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1.
Traditionally estimating pesticide effects by measuring only lethal effect may underestimate the total negative effect on beneficial arthropods and sublethal effects should be assessed to estimate the total effect of their applications. In this study, sublethal effect of the acaricide abamectin (Vermectin® 1.8% EC, Giah, Iran) on the predatory mite Phytoseius plumifer (Canestrini &; Fanzago) (Acari: Phytoseiidae) fed on Tetranychus urticae Koch was assessed in laboratory conditions. The adult predators were exposed to the residues of the acaricide on fig leaves and the LC50 value was determined based on a concentration–response analysis. The results showed that sublethal concentrations (LC10, LC20 and LC30) of abamectin severely affected the fecundity and longevity of the treated females of P. plumifer. Furthermore, reproductive and life table parameters of the subsequent generation were affected. The results indicated that adverse effects of abamectin on population growth of P. plumifer were significant, so the results from this study can be used to develop approximate guidelines for the use of abamectin in order to minimize their impact on P. plumifer and related natural enemies.  相似文献   

2.
The predatory mite Typhlodromips swirskii (Athias–Henriot) is commonly used to suppress pest populations of thrips and whitefly in commercial greenhouses. Many generalist phytoseiid mites can be reared on astigmatid factitious prey. This study investigated the life table parameters of T. swirskii to the astigmatid mite Suidasia medanensis (Oudemans) and the capture success ratio of T. swirskii to different life stages of the prey. Juvenile development time and survival was 5.01 ± 0.10 days and 93 %, respectively. The intrinsic (r m ) and finite (λ) rates of increase were 0.222 and 1.249, respectively, with average oviposition rate of 1.71 ± 0.07 eggs/female/day. The capture success ratio of T. swirskii to S. medanensis was: eggs > freeze killed adults > nymphs > live adults. Typhlodromips swirskii was concluded to exhibit good population growth rates with S. medanensis as prey and, a prey population with predominance of eggs and nymphs to be advantageous to the predator due to an unidentified defence mechanism of adult prey.  相似文献   

3.
Two-spotted spider mite, Tetranychus urticae Koch, is one of the most important pests of agricultural products that have a global distribution. Now, the control is dependent on the use of chemical pesticides. The effects of the sublethal concentrations (LC10 and LC25) of the essential oil of Cinnamomum zeylanicum were evaluated on some parameters of the life table of the pest, at the constant temperature of 30?°C, relative humidity of 40?±?5% and photoperiod of 16L: 8D. Our results showed that the essential oil of cinnamon is effective on female adult stage. Lethal concentration at which 50% mortality (LC50) for the essential oils is from C. zeylanicum on female adult mite was 23.39?μl/L air. Sublethal concentrations of the essential oil of C. zeylanicum also impair the natural biology of the mite. Concentrations of sublethal of essential oil decreased age-specific fertility (mx) of T. urticae compared with the control. Sublethal concentrations (LC10 and LC25) have reduced the life expectancy (ex) in egg stage. Sublethal effects of the essential oil of C. zeylanicum and its impact on T. urticae management are discussed.  相似文献   

4.
Lethal and sublethal effects of the biopesticide Kingbo (oxymatrine 0.2 % + psoralen 0.4 %) on the two-spotted spider mite (Tetranychus urticae Koch) were investigated in laboratory bioassays. The biopesticide was applied to bean leaf discs or primary leaves by using a Potter spray tower. Acute toxicity tests showed no significant ovicidal action: toxic effect (LC50 = 55.49 μl/l) was the result of a residual activity against larvae that hatched from the treated eggs. Preovipositional females and female teleiochrysales showed similar susceptibility (LC50 = 52.68 and 59.03 μl/l, respectively), whereas larvae, protonymphs and female deutonymphs were the most susceptible stages (LC50 = 6.88, 13.03, and 8.80 μl/l, respectively). In a choice test, females preferred the untreated halves of leaves over the halves treated with 2,000, 1,000, and 500 μl/l in the first 24 h, and their oviposition in those treatments was significantly greater on the untreated halves after 24 and 48 h, as well as the summed oviposition over 72 h. Viability and reproduction of survivors, as well as population growth, were strongly affected after the treatments of preovipositional females and female teleiochrysales with 100, 50 and 25 μl/l. On the other hand, sublethal effects on the females that survived treatment at the egg stage or reached adulthood from the eggs laid on the treated surface (treatments with 50 and 25 μl/l) were significantly weaker. Acaricidal and sublethal effects of the biopesticide Kingbo were discussed as a starting point for further research aimed to improve management of T. urticae populations. Regulatory issues and safety concerns regarding further commercialization of this biopesticide are addressed as well.  相似文献   

