Natural Enemy Of Spider Mites Research Articles

Acaricide exposure impairs predatory behavior of the phytoseiid mite Neoseiulus idaeus (Acari: Phytoseiidae).

Predation is an important interaction that can change the structure of arthropod communities across both temporal and spatial scales. In agricultural systems predation can reduce the population levels of several arthropod pest species of a community. This predator-prey interaction involves the predator searching and handling behaviors. Several factors can affect this interaction, such as pesticide exposure, which is a frequent feature in agroecosystems. Thus, the hypothesis of our study is that the predatory behavior of the phytoseiid mite Neoseiulus idaeus Denmark & Muma, an important natural enemy of spider mites, is affected by acaricide exposure. To test that hypothesis, the predatory mite was exposed to the acaricides abamectin, fenpyroximate, and azadirachtin in 4 exposure scenarios. The predatory behavior of N. idaeus was negatively affected by acaricide exposure when the leaf surface containing both prey and predator was sprayed leading to a reduction in the frequency of transitions between predator walking and meeting preys. Prey handling and consumption were also compromised by acaricide exposure through contaminated leaf surface and prey, and contaminated leaf surface, prey, and predator. Abamectin compromised predation regardless of the exposure scenario. Acaricide-exposure reduced the number of prey found, number of attacks, and number prey killed by N. idaeus. Moreover, partial prey consumption was observed with acaricide-exposed mites. Thus, caution is necessary while attempting to integrate acaricide applications and mass release of N. idaeus for spider mite management.

Identification of potential sex determination genes and functional analyses in Neoseiulus californicus under prey stress.

Phytoseiid mites are important natural enemies of spider mites. Sex-determination mechanism are important basic scientific issues in the reproduction and evolution of predatory mites. Clarifying sex-determination mechanism may provide reference for exploring genetic approach to have the phytoseiid mites produce more female offspring, which could improve their effectiveness as a biological control agent. We used transcriptome sequencing to identify and characterize 20 putative sex-determination genes in the phytoseiid mite Neoseiulus californicus, a species with uncommon pseudo-arrhenotoky, including doublesex-like (dsx1-like), transformer-2 (tra-2), intersex (ix), and fruitless-like (BTB2). A significant negative correlation was found between prey stress and offspring sex ratio. But the most genes identified showed no difference in expression between the groups with lowest and highest female offspring ratios. The hatching rate and sex ratio of female offspring were reduced when the ix gene was silenced, and the oviposition days and fecundity were reduced when the BTB2 gene was silenced. The fecundity was reduced when the tra2 gene was silenced and the snf gene is essential for oviposition in female. There was no effect on reproduction and female sex determination when silencing the dsx1-like and dsx2-like gene. The genes BTB2, tra2 and snf are involved in oviposition, and ix may be involved in female sex determination and egg formation in Neoseiulus californicus. The results are conductive to further understanding molecular regulatory mechanism of sex determination in predatory mites and may provide a reference for better use of this predatory by producing more females. © 2022 Society of Chemical Industry.

Environmental RNAi-based reverse genetics in the predatory mite Neoseiulus californicus: Towards improved methods of biological control

The predatory mite Neoseiulus californicus (McGregor) (Mesostigmata: Phytoseiidae) has been commercialized by manufacturers in the pest control industry and is used worldwide as a natural enemy of spider mites. However, because its genome has not been sequenced, reverse genetics techniques that could be used to analyze gene function have not been established. Here we partially sequenced the gene that encodes the vacuolar-type H+-ATPase (V-ATPase), an ATP-dependent proton pump, in N. californicus (NcVATPase) and then conducted a functional analysis using environmental RNA interference (eRNAi) by orally administering sequence-specific exogenous dsRNA (dsRNA-NcVATPase) to larvae and adult females. The larvae treated with dsRNA-NcVATPase took longer to develop and had lower survivorship, fecundity, and offspring viability at the adult stage than those treated with a control dsRNA. Adult females treated with dsRNA-NcVATPase showed significant reductions in survival, fecundity, and prey consumption, and their endogenous gene expression level of NcVATPase was reduced by approximately 65% compared with the control. Our findings suggest that the NcVATPase gene, silencing of which inhibits feeding and reproduction, is an excellent biomarker for investigating the eRNAi mechanism in N. californicus. The highly efficient experimental system of eRNAi established in this study paves the way for applied research using eRNAi to enhance the predatory ability of N. californicus.

