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Aim of study: The seasonal distributions of the western flower thrips, Frankliniella occidentalis (Pergande) and the onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), as well as their primary predators, predatory bugs, Orius spp. (Hemiptera: Anthocoridae), in the polyculture agricultural area were investigated in order to gain a thorough understanding of the prey-predator relationships on various crop plants. Area of study: Adana Province, located in the eastern part of the Mediterranean Region of Türkiye. Materials and methods: Thrips and predatory insects were collected from various plants using the tapping method during 2019-2020. Their diversity, seasonal densities, and distributions were investigated. Main results: A total of 11 predator species were identified, with Orius laevigatus (Fieber) and Orius niger (Wolff) being the most prevalent species. The greatest diversity of predatory insect species was found among plant species from the Fabaceae family. With the exception of field crops, T. tabaci was found to be the most frequent thrips species in the examined cultivated plants when compared to F. occidentalis on common crop plants. Among winter vegetables, a significant number of predators, primarily O. laevigatus, were only collected from broad bean plants. The abundance patterns of thrips and predatory insects were closely associated with the flowering phenology of plants. Research highlights: Strong relationships were observed between Orius spp. and T. tabaci adults. This study suggests that broad beans, a winter crop, could be included in crop rotations during the autumn-to-early spring period to support the populations of predatory insects in various ways.

Frankliniella occidentalis (thrips) is a widespread polyphagous insect pest that causes damage and yield losses. Control of this and other thrips species is challenging due to the emergence of insecticide-resistant populations. Wild sunflower species have proven useful in sunflower breeding programs as a source of resistance genes. Therefore, this work is aimed to evaluate the suseptibility of five annual wild species of Helianthus (H. annuus, H. argophillus, H. neglectus, H. praecox and H. petiolaris) in relation to the tolerance of F. occidentalis. The bioassay was set up in a greenhouse with an uncontrolled thrips population, in ten replicates. The number of adults of F. occidentalis was counted twice during the experiment, within ten days, from five leaves of each plant (replication). The density of non-glandular trichomes on both epidermises was analyzed with a light microscope on the same leaves (except H. argophyllus). According to our results, the highest average number of thrips adults was on H. annuus and H. argophilus during both observation periods that also have a very dense indumetnum. The most tolerant, with the lowest number of thrips adults were H. praecox and H. neglectus, characterized with less developed indumentum. According to our results, we can conclude that the density of non-glandular trichomes does not affect the preference of F. occidentalis. However, the development and distribution of the leaf epidermal cuticle, epicuticular waxes and glandular trichomes (capitate and linear) may be related to the degree of resistance, which is the subject of our future research.

Biological pest control is successful in many agricultural systems, yet various pests can still not be controlled with natural enemies. Examples are invasive thrips species such as Echinothrips americanus Morgan and Thrips parvispinus (Karny) in Europe. The lack of biological control of these pests in several crops has been subscribed to their complex life cycle and cryptic behaviours, but their antipredator behaviours may prevent successful control and have not been studied extensively. One of these behaviours is the potential of thrips to kill the eggs of predatory mites, which we quantified. Furthermore, we observed the behaviour of first- and second-instar thrips larvae when attacked by starved predatory mites Amblyseius swirskii Athias-Henriot. For comparison, we included Frankliniella occidentalis (Pergande), which shows an array of defensive behaviours, but can be controlled successfully by several species of predatory mites. Second-instar larvae and adults of F. occidentalis and T. parvispinus killed predator eggs, but E. americanus did not. First- and second-instar larvae of all three species swung their abdomen to defend themselves, and F. occidentalis and T. parvispinus produced anal droplets, which are also involved in defence. Predators were not successful in attacking any second-instar larvae during 15-minute observations, which is sufficiently long for an attack. First-instar larvae of F. occidentalis and T. parvispinus were sometimes successfully attacked by the predatory mite before they could mount a defence, but first-instar E. americanus always defended themselves and were almost never preyed upon. Cooling thrips larvae to suppress antipredator behaviour increased predation for all species and stages, except for first instars of F. occidentalis. In conclusion, the lack of successful control of E. americanus is not caused by killing predator eggs, but by the efficient defensive behaviour of both larval instars. Our study furthermore suggests that

Arthropod pests cause significant problems in agricultural crops all around the world. As chemical pesticide use becomes less desired, there is a need for alternative methods of pest control. Inspired by the natural adhesiveness of arthropod trapping plants, we examined the effectiveness of adhesive droplets made from oxidised and cross-linked plant-derived oils for control of western flower thrips. Two filter paper droplet adhesiveness assays and three detached chrysanthemum leaf assays were carried out to test efficacy against thrips. Suspensions containing adhesive droplets and other constituents were applied to filter papers and leaves via spraying or dipping. On filter papers, droplets made from oxidised rice germ oil (RGO) of different sizes caught 40–93% of thrips. Droplets made of a mixture of sunflower, olive, and linseed oil (MIX) caught up to 94% of thrips. Likewise, adhesive droplet-treated filter papers showed higher thrips mortality than untreated or control solution-treated filter papers. On chrysanthemum leaves, thrips were caught by both RGO (up to 40%) and MIX droplets (up to 20%) and thrips damage and reproduction were reduced. On MIX-treated leaves, thrips mortality was also increased. Within treatments, droplets of different size classes occurred and larger droplets were more effective at catching thrips in general. Droplets were also robust to rinsing with water, which is of importance for their application in horticulture. In conclusion, adhesive droplets made from edible plant oils show potential for use in control of western flower thrips.

The defense mechanisms of plants evolve as they develop. Previous research has identified chemical defenses against Western flower thrips (WFT) in Gladiolus (Gladiolus hybridus L.). Consequently, our study aimed to explore the consistency of these defense variations against WFT across the various developmental stages of Gladiolus grown under different conditions. Thrips bioassays were conducted on whole plants at three developmental stages, using the Charming Beauty and Robinetta varieties as examples of susceptible and resistant varieties, respectively. Metabolomic profiles of the leaves, buds and flowers before thrips infestation were analyzed. The thrips damage in Charming Beauty was more than 500-fold higher than the damage in Robinetta at all plant development stages. Relative concentrations of triterpenoid saponins and amino acids that were associated with resistance were higher in Robinetta at all plant stages. In Charming Beauty, the leaves exhibited greater damage compared to buds and flowers. The relative concentrations of alanine, valine and threonine were higher in buds and flowers than in leaves. The Metabolomic profiles of the leaves did not change significantly during plant development. In addition, we cultivated plants under different environmental conditions, ensuring consistency in the performance of the two varieties across different growing conditions. In conclusion, the chemical thrips resistance markers, based on the analysis of vegetative plants grown in climate rooms, were consistent over the plant’s lifetime and for plants grown under field conditions.

Herbivorous thrips are considered as one of the most economically important pests worldwide. They cause direct damage by feeding on plants of at least 60 families including many vegetable and ornamental crops, and indirect damage by transferring devastating plant viruses. Their high and parthenogenetic reproductive capacity and hidden lifestyle (pupation in the soil, thigmotactic behavior) make thrips hard to control. Current pest management control relies mainly on the use of chemical pesticides, to which thrips can develop resistance. Exploiting the natural defense mechanisms of plants against thrips can provide the opportunity towards more sustainable resistance breeding. The major aim of this PhD research was to explore the molecular mechanisms underlying natural defenses of the model plant Arabidopsis thaliana (Arabidopsis) in response to the Western flower thrips (Frankliniella occidentalis). To achieve this, several non-destructive bioassays were designed to assess thrips performance on single Arabidopsis leaves or whole plants. Using RNA-sequencing in a high-density time series, combined with bioinformatic analyses, we were able to capture the transcriptional dynamics and chronology of genes within the gene regulatory network that were induced in single Arabidopsis leaves upon thrips infestation. We confirmed that jasmonic acid (JA) is the predominant phytohormone modulating the induced defense response against thrips as (1) most up-regulated genes showed an overrepresentation of bHLH TF binding motifs which correlated with the activation of JA-associated processes, (2) JA-insensitive mutant coi1-34 and the MYC triple mutant myc2,3,4 showed significantly more feeding damage and a higher number of oviposited eggs compared to the Col-0 wild-type and (3) the novel regulators discovered in the thrips-induced gene regulatory network (GRN), although having distinct roles in the thrips-GRN, are closely connected to the JA pathway. However, depending on the thrips d

