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BACKGROUND: The Varroa mite (Varroa destructor) is considered to be the greatest threat to apiculture worldwide. RNA interference (RNAi) using double‐stranded RNA (dsRNA) as a gene silencing mechanism has emerged as a next‐generation strategy for mite control. RESULTS: We explored the impact of a dsRNA biopesticide, named vadescana, designed to silence the calmodulin gene in Varroa, on mite fitness in mini‐hives housed in a laboratory. Two dosages were tested: 2 g/L dsRNA and 8 g/L dsRNA. Vadescana appeared to have no effect on mite survival, however, mite fertility was substantially reduced. The majority of foundress mites exposed to vadescana failed to produce any offspring. No dose‐dependent effect of vadescana was observed, as both the low and high doses inhibited mite reproduction equally well in the mini‐hives and neither dose impacted pupal survival of the honey bee. Approximately 95% of bee pupae were alive at uncapping across all treatment groups. CONCLUSION: These findings suggest that vadescana has significant potential as an effective alternative to conventional methods for Varroa control, with broader implications for the utilization of RNAi as a next‐generation tool in the management of pest species. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Most studies on efficacy of fungal pathogens and predatory mites against Tetranychus urticae have been done on individual species in the laboratory. We evaluated fungi and predatory mites separately and together against glasshouse populations of T. urticae on chrysanthemum plants. First, effectiveness of the fungal pathogens Beauveria bassiana (Bb88) and Metarhizium anisopliae (Ma129) was compared; then, effectiveness of the predatory mites Phytoseiulus persimilis and Neoseiulus californicus. Based on the results, N. californicus and isolate Ma129 were selected and evaluated in combination. In all experiments, treatment effects were assessed for eggs and motile stages of T. urticae. RESULTS: The first experiment showed no significant effect of either fungal isolate on T. urticae populations, except on plants initially infested with 20 mites, where more eggs were found in the control compared to the fungal treatments. In the second experiment, both predatory mites were equally effective at reducing T. urticae populations compared with the control, regardless of initial T. urticae population density. The last experiment demonstrated that populations of T. urticae were reduced most when M. anisopliae (Ma129) and N. californicus were applied together, compared with the control and when each natural enemy was applied separately. CONCLUSIONS: Metarhizium anisopliae (Ma129) and B. bassiana (Bb88) isolates did not have a significant effect on reducing T. urticae populations. Both predatory mites reduced T. urticae populations, regardless of T. urticae density. Combined application of M. anisopliae (Ma129) and N. californicus were more effective against T. urticae than the control or when each agent was applied separately. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The mite Varroa destructor Anderson and Trueman (Mesostigmata: Varroidae) has a dramatic impact on beekeeping and is one of the main causes of honey bee colony losses. This ectoparasite feeds on honey bees' liquid tissues, through a wound created on the host integument, determining weight loss and a reduction of lifespan, as well as the transmission of viral pathogens. However, despite its importance, the mite feeding strategy and the host regulation role by the salivary secretions have been poorly explored. Here, we contribute to fill this gap by identifying the salivary components of V. destructor, to study their functional importance for mite feeding and survival. The differential expression analysis identified 30 salivary gland genes encoding putatively secreted proteins, among which only 15 were found to be functionally annotated. These latter include proteins with putative anti‐bacterial, anti‐fungal, cytolytic, digestive and immunosuppressive function. The three most highly transcribed genes, coding for a chitin‐binding domain protein, a Kazal domain serine protease inhibitor and a papain‐like cysteine protease were selected to study their functional importance by reverse genetics. Knockdown (90%–99%) by RNA interference (RNAi) of the transcript of a chitin‐binding domain protein, likely interfering with the immune reaction to facilitate mite feeding, was associated with a 40%–50% decrease of mite survival. This work expands our knowledge of the host regulation and nutritional exploitation strategies adopted by ectoparasites of arthropods and allows the identification of potential targets for RNAi, paving the way towards the development of new strategies for Varroa mite control. [ABSTRACT FROM AUTHOR]

Insecticide resistance in Panonychus citri is a major obstacle to mite control in citrus orchards. Pyrethroid insecticides are continually used to control mites in China, although resistance to pyrethroids has evolved in some populations. Here, the resistance to the pyrethroid fenpropathrin was investigated and 7 out of 8 field‐collected populations of P. citri exhibited a high level of resistance, ranging from 171‐fold to 15 391‐fold higher than the susceptible (SS) comparison strain. Three voltage‐gated sodium channel (VGSC) mutations were identified in the tested populations: L1031V, F1747L, and F1751I. Amplicon sequencing was used to evaluate the frequency of these mutations in the 19 field populations. L1031V and F1751I were present in all populations at frequencies of 11.6%–82.1% and 0.5%–31.8%, respectively, whereas the F1747L mutation was only present in 12 populations from Chongqing, Sichuan, Guangxi, and Yunnan provinces. Introduction of these mutations singly or in combination into transgenic flies significantly increased their resistance to fenpropathrin and these flies also exhibited reduced mortality after exposure to the pyrethroids permethrin and β‐cypermethrin. Panonychus citri VGSC homology modeling and ligand docking indicate that F1747 and F1751 form direct binding contacts with pyrethroids, which are lost with mutation, whereas L1031 mutation may diminish pyrethroid effects through an allosteric mechanism. Overall, the results provide molecular markers for monitoring pest resistance to pyrethroids and offer new insights into the basis of pyrethroid actions on sodium channels. [ABSTRACT FROM AUTHOR]

