter decomposers, with the potential to act as bioindicators of ecosystem disturbance. Here, we assessed oribatid mite assemblages under ambient and eCO2 (ambient +150 ppm) at the Eucalyptus Free-Air CO2 Enrichment (EucFACE) facility using high-throughput sequencing of the mitochondrial cytochrome oxidase 1 (COI) gene. Our aims were to i) quantify the effect of eCO2 on mite abundance and diversity, and ii) evaluate metabarcoding as a reliable approach for the rapid assessment of oribatid mite assemblages. Three years of eCO2 exposure resulted in lower soil pH but had no significant impact on mite abundances or oribatid mite assemblage structure. Instead, mite densities were found to correlate negatively with soil NH4+, while oribatid species richness using both morphological and metabarcoding datasets were positively correlated with total soil nitrogen content. Additionally, metabarcoding showed that oribatid mite assemblage structure was correlated with total soil carbon and nitrogen content, and soil pH. However, dissimilarity matrices based on the two approaches were not correlated, indicating that metabarcoding can be used as a proxy for shifts in assemblage structure but cannot be directly compared with morphological datasets. This study demonstrates how metabarcoding can rapidly assess belowground assemblages, providing a useful monitoring tool under current and future climate scenarios.

House dust mites (Acari: Astigmata) from mattresses in Panama

The name “house dust mites” is commonly used to refer to species of mites belonging mainly to the Pyroglyphidae family (Astigmata) that are found in association with dust in the human dwellings. They represent the main source of allergens in the home and can cause allergic diseases. Mattresses often provide ideal conditions for mite colonization. In order to compare the diversity of house dust mites in the provinces of Panama and Panama Oeste in 2015, we collected dust from the surfaces of mattresses over an area of one square meter using the vacuum method. We obtained 50 samples using the vacuum method and recovered 10,225 mites. We found that the mites in our samples belonged to 15 families, 15 genera and 22 morphospecies. Relatively, high mean densities of mites per gram of dust on mattresses were obtained in the provinces of Panama (3,577 mites/g of dust) and Panama Oeste (6,273 mites/g of dust). The mite Blomia tropicalis was the most abundant species in mattresses in the Province of Panama and Dermatophagoides pteronyssinus was the most frequent one in Panama Oeste. Our results indicate that the mite community in mattresses is similar between PA and PO. However, our results differ significantly from those found in bedroom floors in a previous study. These differences correspond to a lower species richness, higher density and relative abundance of Astigmata mites in mattresses.

Temperature stress induces mites to help their carrion beetle hosts by eliminating rival blowflies.

Ecological conditions are known to change the expression of mutualisms though the causal agents driving such changes remain poorly understood. Here we show that temperature stress modulates the harm threatened by a common enemy, and thereby induces a phoretic mite to become a protective mutualist. Our experiments focus on the interactions between the burying beetle Nicrophorus vespilloides, an associated mite species Poecilochirus carabi and their common enemy, blowflies, when all three species reproduce on the same small vertebrate carrion. We show that mites compete with beetle larvae for food in the absence of blowflies, and reduce beetle reproductive success. However, when blowflies breed on the carrion too, mites enhance beetle reproductive success by eating blowfly eggs. High densities of mites are especially effective at promoting beetle reproductive success at higher and lower natural ranges in temperature, when blowfly larvae are more potent rivals for the limited resources on the carcass.