Gedurende 2022/2023 heeft Vertify in opdracht van Glastuinbouw Nederland biotoetsen uitgevoerd om verschillen in gevoeligheid van verschillende trips populaties van praktijkbedrijven voor diverse insecticiden te testen. Dit onderzoek is uitgevoerd in navolging op een eerder onderzoek uit 2021 (KijKnummer P20001-3), waarbij de gevoeligheid van 2 populaties voor 3 middelen is vergeleken. Voor de testen hebben diverse telers, afkomstig uit diverse delen van Nederland, plantmateriaal met trips ingestuurd naar Vertify. Daarbij is ook gevraagd om aan te geven welke middelen in de maanden voorafgaand aan de verzending zijn gebruikt. Vanuit het plantmateriaal is de trips geisoleerd en vervolgens vermeerderd tot voldoende larven aanwezig waren om de test in te zetten. De populaties zijn vergeleken met een populatie trips, aanwezig bij Vertify. Deze populatie werd instand gehouden op chrysant, waarop de laatste maanden voorafgaand aan de testen geen middelen zijn gebruikt. De testen zijn onder gecontroleerde omstandigheden uitgevoerd om verschillende populaties met elkaar te kunnen vergelijken. De middelen welke zijn gebruikt in de testen waren alle toegelaten voor de bestrijding van trips en waren van verschillenden resistentiegroepen De middelen zijn in de geregistreerde concentratie gebruikt. De doelstelling van het onderzoek was om een indicatie te krijgen of de reactie van populaties trips van diverse bedrijven op behandeling met middelen verschillen.

Thrips (Thysanoptera: Thripidae) are major pests in horticulture worldwide. Longstanding biological control strategies that have been developed for flower thrips such as Frankliniella occidentalis (Pergande) are being disrupted by the recent introduction of leaf-inhabiting thrips such as Echinothrips americanus Morgan and Thrips setosus Moulton in Northern Europe. In this study, we evaluated the predator–prey interactions, predation capacity, juvenile development and adult reproduction of the two commercial anthocorid predators Orius laevigatus (Fieber) and Orius majusculus (Reuter) (Hemiptera: Anthocoridae) on these thrips. In behavioral assays, predators were more successful in subduing and consuming sedentary leaf-inhabiting thrips adults compared to the highly mobile F. occidentalis. Furthermore, O. laevigatus was more successful in subduing prey compared to the bigger predator O. majusculus. Female adults of O. laevigatus and O. majusculus killed 18 and 20 F. occidentalis adults, respectively, in 24 h, while the kill rate was around two times higher when predators were offered E. americanus or T. setosus as prey. Developmental and reproductive parameters of both Orius predators were more favorable when feeding on the leaf-inhabiting thrips compared to F. occidentalis. This was further evident in the higher intrinsic rates of increase (rm) we recorded on a diet of E. americanus compared to F. occidentalis (0.162 and 0.148 females/female/day for O. laevigatus, respectively; 0.148 and 0.127 for O. majusculus, respectively). Our findings show that E. americanus and T. setosus constitute high quality prey for anthocorid predators, highlighting the potential of these predators for effective pest control.

Discrepancies in the published research as to the attraction of the economically important pest western flower thrips (WFT) to different colours confounds the optimisation of field traps for pest management purposes. We considered whether the different experimental conditions of independent studies could have contributed to this. Therefore, the behavioural response (i.e., landings) to different colour cues of two WFT laboratory populations from Germany (DE) and The Netherlands (NL), which had previously been independently shown to have different colour preferences, were tested in the same place, and under the same experimental conditions. Single-choice wind tunnel bioassays supported previous independent findings, with more of a NL population landing on the yellow LED lamp (588 nm) than the blue (470 nm) (p = 0.022), and a not-statistically significant trend observed in a DE population landing more on blue compared to yellow (p = 0.104). To account for potential original host rearing influences, both populations were subsequently established on bean for ~20 weeks, then yellow chrysanthemum for 4–8 and 12–14 weeks and tested in wind tunnel choice bioassays. Laboratory of origin, irrespective of the host plant rearing regime, remained a significant effect (p < 0.001), with 65% of the NL WFT landing on yellow compared to blue (35%), while 66% of the DE WFT landed on blue compared to yellow (34%). There was also a significant host plant effect(p < 0.001), with increased response to yellow independent of laboratory of origin after rearing onchrysanthemum for 12–14 weeks. Results suggest that differing responses of WFT populations to colour is, in this case, independent of the experimental situation. Long-term separate isolation from the wild cannot be excluded as a cause, and the implications of this for optimising the trap colour is discussed.

Western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is an economically important pest insect in vegetable and ornamental cultivation worldwide. Little is known about host plant resistance in the vegetative and generative phases of chrysanthemum [Chrysanthemum × morifolium (Ramat.) Hemsl. (Asteraceae)] and the role of resistance factors such as flavonols, flower color, and flower shape. We screened a broad range of chrysanthemum cultivars across two seasons to quantify resistance against Western flower thrips. Resistance was based on silver damage on the leaves, and relative flavonol content was measured using a Dualex Scientific 4 hand-held sensor. There was significant variation in silver damage between cultivars, indicating different levels of resistance. There was no correlation between the relative flavonol content in middle leaves and plant silver damage. A clearer resistance level discrimination by flavonols in resistant and susceptible cultivars would be possible in the future by comparing multiple leaf positions during the ontogenetic phases of plant development. Moreover, the influence of flower color and shape on resistance to thrips was investigated by counting the adult thrips and larvae on flowers. The results showed significant differences in flower color preference by adults, but not by larvae. Flower shape influenced thrips larvae and females, but not males. The importance of the results for resistance determination is discussed.

Two strains of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), are found in New Zealand. One strain was recorded in 1934 mainly from outdoor Lupinus arboreus Sims (lupin strain, a non-pest); the other strain was first recorded in 1992 and is found mostly on greenhouse crops (greenhouse strain, a pest). To test whether this differential pest status may be explained by different temperature requirements, a comparative life-history study was carried out assessing the effects of temperature on life-history traits and thermal requirements for development. Thrips strains were verified using sequence alignment of the COI gene. Thrips from each strain were fed sucrose solution and pollen, and they were reared at 8, 10, 12, 17, 22, and 27 (+/- 2) degrees C, respectively (>80% r.h., L16:D8 photoperiod). Longevity decreased with increasing temperature for both strains; however, the greenhouse strain had a significantly longer lifespan at all temperatures. Overall, the greenhouse strain laid more eggs than the lupin strain at all temperatures, with the highest mean number laid at 22 degrees C for the lupin strain (36.3 total eggs/female) and at 17 degrees C for the greenhouse strain (63.2 total eggs/female). No significant difference between the two strains was found in regards to the effect of temperature on development rate, T-min (minimum temperature required for development), and D-o (degree days). We estimated that 227 degree-days, above a threshold temperature of 7.7 degrees C, were required to complete development of the greenhouse strain. No life-history data of either strain were obtained for 8 degrees C as eggs did not hatch or development had not completed. The lupin strain required 261 days above 5.7 degrees C for complete development. The results of the study did not support the hypothesis that the lupin strain's outdoor non-pest status was due to different temperature requirements compared with those of the greenhouse

The greenhouse whitefly Trialeurodes vaporariorum is a major threat in tomato cultivation. In greenhouse grown tomatoes non-trichome based whitefly resistance may be better suited than glandular trichome based resistance as glandular trichomes may interfere with biocontrol, which is widely used. Analysis of a collection of recombinant inbred lines derived from a cross between Solanum lycopersicum and Solanum galapagense showed resistance to the whitefly T. vaporariorum on plants without glandular trichomes type IV. The resistance affected whitefly adult survival (AS), but not oviposition rate. This indicates that S. galapagense, in addition to trichome based resistance, also carries non-trichome based resistance components. The effectiveness of the non-trichome based resistance appeared to depend on the season in which the plants were grown. The resistance also had a small but significant effect on the whitefly Bemisia tabaci, but not on the thrips Frankliniella occidentalis. A segregating F2 population was created to map the non-trichome based resistance. Two Quantitative trait loci (QTLs) for reduced AS of T. vaporariorum were mapped on chromosomes 12 and 7 (explaining 13.9% and 6.0% of the variance respectively). The QTL on chromosome 12 was validated in F3 lines.

