Search

Relevance. The study is aimed at evaluating the biological effectiveness of insecticides to reduce the number of tobacco thrips and gourd aphids in a film greenhouse on gourds. These pests cause significant damage to plants and can carry a viral infection. In greenhouse conditions, tobacco thrips can produce up to 7-8 generations, and melon aphid – up to 16 generations per season. The recommended pest control products have a limited protective duration in protected ground conditions, and in most cases promote the development of resistance in insects.Results. The article presents the results on the use of the insectoacaricide MatrinBio, BP against melon aphids and tobacco thrips, and the biological effectiveness in reducing the number of pests is determined. A single treatment with a bioinsecticide kills up to 90% of tobacco thrips insects. Efficiency against melon aphids is 27% lower. It is noted that the period of the protective action of MatrinBio, BP lasts up to seven days, then decreases. On the fourteenth day, the biological effectiveness against pests is; for thrips – 72%, and for aphids – 40%. For comparison, bioinsecticide Fitoverm, EC, was chosen as a standard, which showed worse results in reducing the number of tobacco thrips (less by 20...25%), but had the best protective effect against melon aphids - by 19...21%. Re-treatment with drugs seven days after the first one significantly reduced the number of pests. To prevent the emergence of resistance in pests in protected ground conditions, it is recommended to include MatrinBio, BP in the integrated protection system and alternate with insectoacaricides from other classes or use in various combinations.

[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 treatment4 (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. [ABSTRACT FROM AUTHOR]

Simple Summary: Transgenic Bt crops are important tools for growers to manage insect pests, but their use is threatened by the evolution of insect resistance, and monitoring programs are essential in detecting and responding to resistance. For Bt products in which insect control is not complete ("non-high-dose crops"), resistance monitoring is challenging, because insects and insect damage will be present even without resistance. Given these challenges, "sentinel plots" (designated monitoring plots) consisting of Bt and non-Bt control plots have been used to monitor for insect resistance to non-high-dose Bt crops by assessing changes in the efficacy of a Bt crop over time relative to a non-Bt control. We used this approach for ThryvOn™ cotton, a new non-high-dose Bt product targeting two sucking pest types—Lygus and thrips—and report here on the thrips monitoring program. Monitoring for insect resistance over time requires knowledge of the baseline susceptibility, which is the initial assessment of the insect population response to a given Bt crop prior to its widespread adoption. To characterize the baseline susceptibility of thrips to ThryvOn, we tested several approaches and found that the number of immature thrips on ThryvOn relative to the control cotton best characterized the efficacy of the trait. Transgenic Bt crops are important tools for growers to manage insect pests, but their durability is threatened by the evolution of insect resistance. Implementing a resistance monitoring program is essential to detect and mitigate resistance. For non-high-dose Bt crops, resistance monitoring is challenging, because insect control is not complete, so targeted insects and insect damage will be present even without resistance. Given these challenges, sentinel plots have been used to monitor for insect resistance to non-high-dose crops by assessing changes in the efficacy of a Bt crop over time relative to a non-Bt control. We optimized a sentinel plot resistance monitoring approach for MON 88702 ThryvOn™ cotton, a new non-high-dose Bt product targeting two sucking pest taxa—Lygus (L. lineolaris and L. hesperus) and thrips (Frankliniella fusca and F. occidentalis)—and report here on the thrips monitoring methods and results. Quantifying thrips immatures was the best metric to characterize the impact of the trait, with at least a 40–60% average reduction of thrips immatures on ThryvOn relative to the control cotton at all sites with higher thrips densities. These data can be used within a ThryvOn resistance monitoring program and represent a case study for establishing a resistance monitoring approach for a non-high-dose trait product. [ABSTRACT FROM AUTHOR]

Transgenic Bt crops are important tools for growers to manage insect pests, but their durability is threatened by the evolution of insect resistance. Implementing a resistance monitoring program is essential to detect and mitigate resistance. For non-high-dose Bt crops, resistance monitoring is challenging, because insect control is not complete, so targeted insects and insect damage will be present even without resistance. Given these challenges, sentinel plots have been used to monitor for insect resistance to non-high-dose crops by assessing changes in the efficacy of a Bt crop over time relative to a non-Bt control. We optimized a sentinel plot resistance monitoring approach for MON 88702 ThryvOn™ cotton, a new non-high-dose Bt product targeting two sucking pest taxa—Lygus (L. lineolaris and L. hesperus) and thrips (Frankliniella fusca and F. occidentalis)—and report here on the thrips monitoring methods and results. Quantifying thrips immatures was the best metric to characterize the impact of the trait, with at least a 40–60% average reduction of thrips immatures on ThryvOn relative to the control cotton at all sites with higher thrips densities. These data can be used within a ThryvOn resistance monitoring program and represent a case study for establishing a resistance monitoring approach for a non-high-dose trait product.

Frankliniella fusca Hinds (Thysanoptera: Thripidae) is an economically important pest of many cultivated crops including cotton, tomatoes, peppers and tobacco. Previous research has focused on the importance of non‐crop weeds for F. fusca populations when estimating crop infestation risk in the spring. Although weeds play an integral role in population development, early‐season cultivated hosts (e.g. wheat and sage) may also contribute and augment overall populations. Few studies have examined the role of early‐season crops as a source habitat for sensitive host crops later in the season. The goal of this study was to investigate the abiotic conditions and landscape components that are associated with F. fusca populations in winter wheat (Triticum aestivum L.). Exploring these relationships will provide insight into early‐season drivers of F. fusca. To do this, we conducted a 2 year study documenting F. fusca populations during an 8 weeks period each spring. We sampled immature thrips abundance on wheat heads while concurrently monitoring adult dispersal from the field using yellow sticky cards. Across both years, we found that immature thrips sampled during the milk and dough development stages best‐predicted adult dispersal 2 weeks later. Cumulative precipitation and the number of precipitation events beginning in the autumn of the prior year were the most important abiotic predictors of F. fusca abundance. At the landscape scale, adult F. fusca density was negatively related to the area of row crop agriculture, grasslands and amount of landscape fragmentation. Results of our study provide a basis to assess larval thrips and forecast dispersal of this pest from wheat using a head sampling method. At a landscape scale, we show that specific combinations of abiotic and landscape variables influence population abundance of F. fusca in North Carolina row crop agroecosystems. [ABSTRACT FROM AUTHOR]

The tobacco thrips, Frankliniella fusca Hinds, is a phytophagous pest and vector of orthotospoviruses in many crops around the world. F. fusca causes direct feeding injury to peanut plants, resulting in leaf chlorosis and curling, and yield loss. Adults and larvae also transmit the economically important tomato spotted wilt orthotospovirus (TSWV) in all peanut market types grown in the U.S. TSWV infection causes spotted wilt disease, a plant disease characterized by chlorosis, stunting, and death. From 1996 to 2006, spotted wilt disease resulted in an estimated U.S.$140 million in annual peanut production losses in the U.S. At present, a thorough documentation of F. fusca 's impacts on the U.S. peanut production system is not available. Here, we describe the morphology, life cycle, and biology of F. fusca and provide images of immature life stages. Feeding injury characteristics and TSWV transmission in peanuts are also discussed. Currently, F. fusca and TSWV are managed in peanut with a combination of tactics, including prophylactic insecticide applications and TSWV-resistant cultivars. However, standardized scouting protocols and economic thresholds for F. fusca are not yet available. Very few biological control agents have been evaluated for use against F. fusca , and few studies have quantified the contributions of native natural enemies. More research into natural enemies' contributions to F. fusca management and the mechanisms underlying TSWV-resistance in peanut could help inform and diversify integrated pest management programs. [ABSTRACT FROM AUTHOR]