5.
Knowledge of the lethal and sublethal effects of pesticides on biological control agents is necessary for successful implementation of integrated pest management programs. The sublethal effect of acaricide fenpyroximate (Ortus®) on performance of females and their offspring of Phytoseius plumifer (Canestrini &; Fanzago), an efficient predator of Tetranychus urticae Koch, was determined under laboratory conditions. The adult predators were exposed to the residues of the acaricide on fig leaves and the LC50 value was determined based on a concentration–response analysis. The results showed that sublethal concentrations of fenpyroximate significantly affected the fecundity and longevity of the treated females of P. plumifer. Reproductive and life table parameters of the subsequent generation were also affected by sublethal concentrations. It could be concluded that sublethal concentrations can significantly reduce the population growth of P. plumifer and this should be considered in integrated pest management programs.  相似文献   

6.
Abstract

The two-spotted spider mite, Tetranychus urticae Koch is one of the most common pests of agricultural crops. The use of sublethal doses can reduce the need of pesticides and prevent pests’ resistance, which is an important step in integrated pest management and safely controlling this pest. The sublethal effects (LC5, LC15 and LC35) of spirodiclofen on demographic parameters of T. urticae based on the age-stage, two-sex life table theory were investigated under laboratory conditions [25?±?2?°C, 60?±?5% RH and 16:8 (L:D) h]. The longevity, total life span, oviposition period and total fecundity reduced after exposure to LC15 and LC35. Oviposition period ranged from 5.64 to 10.92?days. The gross reproduction rate (GRR), net reproductive rate (R0) and the finite rate of increase (λ) of the mites treated with LC15 and LC35 were inferior to the results when treated with LC5, and control. The values of intrinsic rate of increase (r) was 0.2209?day?1 in the control and this was reduced to 0.1714?day?1 in LC35. Based on these results, considering the negative impact of spirodiclofen on the population growth of T. urticae, this acaricide can be helpful to achieve an efficient control for T. urticae in frame of integrated pest management.  相似文献   

7.
We investigated the potential use of anoxic (0% O2) and hypoxic (lower O2 concentration than in the atmosphere) conditions for controlling the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae). Adult T. urticae females were exposed to O2 concentrations of 0, 0.5, 1, 2, or 21% (control) with a constant CO2 concentration of 0.05% at 1 atm and 25 °C under continuous darkness for 24 h. The survival and fecundity at 8 days after treatment significantly decreased when the O2 concentration was lower than 0.5% and 1%, respectively; the lethal concentration at 50% survival (LC50) was 0.55%. The miticidal hypoxic condition (0.5% O2) led to physiological disorders in host plants. The degree of physiological disorders differed among the plant species tested. Although tomato seedlings died after the hypoxia treatment, in kidney bean and cucumber seedlings the primary leaves remained and lateral buds developed instead of the apical buds that ceased. Hypoxia treatment could be useful as a physical measure for controlling spider mites depending on plant species or cultivars.  相似文献   