BACKGROUND: Tetranychus urticae is a hard‐to‐control pest of greenhouse strawberry production. Nighttime ultraviolet B (UV‐B) radiation using light reflection sheets (LRS) has been applied as a physical method to control T. urticae through direct ovicidal effects (the UV method). However, because strawberry leaves grow more densely, UV‐B radiation fails to reach the lower leaf surfaces inhabited by spider mites; therefore, a complementary method is required. We propose the supplemental application of phytoseiid mites in greenhouse strawberry production. We evaluated the control effects of UV‐B irradiation, phytoseiid mite application and their combined use. The effects of UV‐B irradiation on the degree of overlap relative to the independent distributions (ω) between predators and prey were also analyzed. RESULTS: The UV method alone maintained low T. urticae density levels from November to February; however, mite populations increased from March onward. Phytoseiid mite application in January and February without UV‐B irradiation resulted in a temporary increase in spider mites in March and/or April. By contrast, combined application of the UV method and phytoseiid mites had a greater control effect during the strawberry growing season. The ω values were higher for the UV method compared with no UV‐B irradiation, suggesting that UV‐B irradiation increased phytoseiid mite foraging rates. CONCLUSION: The release of phytoseiid mites compensated for the shortcomings of the UV method, and UV‐B irradiation promoted predation by phytoseiid mites by increasing the behavioral numerical response. Consequently, combined application of UV‐B irradiation and phytoseiid mites is optimal for T. urticae control in greenhouse strawberry production. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: To discover and develop novel acaricidal compounds, a series of 2‐fluoro‐4‐methyl/chlorine‐5‐((2,2,2‐trifluoroethyl)thio)aniline/phenol compounds containing N/O‐benzyl moieties were synthesized based on lead compound LZ‐1. RESULTS: The activity of these compounds against carmine spider mites (Tetranychus cinnabarinus) was determined using the leaf‐spray method. Bioassays indicated that most of the designed target compounds possessed moderate to excellent acaricidal activity against adult T. cinnabarinus. The median lethal concentrations of 25b and 26b were 0.683 and 2.448 mg L−1 against adult mites, respectively; exceeding those of bifenazate (7.519 mg L−1) and lead compound LZ‐1(3.658 mg L−1). Compound 25b exhibited 100% mortality in T. cinnabarinus larvae at 10 mg L−1. CONCLUSION: Continuing the study of these compounds in field trials, we compared the efficacy of mite killing by compound 25b with the commercial pesticide spirodiclofen and showed that mite control achieved 95.9% and 83.0% lethality at 10 and 22 days post‐treatment. In comparison, spirodiclofen showed 92.7% lethality at 10 days and 77.2% lethality at 22 days post‐treatment at a concentration of 100 mg L−1. Results showed that 25b produced more facile and long‐lasting control against T. cinnabarinus than the commercial acaricide spirodiclofen. Density functional theory analysis and electrostatic potential calculations of various molecular substitutions suggested some useful models to achieve other highly active miticidal compounds. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: The tomato russet mite, Aculops lycopersici, is a major pest in tomato crops, causing damage through leaf and stem browning, defoliation and russeting of fruit. Biological control of this mite on tomato plants is difficult. While several phytoseiid mites feed on the pest, they cannot survive, move, or reproduce on tomato plants due to the presence of glandular trichomes. Pronematus ubiquitus has recently been identified as a biocontrol agent of A. lycopersici in tomato crops, but the predator–prey interaction between these two species is not well studied. In this paper, we present a validated logistic regression predator–prey model based on a 3‐year study supplemented with additional datasets. Besides the predator and the prey, this model takes into account an extra generalist predator, Macrolophus pygmaeus, and various climate parameters. RESULTS: The population trend of A. lycopersici is best explained by the presence of the predator P. ubiquitus, the relative humidity and the fact that the crop was lit or unlit using artificial light. P. ubiquitus has proved to be an efficient biocontrol agent of A. lycopersici. For P. ubiquitus the presence of M. pygmaeus, the vapour pressure deficit, the number of light hours and radiation explained the population trend best. For both the predator and the prey density‐dependent interactions were identified. Model outcomes are discussed in detail. CONCLUSION: Our study provides insights into the potential use of P. ubiquitus as a biocontrol agent for A. lycopersici in tomato crops in combination with M. pygmaeus. However, we highlight the importance of considering the presence of other predators and environmental conditions when developing integrated pest management strategies. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Olive (Olea europaea L.) is a subtropical tree cultivated in arid, dry and temperate regions. Olive orchards in Al‐Jouf of Saudi Arabia are the largest worldwide and currently face harmful pest infestation. The present study aimed at evaluating the efficiency of the predatory mite Agistemus exsertus Gonzalez (Acari: Stigmaeidae) and the exogenously applied melatonin (MT), glycine betaine (GB) and 5‐aminolevulinic acid (ALA) as eco‐friendly approaches for enhancing the biological control of four mite species (Tegolophus hassani, Oxycenus niloticus, Aceria olivi and Tetranychus urticae) infesting olive trees in Al‐Jouf under laboratory and field conditions. Field experiment was conducted on 6‐year‐old Manzanillo olive trees grown in a private orchard farm in Al‐Jouf during two seasons, 2020 and 2021. Results revealed that A. exsertus developed successfully from egg to adult. The females of T. hassani, O. niloticus, A. olivi, and T. urticae required 7.36, 8.89, 9.98 and 8.38 days, respectively, to develop from egg to adult at 28°C and 65 ± 5% relative humidity. O. niloticus was the most preferred prey of A. exsertus. The net reproductive rate (R0) was 42.1, 38.7, 34.6 and 36.8 females/female/generation, the intrinsic rate of increase (rm) was 0.27, 0.26, 0.23 and 0.20 females/female/day, and the mean generation time (T) was 16.2, 17.1, 18.6 and 17.2 days when a predator consumed T. hassani, O. niloticus, A. olivi and T. urticae, respectively. The adult female consumed daily about 114 O. niloticus, 105 A. olivi, 95 T. hassani and 15.2 T. urticae individuals, respectively. A. exsertus proved to be an effective biocontrol agent against mites infesting olive trees. In addition, the exogenous application of 1 mM MT, 15 mM GB and 25 mg/L ALA, alone or in combination, caused significant mortality for the four mites. Application of these natural compounds, alone or in combination, also significantly enhanced the growth, relative water content, relative chlorophyll, content of flavonoid and nutrients, antioxidant enzymes activities, stress‐related genes expression and fruit yield and quality of the infested olive trees compared to non‐treated infested trees. This study is the first that demonstrates the efficiency of these eco‐friendly approaches for controlling mites infesting olive trees, and could be used as a replacement for the harmful chemical acaricides. [ABSTRACT FROM AUTHOR]