Tobacco thrips (Frankliniella fusca) and tomato spotted wilt (TSW) orthotospovirus (family Tospoviridae, genus Orthotospovirus) can reduce peanut (Arachis hypogaea L.) yield. Systemic insecticides are applied in the seed furrow at planting and to peanut foliage to reduce injury from tobacco thrips and decrease incidence of TSW. Research was conducted in Georgia, North Carolina, South Carolina, and Virginia in 2013 and 2014 to compare the effect of the following treatments on tobacco thrips feeding injury and expression of TSW in peanut: thiamethoxam seed treatment, thiamethoxam seed treatment followed by acephate 3 weeks after planting, phorate applied in the seed furrow at planting, and a nontreated check. Tobacco thrips feeding injury and TSW incidence were significantly higher in thiamethoxam and thiamethoxam followed by acephate‐treated peanut than peanut treated with phorate. Thiamethoxan seed treatment followed by acephate resulted in significantly lower tobacco thrips feeding injury compared to thiamethoxam seed treatment alone. Yield of Virginia market type cultivars was greater when thiamethoxam was followed by acephate applied to peanut foliage or when phorate was applied compared with nontreated peanut or the seed treatment alone. Runner market type cultivars yielded higher when phorate was applied compared with nontreated peanut while peanut treated with thiamethoxam with or with acephate yielded similar to both of these treatments. Core Ideas: Thiamethoxam was less effective than phorate in preventing visible injury caused by thrips.Protection of yield from thrips injury by insecticides was important for both market types.Less tomato spotted wilt was observed when phorate was applied compared with thiamethoxam. [ABSTRACT FROM AUTHOR]

Tobacco thrips (Frankliniella fusca Hinds) can reduce peanut (Arachis hypogaea L.) yield if not controlled in many instances in North Carolina and Virginia. Systemic insecticides are often applied in the seed furrow at planting to suppress tobacco thrips and protect peanut yield. Foliar sprays of acephate [N‐(methoxy[methylsulfanyl]phosphoryl)acetamide] are often made regardless of the insecticide applied at planting. Imidacloprid [(NE)‐N‐[1‐([6‐chloropyridin‐3‐yl]methyl)imidazolidin‐2‐ylidene)nitramide] plus fluopyram [N‐(2‐[3‐chloro‐5‐(trifluoromethyl)pyridin‐2‐yl]ethyl)‐2‐(trifluoromethyl)benzamide])] is registered for use in peanut but information in the peer‐reviewed literature is limited regarding its effectiveness in suppressing tobacco thrips and whether or not a foliar application of acephate is needed when this product is used. Peanut injury caused by tobacco thrips was lower when phorate [diethoxy‐(ethylsulfanylmethylsulfanyl)‐sulfanylidene‐λ5‐phosphane] or imidacloprid were applied alone compared with imidacloprid plus fluopyram in 16 trials conducted in North Carolina and Virginia from 2014 to 2020. However, all insecticides applied at planting protected peanut from injury caused by tobacco thrips well enough to prevent yield loss compared with nontreated peanut. Although acephate decreased visible injury caused by tobacco thrips, yield was not affected by acephate regardless of the systemic insecticide applied at planting. The results from these trials indicate that imidacloprid plus fluopyram offers adequate suppression of tobacco thrips to protect yield. Although acephate suppressed tobacco thrips, yield was not affected by acephate. Core Ideas: Thrips control was greater with imidacloprid and phorate than imidacloprid plus fluopyram.Postemergence acephate increased thrips control regardless of the in‐furrow insecticide used.Peanut yield was similar regardless of insecticide applied the in‐furrow at planting.Acephate did not affect peanut yield when other insecticides were applied at planting. [ABSTRACT FROM AUTHOR]

Relevance. Analysis of the present range of pesticides that are used in flower orangeries showed critical shortage of allowed pesticides. Now there are no methods for registration testing of insecticides designed to protect flowers in greenhouses. Thus, the purpose of our research is to develop methodological approaches to assessment of abundance of major pests for flower cultures of protected ground and determination of biological effectiveness of new insectoacaricides.Methods. The following phytophages represent flower pests that are predominant in the protected ground: aphids: green peach – Myzus persicae Sulz., melon and cotton – Aphis gossypii Glov., greenhouse-potato – Aulacorthum solani Kalt., potato – Macrosiphum euphorbiae Thom., green rose – Macrosiphum rosae Linn.; whiteflies: greenhouse whitefly – Trialeurodes vaporariorum Wstw., silverleaf whitefly – Bemisia tabaci Genn.; thrips: tobacco – Thrips tabaci Lind., rose – Th. fuscipennis Hal., western flower – Frankliniella occidentalis Perg., heterophagous – F. intonsa Tryb., greenhouse – Heliothrips haemorrhoidalis Bouche; mites: red spider – Tetranychus urticae Koch.; red greenhouse – T. cinnabarinus BoisdResults. Researches related to assessment of abundance of major pests for flower cultures and choosing methods related to determination of biological effectiveness of insectoacaricides were performed in flower orangeries of Leningrad Region on hybrid tea roses Rosa L., chrysnatemums Chrysanthemum L., gerberas Gerbera G. As a result, the algorithm for performing tests related to study of new insectoacaricides on flower cultures in greenhouses is developed. Methodology instructions that we offer for assessment of abundance of major pests for flower cultures of protected ground and determination of biological effectiveness of new insectoacaricides are intended for ensuring the uniform methodological approach to performance of registration tests of modern means to fight against these pests and opportunity for analysis of tests in various agroclimatic areas and obtaining a reasonable general conclusion and findings related to pesticides taking into account international requirements.

RelevanceRecently, breeding work with cabbage is aimed at developing F1 hybrids, which provide the population with year-round production. The main requirements for hybrids: excellent presentation with appropriate taste, high yield stability, morphological uniformity, resistance to major diseases and tolerance to pests, as well as high keeping quality during storage. In recent years, tobacco thrips is a serious problem for cultivation of cabbage. Plant resistance to tobacco thrips is becoming increasingly relevant, at the moment in the conditions of Krasnodar region. Since tobacco thrips is the most dangerous pest in the south and quickly adapts to poisons, development of resistant hybrids should be considered the most effective way to control.Methods The purpose of breeding work is to identify highly productive cabbage hybrids with high tolerance to tobacco thrips. It was previously found that late-ripening hybrids are less affected. Therefore, in our studies, we evaluated the effect of growing terms of the same hybrids in different years of research and on their damage with Thrips tabaci Lindeman. The direction of this work is to evaluate hybrids of cabbage for leaf damage by tobacco thrips and to identify sustainable hybrid combinations and their parental forms. Studies were carried out in the central soil-climatic zone of the Krasnodar Territory. The object of research was medium-ripening hybrids of cabbage. ResultsThe degree of susceptibility of hybrids to tobacco thrips varied significantly during the three years of research, but there were distinguished lines that established themselves as the most stable: Yas25p, Ts139, Agrbh82, Pi 714, 272Br-22. Hybrid combinations with these lines showed the least loss of marketable yield and the minimum number of affected leaves in each year of the study. Of the zoned hybrids, the Revansh F1 hybrid shows a high tolerance. It was found that a later planting period significantly reduces the degree of thrips damage.