8.
Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) is a key predator of a wide range of pests including thrips, whitefly and several mite pests. A number of artificial diets have been developed for this predator, but all of these are liquid, complicating their use in mass production. In the present study, we investigated the survival, development and reproduction of A. swirskii fed on several dry artificial diets: the tested diets were freeze dried forms of previously developed liquid meridic artificial diets supplemented with extracts of decapsulated cysts of Artemia franciscana Kellogg (Anostraca: Artemiidae) or with pupal hemolymph of Chinese oak silkworm Antheraea pernyi (Guérin-Méneville) (Lepidoptera: Saturniidae), and newly composed powdered meridic artificial diets supplemented with ground dry A. franciscana cysts or lyophilized pupal hemolymph of A. pernyi. Performance of the mite on the artificial diets was compared with that on cattail pollen (Typha latifolia L.). Developmental time of A. swirskii females offered lyophilized diets was significantly shorter than on powdered diets. Total fecundity was significantly higher for females fed on the lyophilized diets than for those maintained on the powdered diet with A. franciscana. Daily oviposition rates were similar on T. latifolia pollen and both lyophilized diets but lower on both powdered diets. The highest intrinsic rate of increase was observed when A. swirskii was fed on T. latifolia pollen (0.210 females per female per day), followed by the freeze dried diets enriched with A. pernyi and A. franciscana (0.195 and 0.184 females per female per day, respectively), and the lowest growth rates were observed on the powdered diets supplemented with A. franciscana and A. pernyi (0.159 and 0.158 females per female per day, respectively). In conclusion, the phytoseiid was able to effectively feed on solid, powdered artificial diets. Freeze-drying of liquid diets did not influence their value to support the development and reproduction of A. swirskii. For mass rearing purposes, these dry diets have several advantages over liquid ones, including more convenient application and storage. Furthermore, they are believed to have better potential for use as supplemental foods to sustain predatory mite populations in the crop after release.  相似文献   

9.
The toxicity of organic plant extracts to Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) was assessed for three tropical plant species: branches, leaves, and seeds of Annona montana (Annonaceae), branches of Aristolochia paulistana (Aristolochiaceae), and leaves and branches of Casearia sylvestris (Salicaceae). The screening assay resulted that the extracts of A. montana seeds obtained with hexane (LC50?=?534.75 mg kg?1 and LT50?=?6.10 days) and with dichloromethane (LC50?=?424.67 mg kg?1 and LT50?=?5.03 days) were the most promising treatments, followed by the extract prepared from A. montana leaves with hexane (LC50?=?837.70 mg kg?1 and LT50?=?4.90 days). Moreover, extracts (at 1,500 mg kg?1) prepared from C. sylvestris branches with dichloromethane and A. paulistana with hexane caused significant mortality (37% and 41.5%, respectively) beyond sublethal effects on S. zeamais. Therefore, based on the biological assays, extraction yield, and evaluation of the chromatographic profile of the crude extracts by TLC, the hexane extract of A. montana seeds was selected and fractioned using liquid-liquid partitioning. The hydroalcoholic fraction caused mortality of 55.5%, significantly superior to dichloromethane fraction, which caused 35.5% of mortality. Chemical analyses (1H NMR, HPLC, and TLC) were performed, and the results showed the presence of alkaloids and acetogenins in both active fractions, which have been associated with bioactivity. Therefore, extracts prepared from A. montana seeds (especially) is an interesting source of new compounds with promising grain-protectant properties.  相似文献   