Astigmatid mites can be used as prey for mass rearing of phytoseiid predators, but also as a supplemental food source to support predator populations in crops. Here we evaluated the potential of six species of astigmatid mites (living or frozen) as alternative food for the predatory mite Amblyseius swirskii Athias-Henriot in greenhouse crops. All prey mites tested were suitable for predator oviposition. In general, oviposition was greater when prey mites were reared on dog food with yeast than when they were reared on wheat bran with yeast. Amongst prey items provided as frozen diet, larvae of Thyreophagus entomophagus (Laboulbene), Acarus siro L. and Lepidoglyphus destructor (Schrank) that had been reared on dog food with yeast, resulted in the highest oviposition rates of A. swirskii. T. entomophagus larvae as frozen diet resulted in the shortest preimaginal developmental time of A. swirskii. On chrysanthemum plants, we found that the greatest increase in predator density occurred when living mites of T. entomophagous were used as a food source. This increase was greater than when predators were fed cattail pollen, a commonly used supplemental food. Effects on predators of providing living A. siro and L. destructor, or frozen larvae of T. entomophagous as food, were comparable with provision of pollen. Use of supplemental food in crops can be a risk if it is also consumed by omnivorous pests such as western flower thrips, Frankliniella occidentalis Pergande. However, we showed that both frozen and living mites of T. entomophagous were unsuitable for thrips oviposition. Hence, we believe that provision of prey mite species increases A. swirskii density, supporting biological control of thrips and other pests in greenhouse crops.

Understanding the mechanisms involved in host plant resistance opens the way for improved resistance breeding programs by using the traits involved as markers. Pest management is a major problem in cultivation of ornamentals. Gladiolus (Gladiolus hybridus L.) is an economically important ornamental in the Netherlands. Gladiolus is especially sensitive to attack by western flower thrips (Frankliniella occidentalis (Pergande) (Thysanoptera:Thripidae)). The objective of this study was, therefore, to investigate morphological and chemical markers for resistance breeding to western flower thrips in Gladiolus varieties. We measured thrips damage of 14 Gladiolus varieties in a whole-plant thrips bioassay and related this to morphological traits with a focus on papillae density. Moreover, we studied chemical host plant resistance to using an eco-metabolomic approach comparing the1H NMR profiles of thrips resistant and susceptible varieties representing a broad range of papillae densities. Thrips damage varied strongly among varieties: the most susceptible variety showed 130 times more damage than the most resistant one. Varieties with low thrips damage had shorter mesophylls and epidermal cells, as well as a higher density of epicuticular papillae. All three traits related to thrips damage were highly correlated with each other. We observed a number of metabolites related to resistance against thrips: two unidentified triterpenoid saponins and the amino acids alanine and threonine. All these compounds were highly correlated amongst each other as well as to the density of papillae. These correlations suggest that papillae are involved in resistance to thrips by producing and/or storing compounds causing thrips resistance. Although it is not possible to distinguish the individual effects of morphological and chemical traits statistically, our results show that papillae density is an easy marker in Gladiolus-breeding programs targeted at increased resistance to thrips.

Ultraviolet (UV) radiation has emerged as an environmental cue with potential uses to enhance plant protection against arthropod pests in agriculture. UV can augment constitutive and inducible plant defenses against herbivorous arthropods. Here we investigated whether application of supplemental UV to chrysanthemum (Chrysanthemum × morifolium Ramat) cuttings during their rooting phase enhanced plant resistance to an important insect pest, Western flower thrips (Frankliniella occidentalis). For this, we analyzed how several daily UV exposure times affected plant damage by thrips on three different chrysanthemum cultivars. The most effective UV dose and responsive cultivar were further used to determine the UV effects on host plant preference by thrips, leaf metabolome and the induction of jasmonic acid (JA)-associated defenses. Our results showed that while short UV daily exposure times increased chrysanthemum resistance to thrips, longer exposure times had the opposite effect. Furthermore, we showed that UV-mediated induction of chrysanthemum resistance to thrips was genotype dependent and can persist after the end of the of the UV treatment. Yet, this induction was not transferred to the next generation from mother plants to cuttings. Nontargeted metabolomic, enzymatic and hormone analyses further revealed that UV slightly affected the leaf metabolome of chrysanthemum plants, and it enhanced the induction of JA-associated signaling after thrips infestation. Taken together, our results suggest that supplemental UV might modulate both constitutive and inducible chrysanthemum defenses against thrips.

[SPA] La eficiencia insecticida de las mezclas de acrinatrín (piretroide) con fungicidas carbamatos (propamocarb, carbendazima, iprovalicarb y dietofencarb) e insecticidas (carbaril, tiodicarb, pirimicarb y oxamilo) se estudió en una población de campo de Frankliniella occidentalis (Pergande). El método consistió en combinar concentraciones crecientes de acrinatrín con una tasa constante subletal del carbamato como sinergista. Estos carbamatos (carbendazima, iprovalicarb y dietofencarb) no mostraron sinergismo al acrinatrín en una población de laboratorio susceptible al insecticida, pero sí lo hicieron en dos poblaciones de campo, mostrando una mayor resistencia al acrinatrín debido a un mayor sinergismo. Carbamatos como el pirimicarb, el oxamilo y el propamocarb podrían ser candidatos prácticos para su uso en campo como sinergistas, incluso contra otras plagas con resistencia metabólica. [ENG] The insecticidal efficacy of mixtures of acrinathrin (pyrethroid) with carbamate fungicides (propamocarb, carbendazim, iprovalicarb and diethofencarb) and insecticides (carbaryl, thiodicarb, pirimicarb and oxamyl) was studied in a field strain of Frankliniella occidentalis (Pergande). The method consisted of combining increasing concentrations of acrinathrin with a constant sublethal rate of the carbamate as synergist. These carbamates (carbendazim, iprovalicarb and diethofencarb) did not show synergism to acrinathrin in a laboratory insecticide-susceptible strain, but they did in two field strains, with higher acrinathrin resistance corresponding to higher synergism. Carbamates such as pirimicarb, oxamyl and propamocarb could be practical candidates for field use as synergists, even against other pests with metabolic resistance.

The aim of this research was to determine insect pests on vegetable crops in Smederevska Palanka area. By using standard methods, equipment and tools, insect pests that caused significant and less significant damages have been determined on vegetable crops: pepper, tomato, cucumber, melon, zucchini, cabbage, pea, bean, spinach and beet at the arable area at the Institute for Vegetable Crops. The most significant insect pests, causing the most damages were Frankliniella occidentalis and Tuta absoluta, and also several species of aphids (Brevicoryne brassicae, Myzus persicae, Aphis gossypii, Aphis fabae and Macrosiphum euphorbiae), stink bugs (Nezara viridula, Eurydema spp.) and flea beetle (Phyllotreta spp.). These insects caused direct and indirect damages. The most significant damages have been noted in green houses due to favourable conditions for insect reproduction and sufficient food supplies., Cilj ovog rada je bio da se utvrde štetni insekti na povrću na području Smederevske Palanke. Na povrtarskim usevima Instituta za povrtarstvo, korišćenjem uobičajenih metoda, opreme i pribora, utvrđeni su štetni insekti koji su izazvali značajna ili manje značajna oštećenja. Na obradivom zemljištu posmatranog lokaliteta nalazili su se usevi paprike, paradajza, krastavca, dinje, tikvice, kupusa, graška, pasulja, spanaća i cvekle. Insekti koji su izazvali najznačajnija oštećenja su Frankliniella occidentalis i Tuta absoluta, a pored njih je utvrđeno više vrsta biljnih vaši (Brevicoryne brassicae, Myzus persicae, Aphis gossypii, Aphis fabae i Macrosiphum euphorbiae), stenica (Nezara viridula, Eurydema spp.) i buvača (Phyllotreta spp.). Ovi insekti su izazvali direktne i indirektne štete. Značajnije štete su pretrpeli povrtarski usevi u zaštićenim prostorima, zbog pogodnijih uslova za razmnožavanje i izobilja hrane za štetne insekte.