[Display omitted] • In wing-polyphenic insects, crowding generally promotes to macropter production. • Female of F. fusca exhibits wing diphenism governed by environmental conditions. • Effect of larval density on wing form determination was detected by rearing trials. • Percentage of female macropters decreased as larval density increased. • Developmental time and body length did not differ between two wing morphs. The effects of larval density on the wing form determination of female tobacco thrips, Frankliniella fusca , were investigated by rearing thrips on leaf disks at 27.5 °C. The developmental period, head width, body length, and forewing length of individuals in each wing morph were determined to assess the relationships among larval density, growth, and wing form. Data showed that higher rearing densities increased the production of female F. fusca brachypters. There was no consistent difference in the mean developmental periods between the two wing morphs or among all 5 density treatments. The body length of females tended to decrease with increasing rearing density, but there was no significant difference in body size between the two wing morphs when they were reared under the same density level. [ABSTRACT FROM AUTHOR]

BACKGROUND Tobacco thrips, Frankliniella fusca (Hinds), is a pest of cotton. Currently, growers rely on neonicotinoid seed treatments to control F. fusca. However, the occurrence of neonicotinoid‐resistant F. fusca populations has created new challenges for their management. Development of thrips‐active Cry51Aa2.834_16 Bacillus thuringiensis (Bt) toxin expressed in MON 88702 cotton will be an important new tactic for thrips management. Previous studies have shown that MON 88702 causes limited mortality of F. fusca adults and larvae but reduces infestations on seedling cotton by suppressing oviposition from colonizing adults. This suggests that the toxin affects host preference of adult F. fusca. Knowledge of the effect of this trait on F. fusca feeding behavior provides a more complete understanding of MON 88702 activity. Using electropenetrography, we compared the feeding behaviors of adult F. fusca females on MON 88702 cotton and a non‐Bt isoline cotton over 2 h. The number of probes, proportion of probes resulting in ingestion, total duration of ingestion, and duration of ingestion per event were measured. RESULTS: On MON 88702 seedlings, F. fusca probed and ingested fewer times than those on non‐Bt cotton. Probes on MON 88702 were less likely to lead to ingestion than on non‐Bt cotton. The total duration of ingestion and duration of ingestion per event did not differ between treatments. CONCLUSION: The results show that MON 88702 has an antifeedant effect on F. fusca, which provides insight into behavioral responses driving MON 88702 aversion and anti‐oviposition documented in previous studies. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract: The potential for the successful overwintering of female tobacco thrips, Frankliniella fusca（Hinds）（Thysanoptera: Thripidae）, and seasonal changes in their oviposition and wing form composition were assessed through rearing trials under outdoor conditions in Kyoto City from 2009 to 2010. Almost all overwintering female adults did not lay eggs in January and February. Some laid only a few eggs in March and early April, although these eggs did not complete development to the adult eclosion stage. Hibernation at the larval and pupal stages was not observed during the study period. Macropterous females emerged between late May and late September, with their proportion peaking （72.1%）in August ; however, they did not emerge during other periods. In contrast, all females that moulted into adults between October and December as well as in mid-May were brachypters. These results suggest that under outdoor conditions in Kyoto the invasive agricultural pest F. fusca does not reproduce throughout winter and that macropterous females emerge into adults only in summer. [ABSTRACT FROM AUTHOR]

BACKGROUND Insecticide resistance arises at a given location in response to selection acting on novel genotypes or standing variation, or allelic migration. Fitness costs of resistance may slow resistance evolution or result in reversion to susceptibility, but consistent and geographically widespread use of insecticides may provide sufficient selection to offset the fitness costs of resistance. Understanding this relationship is important to the success of insecticide resistance management. We report the existence of fitness costs of neonicotinoid resistance in field‐collected populations of the tobacco thrips (Frankliniella fusca), which increasingly challenge upland cotton production in the southeastern USA. RESULTS: Populations (14 of 15 in 2015; 4 of 5 in 2016) investigated showed a loss of resistance to imidacloprid after multiple generations without exposure to the insecticide. Populations studied in 2016 were each split into two colonies, and one of each pair was repeatedly exposed to imidacloprid. In three of the four populations that lost resistance, imidacloprid‐exposed colonies lost resistance significantly more slowly than did corresponding unexposed colonies. CONCLUSION: For imidacloprid resistance to be broadly increasing in the landscapes of the southeastern USA despite fitness costs of resistance, selection for resistance must be sufficient to overcome the costs. Findings encourage investigation into why costs are overcome in this system, potentially including geographic extent of neonicotinoid use or prevalence of low‐dose exposure. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The article lists members of the periodical's editorial board including Troy Anderson, Gordon Bell, and Robin Blake along with information on the periodical's editorial policies such as aims & scope and the table of content for the June 2019 issue.

At-plant applications of insecticides are the most common method to manage thrips in upland cotton, Gossypium hirstutum L. Because the primary pest species, tobacco thrips, Frankliniella fusca (Hinds), has developed resistance to commonly used neonicotinoid insecticides used in producing cotton, alternative control options are needed for sustainable thrips management programs. A 3-year study (2015–2017) showed that densities of thrips, feeding injury from thrips, cotton growth, and yield varied among 10 planting dates. Densities of thrips were lowest in seedling cotton planted after mid-May in all years. Thrips injury ratings in all years were highest in cotton planted in April, lowest in cotton planted in June, and below intermediate injury (intermediate corresponded to a 3 on the 0–5 scale) levels in cotton planted after mid-May. Cotton planted during May, rather than in April or June, had the highest yield potential, regardless of variety. Results of the study indicated that altering planting date could potentially be useful in mitigating injury and losses from thrips in upland cotton. [ABSTRACT FROM AUTHOR]

A model of late maturing F1 hybrid of white head cabbage for long-term storing and suitable for national recipe “golubci” have been developed based on requirements for varieties and F1 hybrids grown in the South in the conditions of drought, high temperatures and low air humidity. Combining ability of seven self-incompatible inbred lines of white head cabbage was studied by the system of full diallel crosses in conditions of Pridnestrovian Moldavian Republic. These lines were developed on the base of heat tolerant varieties ‘Biruchekutskaya’, ‘Volna’, ‘Lada’, ‘Moldavanka’ and ‘Kharkovskaya Zimnyaya’ bred in the south. Out of 42 hybrid combinations studied 15 significantly surpassed in productivity the variety ‘Zavadovskaya’ that is traditionally grown by local farmers for pickling and recipe “golubci”. High GCA effects for productivity showed the following breeding lines: Bu1, Ml3 and Kl5. Polygenes, controlling the high yield ability, mainly were dominant and single-directed, however the correlation betweenyield ability and GCA effect was middle, r=0.63±0.35. No correlation was observed inbreeding line between GCA effect and truly heterosis effect in hybrid combinations (r=0.19). Disease resistance analysis revealed lines Bu1 and Kl5 that had shown resistance to Fusarium yellows. Two hybrid combination Kl5xBu1 and Ml3xBu1 were highly tolerant to thrips attacks according to analysis of all promising hybrid combinations, carried out in natural infection background. Weak correlation was observed between the number of damaged leaves in cabbage head and dry matter content, r=0.41±0.21, and also there is no correlation revealed with sugar contents, ascorbic acid and nitrate content. High tolerance of hybrids with participation of line Bu1 explained the partial dominance nature of the trait. Hybrid combinations Kl5xBu1 and Ml3xBu1 called ‘Batal’ and ‘Shedevr’, respectively, included in registry of Moldova and PMR.

There are numerous early-season pests of cotton, Gossypium hirsutum L., that are economically important, including tobacco thrips, Frankliniella fusca (Hinds), and reniform nematode, Rotylenchulus reniformis (Linford & Oliveira). Both of these species have the potential to reduce plant growth and delay crop maturity, ultimately resulting in reduced yields. A field study was conducted during 2015 and 2016 to evaluate the influence of tillage, at-planting insecticide treatment, and nematicide treatment on pest management, cotton development, and yield. Treatment factors consisted of two levels of tillage (no-tillage and conventional tillage); seven levels of at-planting insecticide treatments (imidacloprid, imidacloprid plus thiodicarb, thiamethoxam, thiamethoxam plus abamectin, acephate plus terbufos, aldicarb, and an untreated control); and two levels of nematicide (no nematicide and 1,3-dichloropropene). There were no significant interactions between tillage, at-planting insecticide treatment, or nematicide for any parameters nor was there a difference in the main effect of nematicide on thrips control or damage. The main effects of tillage and at-planting insecticide treatment impacted thrips densities and damage. The no-tillage treatments and aldicarb in-furrow or acephate seed treatment plus terbufos in-furrow significantly reduced thrips populations. Early-season plant response was impacted by tillage and at-planting insecticide treatment; however, that did not result in significant yield differences. In regard to nematicide treatment, the use of 1,3-dichloropropene resulted in lower yields than the untreated.