BACKGROUND: Panonychus citri is a globally dominant citrus plant pest mite. Pesticide‐induced population resurgence is a concern for mite control. Exposure to sublethal concentrations of pesticides has stimulated reproduction and outbreak risks in many pests. Pyridaben, a mitochondrial electron transport inhibitor, has been frequently used worldwide in mite control. In the study, sublethal and transgenerational effects of pyridaben exposure on Pyr_Rs (resistant) and Pyr_Control (susceptible) strains were systematically investigated in both exposed parental generation (F0) and unexposed offspring generations (F1 and F2) by evaluating life‐table and physiological parameters. RESULTS: After exposure to pyridaben, the fecundity of both strains was significantly reduced in F0 generation while significantly induced in F1 generation. Interestingly, these effects also stimulated the fecundity of the F2 generation in Pyr_Control strain while no significant effects occurred for Pyr_Rs strain. The intrinsic rate of increase (r) and finite rate of increase (λ) were significantly decreased only in F1 generation of Pyr_Control strain after exposure treatment. Meanwhile, the population projection indicated a smaller population size in F1 generation of Pyr_Control strain while a population increase for Pyr_Rs strain after sublethal treatment. Subsequent detoxification enzyme assays indicated that only P450 activities in F0 generation were significantly activated by LC30 exposure to pyridaben in both strains. Significant downregulation of reproduction‐related (Pc_Vg) genes was observed in the F0 generations of both strains. Significant upregulation of P450 (CYP4CL2) and Pc_Vg of the F1 generation in both strains suggested the presence of delayed hormesis effects on the reproduction and developed tolerance to pyridaben, although the effects did not last over a longer period (F2 generation). CONCLUSION: These results provide evidence for transgenerational hormesis effects of low concentrations of pyridaben exposure that may lead to population increase and resurgence risks of resistant‐mites in natural settings by stimulating reproduction. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Amitraz is a broad‐spectrum formamidine acaricide proven to be effective against mites in all development stages. Under acidic conditions, amitraz is hydrolyzed to N2‐(2,4‐dimethylphenyl)‐N1‐methyformamidine (DPMF), an active metabolite for mite control. Octopamine and tyramine receptors are well known targets of amitraz. Until now, no research has been conducted about the amitraz target in Tetranychus cinnabarinus. This study aimed to identify the target genes of amitraz in T. cinnabarinus and reveal the mechanisms behind the differential acaricidal activities of amitraz and DPMF. RESULTS: Analysis of the toxicity, stress expression, target sensitivity and binding site of amitraz against T. cinnabarinus showed that TcOctβ2R was the main target gene of amitraz. DPMF had more potent acaricidal activity against T. cinnabarinus and was more effective at activating TcOctβ2R than amitraz. Furthermore, the three synergists had no significant effect on amitraz and DPMF, indicating that the detoxification metabolism was not related to the difference in acaricidal activity. CONCLUSION: In this study, TcOctβ2R was identified as the main target gene of amitraz against T. cinnabarinus. The divergence of target binding was responsible for the difference in acaricidal activity between amitraz and DPMF. The results also revealed the physiological and pharmacological functions of octopamine receptors (OARs) in T. cinnabarinus and could provide a basis for the design of new acaricides, with OARs as a special target. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ripened cheeses, such as pecorino, are susceptible to mites and molds contamination on the crust area that must be removed before the product can be marketed. This study investigates the effectiveness of gaseous ozone treatment in the control of microbiological and mite growth without negatively affecting product quality. RESULTS: Cheese samples were treated with gaseous ozone at 200 and 300 ppb for 8 h per day (overnight) for 150 days in storage rooms under controlled conditions (12 °C and 85% relative humidity). The results showed that ozone at 200 ppb limits the growth of mites starting from 25 days of storage and significantly reduced bacteria, molds, and yeasts counts starting from 75 days of storage. Concerning the physicochemical and qualitative parameters evaluated during ripening (weight loss, moisture content, dry weight, ash, fat, protein, total nitrogen, color, non‐destructive firmness), no significant differences were shown between the control samples and ozone treatment at 200 ppb. Sensory analysis (consumer test) also showed no specific defects with the ozone‐treated samples. It was observed that the ozone treatment at 300 ppb had limited microbiological growth and no alteration of sensory aspects but did not have the same positive impact on some aspects of overall quality, compared with ozone treatment at 200 ppb. CONCLUSION: The use of gaseous ozone treatments during ripening of pecorino cheese can potentially offer an excellent solution for the control of mite growth, while preserving the quality and sensory characteristics of the product. For this reason, this technique could be very useful for commercial purposes. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: The success of biological control using predators is normally assumed to be achieved through direct predation. Yet it is largely unknown how the predator‐ and killed prey‐induced stress to prey may contribute to biological control effectiveness. Here, we investigate variations in life‐history traits and offspring fitness of the spider mite Tetranychus ludeni in response to cues from the predatory mite Phytoseiulus persimilis and killed T. ludeni, providing knowledge for evaluation of the nonconsumptive contribution to the biological control of T. ludeni and for future development of novel spider mite control measures using these cues. RESULTS: Cues from predators and killed prey shortened longevity by 23–25% and oviposition period by 35–40%, and reduced fecundity by 31–37% in T. ludeni females. These cues significantly reduced the intrinsic rate of increase (rm) and net population growth rate (R0), and extended time to double the population size (Dt). Predator cues significantly delayed lifetime production of daughters. Mothers exposed to predator cues laid significantly smaller eggs and their offspring developed significantly more slowly but these eggs had significantly higher hatch rate. CONCLUSION: Predator‐ and killed prey‐induced fears significantly lower the fitness of T. ludeni, suggesting that these nonconsumptive effects can contribute to the effectiveness of biological control to a great extent. Our study provides critical information for evaluation of biological control effectiveness using predators and paves the way for identification of chemical odors from the predator and killed prey, and development of new materials and methods for the control of spider mite pests. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The BEEHAVE model simulates the population dynamics and foraging activity of a single honey bee colony (Apis mellifera) in great detail. Although it still makes numerous simplifying assumptions, it appears to capture a wide range of empirical observations. It could, therefore, in principle, also be used as a tool in beekeeper education, as it allows the implementation and comparison of different management options. Here, we focus on treatments aimed at controlling the mite Varroa destructor. However, since BEEHAVE was developed in the UK, mite treatment includes the use of a synthetic acaricide, which is not part of Good Beekeeping Practice in Germany. A practice that consists of drone brood removal from April to June, treatment with formic acid in August/September, and treatment with oxalic acid in November/December. We implemented these measures, focusing on the timing, frequency, and spacing between drone brood removals. The effect of drone brood removal and acid treatment, individually or in combination, on a mite‐infested colony was examined. We quantify the efficacy of Varroa mite control as the reduction of mites in treated bee colonies compared to untreated bee colonies. We found that drone brood removal was very effective, reducing mites by 90% at the end of the first simulation year after the introduction of mites. This value was significantly higher than the 50–67% reduction expected by bee experts and confirmed by empirical studies. However, literature reports varying percent reductions in mite numbers from 10 to 85% after drone brood removal. The discrepancy between model results, empirical data, and expert estimates indicate that these three sources should be reviewed and refined, as all are based on simplifying assumptions. These results and the adaptation of BEEHAVE to the Good Beekeeping Practice are a decisive step forward for the future use of BEEHAVE in beekeeper education in Germany and anywhere where organic acids and drone brood removal are utilized. [ABSTRACT FROM AUTHOR]

Varroa mites are highly attracted to drone brood of honey bees (Apis mellifera), as it increases their chance of successful reproduction. Therefore, drone brood removal with trap frames is common practice among beekeepers in Europe and part of sustainable varroa control. However, it is considered labour‐intensive, and there are doubts about the effectiveness of this measure. At present, it is mostly unknown how many mites a drone frame can carry at different times of the season, and how many mites can be removed on average if this measure is performed frequently. Therefore, we sampled a total of 262 drone frames with varying proportion of capped cells (5–100%) from 18 different apiaries. Mites were washed out from brood collected from mid‐April to mid‐July based on a standard method to obtain comparable results. We found that a drone frame carried a median of 71.5 mites, and with the removal of four trap frames, about 286 mites can be removed per colony and season. In addition, mite counts were significantly higher in June and July than in April and May (Tukey‐HSD, P < 0.05). The number of mites and the proportion of capped cells, however, were not correlated (R2 < 0.01, P < 0.05). Our results suggest that drone brood removal is effective in reducing Varroa destructor numbers in colonies, supporting the findings of previous studies on the efficacy of this measure. Although mite counts varied, we believe that increasing sample size over different seasons and locations could elucidate infestation patterns in drone brood and ultimately improve drone brood removal as an integrated pest management tool for a wider audience of beekeepers. [ABSTRACT FROM AUTHOR]

BACKGROUND: A spider mite control method using night‐time ultraviolet (UV)‐B irradiation was recently developed for strawberry greenhouses (UV method). The control effect of this UV method is negatively affected by increasing temperature. Tetranychus urticae eggs are more resistant to a single dose of UV‐B irradiation than Neoseiulus californicus eggs. By contrast, N. californicus can better survive nightly UV‐B irradiation with the UV method compared with T. urticae. To elucidate the mechanism underlying these phenomena, we explored the hypotheses that higher temperature promotes photoenzymatic repair (PER) and that mortality is determined by UV‐B susceptibility in the embryonic stage exposed to UV‐B. RESULTS: PER efficacy was not promoted by increasing temperature. The lowest hatchability (around zero) of T. urticae eggs after a single dose of UV‐B irradiation (0.288 and 0.432 kJ m−2) without photoreactivation was seen in the morphogenesis stages between "cleavage ended" and "eye points became colored". Based on these results, we developed a linear function of daily UV‐B irradiance and deviation of cumulative irradiance during vulnerable embryonic developmental phases from 50% lethal dose (LD50) after a single dose of UV‐B irradiation. The difference between T. urticae and N. californicus and changes in UV‐B vulnerability due to temperature could be explained by this simple relationship. CONCLUSION: Slower development in T. urticae than N. californicus in nature and developmental delay under low temperatures increase the ovicidal effects of the UV method. This shows the advantage of the simultaneous use of the UV method and biological control, contributing to the development of integrated pest management. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Neoseiulus bicaudus Wainstein (Acari: Phytoseiidae) is a beneficial predatory mite to control spider mites. To evaluate the suitable storage conditions of N. bicaudus, the survival of adult females was observed under different combinations of low temperature (3, 6, 9, or 12°C), food (F) or no food (NF), and high (H) or low (L) humidity conditions for 7, 14, 21, 28, and 35 d. Predator mites' longevity and survival time of 50% and 80% individuals (ST50,80) were measured and compared between treatments. After storage, female and male living mites were paired at 26°C. The progeny parameters were evaluated after storage. Results revealed that survival rate decreased as storage temperature decreased. At 3 and 6°C, fewer mites survived after 28 d. At 9°C, ~50% of the females survived in the FH treatment after 35 d. At 12°C, >80% survived 7–35 d in the FH treatment. Moreover, longevity and ST50,80 were significantly greater in the FH treatment than in the FL or NFH treatments at 3, 9, and 12°C. The highest longevity (48.6 ± 3.7 d) and ST50 (51.6 d) occurred at 12°C in the FH treatment. There was no effect on progeny hatching or survival rates when adults were stored at 9 or 12°C for 28 d. At 9°C, the total preadult development time was 4.20–5.25 d. At 12°C, the total development time was 4.87–4.93 d and there was no significant difference between the storage treatment and control group. These results demonstrated that N. bicaudus females can be successfully stored at 9°C for ~21 d and 12°C for ~28 d with little effect on adult survival or progeny parameters. [ABSTRACT FROM AUTHOR]