Tomato spotted wilt virus (TSWV; species Tomato spotted wilt orthotospovirus; genus Orthotospovirus; family Tospoviridae) is a thrips-transmitted virus that can cause substantial economic losses to many crops, including tomato (Solanum lycopersicum). Since 2005, TSWV emerged as an economically important virus of processing tomatoes in the Central Valley of California, in part due to increased populations of the primary thrips vector, western flower thrips (WFT; Frankliniella occidentalis). To develop an understanding of the epidemiology of TSWV in this region, population densities of WFT and incidence of TSWV were monitored in California's processing tomato transplant-producing greenhouses and associated open fields from 2007 to 2013. Thrips were monitored with yellow sticky cards and in tomato flowers, whereas TSWV incidence was assessed with indicator plants and field surveys for virus symptoms. All thrips identified from processing tomato fields were WFT, and females were three-fold more abundant on sticky cards than males. Symptoms of TSWV infection were observed in all monitored processing tomato fields. Incidences of TSWV ranged from 1 to 20%, with highest incidence found in late-planted fields. There was no single primary inoculum source, and inoculum sources for thrips/TSWV varied depending on the production region. These results allowed us to develop a model for TSWV infection of processing tomatoes in the Central Valley of California. The model predicts that low levels of primary TSWV inoculum are amplified in early-planted tomatoes and other susceptible crops leading to highest levels of infection in later-planted fields, especially those with high thrips populations. Based upon these findings, an integrated pest management (IPM) strategy for TSWV in processing tomatoes in California was devised. This IPM strategy focuses on strategic field placement (identification of high-risk situations), planting TSWV- and thrips-free transplants, planting resistant v

Tomato spotted wilt virus (TSWV; species Tomato spotted wilt orthotospovirus; genus Orthotospovirus; family Tospoviridae) is a thrips-transmitted virus that can cause substantial economic losses to many crops, including tomato (Solanum lycopersicum). Since 2005, TSWV emerged as an economically important virus of processing tomatoes in the Central Valley of California, in part due to increased populations of the primary thrips vector, western flower thrips (WFT; Frankliniella occidentalis). To develop an understanding of the epidemiology of TSWV in this region, population densities of WFT and incidence of TSWV were monitored in California's processing tomato transplant-producing greenhouses and associated open fields from 2007 to 2013. Thrips were monitored with yellow sticky cards and in tomato flowers, whereas TSWV incidence was assessed with indicator plants and field surveys for virus symptoms. All thrips identified from processing tomato fields were WFT, and females were three-fold more abundant on sticky cards than males. Symptoms of TSWV infection were observed in all monitored processing tomato fields. Incidences of TSWV ranged from 1 to 20%, with highest incidence found in late-planted fields. There was no single primary inoculum source, and inoculum sources for thrips/TSWV varied depending on the production region. These results allowed us to develop a model for TSWV infection of processing tomatoes in the Central Valley of California. The model predicts that low levels of primary TSWV inoculum are amplified in early-planted tomatoes and other susceptible crops leading to highest levels of infection in later-planted fields, especially those with high thrips populations. Based upon these findings, an integrated pest management (IPM) strategy for TSWV in processing tomatoes in California was devised. This IPM strategy focuses on strategic field placement (identification of high-risk situations), planting TSWV- and thrips-free transplants, planting resistant v

La connaissance des patrons de diversité des communautés d'insectes herbivores occupe une part importante dans la recherche écologique. Elle est nécessaire en vue d'une lutte biologique, sachant que certains insectes herbivores sont capables de devenir des ravageurs de cultures. Les ennemis naturels et les variables environnementales font partie des facteurs structurant les communautés d'insectes herbivores. Alors que les ennemis naturels assurent la régulation des insectes herbivores, les variables environnementales vont plutôt influencer leur diversité et leur distribution spatiale. L'objectif principal de cette thèse était de comprendre les effets des traits de paysage sur la diversité des communautés de thrips herbivores suivant le gradient altitudinal de La Réunion et d'étudier les effets de la diversité des ennemis naturels dans le contrôle biologique des thrips ravageurs. Dans la première étude, les thrips ont été échantillonnés suivant des gradients d'altitude répliqués, et à chaque site d'échantillonnage, les caractéristiques du paysage et les variables abiotiques ont été estimées dans des zones tampons entourant le site. L'étude a révélé que la plus grande diversité des thrips à La Réunion se concentre en basse altitude, bien que les habitats dans ces altitudes soient fortement dégradés. La diversité des thrips a été particulièrement insensible à la fragmentation et, l'hétérogénéité du paysage et la quantité d'habitat ont interagi pour affecter positivement la diversité des thrips. Dans la deuxième étude, nous avons manipulé dans des cages placées sous serre, des communautés composées de deux thrips ravageurs, Thrips parvispinus et Frankliniella occidentalis, et deux espèces d'acariens prédateurs Amblyseius swirskii et Proprioseiopis mexicanus. L'étude a montré que deux prédateurs assurent une meilleure régulation qu'un seul prédateur, confirmant ainsi l'importance de maintenir de la biodiversité au niveau trophique supérieur dans le contrôle biologique de

The aim of this research was to determine insect pests on vegetable crops in Smederevska Palanka area. By using standard methods, equipment and tools, insect pests that caused significant and less significant damages have been determined on vegetable crops: pepper, tomato, cucumber, melon, zucchini, cabbage, pea, bean, spinach and beet at the arable area at the Institute for Vegetable Crops. The most significant insect pests, causing the most damages were Frankliniella occidentalis and Tuta absoluta, and also several species of aphids (Brevicoryne brassicae, Myzus persicae, Aphis gossypii, Aphis fabae and Macrosiphum euphorbiae), stink bugs (Nezara viridula, Eurydema spp.) and flea beetle (Phyllotreta spp.). These insects caused direct and indirect damages. The most significant damages have been noted in green houses due to favourable conditions for insect reproduction and sufficient food supplies., Cilj ovog rada je bio da se utvrde štetni insekti na povrću na području Smederevske Palanke. Na povrtarskim usevima Instituta za povrtarstvo, korišćenjem uobičajenih metoda, opreme i pribora, utvrđeni su štetni insekti koji su izazvali značajna ili manje značajna oštećenja. Na obradivom zemljištu posmatranog lokaliteta nalazili su se usevi paprike, paradajza, krastavca, dinje, tikvice, kupusa, graška, pasulja, spanaća i cvekle. Insekti koji su izazvali najznačajnija oštećenja su Frankliniella occidentalis i Tuta absoluta, a pored njih je utvrđeno više vrsta biljnih vaši (Brevicoryne brassicae, Myzus persicae, Aphis gossypii, Aphis fabae i Macrosiphum euphorbiae), stenica (Nezara viridula, Eurydema spp.) i buvača (Phyllotreta spp.). Ovi insekti su izazvali direktne i indirektne štete. Značajnije štete su pretrpeli povrtarski usevi u zaštićenim prostorima, zbog pogodnijih uslova za razmnožavanje i izobilja hrane za štetne insekte.

The aim of this research was to determine insect pests on vegetable crops in Smederevska Palanka area. By using standard methods, equipment and tools, insect pests that caused significant and less significant damages have been determined on vegetable crops: pepper, tomato, cucumber, melon, zucchini, cabbage, pea, bean, spinach and beet at the arable area at the Institute for Vegetable Crops. The most significant insect pests, causing the most damages were Frankliniella occidentalis and Tuta absoluta, and also several species of aphids (Brevicoryne brassicae, Myzus persicae, Aphis gossypii, Aphis fabae and Macrosiphum euphorbiae), stink bugs (Nezara viridula, Eurydema spp.) and flea beetle (Phyllotreta spp.). These insects caused direct and indirect damages. The most significant damages have been noted in green houses due to favourable conditions for insect reproduction and sufficient food supplies., Cilj ovog rada je bio da se utvrde štetni insekti na povrću na području Smederevske Palanke. Na povrtarskim usevima Instituta za povrtarstvo, korišćenjem uobičajenih metoda, opreme i pribora, utvrđeni su štetni insekti koji su izazvali značajna ili manje značajna oštećenja. Na obradivom zemljištu posmatranog lokaliteta nalazili su se usevi paprike, paradajza, krastavca, dinje, tikvice, kupusa, graška, pasulja, spanaća i cvekle. Insekti koji su izazvali najznačajnija oštećenja su Frankliniella occidentalis i Tuta absoluta, a pored njih je utvrđeno više vrsta biljnih vaši (Brevicoryne brassicae, Myzus persicae, Aphis gossypii, Aphis fabae i Macrosiphum euphorbiae), stenica (Nezara viridula, Eurydema spp.) i buvača (Phyllotreta spp.). Ovi insekti su izazvali direktne i indirektne štete. Značajnije štete su pretrpeli povrtarski usevi u zaštićenim prostorima, zbog pogodnijih uslova za razmnožavanje i izobilja hrane za štetne insekte.

