An electric dipolar screen with oppositely polarized insulators for excluding whiteflies from greenhouses

Tanaka, Norio; Matsuda, Yoshinori; Kato, Eisuke; Kokabe, Kiyoto; Furukawa, Takeshi; Nonomura, Teruo; Honda, Ken‐ichiro; Kusakari, Shin-ichi; Imura, Takeo; Kimbara, Junji; Toyoda, Hideyoshi

doi:10.1016/j.cropro.2007.05.009

Cited by 33 publications

(28 citation statements)

References 15 publications

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“…Insect‐excluding woven screens with a fine mesh size have been a conventional physical method to minimise insect entry to glasshouses, but the disadvantage of screening is a reduction in ventilation that can cause overheating and increase relative humidity (Weintrub & Berlinger, ). In the interest of protecting crops during production and storage, we have developed electrostatic methods to disinfect bacterial and fungal plant pathogens (Shimizu et al , ; Nonomura et al , ) or to prevent airborne pathogens and flying insect pests from entering greenhouses (Matsuda et al , ; Tanaka et al , ), with the aim of reducing the use of fungicides and insecticides. An electric field screen (EF‐screen) has been practically used as an environment‐friendly tool to exclude pathogens and pests from spaces of plant cultivation (Kakutani et al , ) and storage (Matsuda et al , ) with better air penetration.…”

Section: Introductionmentioning

confidence: 99%

Insects are electrified in an electric field by deprivation of their negative charge

Kakutani

Matsuda

Haneda

et al. 2012

Annals of Applied Biology

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An electric field screen (EF-screen) is a physical device for excluding pest insects from greenhouses and warehouses to protect crops during their production and storage periods. In this study, a simple version of the EF-screen, an insulated conductor iron wire (ICW) paralleled to an earthed net, was constructed to effectively observe the attraction of test insects in relation to their electricity release. The ICW was negatively charged to dielectrically polarise the insulator sleeve of the ICW: negatively on the outer surface and positively on the inner conductor wire surface of the sleeve. The negative surface charge of the ICW caused an electrostatic induction in the earthed net and a resultant positive charge at the ICW-side surface of the net. An electric field formed between the ICW (negative pole) and earthed net (positive pole). Insects were attracted to the ICW when they were placed onto the earthed net. A vital step for the attraction was the creation of a transient bioelectric discharge from an insect. During this discharge, an electric charge of the insect was transferred to the earthed net. Eventually, the insect became net positive and was then attracted to the ICW. The magnitude of the current increased in direct proportion to the increase in voltage applied to the ICW, and the attraction force was directly proportional to the increase in the electric current. Larger voltages were necessary to attract much larger insects because larger insects were stronger and therefore more able to escape from the ICW attraction. Similar results were obtained for a wide range of pest insects belonging to different taxonomic groups (8 orders and 15 families). This study demonstrated that transient bioelectric discharge is common in insects and can be utilised to create an electrostatic force capable of moving insects in a generated electric field.

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Section: Introductionmentioning

confidence: 99%

Insects are electrified in an electric field by deprivation of their negative charge

Kakutani

Matsuda

Haneda

et al. 2012

Annals of Applied Biology

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“…The following examples provide an idea of the solutions available to growers: for the biological control of whitefly (Trialeurodes vaporariorum Westwood), the parasitic wasp Encarsia formosa (Castañé et al, 2004) can be used, and also autochthonous Mediterranean predatory bugs such as Macrolophus caliginosus or Dicyphus tamaninii Wagner (Lucas & Alomar, 2002;Castañé et al, 2004); to combat the Bemisia argentifolii whitefly parasitic wasps such as Eretmocerus eremicus and Encarsia Formosa (Hoddle et al, 1998) can be used; while to combat thrips (Frankliniella occidentalis), the parasitic nematode Thripinema nicklewoodi Siddiqi (Arthurs et al, 2003), the fungus Metarhizium anisopliae (Ansari et al, 2007), the predatory mite Amblyseius cucumeris or the wasp Orius insidiosus (Shipp & Wang, 2003) can all be used. Other methods for combating whitefly have been studied: planting a layer of covering vegetation that attracts these insects in order to reduce their incidence on crops (Hilje & Stansly, 2008); placing chromatographic adhesive traps shaped like a chrysanthemum flower (Mainali & Lim, 2008); and fitting electrostatic meshes (Tanaka et al, 2008).…”

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confidence: 99%

Microclimate evaluation of a new design of insect-proof screens in a Mediterranean greenhouse

López-Martínez

Valera

Molina-Aiz

et al. 2014

Span. j. agric. res.