10.
Development, oviposition, and survival of a commercially available predatory mite, Amblyseius swirskii (Athias-Henriot), were investigated to determine the life history parameters when they consumed a diet of cattail (Typha latifolia L.) pollen or tomato russet mites (Aculops lycopersici [Massee]) at 25 ± 0.5 °C and 70 ± 10% RH. Both diets were favorable for development, oviposition, and survival of A. swirskii. Amblyseius swirskii reared on mite prey showed improved performance as compared to pollen. Females laid a total of 26.8 and 38.1 eggs on the pollen and mite diets, respectively. The mortality of female A. swirskii was very low during the first 20 days on both diets, and the cumulative Weibull models that were used to describe age-specific survival and fecundity of female showed a good fit to the data. The net reproductive rate (R0), intrinsic rate of increase (rm), and finite rate of increase (λ) of A. swirskii were higher on russet mites than when fed on the pollen diet due to their shorter immature development period and higher oviposition rate. The intrinsic rate of increase (rm) of the predatory mite was 0.185 and 0.201 on the pollen and mite diet, respectively. The mean generation time (T) and the population doubling time (Dt) were not significantly different for A. swirskii on the two diets. Our results provide life history information for a commercially available A. swirskii using two favorable diets and can be used to compare population growth under other diet sources.  相似文献   

11.
This study was conducted to ascertain if the predatory phytoseiidMetaseiulus occidentalis (Nesbitt) could contain and regulate a prey population of the two-spotted mite,Tetranychus urticae Koch, on strawberries at both high and low levels of reproductive increase of the prey species, by use of high and low levels of nitrogen fertilization of the strawberry plants which were grown in 2 hydroponic tanks, 1 with full nutrients, 1 with 1/40 full nutrients. A 14-h day length was provided. Temperatures averaged 21°C with R.H. averaging about 75. After inoculation prey and predator counts were made weekly. Fecundity tests were conducted throughout the experiment as were leaf analyses to determine the levels of available nutrients. The phytoseiid gave good control of the spider mite population in spite of (compensating for) an increase in fecundity due to the high nutritional qualities of the host plant over a relatively long period of time. The results showed the numerical response of the predator to be sufficient to respond to and control the prey population under both high and low fertilization, althougheconomic control was less reliable under high nitrogen.  相似文献   

12.
The lower and upper thermal activity thresholds of the predatory mite Phytoseiulus macropilis Banks (Acari: Phytoseiidae) were compared with those of its prey Tetranychus urticae Koch (Acari: Tetranychidae) and one of the alternative commercially available control agents for T. urticae, Phytoseiulus persimilis Athias-Henriot. Adult female P. macropilis retained ambulatory function (CTmin) and movement of appendages (chill coma) at significantly lower temperatures (8.2 and 0.4 °C, respectively) than that of P. persimilis (11.1 and 3.3 °C) and T. urticae (10.6 and 10.3 °C). As the temperature was raised, P. macropilis ceased walking (CTmax) and entered heat coma (42.7 and 43.6 °C), beyond the upper locomotory limits of P. persimilis (40.0 and 41.1 °C), but before T. urticae (47.3 and 48.7 °C). Walking speeds were investigated and P. persimilis was found to have significantly faster ambulation than P. macropilis and T. urticae across a range of temperatures. The lower thermal activity threshold data indicate that P. macropilis will make an effective biological control agent in temperate climates.  相似文献   

13.
During this study the frequency of occurrence and dominance of phytophagous and predatory mites harboring seven vegetable crops in Egypt, namely common bean, cowpea, eggplant, okra, squash, sweet pepper and sweet potato during 2017–2018 were investigated to identify predatory mites that might be useful for the biological control of the phytophagous mites. Three phytophagous and nine predatory mite species were surveyed. The two spotted spider mite Tetranychus urticae Koch of the family Tetranychidae was the dominant pest on these vegetables, while phytoseiids Phytoseiulus persimilis (Athias- Henriot), Typhlodromips swirskii (Athias- Henriot) and Euseius scutalis Chant were the dominant predators. The population of the native or indigenous phytoseiid mite fauna in Egypt such as Phytoseiulus persimilis could be considered as a good biocontrol agent and a part of the Integrated Pest Management (IPM) program in the future. Mite fauna of Egypt especially local populations of Phytoseiulus persimilis can be considered for implementation in future Integrated Pest Management (IPM).  相似文献   

