scholarly journals Developing a Phototactic Electrostatic Insect Trap Targeting Whiteflies, Leafminers, and Thrips in Greenhouses

Insects ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 960
Author(s):  
Yoshihiro Takikawa ◽  
Teruo Nonomura ◽  
Takahiro Sonoda ◽  
Yoshinori Matsuda

Our aim was to develop an electrostatic apparatus to lure and capture silverleaf whiteflies (Bemisia tabaci), vegetable leafminers (Liriomyza sativae), and western flower thrips (Frankliniella occidentalis) that invade tomato greenhouses. A double-charged dipolar electric field producer (DD-EFP) was constructed by filling water in two identical transparent soft polyvinyl chloride tubes arrayed in parallel with fixed separation, and then, inserting the probes of grounded negative and positive voltage generators into the water of the two tubes to generate negatively and positively charged waters, respectively. These charged waters electrified the outer surfaces of the opposite tubes via dielectric polarization. An electric field formed between the oppositely charged tubes. To lure these phototactic insects, the water was colored yellow using watercolor paste, then introduced into the transparent insulator tubes to construct the yellow-colored DD-EFP. This apparatus lured insects in a manner similar to commercially available yellow sticky traps. The yellow-colored DD-EFP was easily placed as a movable upright screen along the plants, such that invading pests were preferentially attracted to the trap before reaching the plants. Furthermore, pests settling on the plants were attracted to the apparatus, which used a plant-tapping method to drive them off the plants. Our study provided an experimental basis for developing an electrostatic device to attract and capture insects that enter greenhouses.

2020 ◽  
Vol 12 (2) ◽  
pp. 50
Author(s):  
Yoshihiro Takikawa ◽  
Yoshinori Matsuda ◽  
Teruo Nonomura ◽  
Koji Kakutani ◽  
Shin-ichi Kusakari ◽  
...  

The present study describes an economically efficient method for controlling viruliferous whiteflies in a plastic hoop greenhouse, using a bamboo blind-type electric field screen (Bb-EFS) to create a pest-free space. The Bb-EFS had a layer of insulated round iron conductor bars (IBs) and two electrostatic direct current voltage generators that supplied negative or positive voltage to the IBs. The IBs were placed parallel at 4-mm intervals and were connected alternately to a negative or positive voltage generator. Adult test insects (whiteflies, western flower thrips, and tomato leaf miner flies) were blown at up to 5 m/s towards the IBs to identify the voltage range that would capture all the test insects. The results showed that a force ≥ 5.0 kV was strong enough for the IBs to capture all test insects, despite a wind speed of 5 m/s. The Bb-EFS was practical for a greenhouse that experienced frequent invasion by numerous viruliferous whiteflies. Seedlings grew normally inside the Bb-EFS-installed greenhouse. As a supplementary method, an electrostatic insect sweeper and electrostatic flying insect catcher were used to trap whiteflies that avoided the Bb-EFS. Both pieces of apparatus were convenient and easy to operate onsite in a greenhouse environment and were used to trap whiteflies residing on tomato plants or flying inside the greenhouse during daily plant care. These methods controlled the whitefly population to negligible levels, and nearly all tomato plants produced normal fruits.


2016 ◽  
Vol 8 (4) ◽  
pp. 13 ◽  
Author(s):  
Yoshihiro Takikawa ◽  
Yoshinori Matsuda ◽  
Teruo Nonomura ◽  
Koji Kakutani ◽  
Kiyotsugu Okada ◽  
...  

<p>The electrostatic nursery shelter reported in this work was a transparent film-covered rectangular box with three electric field screens on each of the long sides of the box. This arrangement prevents flying pests and airborne fungal pathogens from entering the nursery space. Insulated conducting wires (ICWs) were used as electrodes to create electric fields. The ICWs were arrayed in parallel, and linked to direct-current voltage sources. The ICW layers were negatively or positively charged with equal voltages to form dipoles; i.e., ICW(–) and ICW(+). The electric field screen consisted of three layers of the ICWs; i.e., an ICW(–) layer on either side of an ICW(+) layer. Four species of major tomato pests were used in a blowing assay: whiteflies (<em>Bemisia tabaci</em>), western flower thrips (<em>Frankliniella occidentalis</em>), green peach aphids (<em>Myzus persicae</em>) and tomato leaf miner flies (<em>Liriomyza sativae</em>). The ICWs were located to capture test pests that were mechanically blown into the electric-field screen. The electrostatic force to capture the insects was directly proportional to the applied voltage, and at voltages of 1.2 kV or greater, the screen exerted sufficient force to capture all of the test pests. An assay in a pest-infested greenhouse revealed that the ICWs captured all the pests that approached the screen, and the plants within the shelter remained pest-free. In addition, we show that the electric-field-screened shelter remained spore-free in the presence of continuous exposure to the conidia of tomato powdery mildew (<em>Oidium neolycopersici</em>).</p>


Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1384
Author(s):  
Dinar S. C. Wahyuni ◽  
Young Hae Choi ◽  
Kirsten A. Leiss ◽  
Peter G. L. Klinkhamer