Conversion of Andean montane forests into plantations: Effects on soil characteristics, microorganisms, and microarthropods

AbstractTropical montane forests in the Andes are subjected to deforestation and subsequent transformation into pastures. Abandoned pastures are frequently reforested by planting monoculture timber plantations, resulting in reduced aboveground diversity and changes in soil characteristics compared to primary forests. In this study, we evaluated differences in soil properties (litter layer thickness, pH, water content, and C‐to‐N ratio) between degraded primary montane forest and monoculture pine (Pinus patula) and alder (Alnus acuminata) plantations and their effects on density, diversity, and community structure of litter and soil‐living mesofauna, with focus on oribatid mites (Acariformes). The study was performed in a montane region in the southern Ecuadorian Andes (2,000–2,600 m a.s.l.). C‐to‐N ratios in the litter and upper 5 cm soil layer were higher in pine plantations, while other soil characteristics were similar between vegetation types. Surprisingly, microbial biomass and density of soil mesofauna in the litter layer did not differ between vegetation types, while density and species richness of oribatid mites were higher in pine plantations. Community structure of oribatid mites differed between vegetation types with only a few species overlapping. The results indicate that quality and diversity of litter were not the major factors regulating the mesofauna community. Instead, soil animals benefited from increased habitat structure in thicker litter layers and potentially increased availability of root‐derived resources. Overall, the results suggest that from a soil animal perspective, monoculture plantations are less detrimental than commonly assumed and enrichment of abandoned plantations with native tree species may help to restore tropical montane forests.Abstract in Spanish is available with online material.

Preliminary sampling of dry bulb mite, Aceria tulipae Keifer in native garlic in Ilocos Region, Luzon Island, Philippines

The objective of this study was to provide information on the population density and distribution of the dry bulb mite, Aceria tulipae on the leaves and bulbs of native garlic in Ilocos Region, Philippines. Preliminary data showed that the average number of A. tulipae is the same within the leaf and plant canopy. The total number of A. tulipae is highest at the middle section of the leaf. Aceria tulipae is also detected in cloves sampled from harvested bulbs. Results suggest that the leaves and bulbs of native garlic could be considered when designing a sampling method in the future.

Density of Dermatophagoides spp. and Its Relationship with House-dust Mite Specific Serum IgE in Persistent Asthma

Background: Asthma is a chronic inflammation of the bronchial tree that emerges as a response to exogenous factors, such as allergens, irritants, and infections. Some asthmatic patients had been reported having symptoms of asthma due to house-dust mites (HDM) allergen exposure. It is associated with immune responses which were increased in the form of specific Immunoglobulin E (IgE) production against HDM allergens. This case-control study aimed to determine the HDM profiles in persistent asthmatic patients, including density of mites, as well as its relationship with specific IgE anti-HDM serum levels.Materials and Methods: A total of 13 patients with persistent asthma and 12 control patients had their specific anti-HDM IgE levels examined using Immulite 2000 xpi. The house dust samples were taken and analyzed with the Fain method.Results: The results have shown that 69% of patients in the persistent asthma group and 25% of normal patients were positive for IgE anti-HDM. Dermatophagoides pteronyssinus is a predominant species with a total of 120 mites (83.9%) of 143 mites. Correlation analysis indicated a positive relationship between IgE anti-HDM levels within the serums of patients and the density of mites in the dust obtained from bedroom spaces (Spearmen Rho, R=0.35, p=0.04).Conclusion: Positive IgE anti-HDM patients in the persistent asthma group were higher (69%) than those in the clinically normal group (25%). The density of mites were dominated by D. Pteronyssinus. The bedroom-dust mites density revealed a positive correlation with serum IgE anti-HDM levels in persistent asthma patients.Keywords: asthma, density, Dermatophagoides spp.,IgE

The Use of Wood Chips for Revitalization of Degraded Forest Soil on Young Scots Pine Plantation

