Regional selection of insecticides and fungal biopesticides to control aphids and thrips and improve the forage quality of alfalfa crops

The efficacies of biological and conventional chemical insecticides against two major insect pests of alfalfa(aphids and thrips)were compared in three sites across China’s alfalfa belt.In addition,the persistence of the residues of chemical insecticides in alfalfa and their influence on the quality of alfalfa hay were examined.Efficacy varied among the different biological and chemical insecticides.The chemical insecticides were significantly more effective than biopesticides in a short time-frame.The efficacy period of biopesticides was significantly longer than that of chemical insecticides,and the corrected mortality rate of aphids in all regions was above 50%at 14 days after application.The analysis of pesticide residues showed that the residual doses of all the pesticides were within the allowed ranges after the safe period.The acid detergent fiber and neutral detergent fiber contents in alfalfa hay were higher and the protein content was lower in chemical insecticide treatments than in biopesticide treatments in Hebei.The relative feeding value of alfalfa hay treated with Metarhizium anisopliae IPP330189 was the highest among the treatments.Compared with chemical insecticides,the yield of alfalfa hay was higher in the biopesticides treatments.Biopesticides show a stronger control effect on insect populations and also a better improvement in the quality of alfalfa hay than chemical insecticides.This study provides a basis for exploring and developing a comprehensive control regime for alfalfa insect pests in the different alfalfa-growing regions in China,and for reducing chemical insecticide usage and improving forage quality.

Control Effect of UAV Low Volume Spray Technology on Thrips and Tomato Spotted Wilt Virus in Tobacco Field

[Objectives]The paper was to explore the influence of unmanned aerial vehicle(UAV)low volume spray technology on the control effect of viruliferous thrips and tomato spotted wilt virus(TSWV)under different pesticide concentrations,and to explore the effective control nodes and methods of thrips and TSWV.[Methods]According to the occurrence characteristics of thrips and TSWV,the field control effects of 4 pesticides on thrips and TSWV were tested by UAV with the thrips number and disease index as indicators,following the principle of regional and periodic control trials.[Results]In the groups of UAV and artificial prevention and control,4 agents were used alternatively,including 1%emamectin benzoate ME,1.7%abamectin imidacloprid ME,5%emamectin benzoate WDG,and 30%pyriproxyfen dinotefuran SL.There was no significant difference in the control effect of thrips and TSWV among treatment 1(recommended dosage of UAV agent),treatment 2(reduction of recommended dosage of UAV agent by 25%)and treatment 4(recommended dosage of artificial control agent),and the control effects on thrips were more than 83.16%in the 3 treatments.The disease index of TSWV in the 3 treatments decreased from 8.64±1.37 in the blank control group to less than 3,which reached the prevention and control threshold.But treatment 3(reduction of recommended dosage of UAV agent by 50%)did not reach the prevention and control threshold.The disease index of TSWV in the blank control area increased with the increase of the number of live nymphs of thrips,and there was a significant positive correlation,with good fitness.[Conclusions]UAV has a significant impact on the control effect of thrips and TSWV under different pesticide concentrations.In the actual flight control application,it is recommended that the amount of the pesticides is about 3/4 and not less than 1/2 of that of the artificial application.The control area should be extended to 100 m of the ridge of the tobacco field,and UAV is used periodically to control thrips and TSWV for 5 times from pre-transplanting stage to pre-squaring stage of flue-cured tobacco.The control effect is significantly different from the traditional artificial application.

Diversity, Host Plant Range and Distribution of Thrips spp. (Thysanoptera: Thripidae) in Three Vegetable Production Basins in Burkina Faso

Onion is the most important vegetable produced in Burkina Faso. It contributes to food and nutrition security and is a source of income for farmers. Thrips, which feed on the leaves of the plant, are the main insect pest of onion. The objective of this study was to access the diversity, the host range and the distribution of Thrips spp. in three main onion production areas in Burkina Faso. Three sites were chosen in each vegetable production basin, and plant species present were sampled and inspected to determine their thrips’ infestation status. Seventeen cultivated or wild plant species were attacked by thrips. The incidence of attacks was highest on zucchini plants followed by cucumber, eggplant, and onion, respectively. Six thrips species were recorded of which Thrips tabaci (Lindemman) represented more than 70% of the total. The average density of Thrips spp. per plant varied significantly between production basins and plant species. The highest average number of Thrips spp. per plant was recorded on zucchini (40.28 ± 10.28;17.43 ± 13.48 and 14.33 ± 7.11 respectively in the North, Hauts Bassins, and Central Plateau). This study provided basic information that can lead to further research and the development of control methods.