14.
The purpose of this study was to evaluate the performance of Neoseiulus californicus (McGregor) for the control of Tetranychus urticae Koch in commercial strawberry fields, under greenhouse conditions, in association or not with the use of acaricides. The N. californicus strain used in this study was tolerant or resistant to several pesticides. Three experiments were carried out in the State of São Paulo, Brazil. For the first experiment, the initial infestation of T. urticae was 87.1 active stages per leaflet. Two applications of propargite were made on the first and the 14th day of the experiment. Approximately 2 h after each propargite application, N. californicus was released at a rate of 3.0 and 1.9 adult mites per plant, respectively, for each application. The population of T. urticae decreased from 87.1 to 2.8 mites per leaflet in the first three weeks. After this period, the population of T. urticae was maintained at low levels (≤1.5 mites/leaflet) until the end of the experiment (10th week). Propargite and dimethoate sprayed on the strawberry field did not affect significantly the population of this predaceous mite. For the second experiment, the infestation of T. urticae was 29.1 mites per leaflet, when the acaricide chorfenapyr was applied on the strawberry field. The release of N. californicus (2 mites per plant) was made 2 weeks after spraying the acaricide. The population of T. urticae was maintained at low levels (≤2.8 mites/leaflet) for 8 weeks (evaluation period). The T. urticae infestations in plots with N. californicus were significantly lower than in non-release plots, for the experiments 1 and 2. In the third experiment, the initial infestation of T. urticae was 40.5 mites per leaflet (55.5 active stages/leaflet on release plants; 25.5 active stages/leaflet on non-release plants). Three releases of N. californicus (average rate of 3.0 adult mites/plant), without any acaricide application, were not sufficient to reduce significantly the T. urticae population in release plots (release plants + non-release plants) in 6 weeks from the first release, however, the spider mite population decreased from 55.5 to 7.8 active stages per leaflet on release plants, during this period. Interplant dispersal of N. californicus was low in this strawberry field with high infestation of T. urticae. The studies indicate the viability of the use of this strain of N. californicus for the control of T. urticae in strawberry fields under greenhouse conditions, especially in association with selective acaricides.  相似文献   

15.
The predatory phytoseiid mite Amblyseius swirskii (Athias-Henriot) completed its lifespan when fed on females of the broad mite, Polyphagotarsonemus latus (Banks). The development was the quickest and the number of prey consumed was highest when individuals were reared at 28?°C compared with 19?°C. The average number of eggs/female/day was 2.36 and 1.69, respectively. Life table parameters showed that the population of A. swirskii multiplied 16 and 20 times in a generation time of 22 and 18?days at 19 and 28?°C, respectively. Under these conditions, the intrinsic rate of increase (rm) was 0.139 and 0.170 individuals/female/day, respectively.  相似文献   

16.
Sublethal effects of Thymus vulgaris were investigated on life-table parameters of Tetranychus urticae Koch (Acari: Tetranychidae) in the laboratory conditions at 25?±?1?°C, 70?±?10% RH and a 14:10?h (L:D) photoperiod. Bioassay was conducted to assess the effect of different concentrations of T. vulgaris essential oil on two-spotted spider mite. LC50 and LC20 of T. vulgaris on T. urticae were calculated as 18.86 and 6.24?μl/litre air for 24?h after treatment. In the sublethal effects, after 24?h exposure to LC50 concentration, mortality, fecundity and longevity of the females that survived from treatment were determined. Results showed that T. vulgaris caused significant reductions in fecundity and longevity of adults. Life-table assay indicated that the intrinsic rate of increase (r m), net reproductive rate (R 0), finite rate of increase (λ), mean generation time (T), significantly reduced in treated females compared to control. These results suggest that T. vulgaris could be incorporated in integrated pest management programmes of T. urticae.  相似文献   