The aim of the study was to assess the impact of several methods of mulching degraded forest soil with wood chips on the development of mite (Acari) community, with particular emphasis to oribatid mites (Oribatida), and on the growth of young plantings of Scots pine (Pinus sylvestris L.). Mulching with wood chips should contribute to revitalize soil fauna and restore natural forests on degraded soils. Scots pine seedlings were planted at the post-military training ground. Four experimental treatments were tested: control—uncovered soil (C), mulching with wood chips (W), W + mycorrhiza preparation (WM), and W + forest litter (WL). At the end of the growing season in 2012, 2013 and 2014, the following plant measurements were carried out: length of annual increment of the main stem, stem base diameter, number and lengths of lateral shoots in the annual whorl. The mite calculations included average mite density, dominance index, species richness, oribatid mite diversity, average number of species, and Shannon general species diversity index. The use of mulching with wood chips did not significantly affect the growth characteristics of Scots pine plants, but strongly increased the mite community. After mulching, the total number and species diversity of Acari increased many times, and Oribatida began to dominate among micro-arthropods. The number of Oribatida increased most in W. The largest species diversity was observed in WL. 24 species of Oribatida were found that were used as the bio-indicators of soil succession changes. Tectocepheus velatus clearly dominated in all mulching treatments. Oppiella nova and Scutovertex sculptus were also numerous populations of Oribatida. The study shows that mulching with Scots pine wood chips, especially with the addition of forest litter, significantly enriches soil fauna and is therefore useful in the regeneration process of degenerated forest soils.

<p class="Body"><strong>The establishment of an invasive pest mite, <em>Raoiella indica</em>, affects mite abundance and diversity on coconut plants</strong></p>

The introduction and establishment of an invasive species in a new habitat represents a major threat to biodiversity and ecosystem structure. A recent example of a mite that has become an invasive species is the red palm mite, Raoiella indica Hirst (Acari: Tenuipalpidae). After its introduction in the Americas, this species has considerably expanded the number of hosts and has been reported as a key pest of some of these. In the present study we investigated the possibility of mitefauna alteration on coconut leaflets (abundance and diversity) mediated by the introduction and establishment of R. indica. A survey was conducted over a period of 1 year in two areas of coconut cultivation: one infested and one free of R. indica. The results of the present study suggest that the introduction of R. indica modifies the mitefauna existing in coconut leaflets. Differences were detected in the abundance and diversity of mites at the level of the taxonomic categories (family and species) and at the level of the trophic groups (predators, herbivores and mites with undefined feeding mode). Additionally, in plants infested by the invasive species, a similar pattern was observed between the fluctuation of the phytoseiid mites and other tenuipalpid mites. In these plants, the density of the tenuipalpid mites (including R. indica) was also the variable that most contributed to explain the fluctuation of phytoseiid mites. This suggests that the invasive species, R. indica, acts as a keystone species, structuring the mitefauna in coconut plants.

Demodex: a skin resident in man and his best friend.

Demodex mites are microscopic arachnids found in the normal skin of many mammals. In humans, it is well established that Demodex mite density is higher in patients with the skin condition rosacea, and treatment with acaricidal agents is effective in resolving symptoms. However, pathophysiology of rosacea is complex and multifactorial. In dogs, demodicosis is a significant veterinary issue, particularly the generalized form of the disease which can be fatal if untreated. In each species, clinical and molecular studies have shown that the host's immunological interactions with Demodex mites are an important, but not fully understood, aspect of how Demodex can live in the skin either as a harmless commensal organism or as a pathogenic agent. This review outlines the role of Demodex mites in humans and dogs, considering morphology, prevalence, symptoms, diagnosis, histology treatment and pathogenesis.

Ecotoxicological assessment after the world's largest tailing dam collapse (Fundão dam, Mariana, Brazil): effects on oribatid mites.

Worldwide, environmental tragedies involving mining dam ruptures have become more frequent. As occurred a few years ago in Brazil (on 5 November 2015, in Minas Gerais state) the Fundão Dam rupture released 60million m3 of tailings into terrestrial and aquatic ecosystems. Since then, little information on the ecotoxicity of these tailings has been disclosed. In the laboratory, the acute, chronic and bioaccumulation effects of increased Fundão tailing concentrations on oribatid mites (Scheloribates praeincisus) were assessed. Additionally, the bioaccumulation of 11 trace metals (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn) and the total density of oribatid mites found in the areas contaminated by the Fundão tailings were determined. The percentages of mite survival and reproductive inhibition were higher than 60% and 80%, respectively, in all contaminated areas with the highest concentration (100% mine tailings). Field studies showed an expressive reduction in the total density of oribatids per m-2 (up to 54 times) in the contaminated areas compared with the reference area. Metal accumulations in the field were 5.4 and 3.2 higher (for Ni and Hg, respectively) and up to two times higher (for most metals) than those in the laboratory for 42days. The mite responses to the Fundão tailings found in this study suggest long-term interference in their biological development. In this sense, we can conclude that the introduction of mine tailings onto soils tended to compromise the functionality of the mites in the ecosystem, which causes imbalances to cascade other organisms of the trophic web.