Study on Physiological Activity of the Resistance of Medicago sativa to Thrips

[Objective] The experiment explored of resistance of different Medicago sativa through synthetic variations of all physiological indexes and the correlation analysis between physiological activity and damage degree after thrips damage. [Method] According to studying physiological activity (POD activity, SOD activity, PPO activity, PAL activity, MDA content and free proline content) of alfalfa in alfalfa resistance to different number of thrips, the correlation between physiological activity and resistance was investigated. [Result] It was shown that there were negative correlations among POD, SOD, PPO, PAL, MDA, free praline and the number of thrips, and there were negative correlations among POD, SOD, PPO, PAL, MDA, free praline and CAT. The content changes of POD,SOD,PPO,CAT,MDA and free proline in high resistant alfalfa were slow and PAL was quick and the activities of PPO,PAL,CAT were high, and the activities of POD、SOD were low. [Conclusion] The research provided theoretical basis and materials for identifying resistance varieties of alfalfa to thrip.

Thrips: Pests of Concern to China and the United States

Thrips are among the most important agricultural pests globally because of the damage inflicted by their oviposition, feeding, and ability to transmit plant viruses. Because of their invasiveness, a number of pest species are common to both China and the United States and present significant challenges to growers of a wide range of crops in both countries. Among the pest thrips common to both countries are four of the major global thrips pests, Frankliniella occidentalis （Pergande）, Scirtothrips dorsalis Hood, Thrips palmi Karny, and Thrips tabaci Lindeman. This review addresses characteristics that enable thrips to be such damaging pests and how biological attributes of thrips create challenges for their management. Despite these challenges, a number of successful management tactics have been developed for various cropping systems. We discuss some of these tactics that have been developed, including the use of cultural controls, biological controls, and judicious use of insecticides that do not disrupt overall pest management programs. The exchange of this type of information will help to facilitate management of pest thrips, especially in regions where species have recently invaded. A prime example is F. occidentalis, the western flower thrips, which is native to the United States, but has recently invaded China. Therefore, management tactics developed in the United States can be adapted to China. Because further success in management of thrips requires a thorough understanding of thrips ecology, we discuss areas of future research and emphasize the importance of collaboration among different countries to enhance our overall understanding of the biology and ecology of thrips and to improve management programs for these widespread pests.

Spatial Distribution of Mulberry Thrips,Pseudodendrothrips mori Niwa (Thysanoptera:Thripidae)

Pseudodendrothrips mori is a serious pest to mulberry trees and its infestation affects the qualitative and quantitative characteristics of mulberry leaves consumed by silkworm. The spatial distribution of mulberry thrips within plant and orchard was assessed using Taylor＇s power law and Morisita＇s index of dispersion. The results showed that P.mori populations were localized in certain parts of the trees and fields. Distribution of thrips within plant showed that the larval instars were located on lower canopy （leaves 5-10 from top） of trees but adults preferred the upper canopy （leaves 1-5 from top）. The thrips density did not vary significantly among the leaf direction inside the trees. The thrips tended to be more accumulated on the trees located in East, South and North than in Center and West of orchard. The distributions of P.mori adults and larvae on the leaves were aggregated.

The spore-feeding genus Nesothrips(Thysanoptera: Idolothripinae) from China, with one new record

The species from China in the spore-feeding genus Nesothrips Kirkaldy are reviewed and N. propinquus is recorded for the first time from China. An identification key is provided for the four Nesothrips species currently recorded from China.

A new species in the genus Odontothrips Amyot & Serville,1843(Thysanoptera: Thripidae) from China

This paper describes a new species of the genus Odontothrips from China, O. bifurcus sp. nov. This new species can be distinguished from O. pentatrichopus Hart ＆ Cui by the combination of interocellar setae arising on the outside line between fore ocellus and hind ocelli （vs. interocellar setae arising on the middle line between fore ocellus and hind ocelli）, metanotum with a pair of campaniform sensiUa on median part （vs. metanotum without campaniform sensilla）, and abdominal tergite X with a pair of median setae bifurcated （vs. median setae on abdominal tergite X normal, not bifurcated）. It can be distinguished from O. phaseoli Kurosawa by the combination of fore wing first vein uninterrupted （vs. fore wing first vein interrupted, with 2 distal setae） and abdominal tergite X with a pair of median setae bifurcated （vs. median setae on abdominal tergite X normal, not bifurcated）.

A Preliminary Study on the Regularity of Outbreak of Thrips in Asparagus-bean Interplanting Fields

[Objectives]This study was conducted to clarify the composition and occurrence regularity of thrips in asparagus-soybean intercropping fields.[Methods]The species and occurrence dynamics of thrips in asparagus-bean intercropping fields in Luquan District of Shijiazhuang were investigated.[Results]There were 7 species of thrips in this area,namely,tobacco thrips[Thrips alliorum(Priesner)],western flower thrips[Frankliniella occidentalis(Pergande)],Scolothrips takahashii Priesner,Megalurothrips usitatus(Bagrall),Sussericothrips melilotus Han and Aeolothrips fasciatus.As the dominant species,tobacco thrips had two peak outbreaks in late June and late September,and maintained a high quantity level for a long time.Other thrips had fewer population and different occurrence time,but were greatly affected by temperature,humidity and host crop species.[Conclusions]This study provides a theoretical basis for the forecast and comprehensive control of thrips in North China.