17.
Patch-related behaviour of a generalist predator may be influenced by patch prey diversity and result in more time being spent in patches with more than one prey species to increase the benefits of mixed diet. To examine if generalist predators are able to discern differences in prey diversity in and among patches, we examined the patch-related behaviour of the predatory mite Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae). Three lab experiments using clean, single-prey or mixed-prey patches were conducted, using whiteflies and spider mites as prey. The experiments were: (1) patch leaving tendency and residence time in absence and (2) presence of another patch, (3) patch preference. A. swirskii recognized prey-inhabited patches from a distance and showed a preference for mixed-prey patches over single-prey patches. The patch-related behaviour of A. swirskii, which seems tuned to exploiting the fitness gains of a mixed diet, is influenced by both local and distant cues.  相似文献   

18.
Development, survival and reproduction of the predatory mite Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) were assessed when fed on cattail pollen (Typha latifolia L.), dried fruit mite (Carpoglyphus lactis L.), or on two artificial diets. The basic artificial diet (AD1) was composed of honey, sucrose, tryptone, yeast extract, and egg yolk. This diet was enriched (AD2) by adding hemolymph from oak silkworm pupae (Antheraea pernyi (Guérin-Méneville)). Mites fed on C. lactis and AD2 had shorter immature and preoviposition periods than those fed on the other diets. The total number of deposited eggs was significantly higher for females fed on AD2 than for those maintained on the other diets. The intrinsic rate of increase (rm) of A. swirskii was highest on AD2 and C. lactis, followed by T. latifolia pollen, and AD1. In conclusion, the artificial diet AD2 supported development and reproduction of A. swirskii to the same extent as a factitious prey which is routinely used in the mass rearing of the phytoseiid. Our findings indicate the potential of artificial diets for the mass production of this economically important predatory mite.  相似文献   

19.
A relatively new insecticide chemistry for controlling sucking insects, afidopyropen, was investigated for toxicity against Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae). We evaluated the mortality of D. citri eggs, nymphs, and adults treated with afidopyropen using both laboratory-reared and field populations. We also quantified the effects of sublethal doses of afidopyropen on D. citri feeding, host choice selection, and fecundity. For laboratory susceptible adults, the contact LC50, topical application LD50, and leaf dip LC50 were 2.13, 2.00, and 3.08 ng/µL, respectively. For adults collected from a commercially managed citrus grove in Florida, the contact LC50, topical application LD50, and leaf dip LC50 were 1.37, 1.92, and 4.89 ng/µL, respectively. Egg hatch was significantly reduced following exposure to afidopyropen at 100 ng/µL. Furthermore, afidopyropen reduced D. citri nymph survival and adult emergence at concentrations ranging between 0.01 and 100 ng/µL. Diaphorina citri adult feeding decreased on citrus leaves treated with afidopyropen in a concentration-dependent manner as measured indirectly by honeydew excretion, and appeared almost completely inhibited after treatment with 10 and 100 ng/µL solutions of afidopyropen. In choice tests, significantly fewer D. citri adults settled on afidopyropen-treated plants than on control plants at 24, 48, and 72 h after release, with no differences in settling between males and females. Afidopyropen reduced the fecundity of D. citri in a concentration-dependent manner. Collectively, the results suggest that afidopyropen could contribute to the integrated management of D. citri and may therefore be useful in rotational programs to improve resistance management.  相似文献   

20.
Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) is a very efficient generalist predatory mite of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) and Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), worldwide released in horticultural greenhouses. Here, the toxicity of sulfoxaflor and other ten pesticides to A. swirskii adults when applied at their maximum field rate was assessed in the laboratory in terms of mortality and reproductive performance. The duration of the harmful activity when residues were aged under greenhouse was assessed for compounds not classified as harmless in the laboratory, based on the International Organization for Biological Control (IOBC) rules. Sulfoxaflor as well as flonicamid, flubendiamide, metaflumizone, methoxyfenozide, spiromesifen, and spirotetramat were harmless, emamectin was slightly harmful and abamectin, deltamethrin and spinosad were harmful. Emamectin was short-lived and abamectin, deltamethrin and spinosad were slightly persistent under our conditions.  相似文献   

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