In order to investigate the relationship between feather mites and their hosts taking into account host ecology I examined relationships among feather mite load, and sex, age, wing length and body‐condition in the white wagtail Motacilla alba lugens. I captured 288 wagtails in January (the first period) 2002 at a communal roost in Osaka, central Japan. All the wagtails were ringed individually, aged as yearlings (first‐winter) or adults (older) and sexed. I measured wing length, tarsus length and body mass, calculated a body condition index (BCI) and determined the feather mite loads (FML) of each individual by visual examination of the flight feathers of one wing, giving a score using the range 0–5. I recaptured 121 wagtails after an average of 45 days (the second period), and redetermined their FML. FML was not correlated with wing length or body‐condition. Yearlings had higher FML than adults in both periods. Males had greater FML than females in the second period. No significant differences in FML between the first and second periods were detected among yearling females, or adult males, but adult females had significantly lower FML and yearling males had significantly higher FML than the other age–sex classes in the second period. The sexual difference was caused by the lower FML of adult females and the higher FML of yearling males. The BCI of yearling males was the lowest among the four combinations of sex and age‐class. I conclude that wagtails may be able to prevent overpopulation of feather mites on their own plumage. The ability to control mite populations may be related to the condition of the host. [ABSTRACT FROM AUTHOR]

BACKGROUND: Quantifying how chemical tolerance of pest arthropods varies with temperature is important for understanding the outcomes of chemical control, for measuring and monitoring resistance, and for predicting how pesticide resistance will evolve under future climate change. We studied the redlegged earth mite, Halotydeus destructor (Tucker), a winter‐active invasive agricultural pest in Australia. Using a replicated block experiment, we tested the effect of different thermal conditions on the expression of chemical tolerance to a pyrethroid and two organophosphates. Our chemical bioassays were conducted on two redlegged earth mite populations: one possessed organophosphate resistance, whilst the other was susceptible to pesticides. Mites were first acclimated at cool (4 °C) and warm (14 °C) conditions and then exposed to pesticides in both cool (11 °C) and warm (18 °C) test conditions. RESULTS: Warm test conditions generally reduced chemical tolerance to all pesticides relative to cool test conditions. Median lethal dose (LD50) values of mites tested under cool conditions were 1.12–3.57‐fold greater than of mites tested under warm conditions. Acclimation had a variable and small impact on chemical responses. Thermal factors (ratio between test temperatures) were similar between populations for each active ingredient. Despite reduced chemical tolerances under warm test conditions for individual mite populations, resistance factors (ratio between resistant and susceptible mite populations) were relatively consistent. CONCLUSION: Our data provides context for prior theoretical work demonstrating climatically constrained pesticide resistances in Australian redlegged earth mites. Estimates of temperature dependent toxicity measured in this study may be useful in parameterizing models of redlegged earth mite control under an increasingly warm and more variable climate. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND The tomato russet mite (TRM), Aculops lycopersici, and powdery mildew (PM), Oidium neolycopersici, are two major problems in tomato cultivation for which no effective biocontrol solutions exist to date. In a greenhouse compartment, we investigated the potential of preventatively establishing the iolinid omnivorous mite Pronematus ubiquitus on potted tomato plants to control both pest and pathogen simultaneously. RESULTS: Using Typha pollen, P. ubiquitus established well on tomato plants, with numbers reaching up to 250 motiles per tomato leaflet. The built‐up population was capable of controlling subsequent infestations with both TRM and PM. This represents the first report of an arthropod protecting a crop against pests as well as disease. CONCLUSION: The implementation of P. ubiquitus in tomato crops could be a real game‐changer as it eliminates the need for repeated pesticide use or sulphur applications. The finding that arthropods can effectively control diseases opens up new opportunities for biological crop protection. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Brevipalpus yothersi mite is the main vector of Citrus leprosis virus (CiLV), the causal agent of citrus leprosis disease. The acaricide spirodiclofen has been widely used to control this mite. However, failures in control using spirodiclofen have been frequently reported by citrus growers. In this study, we estimated the diagnostic concentration to monitor the resistance to spirodiclofen of B. yothersi populations collected in nine citrus groves in Brazil. We then selected the B. yothersi population that showed lowest mortality with the estimated diagnostic concentration of spirodiclofen to characterize the frequency of resistant individuals, as well as demographic and life table parameters. RESULTS: Variability was higher between populations in terms of susceptibility to spirodiclofen. The frequency of resistant eggs between populations ranged from 0.7% to 85.8%. The resistance ratio of B. yothersi to spirodiclofen was low to moderate. Survival rates of the immature stage, total adult longevity, oviposition days, and female fecundity were lower in the resistant strain. Furthermore, net reproduction rate, intrinsic rate of increase, finite rate of increase, and mean length of a generation were also lower in the R strain. CONCLUSION: Although variations in resistance to spirodiclofen were observed between populations, the resistance ratio was low to moderate. Such data can be useful in the development of resistance management strategies for B. yothersi in Brazilian citrus groves. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Selenium has shown effectiveness in protecting plants from herbivores. However, some insects have evolved adaptability to selenium. RESULTS: Selenium accumulation in host plants protected them against spider mite feeding. Selenium showed toxic effects on spider mites by reducing growth and interfering with reproduction. After 40 generations on selenium‐rich plants, a Tetranychus cinnabarinus strain (Tc‐Se) developed adaptability to selenium, with an increased rate of population growth and enhanced ability for selenium metabolism. The high expression of two genes (GSTd07 and SPS1) in the selenium metabolism pathway might be involved in selenium metabolism in spider mites. After GSTd07 and SPS1 were silenced, the selenium adaptability decreased. Recombinant GSTd07 protein promoted the reaction between sodium selenite and glutathione (GSH) and increased the production of sodium selenite metabolites. The results indicated that GSTd07 was involved in the first step of selenium metabolism. CONCLUSION: Plants can resist spider mite feeding by accumulating selenium. Spider mites subjected to long‐term selenium exposure can adapt to selenium by increasing the expression of key genes involved in selenium metabolism. These results elucidate the mechanism of the interaction between mites and host plants mediated by selenium. This study of the interaction between selenium‐mediated host plants and spider mites may lead to the development of new and less toxic methods for the prevention and control of spider mites. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Evidence regarding the clinical effectiveness of mite allergen avoidance for the treatment of asthma is lacking. In previous meta‐analyses on mite allergen control, the baseline data were not discussed in detail. This study updates and extends the existing Cochrane review by Gøtzsche and Johansen (Cochrane Database of Systematic Reviews, 2008, Art. No: CD001187), with a focus on baseline asthma outcomes and allergen exposures. Methods: We used the existing trials in the original Cochrane review and included newly published studies. The baseline data for the mite allergen load from the mattress, the standardized asthma symptom score (ASS), the forced expiratory volume in 1 s percentage of predicted (FEV1 %pred.), and the histamine provocative concentration causing a 20% drop in FEV1 (PC20) were extracted. First, the mean values of the outcomes were calculated. The influence of the mite allergen load was examined with a random‐effect meta‐regression using the Metafor package in R. Results: Forty‐five trials were included; 39 trials reported strategies for concurrent bedroom interventions, and 6 trails reported strategies for air purification. The mite allergen load ranged from 0.44 to 24.83 μg/g dust, with a mean of 9.86 μg/g dust (95% CI 5.66 to 14.05 μg/g dust, I2 = 99.8%). All health outcomes showed considerable heterogeneity (standardized ASS mean: 0.13, 95% CI 0.08 to 0.18, I2 = 99.9%; FEV1 %pred. mean: 85.3%, 95% CI 80.5 to 90.1%, I2 = 95.8%; PC20 mean: 1.69 mg/mL, 95% CI 0.86 to 2.52 mg/mL, I2 = 95.6%). The covariate mite allergen load did not significantly influence health outcomes. Discussion: This meta‐analysis shows that mite avoidance studies are characterized by the inclusion of patients with rather mild to moderate asthma and with varying and sometimes negligible levels of allergen exposure. Future studies should focus on patients with severe asthma and increased levels of allergen exposure. [ABSTRACT FROM AUTHOR]

