Synergistic influence of the capture effect of western flower thrips(Frankliniella occidentalis)induced by proportional yellow-green light in the greenhouse

To clarify the influence of yellow,green,and proportional yellow-green light on the capture effect,western flower thrips,Frankliniella occidentalis(Pergande),were captured using different self-made light sources in a greenhouse.The bio-activity capture effect of thrips was regulated by light and analyzed to determine the reasons for the changes in their capture by light.The results showed that the thrips’capture effect induced by different light sources with the same brightness was positively correlated with night temperature.When the average night temperature was 27℃(19:00-21:30),the capture effect was optimal,indicating that the coupling effect of light temperature can regulate the capture effect of thrips.Green light intensified and yellow light inhibited the visual trend sensitivity of thrips to yellow-green light of differing proportions.The capture effect trapped by a green-yellow light ratio of 4:1 was optimal(1088.00 individuals in night time),while that of yellow light was the worst(456.67 individuals/night),thus,indicating that visual trend sensitivity of thrips to green light was higher than that of yellow light.Such differences originated from the differences in the photoelectric thermal conversion effect of spectral optical properties,and the spectral photo-thermal effect was the main reason that thrips produced a light-trapped behavior.Night light enhanced the sensitivity of thrips’responses to a white adhesive board during the daytime,and the effect of yellow light intensity was the strongest(1563.00 individuals in the daytime),while that of green light was the weakest(75.33 individuals in the day time).Additionally,yellow light intensified while green light inhibited the regulatory effect of different proportions of yellow-green light on the bio-activity of thrips.However,the capture effect of day and night corresponding to 4:1 green-yellow light was the best(2019.67 individuals in day and night).The function of the photo-thermal effect on the capture effect of thrips was affected by the decrease in night temperature,but the photo-electro-thermal effects of night light intensified the bio-activity of thrips in the daytime and enhanced their color sensitivity.The results provide a theoretical basis for the development of pest light induction equipment.

Visual response effects of western flower thrips manipulated by different light spectra

To understand how spectral light wavelength affects thrips visual sensitivity,the selective response and the approach sensitivity of western flower thrips were examined.The results showed that light intensity affected thrips selective sensitivity to different spectra,with good visual sensitivity to blue,ultraviolet(UV),and green light changes to UV,violet,and yellow light when illumination increased from 120 lx to 6000 lx.Red light was the sensitive spectral light driving thrips to respond to sensitive light.Under illumination,the best sensitivity response to spectra was violet,while under light energy,this changed to UV when light energy was increased to 120 mW/cm^(2).However,the photo-stimulus properties(illumination or light energy)did not affect the optimal approach sensitivity to UV light.Furthermore,when illumination or light energy stimulated thrips to select two different spectral lights,the total response sensitivity to 12000 lx of UV and violet light were the best(83.27%),while at 60 mW/cm^(2) of UV and yellow light was the best(82.15%).But different photo-stimulus properties influenced on the total approach sensitivity to the stimulation of two different spectral lights when the intensity of light increased,showing that to 12000 lx of violet and green light was the best(53.18%),while for 120 mW/cm^(2) of UV and green light was the best(47.74%).The thrips visual selection response effects stimulated by illumination were different from that induced by light energy,and originated from the thrips different bio-regulatory effects caused by the intensity of light energy of illumination and the intensity of illumination of light energy.Therefore,different photo-stimulus effects can manipulate thrips visual sensitivity to enhance the phototactic effect.

Influences of yellow and green lights on the visual response of western flower thrips and field verification

This study aimed to determine the effects of spectral light characteristics on the visual response of the western flower thrips,the strengthening mechanism of thrips response behavior regulated by light,and thrips response characteristics to contrast light.Light with combined and single wavelength were tested by using a self-made behavior response device for thrips.Light sources for trapping thrips were made to verify the trapping effect on thrips in a greenhouse,and the reasons for changes in thrips behavior were analyzed to characterize the mechanism of their phototactic response.The results showed that the light mode(single,contrast,combined light)affected the thrips visual response and approach response,whereas in contrast light,the effects were optimal.Combination light inhibited the thrips visual response,and when the illumination increased,the thrips visual response to single and combination light intensified,and the thrips approach sensitivity to green light increased in contrast and combination light.However,the light mode did not affect the thrips visual response and sensitivity to spectral light characteristics.The degree of thrips visual response to yellow light was stronger than that to green light,while the degree of thrips visual response to green light was stronger than that to yellow light,indicating that the photo-induced mechanism of the thrips visual response differed from that of the thrips approach response.Moreover,in the greenhouse,the trapping effect of different light sources on thrips was positively correlated with temperature.The trapping effect of green light was optimal,followed by a yellow light source,while the difference of light intensity(illumination,illumination energy)and its photo-thermal intensity between yellow and green light was the reason for the differences in the degree of visual trends and the trapping effects of thrips.However,the sensitivity of thrips responding to different light depended on the difference in the heterogeneous stimulation intensity of different spectral light.Thus,light brightness and photo-thermal effects were the causes of thrips visual responses,while bio-photoelectric reaction effects caused thrips to produce a visual response and affected the degree of the thrips visual response.The results reveal the underlying causes of pest control by light,and provide a theoretical basis for the research and development of pest induction equipment and light arrangements.