A vegetable oil-based biopesticide with ovicidal activity against the two-spotted spider mite, Tetranychus urticae Koch.

A recently developed biopesticide made of safflower and cottonseed oils has excellent ovicidal activity against the hard‐to‐control spider mite Tetranychus urticae Koch (Acari: Tetranychidae). It has attracted attention as a sustainable treatment for controlling T. urticae because it has low potential for promoting resistance and little effect on the predatory mite Neoseiulus californicus (McGregor) (Acari: Phytoseiidae), which is an important natural enemy of spider mites. Here, we investigated the mechanism of its ovicidal activity against T. urticae. The oil droplets in the oil‐in‐water emulsion of the biopesticide strongly adhered to T. urticae eggs, seeped through the chorion being cut during hatching, and inhibited the embryonic rotational movement necessary for cutting and hatching. No adverse effect was observed on N. californicus eggs even in undiluted biopesticide. We conclude that this biopesticide and N. californicus can be used simultaneously in the integrated management of T. urticae in oily biopesticide‐tolerant plant species.

Effects of Three Artificial Diets on Life History Parameters of the Ladybird Beetle Stethorus gilvifrons, a Predator of Tetranychid Mites.

Simple SummaryThe ladybird beetle Stethorus gilvifrons is an important natural enemy of spider mites, which are pests of numerous agricultural crops. Mass production of S. gilvifrons would be necessary to generate large numbers of individuals for augmentative biological control. Using alternative prey/foods or artificial diets as a substitute to natural prey (spider mites) would be important in the cost-effective production of S. gilvifrons. The objectives of the current study were to determine the developmental and reproductive characteristics of S. gilvifrons fed on different artificial diets. Artificial diets consisted of sucrose, honey, royal jelly, agar, yeast, date palm pollen supplemented with hen’s egg yolk (AD1, as basic diet), Ephestia kuehniella eggs (AD2), or E. kuehniella eggs and 2,4-dihydroxybenzoic acid (AD3). Adults and larvae of S. gilvifrons performed best on AD3, indicating the potential of this artificial diet for mass rearing of this important predatory ladybird beetle.Background: The ladybird beetle Stethorus gilvifrons (Mulsant) is an important natural enemy of tetranychid mites and functions as a biological control of these plant pests. The development, survival and reproduction of S. gilvifrons were studied when fed on three artificial diets. The components of the artificial diet that S. gilvifrons could be reared successfully on for one generation with no use of tetranychid mites were examined. Methods: Artificial diets consisted of sucrose, honey, royal jelly, agar, yeast, date palm pollen supplemented in different diets with hen’s egg yolk (AD1, as basic diet), Ephestia kuehniella Zeller eggs (AD2), or E. kuehniella eggs and 2,4-dihydroxybenzoic acid (AD3). Results: Adults and larvae of Stethorus gilvifrons fed on AD1 had a shorter immature development and preoviposition periods than those fed on AD2 and AD3. The total number of deposited eggs was significantly higher for the females fed on AD3 than on the other diets. The intrinsic rate of increase (r) of S. gilvifrons was highest on AD3, followed by AD2, and AD1. Conclusion: Stethorus gilvifrons performed best on AD3, indicating the potential of this artificial diet for the mass rearing of this important predatory ladybird beetle.