Summary: Asthma affects three hundred million people worldwide. The effectiveness of house dust mite allergen control for asthma treatment is debatable. One aspect that has been little discussed in existing meta‐analyses is the possible role of environmental strategies. Here, we reintroduce the previously defined strategies for mite allergen control and discuss their importance to the debate on clinical effectiveness. The strategy of concurrent bedroom interventions is related to the combined use of a priori defined interventions, while the strategy of exposure‐based control relates to the treatment of relevant textiles after assessing exposure. The air purification strategy aims to purify the human breathing zone of airborne allergens. In Western European patient practice, the use of these strategies differs. A post hoc study of the dominant Cochrane review by Gøtzsche and Johansen (Cochrane Database of Systematic Reviews, 2008, Art. No: CD001187) appears to indicate that a majority of the underlying trials reported on the strategy of concurrent bedroom interventions, which were mainly executed in a minimal manner. Some trials have reported on the air purification strategy and may potentially alter the debate on effectiveness. No trial has reported on the strategy of exposure‐based control. We therefore hypothesize that the absence of evidence for the effectiveness of mite allergen control for asthma treatment applies to the strategy of concurrent bedroom interventions. The evidence‐based effectiveness of the exposure‐based control strategy appears to be undetermined. The results of our post hoc reanalysis urge that future meta‐analyses of mite allergen control should a priori define the environmental strategy under study. Future trials of mite allergen control are warranted to test the exposure‐based strategy as well as the sparsely tested strategy of air purification. [ABSTRACT FROM AUTHOR]

Background Diagnosis and immunotherapy of allergy against mites is based on complex extracts from large-scale cultures. However, the analysis of their composition using specific antibodies is limited. By taking advantage of the prevailing enzymatic nature of mite allergens, we have developed a broad-spectrum biochemical method for the standardization of native mite products. Methods Microplate-based assays have been implemented for thirteen Dermatophagoides pteronyssinus enzymatic activities, associated with Der p 1, 3, 4, 6, 8, 9, 15 and 20 allergens. The dynamics of these activities along culture growth, and their profile in purified fractions (bodies and faeces) and international reference standards ( WHO/ IUIS, two CBER/ FDA), have been characterized. The stability of enzymatic activities and major allergens under stress conditions (40°C) has been assessed in the presence/absence of specific protease inhibitors. Results The analysis of enzymatic activities revealed distinct profiles along culture growth and between fractions (bodies and faeces). Remarkable differences were found when comparing international reference standards, being consistent with their source material (purified bodies or whole cultures). After 72 h at 40°C, only trypsin and alpha-amylase maintained high activity. Notably, the prominent role of trypsins in the hydrolytic degradation of major allergens is demonstrated by the use of inhibitors. Conclusions Our method offers a robust approach to assess the complexity of mite extracts and highlights the critical importance of source materials for the composition and stability of finished products. The implementation of this approach in industry-based quality control procedures would contribute to the standardization of allergenic extracts used for diagnosis and immunotherapy. [ABSTRACT FROM AUTHOR]

BACKGROUND The two-spotted mite, Tetranychus urticae Koch, is one of the most serious mite pests of crops throughout the world. Biocontrol of the mite with fungal agents has long been paid much attention because of the development of insecticide resistance and the severe restriction of chemical pesticides. In this study, the efficacy of submerged conidia of the entomopathogenic fungus Isaria cateniannulata strain 08XS-1 against T. urticae eggs, larvae and female adults was evaluated at different temperatures and humidity in the laboratory and under field conditions. RESULTS The results showed that a suspension of 2 × 107 submerged conidia mL−1 caused the highest mortalities of mite eggs, larvae and females (100, 100 and 70% respectively) at 100% relative humidity and 25 °C in the laboratory. In the field experiments against the mites, a suspension of 2 × 108 submerged conidia mL−1 achieved significant efficiency - the relative control effects were 88.6, 83.8 and 83%, respectively, in cucumber, eggplant and bean fields after 10 days of treatment. CONCLUSION The results suggest that the I. cateniannulata strain 08XS-1 is a potential fungal agent, with acceptable production cost of conidia, against T. urticae in the field in an area such as southwestern China with higher air humidity. © 2016 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This study illustrates a novel strain (designated as BPU5) of Bacillus thuringiensis ( Bt) isolated from the rumen of Malabari goat, capable of producing polymorphic δ-endotoxin crystals concomitantly with sporulation in Luria-Bertani medium ( LB), and the δ-endotoxin was efficient to combat Tetranychus macfarlanei, a devastating mite. Polymorphic δ-endotoxin crystals produced were assessed by scanning electron microscopy and monitored its production concomitantly with sporulation in LB with or without sugar supplements. Toxicity of the δ-endotoxin was assessed on T. macfarlanei using leaf disc bioassay method. Mortality rate was determined by comparing the survival of mites on the diet (prepared in 10% sucrose and powdered rice husk) containing different concentrations (1-10 mg/ml) of 72-h-old crude pellet (dried mixture of δ-endotoxin (17 mg/g pellet), endospores and a few vegetative cells) or control diet with autoclaved pellet. The maximum production (1.39 mg/ml) of δ-endotoxin was observed at 72 h in LB. Among the sugars (glucose, sucrose, maltose or lactose) tested as additional carbon source, glucose (8 g/l) enhanced (1.82 mg/ml) the production of δ-endotoxin by 30%. The lethal concentration ( LC50) required to kill 50% mites was estimated as 8.024 mg/ml. The δ-endotoxin produced by B. thuringiensis BPU5 is shown to efficiently combat T. macfarlanei, a devastating mite infesting agricultural fields. [ABSTRACT FROM AUTHOR]

BACKGROUND Camptothecin ( CPT), a monoterpene indole alkaloid from Camptotheca acuminate (Nyssaceae), is toxic to some insect pests but insoluble in water. Here we show that an aqueous CPT-Na+ solution can kill the phytophagous mites Tetranychus urticae ( TU), Acaphylla theae ( AT) and Brevipalpus obovatus ( BO) under laboratory and field conditions. RESULTS Modelling of 10 day time-concentration-mortality responses of female adults to 2 mL tower sprays of three CPT-Na+ dilutions generated LC50 and LT50 values that decreased over post-spray days and sprayed amounts respectively. CPT-Na+ sprays required to kill 50% BO, TU and AT were 35, 41 and 124 µg mL−1 on day 1 post-spray, but rapidly decreased to 2.2, 2.5 and 3.6 µg mL−1 on day 5, and to 0.69, 0.77 and 1.17 µg mL−1 on day 7 respectively. In summer field trials, a spray rate of 7.5 g CPT-Na+ ha−1 provided better control efficacy against TU (81-85%) on cotton or AT (90-93%) and BO (83-88%) in tea gardens than aramite (commercial acaricide) at the labelled rate of 56.25 g ha−1. Half of the CPT-Na+ rate controlled the mites as effectively as aramite. CONCLUSION Water-soluble CPT-Na+ is a promising plant-sourced acaricide to combat wide-spectrum pest mites. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