Insecticidal efficacy of neonicotinoid insecticides used against tobacco thrips, Frankliniella fusca (Hinds) (Thysanoptera: Thripidae), in cotton, Gossypium hirisutum L. (Malvales: Malvaceae), was evaluated for field populations collected in Mississippi during 2014–2016. Resistance was documented in 16 and 57% of populations to imidacloprid and thiamethoxam, respectively. Resistance levels did not vary by host plant for any neonicotinoid, but resistance levels varied between the two main agricultural areas (Delta and Hills) of Mississippi and among years for some neonicotinoids. In spite of documented resistance, neonicotinoid seed treatments are still used on cotton in the midsouthern United States due to the lack of reliable alternative management strategies. The development of alternative thrips management strategies is critical to the sustainability of cotton production in the midsouthern United States. [ABSTRACT FROM AUTHOR]

Thrips are major pests of peanut (Arachis hypogaea L.) worldwide, and they serve as vectors of devastating orthotospoviruses such as Tomato spotted wilt virus (TSWV) and Groundnut bud necrosis virus (GBNV). A tremendous effort has been devoted to developing peanut cultivars with resistance to orthotospoviruses. Consequently, cultivars with moderate field resistance to viruses exist, but not much is known about host resistance to thrips. Integrating host plant resistance to thrips in peanut could suppress thrips feeding damage and reduce virus transmission, will decrease insecticide usage, and enhance sustainability in the production system. This review focuses on details of thrips resistance in peanut and identifies future directions for incorporating thrips resistance in peanut cultivars. Research on thrips–host interactions in peanut is predominantly limited to field evaluations of feeding damage, though, laboratory studies have revealed that peanut cultivars could differentially affect thrips feeding and thrips biology. Many runner type cultivars, field resistant to TSWV, representing diverse pedigrees evaluated against thrips in the greenhouse revealed that thrips preferred some cultivars over others, suggesting that antixenosis "non-preference" could contribute to thrips resistance in peanut. In other crops, morphological traits such as leaf architecture and waxiness and spectral reflectance have been associated with thrips non-preference. It is not clear if foliar morphological traits in peanut are associated with reduced preference or non-preference of thrips and need to be evaluated. Besides thrips non-preference, thrips larval survival to adulthood and median developmental time were negatively affected in some peanut cultivars and in a diploid peanut species Arachis diogoi (Hoehne) and its hybrids with a Virginia type cultivar, indicating that antibiosis (negative effects on biology) could also be a factor influencing thrips resistance in peanut. Available field resistance to orthotospoviruses in peanut is not complete, and cultivars can suffer substantial yield loss under high thrips and virus pressure. Integrating thrips resistance with available virus resistance would be ideal to limit losses. A discussion of modern technologies such as transgenic resistance, marker assisted selection and RNA interference, and future directions that could be undertaken to integrate resistance to thrips and to orthotospoviruses in peanut cultivars is included in this article. [ABSTRACT FROM AUTHOR]

Background Frankliniella fusca (Hinds) resistance to neonicotinoid seed treatments (NSTs) used in cotton has created a need for more diverse insecticide options targeting thrips. Alternative insecticides must protect seedlings while they are most vulnerable to F. fusca injury (emergence through five true leaves). In this study, we evaluated non-neonicotinoid foliar insecticide sprays currently registered for use on cotton against a neonicotinoid resistant F. fusca population. Methods During two-seasons, we compared NSTs (imidacloprid, imidacloprid + thiodicarb, and thiamethoxam) to non-neonicotinoid foliar sprays of acephate, spinetoram, abamectin, cyantraniliprole, and cyantraniliprole + abamectin in field trials to evaluate their efficacy against a neonicotinoid resistant F. fusca population. Applications were made to both early- and full-maturity cotton varieties (Stoneville 4946GLB2 & 6448GLB2) to examine F. fusca larval establishment, plant vigor, and seed cotton yield. Results With the exception of abamectin, foliar insecticide treatments consistently reduced F. fusca larval numbers and minimized true leaf damage at a level equal to or greater than NSTs. Yield was not affected by insecticide treatment. Non-neonicotinoid foliar sprays have utility in managing neonicotinoid-resistant F. fusca and should be recommended to alleviate selection pressure against NSTs in cotton and unnecessary economic losses due to ineffective NST use against resistant F. fusca populations. [ABSTRACT FROM AUTHOR]

BACKGROUND: Reports of neonicotinoid seed treatment (NST) failure against Frankliniella fusca in the mid‐south and southeastern USA led to the discovery of widespread resistance in these insect populations. Previous studies of NSTs in other crops have shown the concentration of the insecticide to change over time, which could reduce its efficacy. To understand this temporal effect in cotton with F. fusca, our study examined how plant age alters the effects of NSTs (imidacloprid, imidacloprid + thiodicarb and thiamethoxam) by examining larval establishment at multiple seedling ages during the period of cotton seedling susceptibility to this insect. Additionally, we used F. fusca populations with differing neonicotinoid sensitivity levels to understand how resistance impacts this changing efficacy. RESULTS: Greenhouse studies showed that larval numbers were significantly greater on older NST‐grown cotton seedlings. The population with elevated neonicotinoid resistance had a more rapid increase in larval number on thiamethoxam‐treated plants over time. CONCLUSION: NSTs reduce the number of F. fusca larvae on younger seedlings, but this effect declines as seedlings age. The duration of efficacy is shorter against neonicotinoid‐resistant populations. Neonicotinoid resistance in cotton‐infesting F. fusca populations may be accelerated by this time‐dependent decrease in efficacy, which likely encourages low‐dose exposure to these insecticides. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Tomato spotted wilt orthotospovirus (TSWV) is a major disease in peanut, Arachis hypogaea L. across peanut producing regions of the United States and elsewhere. Two thrips, Frankliniella fusca Hinds and Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), are considered important vectors of TSWV in peanut in the Southeast. We compared the efficiency of acquisition (by larvae) and transmission (adults) of both thrips species for TSWV (Texas peanut-strain) to leaf disks of peanut (Florunner), as well as to Impatiens walleriana Hook. f. (Dwarf White Baby) and Petunia hybrida Juss. 'Fire Chief' using double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). Both species were competent TSWV vectors in peanut and Impatiens, although F. fusca was the more efficient vector overall, i.e. virus acquisition and transmission rates for F. fusca averaged over several bioassays were 51.7 and 26.6%, respectively, compared with 20.0 and 15.3% for F. occidentalis. Neither species effectively transmitted this TSWV strain to Petunia (i.e. ≤3.6% transmission). We found statistically similar virus acquisition and transmission rates between both sexes for each species. We also detected no differences in TSWV-acquisition and transmission frequency between macropterous and brachypterous (short-wing) forms of F. fusca collected from a field population in south Texas. DAS-ELISA failed to detect low levels of TSWV in a few thrips that subsequently proved to be competent vectors. [ABSTRACT FROM AUTHOR]

Peanut growers use a combination of tactics to manage spotted wilt disease caused by thrips-transmitted Tomato spotted wilt virus (TSWV). They include planting TSWV-resistant cultivars, application of insecticides, and various cultural practices. Two commonly used insecticides against thrips are aldicarb and phorate. Both insecticides exhibit broad-spectrum toxicity. Recent research has led to the identification of potential alternatives to aldicarb and phorate. In this study, along with reduced-risk, alternative insecticides, we evaluated the effect of conventional versus strip tillage; single versus twin row seeding pattern; and 13 seed/m versus 20 seed/m on thips density, feeding injury, and spotted wilt incidence. Three field trials were conducted in Georgia in 2012 and 2013. Thrips counts, thrips feeding injuriy, and incidence of spotted wilt were less under strip tillage than under conventional tillage. Reduced feeding injury from thrips was observed on twin-row plots compared with single-row plots. Thrips counts, thrips feeding injury, and incidence of spotted wilt did not vary by seeding rate. Yield from twin-row plots was greater than yield from single-row plots only in 2012. Yield was not affected by other cultural practices. Alternative insecticides, including imidacloprid and spinetoram, were as effective as phorate in suppressing thrips and reducing incidence of spotted wilt in conjunction with cultural practices. Results suggest that cultural practices and reduced-risk insecticides (alternatives to aldicarb and phorate) can effectively suppress thrips and incidence of spotted wilt in peanut. [ABSTRACT FROM AUTHOR]