<p><strong>Effects of</strong><strong> </strong><strong>food sources on the fecundity and gene expression of vitellogenin and its receptor from </strong><strong><em>Amblyseius eharai </em></strong><strong>(Acari: Phytoseiidae)</strong><strong></strong></p>

Vitellogenin (Vg) and Vitellogenin receptor (VgR) play key roles in the reproductive process and development of many arthropod species, including Amblyseius eharai, a dominant natural enemy of spider mites and other small pests. In this study, impacts of different food on A. eharai fecundity were investigated. Two Vg genes (AeVg1 and AeVg2) and AeVgR genes were cloned, with their expression pattern analyzed. When fed with different foods including Tetranychus cinnabarinus, Aleuroglyphus ovatus and Camellia oleifera pollen, the number of eggs for each female of A. eharai was influenced significantly (P<0.05), while the hatching rate of eggs not significantly (P>0.05). The open reading frames of AeVg1, AeVg2 and AeVgR were 5673, 5634 and 5597 bp, encoding 1857, 1851 and 1830 amino acids, respectively. Phylogenetic analysis of the amino acid sequences between the AeVgs and AeVgR and 35 other Vg and VgRs from other arthropod species showed that A. eharai AeVg1 was related most closely to Neoseiulus barkeri Vg1, AeVg2 was related most closely to Neoseiulus cucumeris Vg2, AeVgR was most similar to Varroa jacobsori VgR. AeVgs and AeVgR had similar expression patterns: the highest expression was observed in the oviposition female stage, and the highest expression was observed in A. eharai fed with C. oleifera pollen. Positive correlations between expression of AeVgs and AeVgR and fecundity were observed. These results will help us understand the molecular mechanism of the reproductive capacity in A. eharai.

Gene cloning and difference analysis of vitellogenin in Neoseiulus barkeri (Hughes).

Neoseiulus barkeri (HUGHES) is the natural enemy of spider mites, whiteflies and thrips. Screening for chemically-resistant predatory mites is a practical way to balance the contradiction between the pesticide using and biological control. In this study, the number of eggs laid by fenpropathrin-susceptible and resistant strains of N. barkeri was compared. Additionally, we cloned three N. barkeri vitellogenin (Vg) genes and used quantitative real-time polymerase chain reaction to quantify Vg expression in susceptible and resistant strains. The total number of eggs significantly increased in the fenpropathrin-resistant strain. The full-length cDNA cloning of three N. barkeri Vg genes (NbVg1, NbVg2 and NbVg3) revealed that the open reading frames of NbVg1, NbVg2 and NbVg3 were 5571, 5532 and 4728 bp, encoding 1856, 1843 and 1575 amino acids, respectively. The three N. barkeri Vg possessed the Vitellogenin-N domain (or lipoprotein N-terminal domain (LPD_N)), von Willebrand factor type D domain (VWD) and the domain with unknown function 1943 (DUF1943). The NbVg1 and NbVg2 expression levels were significantly higher in the resistant strain than in the susceptible strain, while the NbVg3 expression level was lower in the resistant strain. Thus, we speculate that the increased number of eggs laid by the fenpropathrin-resistant strain of N. barkeri may be a consequence of changes in Vg gene expression.

Redescriptions and distributions of acarivorous rove beetles, Holobus kashmiricus beneficus and H. yasumatsui (Coleoptera: Staphylinidae: Aleocharinae), in Japan and Taiwan

During extensive field surveys, Holobuskashmiricus beneficus (Naomi) (Coleoptera: Staphylinidae), a prospective natural enemy of spider mites, was recorded for the first time in the Ryukyu Archipelago, while it was not found in Taiwan. On the other hand, another related species, H. yasumatsui (Kistner), was not detected in the Ryukyu Archipelago, but instead was found only in Taiwan. These distributions indicated that species composition varies in the two geographical areas. Holobus kashmiricus beneficus co-occurred with more than six spider mite species (Acari: Tetranychidae) in the Ryukyu Archipelago, suggesting that this species has a broad prey range. Here, we redescribed the two rove beetle species, because the intraspecific variation among the previous diagnostic morphological characters, such as patterns and numbers of carinae on abdominal tergites IV–VI, prevented their use in the definitive classification of the species. We suggest that the shapes of the antennal segment VII and abdominal segment VIII should be considered as new diagnostic characters for H. kashmiricus beneficus and H. yasumatsui.

The effect of synthetic pesticides and sulfur used in conventional and organically grown strawberry and soybean on Neozygites floridana, a natural enemy of spider mites.