Detection of Thrips Defect on Green-Peel Citrus Using Hyperspectral Imaging Technology Combining PCA and B-Spline Lighting Correction Method

In order to find an effective method of detecting thrips defect on green-peel citrus, a defect segmentation method was developed using a single threshold value based on combination of characteristic wavelengths principal component analysis （PCA） and B-spline lighting correction method in this study. At first, four characteristic wavelengths （523, 587, 700 and 768 nm） were obtained using PCA of Vis-NIR （visible and near-infrared） bands and analysis of weighting coefficients; secondarily, PCA was performed using characteristic wavelengths and the second principal component （PC2） was selected to classify images; then, B-spline lighting correction method was proposed to overcome the influence of lighting non-uniform on citrus when thrips defect was segmented; finally, thrips defect on citrus was extracted by global threshold segmentation and morphological image processing. The experimental results show that thrips defect in citrus can be detected with an accuracy of 96.5% by characteristic wavelengths PCA and B-spline lighting correction method. This study shows that thrips defect on green-peel citrus can be effectively identified using hyperspectral imaging technology.

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.

Field Efficacy Test of 22% Fipronil FS against Sugarcane Stem Borers and Thrips

[ Objective] The paper was to explore the field efficacy of 22% fipronil FS against sugarcane stem borer and thrips （Baliothrips serratus Kobus ）. [ Method] The field trial was conducted by foliar spraying of 22% fipronil FS and mixed broadcasting with fertilizer in 2014. [ Result ] Foliar spraying of 22% fipronil FS at the dose of 50 mIV667 m~ had the best control effect against sugarcane stem borer, and the control effect at 90 d post administration was 70.70%, significantly higher than that of control agent （61.86%）. Medium and high dose of 22% fipronil FS had better control effects against sugarcane thrips. [ Conclusion ] Considering control effects against sugarcane stem borers and thrips as well as sugarcane yield, it is recommended that 22% fipronil FS is sprayed at medium concentration （50 mL/667 m2 ）.

Improving a method for evaluating alfalfa cultivar resistance to thrips

The thrips quantity ratio（TQR） model is an important tool for evaluating crop resistance to thrips based on the correlation between thrips quantities and cultivars. Unfortunately, it is inaccurate, and the results appear significantly inconsistent when analysing the same cultivars in the same field study. To improve this model, we first studied the resistance of 28 alfalfa cultivars to thrips in Cangzhou, Hebei Province, north China. The results showed that the most suitable evaluation period was from May to June, as the thrips population was stable during this period. Second, we found that the natural enemy population was significantly positively correlated with the thrips population density（R=0.7275, P〈0.0001）, which might influence resistance estimation. Hence, we introduced a parameter ‘α＇, corresponding to the natural enemy quantity ratio, to eliminate the effect of the natural enemy using ＂αTQR＂. Using the improved method, 28 cultivars were clustered into three classes： the resistant class, sensitive class, and median class. All numerical values were calculated for αTQR displayed as a Gaussian distribution. This information showed that all data should be divided into nine groups using a median value of 1±0.1 with an equal difference of 0.1. Based on the new standard cultivars, Gongnong 1, Alfaking, Cangzhou and Algonquin were classified as highly resistant cultivars; Zhongmu 3, Gongnong 2, Zhongmu 1 and Zhongmu 2 were classified in the resistant group; Queen was classified in the moderately resistant group; Derby, WL354HQ, KRIMA, Apex, 53 HR, SARDI 5 and Farmers Treasure were classified in the median class; WL319HQ, WL343HQ and Sitel were classified as the low sensitive group; WL440 HQ and SARDI7 as the moderately sensitive group; WL168HQ and Sanditi as the sensitive group; and SARDI 10, WL363HQ, FD4, WL323 and SOCA as the highly sensitive group.