Understanding the mechanisms involved in host plant resistance opens the way for improved resistance breeding programs by using the traits involved as markers. Pest management is a major problem in cultivation of ornamentals. Gladiolus (Gladiolus hybridus L.) is an economically important ornamental in the Netherlands. Gladiolus is especially sensitive to attack by western flower thrips (Frankliniella occidentalis (Pergande) (Thysanoptera:Thripidae)). The objective of this study was, therefore, to investigate morphological and chemical markers for resistance breeding to western flower thrips in Gladiolus varieties. We measured thrips damage of 14 Gladiolus varieties in a whole-plant thrips bioassay and related this to morphological traits with a focus on papillae density. Moreover, we studied chemical host plant resistance to using an eco-metabolomic approach comparing the 1H NMR profiles of thrips resistant and susceptible varieties representing a broad range of papillae densities. Thrips damage varied strongly among varieties: the most susceptible variety showed 130 times more damage than the most resistant one. Varieties with low thrips damage had shorter mesophylls and epidermal cells, as well as a higher density of epicuticular papillae. All three traits related to thrips damage were highly correlated with each other. We observed a number of metabolites related to resistance against thrips: two unidentified triterpenoid saponins and the amino acids alanine and threonine. All these compounds were highly correlated amongst each other as well as to the density of papillae. These correlations suggest that papillae are involved in resistance to thrips by producing and/or storing compounds causing thrips resistance. Although it is not possible to distinguish the individual effects of morphological and chemical traits statistically, our results show that papillae density is an easy marker in Gladiolus-breeding programs targeted at increased resistance to thrips.


2008 ◽  
Vol 98 (4) ◽  
pp. 355-359 ◽  
Author(s):  
P. Bielza ◽  
V. Quinto ◽  
C. Grávalos ◽  
E. Fernández ◽  
J. Abellán ◽  
...  

AbstractThe stability of spinosad resistance in western flower thrips (WFT),Frankliniella occidentalis(Pergande), populations with differing initial frequencies of resistance was studied in laboratory conditions. The stability of resistance was assessed in bimonthly residual bioassays in five populations with initial frequencies of 100, 75, 50, 25 and 0% of resistant individuals. There were no consistent changes in susceptibility of the susceptible strain after eight months without insecticide pressure. In the resistant strain, very highly resistant to spinosad (RF50>23,000-fold), resistance was maintained up to eight months without further exposure to spinosad. In the absence of any immigration of susceptible genes into the population, resistance was stable. In the case of the population with different initial frequency of resistant thrips, spinosad resistance declined significantly two months later in the absence of selection pressure. With successive generations, these strains did not change significantly in sensitivity. Spinosad resistance inF. occidentalisdeclined significantly in the absence of selection pressure and the presence of susceptible WFT. These results suggest that spinosad resistance probably is unstable under field conditions, primarily due to the immigration of susceptible WFT. Factors influencing stability or reversion of spinosad resistance are discussed.


2015 ◽  
Vol 16 (4) ◽  
pp. 211-215 ◽  
Author(s):  
Surendra K. Dara

Greenhouse white fly, Trialeurodes vaporariorum (Westwood); western flower thrips, Frankliniella occidentalis (Pergande); and strawberry aphid, Chaetosiphon fragaefolii (Cockerell), are common pests of strawberries in California and are vectors of one or more viruses. Most of the viruses transmitted by these vectors do not cause symptoms on strawberry when the infection occurs individually. However, when one of the viruses (Beet pseudoyellows virus or Strawberry pallidosis-associated virus) transmitted by T. vaporariorum is present along with one of the viruses transmitted by F. occidentalis, C. fragaefolii, or other sources, it results in a virus decline of strawberry, which can cause significant crop losses. Stunted root and plant growth, purple coloration of foliage, and dieback of the plant are some of the symptoms associated with virus decline. Increases in T. vaporariorum infestations during the past few years significantly elevated the risk of whitefly as a crop pest and a disease vector. This article reviews virus decline of strawberry, symptoms of infection, and the current status of insect vectors in California strawberries. Accepted for publication 17 November 2015. Published 20 November 2015.


2008 ◽  
Vol 9 (1) ◽  
pp. 30 ◽  
Author(s):  
Mrittunjai Srivastava ◽  
Lara Bosco ◽  
Joe Funderburk ◽  
Anthony Weiss

Feeding by the western flower thrips, Frankliniella occidentalis, causes damage to the fruits of pepper, and the species is the key vector of Tomato spotted wilt virus. Effective management integrates conservation of populations of the natural predator, Orius insidiosus, with the use of reduced-risk insecticides, namely spinosad. We conducted field experiments in northern Florida in 2005 and 2006 and in central Florida in 2006 to evaluate the new reduced-risk insecticide spinetoram for control of thrips and to determine the impact on natural populations of O. insidiosus. Spinetoram at 61 g ai/ha was as effective as spinosad at 140 g ai/ha against the western flower thrips and the other common thrips in Florida, Frankliniella tritici and Frankliniella bispinosa. The mean numbers of the predator were very high in all treatments in each experiment, and their numbers relative to the numbers of thrips indicated that predation was sufficient to suppress thrips populations in all treatments. Broad-spectrum insecticides when included in the experiments provided little or no control; sometimes, they flared thrips numbers compared to untreated pepper. Accepted for publication 25 October 2007. Published 18 January 2008.


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