The beneficial fungus Neozygites floridana kills the two-spotted spider mite Tetranychus urticae, which is a serious polyphagous plant pest worldwide. Outbreaks of spider mites in strawberry and soybean have been associated with pesticide applications. Pesticides may affect N. floridana and consequently the natural control of T. urticae. N. floridana is a fungus difficult to grow in artificial media, and for this reason, very few studies have been conducted with this fungus, especially regarding the impact of pesticides. The aim of this study was to conduct a laboratory experiment to evaluate the effect of pesticides used in strawberry and soybean crops on N. floridana. Among the pesticides used in strawberry, the fungicides sulfur and cyprodinil + fludioxonil completely inhibited both the sporulation and conidial germination of N. floridana. The fungicide fluazinam affected N. floridana drastically. The application of the fungicide tebuconazole and the insecticides fenpropathrin and abamectin resulted in a less pronounced negative effect on N. floridana. Except for epoxiconazole and cyproconazole, all tested fungicides used in soybean resulted in a complete inhibition of N. floridana. Among the three insecticides used in soybean, lambda-cyhalothrin and deltamethrin resulted in a significant inhibition of N. floridana. The insecticides/ acaricides abamectin and lambda-cyhalothrin at half concentrations and fenpropathrin and permethrin and the fungicide tebuconazole at the recommended concentrations resulted in the lowest impact on N. floridana. The fungicides with the active ingredients sulfur, cyprodinil + fludioxonil, azoxystrobin, azoxystrobin + cyproconazole, trifloxystrobin + tebuconazole and pyraclostrobin + epoxiconazole negatively affected N. floridana. © 2015 Society of Chemical Industry.

Does Use of Pesticides Known to Harm Natural Enemies of Spider Mites (Acari: Tetranychidae) Result in Increased Number of Miticide Applications? An Examination of California Walnut Orchards

Integrated pest management (IPM) offers guidelines to reduce spider mite (Acari: Tetranychidae) outbreaks by avoiding pesticides known to be harmful to the natural enemies of spider mites. However, in practice, these guidelines can be inconsistent in their effectiveness. The project examined whether California walnut (Juglans L.) growers, following IPM guidelines to avoid pesticides harmful to the natural enemies of spider mites, achieved lower miticide use. Significant statistical tests suggested that fields with harmful applications were 40% more likely to have a miticide application than fields without. Although the IPM guidelines achieved the goal of reducing miticide use, further analysis of other potential causal mechanisms behind outbreaks could strengthen the effectiveness of the guidelines, potentially increasing IPM adoption.

Survey of natural enemies of spider mites (Acari: Tetranychidae) in citrus orchards in eastern Spain

Field surveys were conducted from 2004 to 2007 to determine the species composition and relative abundance of natural enemies associated with colonies of either the citrus red mite, Panonychus citri, or the two spotted spider mite, Tetranychus urticae, in Valencian citrus orchards (eastern Spain). Fourteen species were recorded, six phytoseiid mites and eight insect predators. Two of them are reported for the first time on citrus in Spain and two more are first reports as predators associated with T. urticae. The community of predators associated with T. urticae and P. citri was almost identical, and the Morisita-Horn index of similarity between both natural enemy complexes was close to one, suggesting that predators forage on both pest species. Quantifying the presence of many known spider mites predators in Valencian citrus orchards is an important first step towards spider mite control. A challenge for future studies will be to establish conservation and/or augmentation management strategies for these predators, especially to improve T. urticae biological control.

Prey and Non-prey Arthropods Sharing a Host Plant: Effects on Induced Volatile Emission and Predator Attraction