Traditional identification of thrips species based on morphology is difficult, laborious, and especially challenging for immature thrips. To support monitoring and management efforts of thrips as consistent and widespread pests of cotton (Gossypium hirsutum L.), a probe-based quantitative PCR (qPCR) assay with crude DNA extraction was developed to allow efficient and specific identification of the primary species of thrips infesting cotton. The assay was applied to identify over 5,000 specimens of thrips (including 3,366 immatures) collected on cotton seedlings from Alabama, Georgia, North Carolina, South Carolina, and Virginia in 2016. One half of all adult samples were examined by morphological identification, which provided a statistically equivalent species composition as the qPCR method. Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) was the dominant species across all the locations (76.8-94.3% of adults and 81.6-98.0% of immatures), followed by Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) in Georgia, North Carolina, and Virginia (4.6-19% of adults and 1.7-17.3% of immatures) or Frankliniella tritici (Fitch) (Thysanoptera: Thripidae) in South Carolina (10.8% of adults and 7.8% of immatures). Thrips tabaci (Lindeman) (Thysanoptera: Thripidae) and Neohydatothrips variabilis (Beach) (Thysanoptera: Thripidae) were occasionally found among adults but were rarely present among immature thrips. These five species of thrips represented 98.2-100% of samples collected across the Southeast. The qPCR assay was demonstrated to be a valuable tool for large-scale monitoring of species composition of thrips at different life stages in cotton. The tool will contribute to a better understanding of thrips population structure in cotton and could assist with development and application of improved management strategies. [ABSTRACT FROM AUTHOR]

The microbiological insecticides whit bacterial, fungal and viral origin are an alternative of chemicals. They are widely used in organic plant cultivation. The specific usage of tobacco and the increased restrictions on smoking discourage the testing and application of the bio-insecticides оn tobacco crop. The aim of field experiments was to assess the possibility of using bioinsecticides containing various natural substances and its effectiveness against thrips and leaf aphids on tobacco crop. For the thrips control have been tested effectiveness of Naturalis (a. i. Beauveria bassiana strain АТСС 74040 – 0.185 g/kg) at a dose of 150 ml/da; Neem Azal T/S (1% azadirachtin А + 0.5% azadirachtin B,W,G,D and 2.5% neem substance) at the dose of 0.3%; Savona (potassium salt of fatty acids) at the dose of 1l/0.5 da and Sineis 480 SK (spinosad 480 g/l) at the dose of 35 ml/da. The product Naturalis (a. i. Beauveria bassiana) have also been tested against tobacco leaf aphids at the dose of 150 ml/da. The best control and the longest suppression of the thrips` population are realized when Sineis 480 SK is applied. The product Naturalis has high effectiveness (over 85%) against thrips and leaf aphids and might be recommended for the joint control. Neem Azal T/S demonstrates intermediate effectiveness (over 65%) against the thrips. A relatively short action period of Neem Azal T/S and Naturalis may be overcomes by twice application in 7 days interval. The effectiveness of Savona against the thrips is unsatisfied (≈ 40%). [ABSTRACT FROM AUTHOR]

BACKGROUND Detection of neonicotinoid resistance in populations of tobacco thrips, Frankliniella fusca Hinds, throughout the southeastern USA has motivated an examination of alternative insecticides to control problematic infestations on seedling cotton. The objective of this study was to refine understanding of stage-specific mortality and reduced oviposition of several common insecticides (acephate, abamectin, cyantraniliprole, spinetoram, imidacloprid, imidacloprid+thiodicarb, thiamethoxam) on neonicotinoid resistant and susceptible F. fusca populations under laboratory and field conditions. RESULTS Laboratory studies revealed that the average number of eggs per female and larval or adult survivorship responses differed by insecticide and were dependent on the resistance status of the population . In the presence of neonicotinoids, the resistant F. fusca populations exhibited lower mortality and higher egg counts than the susceptible population. In the field study, similar patterns of oviposition suppression were observed, indicating that some insecticides may impact reproductive rate. CONCLUSION This study shows that insecticides have different effects on F. fusca oviposition events, larval and adult mortality that are dependent on neonicotinoid resistance status. Because insecticides tested in this study have varied activity on specific F. fusca life stages (e.g. oviposition suppression, larvicidal activity, adulticidal activity), knowledge of stage-specific activity can be used to improve control and enhance long-term product stewardship. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Thrips (Thysanoptera) are the most prevalent early season pests of cotton and are often detrimental to the establishing crop. Heavy reliance on prophylactic insecticides, primarily used as seed treatments, has led to insecticide resistance in populations of Frankliniella fusca Hinds. Sustainable, alternative management tactics are needed to protect seedling cotton from thrips. We evaluated day-neutral, exotic landraces (N = 164) of Upland cotton (Gossypium hirsutum L.) for thrips-resistance traits in three field trials using insecticide-treated and -untreated plots. The cotton landraces were chosen for their diverse backgrounds, unique genotypes, and day-neutrality, allowing them to easily cross with USA breeding lines. The trials were conducted at the North Carolina State University Sandhills Research Station in Jackson Springs, NC (NC2018), and the Clemson University Pee Dee Research and Education Center in Florence, SC (SC2018 and SC2020). A selection index was created to quantify thrips resistance based on densities of thrips and ratings of injury by thrips at the first and third true-leaf stages in untreated plots, and genotypic differences in above-ground dry biomass between treated and untreated plots at 42 days after planting. Subsamples of adult thrips were collected for species identification. Dominant thrips species were F. fusca in NC2018 and SC2020 and Frankliniella tritici in SC2018. Eight putatively thrips-resistant genotypes (TX-1109, TX-1975, TX-2320, TX-2383, TX-101, TX-2347, TX-2362, TX-251) and four putatively thrips-susceptible genotypes (TX-203, TX-1212, TX-1094, TX-2403-2) were identified in the field trials. Further investigation of the putatively thrips-resistant and -susceptible genotypes should focus on mechanisms of thrips resistance to enhance future breeding efforts. • Thrips are key pests of cotton that are resistant to commonly used insecticides. • Host plant resistance has potential as an alternative control tactic. • Exotic cotton landraces were screened using multiple field trials. • A novel selection index was used to identify resistant and susceptible genotypes. [ABSTRACT FROM AUTHOR]

Soybean vein necrosis virus (SVNV) is an emerging Tospovirus that is now considered to be the most widespread soybean virus in the United States. SVNV is transmitted from plant-to-plant by soybean thrips, Neohydatothrips variabilis (Beach). We hypothesized that a positive interaction between the host plant, SVNV, and the vector may have resulted in the widespread distribution of the virus in a short span of time. Our study found that SVNV-infected N. variabilis females produced significantly more offspring compared with noninfected females. No other life-history trait varied between SVNV-infected and non-infected thrips. There was considerable variation in SVNV copy number in infected thrips ranging from 102 -106. Moreover, there was a significant negative correlation between SVNV copy number and fecundity in infected N. variabilis. This suggests that excessive virus accumulation may result in lower viability of N. variabilis. In choice tests, SVNVinfected N. variabilis preferred to feed on non-infected leaflets compared with infected leaflets. Vector competence assays indicated that Frankliniella tritici and Frankliniella fusca can transmit SVNV, but at a lower efficiency than N. variabilis. Comparison of life history of between the primary and secondary vectors showed that N. variabilis had the highest fecundity, but F. tritici had the shortest development time and greatest larval survival. Taken together, the increased fecundity of SVNV-infected N. variabilis, their apparent preference for noninfected host plants, in conjunction with the ability of secondary vectors to survive and reproduce on soybean may, in part, explain the rapid spread of SVNV in the United States. [ABSTRACT FROM AUTHOR]