Using mathematical models to describe aerial dispersal and silk ball formation of peanut red spider mite, Tetranychus ogmophallos (Acari: Tetranychidae).

Peanut red spider mite, Tetranychus ogmophallos, exhibits a peculiar dispersal behavior using silk balls, which involves clustering of mites and spinning of webs at the top of plants. Such a dispersal mechanism has not been studied for this species yet. Therefore, this study aimed at using mathematical models to describe aerial dispersal and silk ball formation of peanut red spider mite on peanut plants. The influence of wind speed, generated by a wind tunnel, on the dispersal of mites was studied in two experiments, one with 500 mites per plant and one with 1000 mites per plant, and six wind speeds (5, 10, 15, 20, 25, and 30kmh-1) for each mite density. The proportion of displaced mites and the distance they were blown were measured. Another series of experiments considered the formation of silk balls to assess how fast balls were formed as a function of time and the number of mites present on a peanut plant. Data from the wind tunnel experiments were analyzed by logistic regression and multiple regression to assess the proportion of displaced mites and the distance moved, respectively, as functions of wind speed and the initial density of mites on the donor plant. The distribution of dispersal distances from the donor plant was fitted by a mathematical model proposed by Ricker (J Fish Res Board Can 11:559-623, 1954). The number of mites moving upwards on a plant to be involved in silk ball formation was modeled as a function of time based on the initial number of spider mites and their estimated birth, death and movement rates per capita. Logistic regression was used to analyze the presence of balls as a function of time elapsed since a plant was infested with spider mites. Finally, non-linear regression was applied to link ball size to the total number of mites occupying the ball. The data analyses revealed that wind speed had a significant positive effect on take-off probability and distance moved by individual mites, whereas mite density had little influence. Ricker's model adequately described the distribution of dispersal distances. The models describing silk ball formation also described data very well. Ball size was found to increase almost linearly with the number of mites found in the ball. We expect that the knowledge provided by the present study will help to develop efficient management strategies against T. ogmophallos in peanut crops as dispersal seems to be a key factor in the species' capability to become a serious pest.

<p><strong>Is </strong><strong><em>Pyemotes zhonghuajia</em></strong><strong> (Acari: Pyemotidae) a suitable biological control agent against the fall armyworm </strong><strong><em>Spodoptera frugiperda</em></strong><strong> (Lepidoptera: Noctuidae)?</strong><strong></strong></p>

The fall armyworm (FAW), Spodoptera frugiperda Smith (Lepidoptera: Noctuidae), is one of the most damaging noctuid pests of maize and is reported in China at the beginning of 2019. It poses a serious threat to the food security of China. In order to find an attractive alternative to reduce the application of chemical insecticides, we screened different initial mite densities of Pyemotes zhonghuajia on the mortality rate of different stages of FAW and also recorded the number of P. zhonghuajia on FAW at the different times (24, 48, and 72 h). The results showed that initial mite densities had a significant effect on the mortality rates of all stages of FAW and the number of P. zhonghuajia found on the surface of FAW. One P. zhonghuajia female was able to significantly induce the mortality of FAW in the 1st to 3rd instar larvae, and the mite density of 40 could achieve 100% FAW mortality when added 1st to 5th instar larvae and prepupae. There was an increasing number of P. zhonghuajia on FAW from the 2nd to 4th instar larvae stages at all three days. These results provide the basic information for considering P. zhonghuajia as a suitable bio-control agent against FAW in China.