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Frankliniella flower thrips are pests of numerous fruit and vegetable crops as they feed and reproduce in the flowers and fruits. The invasive Frankliniella occidentalis (Pergande) from the Southwestern United States, an economic pest in Florida since 2005, and the native Frankliniella bispinosa Morgan are both found in Florida strawberries. The objective of this research was to characterize injury to strawberry fruit from these species. Densities of 0, 2, 4, 8, 16, or 32 adult females of each species were caged on a strawberry plant with one flower. The cages were removed after 2, 5, or 10 d, and the number of surviving adults and the number of larvae determined. Injury was quantified on the mature fruit 21 d after thrips were introduced onto the experimental plant. Initial densities as low as two adult F. occidentalis females per flower decreased fruit set and increased cat-facing on the fruits that developed. There were no significant effects on fruit set and cat-facing by any initial density of F. bispinosa. Feeding by thrips on the small, green fruit affected the size and shape of the mature fruit: the diameters were decreased as a linear function of increased feeding by F. bispinosa, and the weights were decreased as a linear function of increased feeding by F. occidentalis. Overall, results showed that F. occidentalis was more damaging to strawberry than F. bispinosa. The differences in pest status between these common flower thrips species in Florida presents challenges to management programs.

Western flower thrips, Frankliniella occidentalis, first arose as an important invasive pest of many crops during the 1970s–1980s. The tremendous growth in international agricultural trade that developed then fostered the invasiveness of western flower thrips. We examine current knowledge regarding the biology of western flower thrips, with an emphasis on characteristics that contribute to its invasiveness and pest status. Efforts to control this pest and the tospoviruses that it vectors with intensive insecticide applications have been unsuccessful and have created significant problems because of the development of resistance to numerous insecticides and associated outbreaks of secondary pests. We synthesize information on effective integrated management approaches for western flower thrips that have developed through research on its biology, behavior, and ecology. We further highlight emerging topics regarding the species status of western flower thrips, as well as its genetics, biology, and ecology that facilitate its use as a model study organism and will guide development of appropriate management practices.

The economic impact of the greenhouse thrips, Heliothrips haemorrhoidalis (Bouche) (Thysanoptera: Thripidae), has increased on Chilean avocados as a consequence of the high value of the crop and the increased injury to the fruit surface. The population dynamics, phenology, and patterns of aggregation of H. haemorrhoidalis was determined with the objective of rationalizing the use of pesticides using a therapeutic control approach. The study was conducted in 2 avocado fields during 2005 to 2007 in the Valparaiso Region of Chile. New colonies developed on the leaves and small fruits, reaching greatest numbers at the beginning of the winter months. Immature stages were greater in number than the adults during most of the production season. The spatial distribution was calculated using Taylor's power law, showing an aggregated pattern with indices of 1.46 and 1.53 on leaves and fruits, respectively. Pooled data were used to describe the relationship between population density and the proportion of infested leaves and fruit. In the case of a density of about 2 thrips per leaf or fruit, the proportion of infested samples was 0.8. Sample size curves were generated as a function of mean density of thrips with about 20 presence/absence samples needed to estimate densities of 0.5 thrips or more at a precision level of 25%.

Frequent US port of entry quarantine interceptions of unidentifiable larval Leucothrips (Thysanoptera: Thripidae) species in association with Codiaeum variegatum (L.) Rumph. ex A. Juss. (Euphorbiaceae) ornamental plants from Costa Rica, initiated research to determine if these thrips were an invasive threat to US agriculture. Larval and adult Leucothrips were collected from the new growth leaves of C. variegatum and other plants in Florida and Costa Rica. There were no morphological differences among adult specimens from different hosts in Florida and Costa Rica; all identified as Leucothrips furcatus Hood by comparison with type specimens. However, morphological differences in larvae associated with these adult specimens were evident. DNA sequences of the mitochondrial cytochrome oxidase c subunit 1 gene (COI), and 2 regions of the nuclear ribosomal cistron (rRNA; the complete internal transcribed spacer 2 [ITS2], and a section of the 28S large subunit rRNA) were used to verify that larvae and a...