BACKGROUND Over the past two decades, neonicotinoid seed treatments have become the primary method to manage tobacco thrips, Frankliniella fusca Hinds, on seedling cotton. Because this insect is highly polyphagous and the window of insecticide exposure is short, neonicotinoid resistance was expected to pose a minimal risk. However, reports of higher than expected F. fusca seedling damage in seed-treated cotton fields throughout the Mid-South and Southeast US production regions suggested neonicotinoid resistance had developed. To document this change, F. fusca populations from 86 different locations in the eastern United States were assayed in 2014 and 2015 for imidacloprid and thiamethoxam resistance to determine the extent of the issue in the region. RESULTS Approximately 57 and 65% of the F. fusca populations surveyed had reduced imidacloprid and thiamethoxam sensitivity respectively. Survivorship in diagnostic bioassays was significantly different at both the state and regional scales. Multiple-dose bioassays conducted on 37 of the populations documented up to 55- and 39-fold resistance ratios for imidacloprid and thiamethoxam respectively. CONCLUSION Estimates of neonicotinoid resistance indicate an emerging issue for management of F. fusca in the eastern United States. Significant variation in survivorship within states and regions indicated that finer-scale surveys were needed to determine factors (genetic, insecticide use) driving resistance evolution. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Thrips tabaci Lindeman and Frankliniella occidentalis (Pergande) are the most studied members of Thysanoptera: Thripidae, since these thrips species have already become worldwide spread pests causing serious yield losses. Thrips damage host plants directly through the feeding process and indirectly by transmitting plant viruses. Biological characteristics of these species make them difficult to manage and prevent the damage they cause. This study is aimed to find the most attractive colour of the commonly used sticky traps for mass trapping of these two species, and generate information about the vision system of both specimens by investigating the reflectance spectrum of these traps. The attractiveness of white, yellow, blue and fluorescent yellow sticky traps for T. tabaci was investigated in a white cabbage field during summer production. The order of attractiveness of yellow, blue and fluorescent yellow traps was also investigated for F. occidentalis in a greenhouse during the pollination season of selected cauliflower plants. In this study number of captured thrips specimens was significantly affected by trap's colour in open field for T.tabaci (x2(3)=147,4; p<0,001) and also in the greenhouse for F.occidentalis (x2(2)=457,8; p<0,001). No significant differences were found between the numbers of the specimens of T. tabaci caught by the yellow (average 36,03 specimens per trap) and white (average 33,25 specimens per trap) coloured traps (Mean dif. 2,06; SE 3,79; Bonferroni sig. p=l,000), while the blue colour (average 18,1 specimens per trap) proved to be the least attractive. Fluorescent yellow coloured traps caught the highest number of the specimens (average 82,88 specimens per trap) of T. tabaci. The highest numbers of F. occidentalis were also caught with fluorescent yellow sticky traps (average 47,88 specimens per trap), followed by blue (average 21,67 specimens per trap) and yellow (average 9,29 specimens per trap). Thereby, fluorescent yellow traps proved to be the most effective in this study for monitoring thrips species both in the field and in the greenhouse. The light reflectance of the coloured sticky traps used in this study and the petals of cauliflower flowers were also measured both in the UV and visible light ranges. The proportion of captured thrips specimens of the two species (T. tabaci and F. occidentalis) and the light reflectance spectrum of the most preferred coloured traps suggest that these thrips species might have different photoreceptor systems. Results of this study also suggest that light reflectance in the yellow region and in the UV range has the most important effect on host plant selection of T. tabaci and F. occidentalis. [ABSTRACT FROM AUTHOR]

Thrips are important pests of peanut. They cause severe feeding injuries on peanut foliage in the early season. They also transmit Tomato spotted wilt virus (TSWV), which causes spotted wilt disease. At-plant insecticides and cultivars that exhibit field resistance to TSWV are often used to manage thrips and spotted wilt disease. Historically, peanut growers used the broad-spectrum insecticides aldicarb (IRAC class 1A; Temik) and phorate (IRAC class 1B; Thimet) for managing thrips and thereby reducing TSWV transmission. Aldicarb has not been produced since 2011 and its usage in peanut will be legally phased out in 2018; therefore, identification of alternative chemistries is critical for thrips and spotted wilt management. Here, eight alternative insecticides, with known thrips activity, were evaluated in field trials conducted from 2011 through 2013. In addition, different application methods of alternatives were also evaluated. Imidacloprid (Admire Pro), thiamethoxam (Actara), spinetoram (Radiant), and cyantraniliprole (Exirel) were as effective as aldicarb and phorate in suppressing thrips, but none of the insecticides significantly suppressed spotted wilt incidence. Nevertheless, greenhouse assays demonstrated that the same alternative insecticides were effective in suppressing thrips feeding and reducing TSWV transmission. Spotted wilt incidence in the greenhouse was more severe (~80%) than in the field (5–25%). In general, field resistance to TSWV in cultivars only marginally influenced spotted wilt incidence. Results suggest that effective management of thrips using alternative insecticides and subsequent feeding reduction could improve yields under low to moderate virus pressure. [ABSTRACT FROM AUTHOR]

Spotted wilt caused by tomato spotted wilt virus (TSWV; family Bunyaviridae; genus Tospovirus) is a serious disease of peanut (Arachis hypogaea L.) in the southeastern United States. Peanut genotypes with field resistance to TSWV are effective in suppressing spotted wilt. All commercially available genotypes with field resistance to TSWV were developed through conventional breeding. As a part of the breeding process, peanut genotypes are regularly screened under field situations. Despite numerous advantages associated with field screening, it is often limited by inconsistent vector (thrips) and TSWV pressure. A greenhouse transmission protocol would aid in thorough screening of selected genotypes and conserve time. In this study, various parameters associated with TSWV transmission, including tobacco thrips, Frankliniella fusca (Hinds) density, mode of inoculation, and plant age, were evaluated. Greater incidences of TSWV infection were obtained with thrips-mediated inoculation when compared with mechanical inoculation. TSWV inoculation with three, five, and 10 thrips resulted in greater incidences of TSWV infection in plants than inoculation with one thrips. However, incidences of TSWV infection did not vary between plants inoculated with three, five, and 10 viruliferous thrips. With both thrips-mediated and mechanical inoculation methods, incidences of TSWV infection in 1-wk-old plants were greater than in 4-wk-old plants. TSWV copy numbers, as determined by qPCR, also decreased with plant age. Results suggest that using at least three thrips per plant and 1- to 2-wk-old plants would maximize TSWV infection in inoculated plants. [ABSTRACT FROM PUBLISHER]

The Vidalia onion crop in Georgia is grown in the winter, and the key insect pests in Georgia are thrips (Thysanoptera: Thripidae). The thrips complex consists predominantly of tobacco thrips, Frankliniella fusca (Hinds), with smaller percentages of western flower thrips, F. occidentalis Pergande, eastern flower thrips, F. tritici (Fitch) and onion thrips, Thrips tabaci Lindeman. Onion thrips has become a greater concern in the last 10 years likely due to the introduction of a more aggressive biotype of T. tabaci on onions coming from Peru into the Vidalia region. A preliminary laboratory bioassay at 25 °C suggested that this onion thrips biotype could out-compete tobacco thrips on onions. Surveys were conducted from 2004 through 2013 in commercial Vidalia onion fields to determine if this increase in the percentage of onion thrips would occur. Average seasonal temperatures were highly correlated (r = 0.811) with percent T. tabaci and negatively correlated (r = -0.807) with F. fusca. The results suggest that temperature might regulate the proportion of onion thrips to tobacco thrips in the field, with a higher percentage of tobacco thrips occurring during cool winters and more onion thrips occurring in warm winters. Nevertheless, F. fusca continues to be the dominant thrips species in the Vidalia onion winter growing region of Georgia averaging 78% of the adult thrips population from 2004 to 2013. [ABSTRACT FROM AUTHOR]