It is well established that plants infested with a single herbivore species can attract specific natural enemies through the emission of herbivore-induced volatiles. However, it is less clear what happens when plants are simultaneously attacked by more than one species. We analyzed volatile emissions of lima bean and cucumber plants upon multi-species herbivory by spider mites (Tetranychus urticae) and caterpillars (Spodoptera exigua) in comparison to single-species herbivory. Upon herbivory by single or multiple species, lima bean and cucumber plants emitted volatile blends that comprised mostly the same compounds. To detect additive, synergistic, or antagonistic effects, we compared the multi-species herbivory volatile blend with the sum of the volatile blends induced by each of the herbivore species feeding alone. In lima bean, the majority of compounds were more strongly induced by multi-species herbivory than expected based on the sum of volatile emissions by each of the herbivores separately, potentially caused by synergistic effects. In contrast, in cucumber, two compounds were suppressed by multi-species herbivory, suggesting the potential for antagonistic effects. We also studied the behavioral responses of the predatory mite Phytoseiulus persimilis, a specialized natural enemy of spider mites. Olfactometer experiments showed that P. persimilis preferred volatiles induced by multi-species herbivory to volatiles induced by S. exigua alone or by prey mites alone. We conclude that both lima bean and cucumber plants effectively attract predatory mites upon multi-species herbivory, but the underlying mechanisms appear different between these species.

Diversity and abundance of phytoseiid mites in natural vegetation in the vicinity of apple orchards in Japan

Mite species of the family Phytoseiidae, which includes some important natural enemies of spider mites and insect pests, found on wild plants in the vicinity of apple orchards in north Japan, were studied during 2001 to 2006. Euseius finlandicus, Typhlodromus vulgaris, and Amblyseius orientalis were recognized as the dominant species of phytoseiid mites in natural vegetation. Of 18 plant species, 5 hosted an abundant number of phytoseiid mites. Especially on Viburnum dilatatum and Morus australis, the density of phytoseiid mites on leaves was low in spring and increased gradually until autumn. When we used a “Phyto trap” as a tool to collect phytoseiid mites walking on branches, the density on V. dilatatum was high in spring and low in autumn. Phytoseiid mites in traps on M. australis had 2 peaks of occurrence, in spring and autumn. Transeius fulvus was not collected from leaves but from traps, and E. finlandicus was not collected from traps but from leaves.

Intact lima bean plants exposed to herbivore-induced plant volatiles attract predatory mites and spider mites at different levels according to plant parts

Previous studies have shown that intact lima bean plants exposed to volatiles emitted from conspecific plants infested by two-spotted spider mites, Tetranychus urticae (Acari: Tetranychidae), attract Phytoseiulus persimilis (Acari: Phytoseiidae), a carnivorous natural enemy of spider mites. Here, we investigated the olfactory responses of P. persimilis and T. urticae to different parts of intact lima bean plants exposed to these volatiles using a Y-tube olfactometer. Predators responded in greater number to volatiles from the first trifoliate leaves compared to those from primary leaves, and to volatiles from the parts above the first trifoliate leaves compared to those from the first trifoliate leaves. Conversely, spider mites responded more to volatiles from primary leaves compared to those from the first trifoliate leaves, and showed equal preference for volatiles released from the first trifoliate leaves or the parts above the first trifoliate leaf. The reproduction of spider mites in primary leaves was higher than those on trifoliate leaves. Based on these data, the potential adaptive value of differential attractiveness of different parts of intact lima bean plants to T. urticae and P. persimilis is discussed.

Predation by Allothrombium pulvinum on the spider mites Tetranychus urticae and Amphitetranychus viennensis: Predation Rate, Prey Preference and Functional Response

The deutonymphs of Allothrombium pulvinum Ewing (Acari: Trombidiidae) are among the most important natural enemies of spider mites in North, North East and West Iran. In this study, maximum predation rate and preference experiments were conducted with A. pulvinum deutonymphs on apple leaf discs, to determine their preference for either of two spider mite species: Amphitetranychus viennensis (Zacher) and Tetranychus urticae Koch (Acari: Tetranychidae). Maximum predation rate tests showed that the predatory mite consumed more eggs and females of T. urticae than of A. viennensis. Furthermore, the Manly's preference index for eggs and females of T. urticae confirmed that T. urticae were the preferred prey. The functional response of A. pulvinum deutonymphs on females of T. urticae was examined over a 24-h period. Predation of A. pulvinum deutonymphs presented with females of T. urticae followed a type III functional response. Estimated handling time for the predatory mites was 4.51 h and attack coefficient b, which describes the changes in attack rate with prey densities in a type III functional response, was 0.021.