Els trips (Insecta: Thysanoptera) constitueixen una plaga important en els cultius de fruiters de pinyol, a Catalunya i arreu, especialment en els fruits de pell llisa com les nectarines. L’espècie més important és Frankliniella occidentalis, una espècie molt polífaga que també es troba a les plantes dicotiledònies. El seu control s’efectua gairebé de manera exclusiva mitjançant tractaments insecticides, encara que existeix una fauna útil la importància de la qual està per determinar. Les pèrdues econòmiques que causen estan associades majoritàriament als danys estètics que provoquen i comporten una gran quantitat d’aplicacions de productes insecticides, fins i tot en moments propers a la recol·lecció. Els danys estètics no influeixen en la qualitat interna de la fruita i, per tant, no deixa d’estar en mans del consumidor acceptar un cert nombre de petites taques blanques a la pell, cosa que permetria millorar notablement la qualitat total de la fruita en tots els aspectes del procés productiu.Paraules clau: trips, Frankliniella occidentalis, nectarina, Catalunya., Thrips (Insecta: Thysanoptera) are important arthropod pests on stone fruit orchards and especially nectarines, both in Catalonia and worldwide. In this respect, Frankliniella occcidentalis is the foremost species. It is a polyphagous insect that is also found on dicotyledonous plants forming the ground cover. It is controlled almost exclusively by using chemical means, although natural enemies, whose importance is still to be determined, are found in both trees and the ground cover. The economic losses caused by F. occidentalis are mostly due to aesthetic injury and are responsible for a great number of insecticide applications, even near harvest time. Aesthetic injury does not affect nectarine internal quality. Thus, by acquiescing to a certain amount of very small white dots on nectarine skin, consumers have the opportunity to obtain a great increase in total fruit quality in all aspects of the production process.Keywords: thrips, Frankliniella occidentalis, nectarine, Catalonia., Los trips (Insecta: Thysanoptera) constituyen una plaga importante en los cultivos de frutales de hueso, en Cataluña y en todas partes, especialmente en los frutos de piel lisa como las nectarinas. La especie más importante es Frankliniella occidentalis, una especie muy polífaga que también se encuentra en las plantas dicotiledóneas. Su control se realiza de forma casi exclusiva mediante tratamientos insecticidas, aunque existe una fauna útil cuya importancia está por determinar. Las pérdidas económicas que causan están asociadas mayoritariamente a los daños estéticos que provocan y son responsables de una gran cantidad de aplicaciones de productos insecticidas, incluso en momentos cercanos a la recolección. Los  años estéticos no influyen en la calidad interna de la fruta y, por lo tanto, no deja de estar en manos del consumidor aceptar una cierta cantidad de pequeñas manchas blancas en la piel, lo que permitiría mejorar notablemente la calidad total de la fruta en todos los aspectos del proceso productivo.Palabras clave: trips, Frankliniella occidentalis, nectarina, Cataluña.

Induction of defenses is one of the most widely accepted eco-friendly approachesfor management of pests and diseases. Seeds are receptive to resistance-inducing chemicals and could offer broad-spectrum protection at the early stages of development. However, seed treatment with elicitors has previously been shown to differentially influence induced defense responses among cultivars and thus, could hamper commercial exploitation. In this context, the objective of the present study was to evaluate the genotype-dependent ability of jasmonic acid (JA) to induce resistance against western flower thrips (WFT) at the seed stage. We examined the variation in inducibility of resistance in eight commercial tomato cultivars. Causal factors accounting for discrepancies in JA-induced responses at the seed stage were phenotypically and biochemically evaluated. Seed receptivity to exogenous JA appeared to be cultivar dependent. Thrips associated silver damage was only reduced in JA seed-treated plants of cultivar Carousel. Enhancement of resistance, was not associated with activation of defense-related traits such as polyphenol oxidase activity (PPO), trichomes or volatiles.Sulfuric acid scarification, prior to JA seed incubation, significantly augmented theembryonic responsiveness to JA in cv. Moneymaker without an adverse effect ongrowth. Hence, these results support the hypothesis that seed coat permeability is a key factor for successfully inducing JA mediated thrips defenses. The outcome of our study is of translational value as it creates opportunities for the seed industry to perform pre-treatments on non-responsive cultivars as well as for tomato breeding programs to select for genetic traits that affect seed permeability.

Thrips are a worldwide threat to Capsicum because they damage fruits, flowers and leaves directly by feeding, and indirectly by vectoring tospoviruses such as tomato spotted wilt virus. Therefore, growers would benefit from thrips-resistant varieties. Previously, a quantitative trait locus (QTL) that provides resistance to Frankliniella occidentalis has been identified. Here we explore the potential of this QTL for breeding thrips-resistant varieties by studying its effect on two thrips species (i.e. F. occidentalis and Thrips tabaci) in four different Capsicum annuum backgrounds. We observed differences in thrips resistance between different genetic backgrounds, both in plants that have the resistance allele for the QTL region in homozygous state as well as in plants with the susceptibility allele in homozygous state. This suggests the presence of factors in these backgrounds that either increase or reduce thrips resistance. Altogether, we confirmed the major effect of the QTL on thrips resistance in all four genetic backgrounds to both F. occidentalis and T. tabaci, thus showing its general applicability as a source for breeding thrips-resistant Capsicum varieties.

Auxins are commonly used for commercial propagation of chrysanthemums by stem cuttings. Recent studies imply that these root-promoting hormones also affect plant defense responses. The underlying motive of this study stems from the serendipitous observation that water dipping of auxin-coated cuttings beneficially affected thrips herbivory. Therefore, the primary objective of this investigation was to explore the role of indole-3-butyric acid (IBA) in relation to herbivore susceptibility in chrysanthemum. We observed contrasting findings concerning the physical presence of IBA and it’s role in promoting susceptibility of cuttings to thrips, which may in part be explained by the phenotypical variations of cuttings generated from mother plants. Nonetheless, we repeatedly demonstrated considerable protection, in some experiments up to 37%, against thrips and leaf miner upon water dipping of IBA-coated cuttings. Assessment of polyphenol oxidase activity (PPO), 14 days after dipping treatment, suggests that neither direct induction nor priming of plant defenses are involved. Future experiments aimed at understanding the early signaling events may help to explain the underlying mechanisms involved in conferring herbivore protection. We propose a dual role for auxins in early integrated pest management strategies to maximize plant development and minimize herbivory through feasible, cost-effective water dipping treatments.

‘Lure-and-infect’ is an insect pest management strategy with high potential but so far there are few examples of its application. Using traps as surrogates for auto-dissemination devices, we tested the attractiveness to naturally occurring thrips (Thysanoptera: Thripidae) of three trap types differing in colour and structure, with and without the thrips lure methyl isonicotinate (MI), and sticky plate traps as a control. The aim was to find more effective traps that could be further developed into devices for auto-dissemination and lure-and-infect of thrips. The number of thrips captured varied substantially with trap type and the presence of the MI lure. We found a high visual response to a sticky ‘white ruffle’ trap (i.e., a 30-cm-long cylindrical outline of folded fabric), compared to a commonly used blue sticky plate trap (Bug-scan) as the control. This effect was seen both in a greenhouse with roses (Rosa spp.), where we encountered western flower thrips, Frankliniella occidentalis (Pergande), and in a grass field, where we encountered onion thrips, Thrips tabaci Lindeman, and New Zealand flower thrips, Thrips obscuratus (Crawford). In the absence of MI, the white ruffle trap caught 7–22× more thrips than the control Bug-scan trap. A similarly designed blue ruffle trap and a modified Lynfield trap caught lower thrips numbers than the white ruffle and the control Bug-scan traps. Presence of MI substantially increased the captures of T. tabaci in all three trap types in the field (2.5–18×). In the greenhouse, without MI the white ruffle trap caught 3.5–14× more thrips than the Bug-scan, blue ruffle, or modified Lynfield traps. Presence of MI increased the captures of F. occidentalis males and females in the Lynfield and blue ruffle traps (1.4–2.8×), but not in the white ruffle trap in the greenhouse (ca. 1.1×). The importance of visual and olfactory factors for the design of effective auto-dissemination and lure-and-infect strategies for thrips management is disc