Tomato spotted wilt virus (TSWV) severely affects peanut production in the southeastern United States. Breeding efforts over the last three decades resulted in the release of numerous peanut genotypes with field resistance to TSWV. The degree of field resistance in these genotypes has steadily increased over time, with recently released genotypes exhibiting a higher degree of field resistance than older genotypes. However, most new genotypes have never been evaluated in the greenhouse or laboratory against TSWV or thrips, and the mechanism of resistance is unknown. In this study, TSWV-resistant and -susceptible genotypes were subjected to TSWV mechanical inoculation. The incidence of TSWV infection was 71.7 to 87.2%. Estimation of TSWV nucleocapsid (N) gene copies did not reveal significant differences between resistant and susceptible genotypes. Parsimony and principal component analyses of N gene nucleotide sequences revealed inconsistent differences between virus isolates collected from resistant and susceptible genotypes and between old (collected in 1998) and new (2010) isolates. Amino acid sequence analyses indicated consistent differences between old and new isolates. In addition, we found evidence for overabundance of nonsynonymous substitutions. However, there was no evidence for positive selection. Purifying selection, population expansion, and differentiation seem to have influenced the TSWV populations temporally rather than positive selection induced by host resistance. Choice and no-choice tests indicated that resistant and susceptible genotypes differentially affected thrips feeding and survival. Thrips feeding and survival were suppressed on some resistant genotypes compared with susceptible genotypes. These findings reveal how TSWV resistance in peanut could influence evolution, epidemiology, and management of TSWV. [ABSTRACT FROM AUTHOR]

Numerous agrochemicals can be applied in peanut to control pests. Field and laboratory experiments were conducted in North Carolina during 2009 and 2010 to determine peanut response to paraquat and tobacco thrips ( Frankliniella fusca Hinds.) when acephate was applied in combination with chloroacetamide and contact herbicides. Experiments were also conducted during 2011 to determine peanut response to acephate applied alone or with paraquat when peanut was planted either without aldicarb or when aldicarb was applied in the seed furrow at planting. Visible peanut damage caused by tobacco thrips feeding was greater when chloroacetamide herbicides were applied without acephate compared with application with acephate regardless of paraquat treatment. Visible injury caused by paraquat was higher when chloroacetamide herbicides were included compared with paraquat alone in one of two years. Visible injury by paraquat was lower when applied with acephate compared to paraquat alone in one of two years. Acephate applied to peanut foliage and aldicarb applied in the seed furrow at planting protected peanut similarly from damage associated with tobacco thrips feeding. Acephate alone or with chloroacetamide herbicides changed solution pH from slightly acidic to highly acidic. Several combinations of pesticides formed either transient or permanent precipitates. [ABSTRACT FROM AUTHOR]

Abstract: The anthranilic diamide insecticide cyantraniliprole was previously shown to reduce transmission of Tomato spotted wilt virus (TSWV) to pepper, Capsicum annuum, by Frankliniella fusca but not Frankliniella occidentalis. This study examines the effects of cyantraniliprole and imidacloprid on thrips feeding using electrical penetration graphing (EPG), and on TSWV transmission in field cage studies. Some antifeedant responses were observed in the EPG studies when thrips fed on cyantraniliprole- and imidacloprid-treated plants; however, these responses were variable between species and among the 2, 6, and 10 day post-treatment time intervals during which feeding behavior was observed. Cyantraniliprole significantly reduced the probability of TSWV infection when spread by F. fusca in field-grown pepper when viruliferous thrips were released 7 days but not when released at 14 days after the insecticide treatment in one of 2 field trials. In the second trial cyantraniliprole significantly reduced the probability of infection when F. fusca were released 14 days but not 7 days after treatment. In both years, imidacloprid prevented or significantly reduced transmission of TSWV by F. fusca in field-grown pepper when viruliferous thrips were released 7 days and 14 after treatment. In one of two years, cyantraniliprole significantly reduced the incidence of TSWV in field-grown pepper that was spread by F. occidentalis when viruliferous thrips were released 7 days after the insecticide treatment, but not 14 days after the treatment. Imidacloprid did not reduce the incidence of TSWV in field-grown pepper when viruliferous F. occidentalis were released. Although these studies demonstrate that probing behavior of these thrips species is altered on cyantraniliprole-treated pepper plants, results of field cage studies did not consistently show a reduction in incidence of TSWV-infected plants. [Copyright &y& Elsevier]

Spotted wilt disease caused by Tomato spotted wilt virus (TSWV) (family Bunyaviri-dae\ genus Tospovirus) is a major constraint to peanut (Arachis hypogaea L.) production in the southeastern United States. Reducing yield losses to TSWV has heavily relied on planting genotypes that reduce the incidence of spotted wilt disease. However, mechanisms conferring resistance to TSWV have not been identified in these genotypes. Furthermore, no information is available on how these genotypes influence thrips fitness. In this study, we investigated the effects of newly released peanut genotypes (Georganic, GA-06G, Tifguard, and NC94022) with field resistance to TSWV and a susceptible genotype (Georgia Green) on tobacco thrips, Frankliniella fusca (Hinds), fitness, and TSWV incidence. Thrips-mediated transmission resulted in TSWV infection in both TSWV-resistant and susceptible genotypes and they exhibited typical TSWV symptoms. However, some resistant genotypes had reduced viral loads (fewer TSWV N-gene copies) than the susceptible genotype. F. fusca larvae acquired TSWV from resistant and susceptible genotypes indicating that resistant geno-types also can serve as inoculum sources. Unlike resistant genotypes in other crops that produce local lesions (hypersensitive reaction) upon TSWV infection, widespread symptom development was noticed in peanut genotypes. Results indicated that the observed field resistance in peanut genotypes could be because of tolerance. Further, fitness studies revealed some, but not substantial, differences in thrips adult emergence rates and developmental time between resistant and susceptible genotypes. Thrips head capsule length and width were not different when reared on different genotypes. [ABSTRACT FROM AUTHOR]

Phytoviruses including tospoviruses are known to affect the behavior and fitness of their vectors both positively and negatively. In this study, we investigated the effects of Tomato spotted wilt virus ( TSWV) (family Bunyaviridae, genus Tospovirus) infection on the fitness and feeding ability of tobacco thrips, Frankliniella fusca ( Hinds) ( Thysanoptera: Thripidae) using peanut, Arachis hypogaea L. ( Fabaceae), as a host. Potentially viruliferous F. fusca laid more eggs than non-viruliferous F. fusca. In contrast, fewer potentially viruliferous F. fusca developed into adults and required a longer developmental time than non-viruliferous F. fusca, indicating a direct negative effect of the virus on thrips fitness. In addition, no-choice feeding tests indicated that non-viruliferous F. fusca fed more rapidly than potentially viruliferous F. fusca. Typically, phytovirus infections are known to enhance the availability of vital nutrients such as free amino acids in infected host plants and to affect other important physiological processes negatively. Free amino acids are known to play a vital role in egg production and development. Further investigations in this study revealed that leaflets of infected plants had ca. 15 times more free amino acids than non-infected leaflets. TSWV-infected leaflets were used to rear potentially viruliferous thrips. Higher amino acid levels in TSWV-infected leaflets than in non-infected leaflets could have contributed to increased oviposition by potentially viruliferous F. fusca compared to non-viruliferous F. fusca. Taken together, these results suggest that increased concentrations of free amino acids in TSWV-infected plants might serve as an incentive for thrips feeding on otherwise unsuitable hosts, thereby facilitating TSWV acquisition and transmission. [ABSTRACT FROM AUTHOR]

We used light and electron microscopy to detail the in vivo life cycle of the nematode Thripinema fuscum and to determine the effects of parasitism on tissues of the thrips host Frankliniella fusca. The parasitic T. fuscum female produced eggs within 4–5 days after ingress and the host haemocoele became packed with eggs and developing juvenile nematodes. Mature juveniles migrated to the hindgut and fully developed juveniles first emerged from the posterior end of the male or female F. fusca 9 days after parasitization. Parasitization induced a displacement of the host alimentary tract, an atrophy of the ovaries and fat body, and an alteration of energy and waste reserves in host tissues. Our observations reveal a specialized relationship showing that this parasite is well adapted to exploit the host digestive, reproductive and excretory systems. [ABSTRACT FROM PUBLISHER]