Olfactory responses of two specialist insect predators of spider mites toward plant volatiles from lima bean leaves induced by jasmonic acid and/or methyl salicylate.

The responses of two insect predators of spider mites, Scolothrips takahashii (Thysanoptera: Thripidae) and Oligota kashmirica benefica (Coleoptera: Staphylinidae), to volatile compounds from leaves treated with aqueous jasmonic acid (JA) and/or gaseous methyl salicylate (MeSA) in an olfactometer were examined. Adult females of O. kashmirica benefica exhibited a significant preference for JA+MeSA-treated leaves when compared with uninfested leaves. In contrast, adult females of S. takahashii significantly preferred MeSA- and JA+MeSA-treated leaves to uninfested leaves. Neither predator showed any preference for JA-treated leaves when compared with uninfested leaves. The results argue in favor of manipulating the behavior of natural enemies of herbivores as a method of biological control against herbivorous pests in agroecosystems. This is the first report to suggest that MeSA can be a useful tool for enhancing the effectiveness of carnivorous natural enemies of spider mites.

Side‐effects of neem (Azadirachta indica) products on insect pathogens and natural enemies of spider mites and insects*

AbstractNeem products are safe to spiders, adults of numerous beneficial insect species and eggs of many predators such as coccinellids. Nymphal/larval instars are more or less susceptible, especially under laboratory conditions. No or only slight side‐effects are, as a rule, observed under semi‐field or field conditions. Due to their relative selectivity (‘stage selectivity’) neem products can be recommended for many programmes of Integrated Pest Management as it is unlikely that they will cause severe disturbances in ecosystems. In a few exceptional cases caution is recommended but it should be borne in mind that many more so‐called indifferent as well as beneficial insects and spiders are killed by synthetic pesticides as compared with neem products. Or in other words, the use of neem‐based pesticides can be a substantial contribution towards preservation of biodiversity in ecosystems in spite of the fact that they are not completely safe to all stages of beneficial nematodes, mites, and insects.

ハダニ類の天敵である２種のケシハネカクシの簡易識別法と種々の植物上での生息割合

ハダニ類の天敵である２種のケシハネカクシの簡易識別法と種々の植物上での生息割合

Predatory Gall Midge (unofficial common name), Feltiella acarisuga (Vallot) (Insecta: Diptera: Cecidomyiidae)

The predatory gall midge, Feltiella acarisuga (Vallot), is one of the most effective and widespread natural enemies of spider mites (Tetranychidae) (Gagne 1995). It is a particularly important natural enemy of the twospotted spider mite, Tetranychus urticae Koch, in a number of cropping systems (Opit et al. 1997). F. acarisuga could be particularly useful for integrated pest management of spider mites that attack greenhouse crops (Gillespie et al. 1998). This document is EENY-269, one of a series of Featured Creatures from the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published: June 2002. 
 EENY269/IN549: Predatory Gall Midge (Unofficial Common Name), Feltiella acarisuga (Vallot) (Insecta: Diptera: Cecidomyiidae) (ufl.edu)

Die Feinde der Raubmilben als Reduzierender Faktor der Spinnmilben

The relations betweenMetatetranychus ulmi living on apple trees and its different predators are complex. The most important natural enemy of this spider mite is the predacious miteTyphlodromus pyri (= T. tiliae). It destroys more spider mites than the beneficial insects do. In the district of Stuttgart-Hohenheim about 38 species of insects and spiders feed onTyphlodromus mites. For instanceT. pyri is reduced considerably byOrius minutus. This bug is a natural enemy of aphids and spider mites, however it prefers the predatory mites. It attacks the spider mites and aphids only ifTyphlodromus mites are not available.Chrysopa vulgaris andAnthocoris nemorum are similar in their feeding habits. These two destroyTyphlodromus pyri also but they are less important thanO. minutus. The other beneficial insects in our orchards have little effect on spider mites or predacious mites. If we have enough pests on our apple trees to make spraying necessary, we should look forTyphlodromus mites and be careful no to destroy them. We should always examine the composition of the biocoenosis applying chemical agents because the populations of insects and predacious mites may vary from one area to the other.