Photo-induced visual response of western flower thrips attracted and repulsed by their phobotaxis spectrum light

This study aimed to clarify the synergistic phototactic attraction-repulsion effect formed by the photo-induced approach-avoidance behavior of thrips,construct phototactic attraction-repulsion light control technologies.The phototactic push-pull effects of red light and UV(365 nm),violet(405 nm),green(520 nm),and yellow(560 nm)single light,as well as their pairwise combined light on the behavior of western flower thrips were investigated using an apparatus that measured thrips response.The study also analyzed the influence of light properties on the phototactic attraction-repulsion effects of thrips and the synergistic effects of red light,and the attraction-repulsion regulation mode.The influence factors on the photo-induced attraction-repulsion effect of thrips were also discussed.The results showed that the red light,presenting the push effect,drove thrips to respond to the sensitive light.The synergistic attraction-repulsion effect of red light and singlelight,as well as that of red light and combined light was related to the light intensity.However,the attraction-repulsion synergism did not reflect thrips response effect and approach effect pulled and pushed by red light and single light,red light and combined light.Thrips preference for green-yellow light,and their behavior depended on the degree of UV light,making the attraction-repulsion synergy of red and green light the strongest.When the light intensity increased,the attraction-repulsion synergy of red and yellow light was the strongest.The attraction-repulsion response to red light and single light was related to the spectral attribute of the single light,with that of red lightand UV light being better.The attraction-repulsion response to red light and combined light was related to light intensity.The intensity of combined light made the attraction-repulsion response to red light and the combined UV and violet light be the best,and the brightness of long-short spectrum light rendered red light and the combined UV and yellow light the best.All such light and combinations were remarkably better than that of red light and UV light.Relative to red light and UV light,the use ofred light and combined light provided limited enhancement to the approach effect of thrips;however,under red light and combined light,violet light intensified the approach of thrips to UV light,with yellow light strengthening the approach to green light.Those results provided a scientific basis for the development of light trapping equipment and the adjustment of light control strategies for thrips.

Impact Assessments of Transgenic cry1Ab Rice on the Population Dynamics of Five Non-Target Thrips Species and Their General Predatory Flower Bug in Bt and Non-Bt Rice Fields Using Color Sticky Card Traps

A 2-yr field study was conducted to assess the effects of transgenic japonica rice（KMD1 and KMD2） with a synthetic cry1 Ab gene from Bacillus thuingiensis Berliner on population dynamics and seasonal average densities of five thrips species including Stenchaetothrips biformis（Bagnall）,Frankliniella intonsa（Trybom）,F.tenuicornis（Uzel）,Haplothrips aculeatus（Fabricius）,Haplothrips tritici（Kurd） and their general predatory flower bug,Orius similis Zheng as compared to the parental control rice line using the white,blue and yellow sticky card traps.Population dynamics and seasonal average densities of these five thrips species and their general predatory flower bug were not significantly affected by rice type.Additionally,the white sticky card trap was suggested to be the most suitable for monitoring the population of these five thrips species and their general predator.These results show that our tested Bt rice lines do not interrupt the population of non-target thrips species and their general predatory flower bug in the field,and also cannot result in more occurrence of these thrips species in the rice ecosystem.

Mechanisms of resistance to spinosad in the western flower thrip, Frankliniella occidentalis （Pergande） （Thysanoptera： Thripidae）

Cross-resistance, resistance mechanisms, and mode of inheritance of spinosad resistance were studied in the western flower thrip, Frankliniella occidentalis （Pergande）. Spinosad （naturalyte insecticide） showed low cross-resistance to prothiophos （organophosphorus insecticide） and chlorphenapyr （respiratory inhibitor） showed some cross-resistance to thiocyclam （nereistoxin）. The synergists PBO （piperonyl butoxide）, DEM （diethyl maleate）, and DEF （s,s,s-tributyl phosphorotrithioate） did not show any synergism on the toxicity of spinosad in the resistant strain （ICS）, indicating that metabolic- mediated detoxification was not responsible for the spinosad resistance, suggesting that spinosad may reduce sensitivity of the target site： the nicotinic acetylcholine receptor and GABA receptor. Following reciprocal crosses, dose-response lines and dominance ratios indicated that spinosad resistance was incompletely dominant and there were no maternal effects. The results of backcross showed that spinosad resistance did not fit a single-gene hypothesis, suggesting that resistance was influenced by several genes.