In complex food webs, plants are commonly attacked by multiple herbivorous species, affecting the preference and performance of other herbivores and natural enemies. The role of omnivorous insects in ecosystems may be more complex because of the consumption of both plant and animal organisms. However, the effect of omnivorous insects on herbivores and natural enemies, has received little attention so far. The main goal of this study was to investigate whether the dual herbivore interaction between aphids and thrips, an omnivorous pest, on a sweet pepper system, may affect different trophic levels, from plant and aphid performance until the third trophic level, i.e., preference and performance of the predatory hoverfly Sphaerophoria rueppellii. Additionally, we tested whether the aggregation pheromone of the thrips Frankliniella occidentalis, could disturb the oviposition behavior of the predatory hoverfly. Our results show that the presence of thrips decreases host plant and aphid performance. Furthermore, despite not affecting syrphid larval performance, thrips presence reduces fecundity of the adults that emerge from those larvae. Additionally, we observed that syrphids avoid ovipositing on plants with either thrips or thrips aggregation pheromone. The present study reveals how the presence of thrips or a semiochemical compound related to thrips, can impact the behavior and performance of an aphidophagous predator.

In complex food webs, plants are commonly attacked by multiple herbivorous species, affecting the preference and performance of other herbivores and natural enemies. The role of omnivorous insects in ecosystems may be more complex because of the consumption of both plant and animal organisms. However, the effect of omnivorous insects on herbivores and natural enemies, has received little attention so far. The main goal of this study was to investigate whether the dual herbivore interaction between aphids and thrips, an omnivorous pest, on a sweet pepper system, may affect different trophic levels, from plant and aphid performance until the third trophic level, i.e., preference and performance of the predatory hoverfly Sphaerophoria rueppellii. Additionally, we tested whether the aggregation pheromone of the thrips Frankliniella occidentalis, could disturb the oviposition behavior of the predatory hoverfly. Our results show that the presence of thrips decreases host plant and aphid performance. Furthermore, despite not affecting syrphid larval performance, thrips presence reduces fecundity of the adults that emerge from those larvae. Additionally, we observed that syrphids avoid ovipositing on plants with either thrips or thrips aggregation pheromone. The present study reveals how the presence of thrips or a semiochemical compound related to thrips, can impact the behavior and performance of an aphidophagous predator.

Western flower thrips [Frankliniella occidentalis (Pergande)] is a worldwide pest insect that causes damage in pepper cultivation, so growers would benefit from host plant resistance. The objectives of this study were (1) to evaluate the effect of plant age on thrips resistance using nine Capsicum accessions with different levels of thrips resistance at three different plant ages, and (2) to study the effect of leaf age on thrips resistance in a resistant and a susceptible pepper accession. The fraction of first instar larvae that did not develop into second instar was used as a measure for thrips resistance. Our results show that plants start to develop thrips resistance when they are between 4 and 8 weeks old. This transition was most marked on the resistant accession CGN16975, on which about 50% of the L1 larvae developed into the next stage on 4-week-old plants, whereas none of them developed beyond the L1 stage on 8- or 12-week-old plants. Furthermore, it is shown that youngest fully opened leaves of the resistant accession CGN16975 are significantly more resistant to thrips than older leaves; 89% of the L1 larvae did not develop into the next stage on the youngest leaves, whereas 57% did not develop beyond the L1 stage on the oldest leaves. Young leaves of the susceptible accession CGN17219 are more susceptible than older leaves; 9 versus 52% of the L1 larvae did not develop into the next stage on young and old leaves, respectively. These findings can be used to improve integrated pest management strategies.

Host-plant resistance to insects like thrips and aphids is a complex trait that is difficult to phenotype quickly and reliably. Here, we introduce novel hardware and software to facilitate insect choice assays and automate the acquisition and analysis of movement tracks. The hardware consists of an array of individual T-mazes allowing simultaneous release of up to 90 insect individuals from their individual cage below each T-maze with choice of two leaf disks under a video camera. Insect movement tracks are acquired with computer vision software (EthoVision) and analyzed with EthoAnalysis, a novel software package that allows for automated reporting of highly detailed behavior parameters andstatistical analysis. To validate the benefits of the system we contrasted two Arabidopsis accessions that were previously analyzed for differential resistance to western flower thrips. Results of two trials with 40 T-mazes are reported and we show how we arrived at optimized settings for the different filters and statistics. The statistics are reported in terms of frequency, duration, distance and speed of behavior events, both as sum totals and event averages, and both for the total trial period and in time bins of 1 h. Also included are higher level analyses with subcategories like short-medium-long events and slow-medium-fast events. The time bins showed how some behavior elements are more descriptive of differences between the genotypes during the first hours, whereasothers are constant or become more relevant at the end of an 8 h recording. The three overarching behavior categories, i.e., choice, movement, and halting, were automatically corrected for the percentage of time thrips were detected and 24 out of 38 statistics of behavior parameters differed by a factor 2–6 between the accessions. The analysis resulted in much larger contrasts in behavior traits than reported previously. Compared to leaf damage assays on whole plants or detached leaves that take a week or more t

The objective of the present investigation was to evaluate the chemical control of trips Frankliniella occidentalis Pergande (Thysanoptera:Thripidae) with the application of four seed products (thiodicarb, acephato, bifenthrin + imidacloprid and thiametoxan + lambda cyalotrina) with two doses; one according to the dosage of the commercial house and the other 50% smaller, in the variety Roque 1. A randomized block design with four repetitions, 10 treatments and two controls, a hybrid (Ares®-Unisem) was used and a white one. The sampling of the density of trips was carried out by means of a manual aspirator and blue traps, the samplings were made from the emergence of the plants and during eight weeks, carrying out two samplings per week. The results show that the treatment with thiamethoxane + lambda cyalotrine presented the lowest density of trips with a value of 1.53 trips per plant, while the absolute control was the one with the highest value with 2.14., Resumen El objetivo de la presente investigación fue evaluar el control químico de trips Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) con la aplicación de cuatro productos a la semilla (thiodicarb, acephato, bifentrina + imidacloprid y thiametoxan + lambda cyalotrina) con dos dosis; una de acuerdo a la dosificación de la casa comercial y la otra al 50% menor, en la variedad Roque 1. Se usó un diseño de bloques al azar con cuatro repeticiones, 10 tratamientos y dos testigos, un hibrido (Ares®-Unisem) y uno blanco. El muestreo de la densidad de trips se realizó mediante un aspirador manual y trampas azules, los muestreos se realizaron desde la emergencia de las plantas y durante ocho semanas, efectuando dos muestreos por semana. Los resultados muestran que el tratamiento con thiametoxan + lambda cyalotrina presentó la densidad de trips más baja con un valor de 1.53 trips por planta, mientras que el testigo absoluto fue el que presentó el valor más alto con 2.14.

vegetable crops. Micro-Tom is a model tomato cultivar used for research due to its small size and short time to fruiting. This project evaluated I. walleriana and Micro-Tom transformed with Agrobacterium. The construct contained GFP (green fluorescent protein) and hygromycin antibiotic-resistant selectable markers, and the antisense sequence of open reading frame of INSV nucleocapsid protein (N). The N gene is expected to confer INSV resistance by RNA interference or gene silencing. The presence of transgenes was confirmed by PCR. Transgenic Impatiens was selfed for two generations. Transgenic Micro-Tom was selfed for 4 generations. Spinach was used as an INSV reservoir. Impatiens, spinach and Micro-Tom were mechanically inoculated with INSV and evaluated visually, with assay tests, ELISA testing, and PCR. Spinach was successfully infected with INSV six times of seven attempts. Impatiens and Micro-Tom had no successful inoculations of three and five attempts, respectively.