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This work studies natural ventilation in a Mediterranean greenhouse, comparing a new experimental screen of 13×30 threads cm-2 (porosity 39.0%) with a commercial control screen of 10×20 threads cm-2 (porosity 33.5%). In addition, both screens were tested in a wind tunnel to determine the discharge coefficients Cd of the greenhouse side and roof vents, which proved to be 0.16 for the commercial control screen and 0.18 for the experimental screen at both vents. These values represent a theoretical increase of 11% (Cd,φ-10×20 /Cd,φ-13×30 = 0.89) in the natural ventilation capacity of the greenhouse when the experimental screen is used. The greenhouse was divided into two separate sections allowing us to analyze natural ventilation in both sectors simultaneously. Air velocity was measured in the lateral and roof vents with two 3D and six 2D sonic anemometers. Using the commercial control screen there was an average reduction of 16% in ventilation rate, and an average increase of 0.5ºC in the average indoor air temperature, compared to the experimental screen. In addition, the ventilation efficiency ηT was higher with the experimental screen (mean value of 0.9) than with the control (mean value 0.6). We have designed an experimental insect-proof screen (13×30 threads cm-2) with smaller thread diameter, higher thread density, smaller pore size and higher porosity than are used in most commercial meshes. All of these factors promote natural ventilation and improve the greenhouse microclimate.

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“…Previous studies have suggested that HVEF exposure leads to dramatic increases in the production of various reactive oxygen species (ROS) and results in oxidative stress [Lopez‐Martinez et al, ; Wang et al, ]. In general, the anti‐oxidative enzymes superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), and peroxidase (POD, EC 1.11.1.7) play crucial roles in scavenging ROS compounds [Kanazawa et al, ; Tanaka et al, ]. In the present study, we evaluated the changes in the activities of anti‐oxidative enzymes of S. avenae in response to direct exposure to HVEFs of different strengths for different durations over multiple generations as well as those in response to feeding on plants from seeds similarly exposed to HVEFs (hereafter, seed exposure).…”

Section: Introductionmentioning

confidence: 69%

High‐voltage electrostatic field‐induced oxidative stress: Characterization of the physiological effects in Sitobion avenae (Hemiptera: Aphididae) across multiple generations

Luo

Luo²,

et al. 2018

Bioelectromagnetics

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In recent decades, man-made electric fields have greatly increased the intensity of electrostatic fields that are pervasively present in the environment. To better understand the physiological alterations exhibited by herbivorous insects in response to changing electric environments, we determined the activities of anti-oxidative enzymes and the metabolic rate of Sitobion avenae Fabricius (Hemiptera: Aphididae) over multiple generations in response to direct and host-seed exposure to a high-voltage electrostatic field (HVEF) of varying strength for different durations. Under controlled greenhouse conditions, 20-min direct exposure of S. avenae and wheat seeds to a 2-or 4-kV/cm HVEF resulted in significantly increased superoxide dismutase (SOD) activity in the sixth, 11th, 16th, and 21st generations relative to the control activities, whereas significantly decreased SOD activity was detected in the second generation. In addition, the activities of catalase (CAT) and peroxidase (POD) in S. avenae showed significant decreases over multiple generations. We also examined the suppressive effects of the duration of 4-kV/cm treatment on aphid physiology. The results showed that exposure to the 4-kV/cm HVEF for 20 min exerted adverse effects on CAT and POD activities and significantly decreased the metabolic rates of S. avenae, as demonstrated through evaluations of CO 2 production rate, and these parameters were not significantly affected by higher HVEF durations. Overall, these findings increase our understanding of plant-pest interactions under novel HVEF environments and provide information that can improve integrated management strategies for S. avenae. Bioelectromagnetics. 40:52-61, 2019.

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An electric dipolar screen with oppositely polarized insulators for excluding whiteflies from greenhouses

Cited by 33 publications

References 15 publications

Insects are electrified in an electric field by deprivation of their negative charge

Insects are electrified in an electric field by deprivation of their negative charge

Microclimate evaluation of a new design of insect-proof screens in a Mediterranean greenhouse

High‐voltage electrostatic field‐induced oxidative stress: Characterization of the physiological effects in Sitobion avenae (Hemiptera: Aphididae) across multiple generations

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