There is a growing body of evidence indicating the potential value of essential oils as control agents against a range of arthropod ectoparasites, particularly lice, mites and ticks. Toxicity has been demonstrated following immersion and physical contact with treated surfaces, as well as after exposure to the vapour of these oils; the last of these factors implies that there is a neurotoxic, rather than simply a mechanical, pathway in their mode of action. However, the volatile nature of essential oils suggests that their residual activity is likely to be short-lived. A possible advantage of essential oils over conventional ectoparasite treatments may refer to their reported ovicidal efficacy, although it is unclear whether this results from neurotoxicity or mechanical suffocation. There are many difficulties in comparing the findings of existing studies of essential oil toxicity. One major issue is the wide variation among batches in the relative concentrations of oil constituents. A second issue concerns the fact that many experimental designs make it difficult to confirm that the effect seen is attributable to the oil; in many cases inappropriate controls mean that the effects of the excipient on mortality cannot be distinguished. Hence, it is important that an excipient-only control is always included in these bioassays. Furthermore, in direct contact assays, when attempting to identify the toxicity pathway of the essential oil tested, it is important to include a hydrophobic control. Without this, it is impossible to distinguish simple mechanical effects from neurological or other cellular toxicity. The use of essential oils in the control of veterinary ectoparasites is an area which holds considerable potential for the future and research into their use is still at an early stage. More extensive field trials, the standardization of components, the standardization of extraction, the standardization of good experimental design, mammalian toxicology profiling and excipient development, as well as further investigation into the residual activities and shelf-lives of these oils are all required to allow the full realization of their potential. [ABSTRACT FROM AUTHOR]

Objective To evaluate contamination of unopened and opened stored sources of commercial dry dog food by viable storage mites. Design Prospective laboratory and field study. Material and methods Samples were collected from nine brands of previously unopened bags (new bags) of dry food and 20 field sources of stored dry food in homes in Sydney and Canberra, Australia. All samples were initially examined for the presence of mites using a stereo-binocular microscope and then placed in separate filter-paper-sealed containers. Field samples were incubated at an average temperature of 29°C and 78% relative humidity ( RH) for 5 weeks and then at average 26°C/83% RH for 8 weeks. Paired new-bag samples were stored under room conditions (average 23°C/47% RH) and controlled incubator conditions (average 26°C/80% RH) for 6 weeks. All samples were thoroughly examined for mites, mite eggs and visible mould once weekly using a stereo-binocular microscope. Results Storage mites were not visualised in any of the field samples or in new-bag samples stored at room temperature. Storage mites, identified as Tyrophagus putrescentiae, were visualised in increasing numbers in seven of nine new-bag samples after incubation, with first mites and then eggs evident after 3 weeks of incubation. Conclusions We confirmed the presence of viable storage mites in a range of previously unopened commercial dry dog foods in Australia and confirmed the possibility of heavy storage mite contamination for dry food stored under conditions of moderate temperature and high humidity. These findings have relevance to storage mite and/or dust mite sensitivity in canine atopic dermatitis. [ABSTRACT FROM AUTHOR]

Background Chirodiscoides caviae is the most common fur mite affecting guinea pigs; infestation is generally asymptomatic. No studies have been published on the prevalence of such mites in guinea pigs in southern Italy. Hypothesis/Objectives We sought to evaluate the prevalence and the clinical signs of C. caviae infestation in guinea pigs in southern Italy. Animals Clinical records of guinea pigs evaluated from August 2012 to July 2013 were retrospectively searched. Methods In this retrospective matched case-control study, records of guinea pigs with evidence of C. caviae infestation were selected. The prevalence of C. caviae infestation was evaluated and exposure variables were assessed among guinea pigs with and without infestation using stepwise conditional logistic regression. Guinea pigs seen during the same time period, but without a diagnosis of C. caviae, were included as control animals. Results The prevalence of C. caviae was 32% (42 of 131); 66.6% of affected guinea pigs (28 of 42) originated from pet shops, whereas 28% (14 of 42) were privately owned. Thirty-one guinea pigs (73.8%) were asymptomatic, whereas 11 (26.1%) showed clinical signs (pruritus, alopecia, erythema and scaling). The most frequently affected area was the lumbosacral region (38 of 42). Guinea pigs in pet shops were more likely to be affected by C. caviae than owned guinea pigs (odds ratio, 5.12; 95% confidence interval, 2.32-11.29; P < 0.0001). Conclusions and clinical importance The results of this study indicate a high prevalence of C. caviae infestation in guinea pigs in southern Italy. Chirodiscoides mites should be sought in guinea pigs, particularly in animals coming from pet shops. [ABSTRACT FROM AUTHOR]

BACKGROUND Cyflumetofen and cyenopyrafen are novel acaricides acting as complex II inhibitors. This new mode of action is extremely useful for devising efficient resistance management strategies for mite control. The authors determined the cross-resistance risk of both compounds, using a collection of well-characterised resistant strains of Tetranychus urticae, and also selected for cyflumetofen resistance in the laboratory. RESULTS Cross-resistance to cyflumetofen and cyenopyrafen was detected in field strains, with LC50 values exceeding the registered field dose. Synergism experiments suggested that P450 monooxygenases are involved in resistance, and that the activation mechanism of the two compounds most likely differs. Laboratory selection with cyflumetofen resulted in a highly resistant T. urticae strain that displayed negative cross-resistance to cyenopyrafen. CONCLUSIONS The cross-resistance risk of cyflumetofen and cyenopyrafen documented in this study needs to be integrated in resistance management strategies, especially in regions or crops with a history of frequent acaricide applications, in order to safeguard the efficacy of these compounds with a valuable new mode of action. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND Humidity-controlled cold storage, in which the water vapour pressure is saturated, can prolong the survival of the predatory mites Neoseiulus californicus ( McGregor) and Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae). However, information on the optimum air temperature for long-term storage by this method is limited. The authors evaluated the survival of mated adult females of N. californicus and P. persimilis at 5.0, 7.5, 10.0 and 12.5 °C under saturated water vapour condition (vapour pressure deficit 0.0 kPa). RESULTS N. californicus showed a longer survival time than P. persimilis at all the air temperatures. The longest mean survival time of N. californicus was 11 weeks at 7.5 °C, whereas that of P. persimilis was 8 weeks at 5.0 °C. After storage at 7.5 °C for 8 weeks, no negative effect on post-storage oviposition was observed in N. californicus, whereas the oviposition of P. persimilis stored at 5.0 °C for 8 weeks was significantly reduced. CONCLUSION The interspecific variation in the response of these predators to low air temperature might be attributed to their natural habitat and energy requirements. These results may be useful for the long-term storage of these predators, which is required for cost-effective biological control. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Background Cyflumetofen is a novel acaricide developed by Otsuka AgriTechno Co., Ltd. It affects only spider mites and has no effect on insects, crustaceans or vertebrates under conditions of practical use. The mode of action of cyflumetofen, its selectivity for mites and its safety for insects and vertebrates were investigated. Results The research showed that cyflumetofen inhibited mitochondria complex II in mites. In addition, the de-esterified form ( AB-1) of cyflumetofen inhibited mitochondria complex II at extremely low concentrations. AB-1 was also detected as the main metabolite in mites. Conclusion The mode of action of cyflumetofen is to inhibit mitochondria complex II by affecting its action site after being metabolised to AB-1. However, inhibition by cyflumetofen and AB-1 in other organisms was very weak. Selectivity for other organisms has contributed to differences in action site activities. © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