The objective of the present investigation was to evaluate the chemical control of trips Frankliniella occidentalis Pergande (Thysanoptera:Thripidae) with the application of four seed products (thiodicarb, acephato, bifenthrin + imidacloprid and thiametoxan + lambda cyalotrina) with two doses; one according to the dosage of the commercial house and the other 50% smaller, in the variety Roque 1. A randomized block design with four repetitions, 10 treatments and two controls, a hybrid (Ares®-Unisem) was used and a white one. The sampling of the density of trips was carried out by means of a manual aspirator and blue traps, the samplings were made from the emergence of the plants and during eight weeks, carrying out two samplings per week. The results show that the treatment with thiamethoxane + lambda cyalotrine presented the lowest density of trips with a value of 1.53 trips per plant, while the absolute control was the one with the highest value with 2.14., Resumen El objetivo de la presente investigación fue evaluar el control químico de trips Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) con la aplicación de cuatro productos a la semilla (thiodicarb, acephato, bifentrina + imidacloprid y thiametoxan + lambda cyalotrina) con dos dosis; una de acuerdo a la dosificación de la casa comercial y la otra al 50% menor, en la variedad Roque 1. Se usó un diseño de bloques al azar con cuatro repeticiones, 10 tratamientos y dos testigos, un hibrido (Ares®-Unisem) y uno blanco. El muestreo de la densidad de trips se realizó mediante un aspirador manual y trampas azules, los muestreos se realizaron desde la emergencia de las plantas y durante ocho semanas, efectuando dos muestreos por semana. Los resultados muestran que el tratamiento con thiametoxan + lambda cyalotrina presentó la densidad de trips más baja con un valor de 1.53 trips por planta, mientras que el testigo absoluto fue el que presentó el valor más alto con 2.14.

In cultivated tomato (Solanum lycopersicum), increases in photosynthetically active radiation (PAR) induce type VI leaf glandular trichomes, which are important defensive structures against arthropod herbivores. Yet, how PAR affects the type VI trichome-associated leaf chemistry and its biological significance with respect to other photomorphogenic responses in this agronomically important plant species is unknown. We used the type VI trichome-deficient tomato mutant odorless-2 (od-2) and its wild type to investigate the influence of PAR on trichome-associated chemical defenses against thrips (Frankliniella occidentalis). High PAR increased thrips resistance in wild-type plants, but not in od- 2. Furthermore, under high PAR, thrips preferred od-2 over the wild type. Both genotypes increased type VI trichome densities under high PAR. Wild-type plants, however, produced more trichome-associated allelochemicals, i.e. terpenes and phenolics, these being undetectable or barely altered in od-2. High PAR increased leaf number and thickness, and induced profound but similar metabolomic changes in wild-type and od-2 leaves. Enhanced PAR also increased levels of ABA in wild-type and od-2 plants, and of auxin in od-2, while the salicylic acid and jasmonate concentrations were unaltered. However, in both genotypes, high PAR induced the expression of jasmonic acid-responsive defense-related genes. Taken together, our results demonstrate that high PAR-mediated induction of trichomeassociated chemical defenses plays a prominent role in tomato-thrips interactions.

Plants possess various inducible defences that result in synthesis of specialized metabolites in response to herbivory, which can interfere with the performance of herbivores of the same and other species. Much less is known of the effects of plant feeding by omnivores. We found that previous feeding of the omnivorous predator Macrolophus pygmaeus on sweet pepper plants significantly reduced reproduction of the two-spotted spider mite Tetranychus urticae and western flower thrips Frankliniella occidentalis on the same plants, also on leaves that had not been exposed to the omnivore. In contrast, no effect was found on the reproduction of the green peach aphid Myzus persicae. Juvenile survival and developmental time of T. urticae and M. persicae, and larval survival of F. occidentalis were not affected by plant feeding by M. pygmaeus. Larvae of F. occidentalis feeding on leaves previously exposed to M. pygmaeus required longer to develop into adults. Defence-related plant hormones were produced locally and systemically after exposure to M. pygmaeus. The concentrations of 12-oxo-phytodienoic acid and jasmonic acid–isoleucine in the attacked leaves were significantly higher than in the corresponding leaves on the uninfested plants, and jasmonic acid concentrations showed the same trend, suggesting that jasmonic-acid-related defence pathways were activated. In contrast, similar concentrations of salicylic acid were found in the attacked leaves of M. pygmaeus-infested plants and uninfested plants. Our results show that plant feeding by omnivorous predators decreases the performance of herbivores, suggesting that it induces plant defences.

Variation in the induction of plant defenses along the plant canopy can determine distribution and colonization of arthropod herbivores within the plant. In tomato, type VI glandular trichomes, which are epidermal defensive structures, and their derived volatiles are induced by the phytohormone jasmonic acid (JA). How JA-mediated induction of these trichome-associated chemical defenses depends on the leaf developmental stage and correlates with resistance against herbivory is unknown. We showed that application of JA reduced thrips-associated damage, however the amplitude of this response was reduced in the fully developed leaves compared to those still developing. Although JA increased type-VI trichome densities in all leaf developmental stages, as well as JA-inducible defensive proteins, these increases were stronger in developing leaves. Remarkably, the concentration of trichome-derived volatiles was induced by JA to a larger degree in developing leaves than in fully developed leaves. In fully developed leaves, the increase in trichome-derived volatiles was explained by an enhanced production per trichome, while in developing leaves this was mainly caused by increases in type-VI trichome densities. Together, we showed that JA-mediated induction of trichome density and chemistry depends on leaf development stage, and it might explain the degree of thrips-associated leaf damage in tomato.

Western flower thrips (WFT) Frankliniella occidentalis (Pergande) is a key agricultural pest of cultivated tomatoes. Induced host plant resistance by activating jasmonic acid (JA) signaling pathway constitutes a promising method for WFT control. The phytotoxin coronatine (COR), produced by Pseudomonas syringae pv. tomato DC3000 (Pst), mimics the plant hormone JA-Isoleucine and can promote resistance against herbivorous arthropods. Here we determined the effect of Pst and COR on tomato resistance against WFT, induction of JA and salicylic acid (SA) associated defenses, and plant chemistry. Additionally, we investigated the presence of other components in Pst-derived and filtered culture medium, and their interactive effect with COR on tomato resistance to WFT. Our results showed that infiltration of COR or Pst reduced WFT feeding damage in tomato plants. COR and Pst induced the expression of JA-associated gene and protein marker. COR also induced expression of a SA-related responsive gene, although at much less magnitude. Activation of JA defenses in COR and Pst infiltrated plants did not affect density of type VI leaf trichomes, which are defenses reported to be induced by JA. An untargeted metabolomic analysis showed that both treatments induced strong changes in infiltrated leaves, but leaf responses to COR or Pst slightly differed. Application of the Pst-derived and filtered culture medium, containing COR but not viable Pst, also increased tomato resistance against WFT confirming that the induction of tomato defenses does not require a living Pst population to be present in the plant. Infiltration of tomato plants with low concentrations of COR in diluted Pst-derived and filtered culture medium reduced WFT feeding damage in a greater magnitude than infiltration with an equivalent amount of pure COR indicating that other elicitors are present in the medium. This was confirmed by the fact that the medium from a COR-mutant of Pst also strongly reduced silver damage.

Plants are sessile organisms and, consequently, are exposed to a plethora of stresses in their local habitat. As a result, different populations of a species are subject to different selection pressures leading to adaptation to local conditions and intraspecific divergence. The annual brassicaceous plant Arabidopsis thaliana is an attractive model for ecologists and evolutionary biologists due to the availability of a large collection of resequenced natural accessions. Accessions of A. thaliana display one of two different life cycle strategies: summer and winter annuals. We exposed a collection of 308 European Arabidopsis accessions, that have been genotyped for 250K SNPs, to a range of stresses: one abiotic stress (drought), four biotic stresses (Pieris rapae caterpillars, Plutella xylostella caterpillars, Frankliniella occidentalis thrips and Myzus persicae aphids) and two combined stresses (drought plus P. rapae and Botrytis cinerea fungus plus P. rapae). We identified heritable genetic variation for responses to the different stresses, estimated by narrow-sense heritability. We found that accessions displaying different life cycle strategies differ in their response to stresses. Winter annuals are more resistant to drought, aphids and thrips and summer annuals are more resistant to P. rapae and P. xylostella caterpillars. Summer annuals are also more resistant to the combined stresses of drought plus P. rapae and infection by the fungus Botryris cinerea plus herbivory by P. rapae. Adaptation to drought displayed a longitudinal gradient. Finally, trade-offs were recorded between the response to drought and responses to herbivory by caterpillars of the specialist herbivore P. rapae.