Frankliniella fusca (Hinds) naturally disperses from winter weeds to crops in spring, causing direct and indirect damage. Field preparation before planting includes use of herbicides or cultivation to kill unwanted vegetation, which adversely affects F. fusca host plants and potentially influences F. fusca dispersal. Common chickweed, Stellaria media (L.), infested with F. fusca, was used as a model to study effects of timing and type of vegetation management on adult dispersal. Infested weeds were caged and F. fusca weekly dispersal was monitored using sticky traps. Weed management treatments performed at an early (14 April-11 May) or late (2 wk after early treatment) date consisted of glyphosate, paraquat, disking, hoeing, or untreated control. Late glyphosate and hoeing treatments resulted in cumulative dispersal statistically similar to or greater than from control plots. Compared with the control, significantly more F. fusca dispersed from the glyphosate and hoeing plots during the 3 wk after treatment. More thrips dispersed from the late paraquat treatment 1 wk post-application than from the control. Dispersal from the disked treatment and early paraquat treatment was similar to that of the control 1- to 3-wk post-treatment. Early treatments resulted in significantly smaller cumulative dispersal than the control in all but one instance. Late disking and paraquat treatments resulted in cumulative F. fusca captures that were statistically similar or less than that in the control. Winter weed management type and timing affect F. fusca dispersal magnitude and duration. [ABSTRACT FROM AUTHOR]

The marigold is a very ornamental plant that is commonly grown in the flower garden, and occasionally as a culinary herb. Marigolds had an important economic values, its cropping knew a continual increase in the last years thanks to its usage in a more and more large area in the pharmaceutic and cosmetic domain. Thrips tabaci are feeding drains underlying cells, leaving air-filled spaces which impart a silvery sheen and cause distortion during growth and reduction in photosynthetic capacity. In the West Plain of the country relative existed a few investigations about that pest attack on the marigolds crop, an important crop both from medical point of view and culinary point of view. The purpose of that work was to determine the correlation of pests attack degree and flowers diameter to 10 local population of Calendula officinalis L. from Arad district. In the thrips experiments, the results showed that flowers with bigger attack degree were smaller compared to flowers with smaller attack degree. This difference in flower diameter was due to deformations of the flowers and was more pronounced at a bigger density of common thrips. The flowers deformation and its decrease in diameter implied also the production increase, but the obtained quantity of flowers was lower. The results obtained through correlation between Thrips tabaci attack degree and morphological features of Calendula officinalis L. flowers permitted the identification of frequency and intensity of attack, and connection between them and density of the pest. Accordingly, tobacco trips produced great damages in Calendula officinalis L. crop depreciating from a qualitative point of view, the diminution and bending flowers diameter and qualitative speaking the production decreased. The present paper belongs to a big work which had like study "Resistance testing of some species of Calendula officinalis L. to Thysanoptera pest attack through different methods/techniques of analysis concerning the improvement of raw material quality", that represented the theme of postdoctoral-dissertation. [ABSTRACT FROM AUTHOR]

Thrips-transmitted Iris yellow spot virus (IYSV) (Family Bunyaviridae, Genus Tospovirus) affects onion production in the United States and worldwide. The presence of IYSV in Georgia was confirmed in 2003. Two important thrips species that transmit tospoviruses, the onion thrips (Thrips tabaci (Lindeman)) and the tobacco thrips (Frankliniella fusca (Hinds)) are known to infest onion in Georgia. However, T. tabaci is the only confirmed vector of IYSV. Experiments were conducted to test the vector status of F. fusca in comparison with T. tabaci. F. fusca and T. tabaci larvae and adults reared on IYSV-infected hosts were tested with antiserum specific to the nonstructural protein of IYSV through an antigen coated plate ELISA. The detection rates for F. fusca larvae and adults were 4.5 and 5.1%, respectively, and for T. tabaci larvae and adults they were 20.0 and 24.0%, respectively, indicating that both F. fusca and T. tabaci can transmit IYSV. Further, transmission efficiencies of F. fusca and T. tabaci were evaluated by using an indicator host, lisianthus (Eustoma russellianum (Salisbury)). Both F. fusca and T. tabaci transmitted IYSV at 18.3 and 76.6%, respectively. Results confirmed that F. fusca also can transmit IYSV but at a lower efficiency than T. tabaci. To attest if low vector competency of our laboratory-reared F. fusca population affected its IYSV transmission capability, a Tomato spotted wilt virus (Family Bunyaviridae, Genus Tospovirus) transmission experiment was conducted. F, fusca transmitted Tomato spotted wilt virus at a competent rate (90%) suggesting that the transmission efficiency of a competent thrips vector can widely vary between two closely related viruses. [ABSTRACT FROM AUTHOR]

Abstract: Spotted wilt disease of peanut (Arachis hypogaea) (SWP), caused by Tomato spotted wilt virus (TSWV) (genus Tospovirus, family Bunyaviridae), was first observed in Alabama, Florida, and Georgia in the late 1980s and rapidly became a major limiting factor for peanut production in the region. Tobacco thrips (Frankliniella fusca) and western flower thrips (Frankliniella occidentalis) both occur on peanut throughout the southeastern U.S., but F. fusca is the predominant species that reproduces on peanut, and is considered to be the more important vector. Several non-crop sources of potential primary vectors and TSWV inoculum have been identified, but their relative importance has not been determined. The peanut growing season in Alabama, Florida, and Georgia is from April through November, and ‘volunteer’ peanut plants can be present for much of the remainder of the year. Therefore peanut itself has huge potential for perpetuating both vector and virus. Symptoms are often evident within a few days of seedling emergence, and disease progress is often rapid within the first 50–60 days after planting. Based on destructive sampling and assays for TSWV, there is often a high incidence of asymptomatic infections even in peanut genotypes that produce few and mild symptoms of infection in the field. Severity of SWP epidemics fluctuates significantly from year to year. The variability has not been fully explained, but lower incidences have been associated with years categorized as “La Niña” in the El Niño-Southern Oscillation. Planting date can have a large effect on disease incidence within a location. This may be linked to the thrips reproductive cycle and environmental effects on the plant and plant–thrips–virus interactions. Row pattern, plant population, and in-furrow applications of phorate insecticide can also affect epidemics of SWP. Considerable progress has been made in developing cultivars with natural field resistance to TSWV. Use of cultivars with moderate field resistance combined with other suppressive measures has been very successful for managing spotted wilt disease. Several new cultivars with higher levels of field resistance can improve control and allow more flexibility in the integrated management programme. Although effects of these factors on epidemics of SWP have been documented, mechanisms responsible for disease suppression by most factors have not been fully elucidated. [Copyright &y& Elsevier]

Abstract: Tomato spotted wilt virus (TSWV) is a thrips-transmitted virus that causes major losses in many crops worldwide. Management of TSWV is complex, requiring multiple preventive measures. Currently, there are few chemical options that control thrips populations before they feed upon and transmit TSWV to crop plants. Cyantraniliprole (Cyazypyr™) is an anthranilic diamide insecticide currently under development that exhibits anti-feedant properties. Transmission of TSWV by Frankliniella fusca (Hinds) to Capsicum annuum L. seedlings was reduced in plants treated with Cyazypyr™ applied to the soil at the rates of 1.45, 2.90 and 4.41 mg ai/plant. Mortality of F. fusca at 3 days post treatment did not differ significantly on excised foliage of Cyazypyr™ treated and control plants, but feeding injury was significantly less on treated foliage. Transmission of TSWV by Frankliniella occidentalis (Pergande) was not reduced in plants treated with 4.41 mg ai/plant. [Copyright &y& Elsevier]