An ultrasound-enhanced in situ solvent formation microextraction has been developed first time and compared with ultrasound-enhanced ionic-liquid-assisted dispersive liquid-liquid microextraction for the HPLC analysis of acaricides in environmental water samples. A ionic liquid ([C8MIM][PF6]) was used as the green extraction solvent through two pathways. The experimental parameters, such as the type and volume of both of the extraction solvent disperser solvent, ultrasonication time, and salt addition, were investigated and optimized. The analytical performance using the optimized conditions proved the feasibility of the developed methods for the quantitation of trace levels of acaricides by obtaining limits of detection that range from 0.54 to 3.68 μg/L. The in situ solvent formation microextraction method possesses more positive characteristics than the ionic-liquid-assisted dispersive liquid-liquid microextraction method (except for spirodiclofen determination) when comparing the validation parameters. Both methods were successfully applied to determining acaricides in real water samples. [ABSTRACT FROM AUTHOR]

Background Plasma treatment enables effective binding of chitosan film to textile fibres. Heavy metal ions such as Ag+ adsorbed onto the chitosan coating are known to enhance toxicity to microorganisms. The acaricidal effect of chitosan and chitosan/metal adducts with Ag+, Zn2+ and Cu2+ was tested in laboratory experiments. Tested species Acarus siro, Dermatophagoides farinae, D. pteronyssinus and Tyrophagus putrescentiae are allergen producers and important pests in house dust, stored food and feed. The mortality was compared after 24 h of exposure of mites to plasma-treated textiles. Results Chitosan/Ag+ textile caused at least 80% mortality of all species tested. Chitosan/Zn2+ and chitosan/Cu2+ textiles had a smaller effect on mite mortality than chitosan/Ag+. The conversion of chitosan/Ag+ finishing to chitosan/ Ag2O did not influence the mortality of mites in biotests, except that of Tyrophagus putrescentiae, where the mortality decreased from 86 to 64%. Conclusion The results support a great potential of chitosan/Ag+ fibres in acaricidal materials and/or mite protective food packages. © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The complete genome of the two-spotted spider mite, Tetranychus urticae, has been reported. This is the first sequenced genome of a highly polyphagous and resistant agricultural pest. The question as to what the genome offers the community working on spider mite control is addressed. Copyright © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

A metabolite of the fungus Meira argovae Boekhout, Scorzetti, Gerson & Sztejnberg (Exobasidiomycetidae) was assayed as an antagonist of mites. Separation of extracted fungal metabolites by reversed phase liquid chromatography (RPLC), with subsequent testing of the obtained fractions, allowed us to isolate a single mite-antagonistic fraction (also active against a bacterium) that primarily includes one major component. This active compound (herein termed 'argovin') was identified by analyzing its spectral characteristics as 4,5-dihydroxyindan-1-one, which has previously only been described as a product of chemical reactions. The growth rate of the fungus was higher at a neutral pH than at an acidic one. Meira argovae adjusts the pH of its media to values optimal for its colony growth and toxic secretions. RPLC-cleaned argovin at 0.2 mg ml−1 killed 100% of a population of the citrus rust mite, Phyllocoptruta oleivora (Ashmead) (Acari: Eriophyidae). This trait may be used to control citrus rust mites in the field, as well as for toxin production for industrial and pharmaceutical uses. [ABSTRACT FROM AUTHOR]

BACKGROUND: As previously reported, methyl ( E)-2-[2-(2-phenylamino-6-trifluoromethylpyrimidin-4-yloxymethyl)phenyl]-3-methoxyacrylate has proven to be a new lead with highly acaricidal activity. Following on from this, in an effort to discover new strobilurin analogues with improved activity, a series of substituted pyrimidines were synthesised and bioassayed. RESULTS: All compounds were characterised by 1H NMR, IR, MS and elemental analysis. Preliminary bioassays demonstrated that some of the title compounds exhibited notable control of Tetranychus cinnabarinus (Boisd.) at 1.25 mg L−1. The relationship between structure and acaricidal activity is discussed. CONCLUSION: Two compounds of particular interest, 6j (SYP-10913) and 6k (SYP-11277), exhibited potent acaricidal activity. The acaricidal potencies of these analogues are higher than that of fluacrypyrim in greenhouse applications, and are comparable with those of commercial acaricides such as spirodiclofen and propargite in field trials. Copyright © 2011 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The persea mite, Oligonychus perseae Tuttle, Baker & Abbatiello (Acari: Tetranychidae), a pest of avocado, was first discovered in Israel in the autumn of 2001. It has since spread to most avocado growing areas in Israel. To establish an economic injury level (EIL), based on the percentage of leaf area damaged (PLAD), we conducted an extensive field study. For three consecutive seasons we created distinct pest infestation levels on the Hass avocado cv., by applying acaricides (spirodiclofen and abamectin) at 50, 100, and 250 mites per leaf levels, along with non-sprayed controls in a replicated block design. At harvest time we evaluated the level of leaf damage and fruit yields across treatments. In two out of the 3 years, trees sprayed at 50 and 100 mites per leaf levels had similar PLAD values, differing from trees treated at the 250 mites per leaf level and the non-treated control, the latter pair also being similar. Over the 3 years, mean yield attained at the two higher infestation levels was reduced by 20% in comparison to the mean yields recorded for plots sprayed at the lower thresholds. Accordingly, we suggest that scouts adopt an action threshold (AT) of 50-100 mites per leaf. Future research is needed to refine this AT. Mean annual cumulative mite days (CMDs) of the two higher levels was ca. 13500 ± 700 per leaf. Using the linear regression equation PLAD = 0.0009CMDs + 2.42, describing leaf damage as a function of CMDs, we estimated an EIL of ca. 15 PLAD. [ABSTRACT FROM AUTHOR]

Non-crop vegetation adjacent to broad-acre pastures and crops can influence the abundance of invertebrate pests by promoting populations of beneficial natural enemies. However, characteristics of adjoining vegetation that consistently promote natural enemies are often unknown. Here we manipulate the height of grasses and herbaceous plants within windbreaks at five geographically separated sites in south-eastern Australia to examine the effects of on-ground vegetation structure on the abundance of pest mites and natural enemy complexes. Reducing the height and cover of vegetation across 2 years led to decreased numbers of predatory mites, predatory beetles and spiders within windbreaks and at sites 5 m from the windbreak edge within adjacent pastures. There was also an associated increase in numbers of pest earth mites, the redlegged earth mite ( Halotydeus destructor) and blue oat mites ( Penthaleus spp.). Similar findings were found in manipulative experiments under semifield conditions using microcosms. These results suggest that an increase in height and perhaps complexity of groundcover act to promote populations of beneficial natural enemies with potential suppression of pest mite species. These findings point to a simple way for increasing populations of beneficial invertebrate species at the farm scale that could contribute to integrated pest management programs. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the resistance citrus red mite Panonychus citri which are considered to be the most important pesticide-resistant pests in China. The study collected six populations of the mite from Chinese citrus orchards to monitor their resistance to spirodiclofen and other five acaricides. Conclusion shows that there are essential difference in resistance to the evaluated acaricides among the examined populations of mite.

The article presents a study on potential hazards of classical and novel acaricides against the bumblebee, Bombus terrestris. The study uses 23 acaricides in the control of phytophagous mites and considers their side effects such as acute mortality and sublethal effects on nest production. Based on results, bifenthrin and abamectin cause 100% mortality of bumbles through contact. In conclusion, most of the acaricides are compatible with bumblebees, depending on the type of treatment.