Tomato spotted wilt virus (TSWV) is mainly vectored by Frankliniella occidentalis Pergande, and it potentially activates the vector's immune response. However, molecular background of the altered immune response is not clearly understood. Therefore, using a proteomic approach, we investigated the immune pathways that are activated in F. occidentalis larvae after 24 h exposure to TSWV. Two-dimensional isoelectric focusing/sodium dodecyl sulfate polyacrylamide gel electrophoresis (2D-IEF/SDS/PAGE) combined with mass spectrometry (MS), were used to identify proteins that were differentially expressed upon viral infection. High numbers of proteins were abundantly expressed in F. occidentalis exposed to TSWV (73%) compared to the non-exposed (27%), with the majority functionally linked to the innate immune system such as: signaling, stress response, defense response, translation, cellular lipids and nucleotide metabolism. Key proteins included: 70 kDa heat shock proteins, Ubiquitin and Dermcidin, among others, indicative of a responsive pattern of the vector's innate immune system to viral infection. © 2016 Elsevier Ltd

Western flower thrips (WFT) (Frankliniella occidentalis) is an introduced pest that harms French bean production in Kenya and other countries. Since new WFT management approaches are being developed, a closer look at the genetic makeup of WFT populations can give new insights into source habitats, crop colonization patterns or host plant preferences, which are prerequisites for integrated pest management (IPM) strategies. For this purpose, we used six microsatellite loci to analyse the genetic structure, diversity and gene flow of WFT sampled on French beans, intercrops and weeds in Kenyan French bean production areas. The results of this preliminary study indicate that the available microsatellites are sufficiently polymorphic for more detailed analyses on local dispersal patterns of WFT in Kenya. Even with the limited data set, the results reveal that F. occidentalis populations show considerable genetic differentiation between host plant species but not between regions, which suggests reduced gene flow and a possible development of biotypes. Possible consequences of the results on IPM are discussed. Copyright © icipe 2017

The short-range diurnal dispersal pattern of adult western flower thrips Frankliniella occidentalis (Pergande), in relation to spatial distribution of French beans, was determined in the field. A total of 1200 adult female F. occidentalis were released on 60 French bean plants with 20 adult thrips per plant at the central release point of 3.14 m2. Dispersal was determined in terms of the number of thrips recorded on French beans planted on concentric circles at 0.9, 1.8, 3.6, 7.2 and 14.4 m radii from a circular central release point for five days. Results indicated that there was a steady increase in the proportion of dispersing adult F. occidentalis from the first to the fourth day in the first planting season, and from the first to the third day in the second planting season. The peak hour for dispersal was 10.15 h in the first season while it was 13.15 h in the second season. Temperature and wind speed were positively associated with the dispersal activity of adult F. occidentalis. Minimal flight activity was at temperatures below 15 °C and peak flight activity was at 19 °C. The prevailing wind direction did not influence the dispersal pattern of adult F. occidentalis in both seasons. Adult F. occidentalis moved up to 7.2 m on French beans on the first day. In both seasons, the mean direction of thrips dispersal was mostly uniformly distributed (not oriented to a particular compass direction) around the central release point. The results provide an insight into developing integrated management strategies against the pest based on isolation of farm fields, management of alterative hosts around French bean fields and insecticide application. Copyright © icipe 2017

Plants are sessile organisms and, consequently, are exposed to a plethora of stresses in their local habitat. As a result, different populations of a species are subject to different selection pressures leading to adaptation to local conditions and intraspecific divergence. The annual brassicaceous plant Arabidopsis thaliana is an attractive model for ecologists and evolutionary biologists due to the availability of a large collection of resequenced natural accessions. Accessions of A. thaliana display one of two different life cycle strategies: summer and winter annuals. We exposed a collection of 308 European Arabidopsis accessions, that have been genotyped for 250K SNPs, to a range of stresses: one abiotic stress (drought), four biotic stresses (Pieris rapae caterpillars, Plutella xylostella caterpillars, Frankliniella occidentalis thrips and Myzus persicae aphids) and two combined stresses (drought plus P. rapae and Botrytis cinerea fungus plus P. rapae). We identified heritable genetic variation for responses to the different stresses, estimated by narrow-sense heritability. We found that accessions displaying different life cycle strategies differ in their response to stresses. Winter annuals are more resistant to drought, aphids and thrips and summer annuals are more resistant to P. rapae and P. xylostella caterpillars. Summer annuals are also more resistant to the combined stresses of drought plus P. rapae and infection by the fungus Botryris cinerea plus herbivory by P. rapae. Adaptation to drought displayed a longitudinal gradient. Finally, trade-offs were recorded between the response to drought and responses to herbivory by caterpillars of the specialist herbivore P. rapae.

The avocado is one of the perennial crops of major economic importance in Mexico, like any other crop, affected by pests and diseases that cause economic and environmental damage. One of the major insect that attacks the crop is Frankliniella occidentalis , these injured avocado leaves and fruit as a result of feeding in the layers of cells of the epidermis, creating areas or pale brown. The lesions may be caused entry points of pathogenic microorganisms. In fruits, the insects come to cause scars or marks, reducing its market value, can cause birth defects in fruit by causing alterations in the newly formed shell fruits, f lowers inhibit fertilization and cause them to fall. The objective was to determine the spatial distribution of populations of thrips and mapping the density of three plots four hectares located in the municipality of Coatepec Harinas through the application of geostatistical analysis. The results showed that populations of thrips are grouped into aggregation centers and conform to spherical models mostly. In addition to this, it was determined the area infested by the insect, which will accurately direct control measures in the areas with the largest number of insects through density maps, El aguacate es uno de los cultivos perennes de mayor importancia económica en México, como cualquier otro cultivo, se ve afectado por plagas y enfermedades que causan daños económicos y ecológicos. Uno de los principales insectos que ataca el cultivo es Frankliniella occidentalis , estos lesionan hojas y frutos de aguacate como resultado de su alimentación en las capas de células de la epidermis, creando áreas pálidas o cafés. Las lesiones originadas pueden ser puntos de entrada de microorganismos patógenos. En los frutos, estos insectos llegan a causar cicatrices o marcas, reduciendo su valor en el mercado, pueden producir malformaciones en la fruta al provocar alteraciones en la cáscara de frutos recién formados, inhiben la fecundación de f lores y provocan su caída. El objetivo fue determinar la distribución espacial de las poblaciones de trips y la elaboración de mapas de densidad de tres parcelas de cuatro hectáreas ubicadas en el municipio de Coatepec Harinas mediante la aplicación del análisis geoestadístico. Los resultados mostraron que las poblaciones de trips se agrupan en centros de agregación y se ajustan a modelos esféricos en su mayoría. Adicional a ello, se pudo determinar la superficie infestada por el insecto, lo que permitirá dirigir certeramente las medidas de control en las áreas con mayor número de insectos a través de los mapas de densidad

Earlier studies have shown that Tomato spotted wilt virus (TSWV) influences the biology, performance, and behavioral patterns of its vector Frankliniella occidentalis Pergande. In this study, using Capsicum annuum L. as the host plant, we aimed to determine the manipulation of F. occidentalis by TSWV through switching of the diet (+ or TSWV) during vector's development. Behavioral patterns, fitness, as well as vector performance were evaluated. The specific parameters investigated included longevity/survival, fecundity, development time, feeding, and preferential behavior. F. occidentalis were reared on either TSWV-infected (exposed) or healthy leaves (non-exposed) throughout their larval stages. The emerging adults were then individually transferred to either healthy or TSWV-infected leaf disks. This resulted into four treatments, consisting of exposed or non-exposed thrips reared on either infected or healthy leaf disks as adults. All F. occidentalis exposed to TSWV in their larval stages had shorter development time regardless of the adults' diet. Whereas, the ones that were later reared on healthy leaf disks as adults recorded the highest longevity and reproduction rate. Furthermore, adults of F. occidentalis that were exposed to TSWV in their larval stages showed preference toward healthy leaf disks (TSWV), whereas the non-exposed significantly preferred the infected leaf disks (+TSWV). These are further indications that TSWV modifies the nutritional content of its host plants, which influences vector's biology and preferential behavior, in favor of its multiplication and dispersal. The findings offer additional explanation to the often aggressive spread of the virus in crop stands.

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