Toxicity and Field Efficacy of Six Insecticides on Alfalfa Thrips (Thysanoptera: Thripidae)

Alfalfa thrips,especially the bird s-foot trefoil thrips(Odontothrips loti Haliday),is a major pest in the alfalfa field.Toxicity and field efficacy of 6 insecticides were determined by leaf disk in tube method and foliar spray,respectively.The results showed LC 50 values of chlorfenapyr 24%SC,lambda-cyhalothrin 5%EW,sulfoxaflor 22%SC,dinotefuran 20%SG,spinetoram 60 g/L SC and tolfenpyrad 30%SC to Odontothrips loti were 0.11,0.62,2.92,4.24,10.47 and 13.42 mg/L,respectively.The control effects of tolfenpyrad 30%SC,spinetoram 60 g/L SC,sulfoxaflor 22%SC,lambda-cyhalothrin 5%EW and dinotefuran 20%SG against alfalfa thrips were more than 80%after 1 d treatment,showing good readily availability.The control of spinetoram 60 g/L SC and dinotefuran 20% SG was 74.63% and 75.65% after 7 d treatment,showing a long persistence effect respectively.Therefore,spinetoram 60 g/L SC and dinotefuran 20% SG can be used as the first option to control alfalfa thrips.

A new species in the genus Hydatothrips Karny, 1913(Thysanoptera: Thripidae) from Hainan, China

This paper describes and illustrates a new species in the genus Hydatothrips from Hainan Island, China,H.hainanensis sp.nov.The type specimens are deposited in the Entomological Museum,Northwest A&F University.

Prediction Method and Green Control Technology of Thrips on Winter Vegetable Cowpea in Sanya City

[ Objectives ] The paper investigated the occurrence and damage of thrips on winter vegetable cowpea in Sanya City, to summarize prediction method and control measures against the insect pest. [ Methods] Prediction through analogy suggested that cowpea could be damaged by thrips throughout the entire growth period. [Results] The peak occurrence and damage period of thrips was after transplanting of cowpea from December to early March in the following year. The occurrence of thrips was severe in the case of high temperature and drought, or was light when encountering rainy season. [ Conclusions ] Using fivepoint sampling method, blue boards were hanged up for monitoring （five pieces each point, specifieation 25 cm × 30 cm）. When the number of thrips on blue board reached 10 specimen/piece, it was the optimal control period of thrips, and different prevention and control measures could be adopted according to the specifi growth stages of cowpea.

Occurrence Characteristics and Control of Thrips tabaci in Yanji City

With the increasing plant area of welsh onion, onion and Chinese onion, the damage of Thrips tabaci in Yanji City is aggravating day by day. Through preliminary investigation and literature reading, we summarized occurrence status, morphological characteristics, damage characteristics, occurrence regularity, living habit, outbreak cause and integrated control technology of T. tabaci in Yanji City, in order to control the hazard of T. tabaci effectively.

Developmental and Reproductive Performance of the Tobacco Thrips, <i>Frankliniella fusca</i>(Hinds) (Insecta: Thysanoptera), on Leaves of Nicotiana spp.

Tobacco thrips, Frankliniella fusca, which is a vector of Tospovirus, is a serious pest of tobacco, peanuts, and cotton in the United States. It was said that immigration of the adult thrips from weed hosts into crop fields is a cause of TSWV epidemy in the field. Recently this pest thrips was introduced into Japan. We investigated survival rate, developmental time, and fecundity of a Japanese strain of F. fusca on leaves of tobacco, peanut, and green bean at 18°C. Thrips could not complete larval development on 3 Nicotiana species, N. tabacum, N. gossei, and N. rustica. On the other hand, survival rate from hatching to adult emergence on peanut and green bean is 78% and 86%, respectively. A female adult thrips lived during about 25 days and deposited 101 eggs on green bean, but died within 10 days without ovipositing on Nicotiana spp. The tobacco is not a reproductive host plant that permits tobacco thrips to propagate, but an adult food source that is susceptible of TSWV.

Efficacy of Reduced-Risk Insecticides to Control Flower Thrips in Early-Season Blueberries and Their Effect on <i>Orius insidiosus</i>, a Natural Enemy of Flower Thrips

Flower thrips are one of the key pests in production of southern highbush blueberries (Vaccinium corymbosum L. × V. darrowi Camp). They feed on the reproductive parts of the flower and reduce yield. Very few insecticides are available to manage thrips population. Therefore, it is necessary to evaluate pre-existing and experimental insecticides for their efficacy against thrips. There is also a high demand for reduced-risk insecticides that are less toxic to beneficial insects and the environment. In this study, a number of conventional and reduced-risk insecticides were evaluated against flower thrips on farms in Florida and Georgia and in the laboratory. The best performing insecticides were also evaluated in the laboratory for their effects on Orius insidiosus Say, which is a common thrips’ predator in Florida. Assail 70WP (Acetamiprid) and SpinTor 2SC (Spinosad) were the most promising insecticides in reducing thrips numbers in the field as well as in laboratory experiments. SpinTor 2SC killed all of the thrips in laboratory arenas within 4 hours of application and showed low toxicity toward O. insidiosus. All of the compounds tested performed as well as the conventional pesticide malathion.

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.