To cite this article: Spertini F, Berney M, Foradini F, Roulet C-A. Major mite allergen Der f 1 concentration is reduced in buildings with improved energy performance. Allergy 2010; 65: 623–629. Background: Environmental conditions play a crucial role in mite growth, and optimal environmental control is key in the prevention of airway inflammation in chronic allergic rhinoconjunctivitis or asthma. Objective: To evaluate the relationship between building energy performance and indoor mite allergen concentration in a cross-sectional study. Methods: Major allergen concentration (Der f 1, Der p 1, mite group 2, Fel d 1 and Bla g 2) was determined by quantitative dot blot analysis from mattress and carpet dust samples in five buildings designed for low energy use (LEB) and in six control buildings (CB). Inhabitants had received 4 weeks prior to mite measurement a personal validated questionnaire related to the perceived state of health and comfort of living. Results: Cumulative mite allergen concentration (with Der f 1 as the major contributor) was significantly lower in LEB as compared with CB both in mattresses and in carpets. In contrast, the two categories of buildings did not differ in Bla g 2 and Fel d 1 concentration, in the amount of dust and airborne mould collected. Whereas temperature was higher in LEB, relative humidity was significantly lower than in CB. Perceived overall comfort was better in LEB. Conclusions: Major mite allergen Der f 1 preferentially accumulates in buildings not specifically designed for low energy use, reaching levels at risk for sensitization. We hypothesize that controlled mechanical ventilation present in all audited LEB may favour lower air humidity and hence lower mite growth and allergen concentration, while preserving optimal perceived comfort. [ABSTRACT FROM AUTHOR]

Seven essential oils with potential as acaricides for use against the poultry red mite, Dermanyssus gallinae (De Geer) (Acari: Dermanyssidae), were selected for study. These products (essential oils of manuka, cade, pennyroyal, thyme, garlic, clove bud and cinnamon bark) were deployed against different life stages of D. gallinae in laboratory tests at the (lethal concentration) LC50 level for adult mites. For all essential oils tested, toxicity to D. gallinae juveniles was as high as toxicity to adults, if not higher. However, at the LC50 level determined for adults, some oils were ineffective in preventing hatching of D. gallinae eggs. The essential oils were also tested under laboratory conditions at their LC90 levels for D. gallinae adults on two model non-target species, the brine shrimp, Artemia salina (L.), and the mealworm beetle, Tenebrio molitor (L.). Results showed that not all essential oils were as toxic to A. salina and T. molitor as they were to D. gallinae, suggesting that it may be possible to select certain oils for development as acaricides against D. gallinae that would have minimal impact on non-target organisms. However, the level of toxicity to A. salina and T. molitor was not consistent across the selected essential oils. [ABSTRACT FROM AUTHOR]

The toxicity of a range of plant essential oils to the poultry red mite, Dermanyssus gallinae (De Geer) (Acari: Dermanyssidae), a serious ectoparasitic pest of laying hens throughout Europe and elsewhere, was assessed in the laboratory. Dermanyssus gallinae may cause losses in egg production, anaemia and, in extreme cases, death of hens. With changes in legislation and consumer demand, alternatives to synthetic acaricides are needed to manage this pest. Fifty plant essential oils were selected for their toxicity to arthropods reported in the literature. Twenty-four of these essential oils were found to kill > 75% of adult D. gallinae in contact toxicity tests over a 24-h period at a rate of 0.21 mg/cm2. Subsequent testing at lower rates showed that the essential oils of cade, manuka and thyme were especially toxic to adult D. gallinae. The toxicity of the seven most acaricidal essential oils was found to be stable at different temperatures likely to be encountered in commercial poultry housing (15°C, 22°C and 29°C), although results suggest that humidity and dust might influence the toxicity of some of the oils tested. The toxicity of clove bud essential oil to D. gallinae, for example, was increased at high humidity and dust levels compared with ambient levels. The results suggest that certain essential oils may make effective botanical pesticides for use against D. gallinae, although it is likely that issues relating to the consistency of the toxic effect of some oils will determine which oils will be most effective in practice. [ABSTRACT FROM AUTHOR]

We studied patterns of species co-occurrence in communities of ectoparasitic arthropods (ixodid ticks, mesostigmate mites and fleas) harboured by rodent hosts from South Africa ( Rhabdomys pumilio), South America ( Scapteromys aquaticus and Oxymycterus rufus) and west Siberia ( Apodemus agrarius, Microtus gregalis, Microtus oeconomus and Myodes rutilus) using null models. We compared frequencies of co-occurrences of parasite species or higher taxa across host individuals with those expected by chance. When non-randomness of parasite co-occurrences was detected, positive but not negative co-occurrences of parasite species or higher taxa prevailed (except for a single sample of mesostigmate mites from O. rufus). Frequency of detection of non-randomness of parasite co-occurrences differed among parasite taxa, being higher in fleas and lower in mites and ticks. This frequency differed also among host species independent of parasite taxon, being highest in Microtus species and lowest in O. rufus and S. aquaticus. We concluded that the pattern of species co-occurrence in ectoparasite communities on rodent hosts is predominantly positive, depends on life history of parasites and may be affected to a great extent by life history of a host. [ABSTRACT FROM AUTHOR]

Recent reviews on trait-mediated interactions in food webs suggest that trait-mediated effects are as important in triggering top–down trophic cascades as are density-mediated effects. Trait-mediated interactions between predator and prey result from non-consumptive predator effects changing behavioural and/or life history traits of prey. However, in biological control the occurrence of trait-mediated interactions between predators, prey and plants has been largely ignored. Here, we show that non-consumptive predator effects on prey cascade down to the plant in an agro-ecological food chain. The study system consisted of the predatory mites P. persimilis and N. californicus, the herbivorous non-target prey western flower thrips F. occidentalis and the host plant bean. Irrespective of predator species and risk posed to prey, the presence of predator eggs led to increased ambulation, increased mortality and decreased oviposition of thrips. Furthermore, the presence of predator eggs reduced leaf damage caused by thrips. To our knowledge this is the first experimental evidence suggesting a positive trophic cascade triggered by non-consumptive predator effects on non-target prey in an augmentative biological control system. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the acaricidal properties of piperazine derivatives against Dermatophagoides farinae or house-dust mites and Tyrophagus putrescentiae or stored-food mites using filter paper and fumigant methods. It notes that 1-phenylpiperazine was found to be 4.7 times more toxic than N,N0-diethyl-meta-toouamide (DEET) against Dermatophagoides farinae. Further, it stresses the suitability of piperazine derivatives to replace ineffective acaricides due to their ability to function as mite indicators.

The article focuses on the discovery of lead compound 9a. Synthesis of compounds analogous to the commercialized fungicide metominostrobin and the acarcide fluacrypyrim led to the discovery of the lead compound. Optimization of compound 3b was achieved by introducing an oxime either bridge along with an alkylthio branch in place of the oxymethylene chain. The two compounds were shown to exhibit potent acaricidal and fungicidal activity. The acaricidal potency is comparable with those of commercial acaricides such as fluacrypyrim, tebufenpyrad and chlorfenapyr.

Tetranychus urticae is a polyphagous mite which is an important pest of citrus worldwide. This mite can be found feeding on many plant species occurring in the citrus agrosystem moving from weeds to trees. Because field samples consist of a mixture of different Tetranychidae species, as a first step necessary to further implement population characterisation of T. urticae, species-discriminating criteria based on molecular techniques are needed. In this study, the nucleotide variation of the internal transcribed spacers (ITS) 1 and 2 and the intergenic 5.8S fragment of nuclear rDNA of T. urticae, Tetranychus turkestani, Tetranychus evansi, Tetranychus ludeni and Panonychus citri have been determined. Results demonstrate that for these species, the rDNA ITS2 regions are much more conserved than the corresponding rDNA ITS1. The high homogeneity of the ITS2 sequence observed among the specimens of T. urticae obtained from the same ecoregion makes this DNA sequence an excellent tool for species discrimination. ITS sequences differentiate not only species but also specimens from different geographical origin. Furthermore, polymerase chain reaction–restriction fragment length polymorphism analysis of the ITS2 proved adequate for a quick screening of high numbers of field samples. [ABSTRACT FROM AUTHOR]