A push-pull strategy for reducing populations of the thrips Frankliniella occidentalis (Pergande), F. bispinosa (Morgan) and F. tritici (Fitch) in tomato was evaluated. Push components consisted of ultraviolet (UV)-reflective mulch and foliar applications of kaolin and the pull component consisted of the companion plant Bidens alba (L.). Replicated field experiments were conducted in 2011 and 2012. Adult and larval thrips were reduced by UV-reflective mulch during early and mid-flowering of tomato. Spray applications of kaolin were effective in reducing adult and larval thrips during early, mid- and late-flowering. The pull effects of the B. alba companion plants were additive and sometimes interactive with the push effects of UV-reflective mulch and kaolin in reducing the adult males of each thrips species and the females of F. bispinosa. The strategy was not effective in reducing the adult females of F. tritici and F. occidentalis. In addition to attracting the Frankliniella species adults, the companion plants were hosts for the thrips predator Orius insidiosus (Say). The companion plants combined with UV-reflective mulch and kaolin proved effective as a push-pull system for suppressing flower thrips, including F. occidentalis which is a serious pest of tomato worldwide.

Few publications exist toward the identification of larval thrips. As a result, researchers and practitioners often are unable to report larval species data or may misinterpret what is a host plant when adults of multiple species are collected. Therefore, we conducted repetitive plant sampling and detailed examination of larvae with adults, which revealed morphological differences of some undescribed Frankliniella (Thysanoptera: Thripidae) larvae. The morphological differences were confirmed by non-destructive DNA extraction, PCR, and sequencing of the COI mitochondrial gene. A larva II morphological key to 7 Frankliniella species found in Florida is presented with new larval descriptions of 4 species.

Environmental factors are hypothesized to account for spatial and temporal differences in Florida in the abundance and distribution of the native thrips species Frankliniella bispinosa (Morgan) and the invasive Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Laboratory experiments were conducted at a constant temperature of 23 ± 1 °C to investigate the effects of humidity on the fecundity and egg incubation of F. bispinosa and F. occidentalis. Adult thrips were allowed to oviposit on green bean (Phaseolus vulgaris L.; Fabaceae) pods. Eggs were maintained at relative humidity treatment levels of 40 ± 5, 55 ± 5, 70 ± 5, and 80 ± 5%. Fecundity and time of egg hatch were determined every 12 h. Results showed that F. bispinosa had a higher fecundity and a shorter time to egg hatch compared with F. occidentalis at higher humidity levels. These results partially explained patterns of abundance and distribution of F. bispinosa and F. occidentalis in Florida. When relative humidity was hi...

Summary The African thrips Ceratothripoides brunneus Bagnall (Thysanoptera: Thripidae) is reported for the first time from North America, collected from flowers of Asystasia gangetica (L.) T. Anderson (Acanthaceae) in Miami-Dade County, Florida. The affinity of C. brunneus for solanaceous plants in other regions of the world suggests that future detection in Florida commercial tomato, pepper, and eggplant production areas is possible. A literature summary of geographic distribution and biology and a morphological description of adults are provided.

Frankliniella invasor is an important pest of mango in Central America; however, information is limited concerning the activity of insecticides with different modes of action. Eight insecticides representing 5 different chemical classes were assayed for control of F. invasor in Costa Rica. The spinosyns, spinetoram, and spinosad were highly active, whereas malathion and α-cypermethrin were the least active. The neonicotinoids imidacloprid and thiamethoxam resulted in intermediate toxicity to this thrips pest. Resumen Frankliniella invasor es una plaga importante del cultivo de mango en Costa Rica. Sin embargo, hasta la fecha se han publicado muy pocos ensayos de toxicologia en esta especie de trips. Se eligieron ocho insecticidas con diferentes modos de accion. Se realizaron dos ensayos toxicologicos consecutivos. Entre los insecticidas probados, las espinosinas (spinetoram y spinosad) fueron las mas eficientes. El malation, α-cipermetrina, fue el menos eficiente. Los neonicotinoides mostraron resultados diferentes con imidacloprid que no logro controlar la plaga F. invasor, y el tiametoxam dio un resultado toxicologico aceptable para esta especie. Key Words: mango; spinosyns; neonicotinoids; Central America View this article in BioOne

The spread of the western flower thrips, Frankliniella occidentalis (Pergande), has resulted in the world-wide destabilization of established integrated pest management programs for many crops. It is hypothesized that frequent exposure to insecticides in intensive agriculture selected for resistant populations, which allowed invasive populations in the eastern USA to overcome biotic resistance from the native community of species. Research conducted in Florida to understand the role of biotic factors in limiting the abundance of the western flower thrips is reviewed. Orius spp. (Hemiptera: Anthocoridae) are effective predators that suppress populations of thrips on crop and non-crop hosts in southern and northern Florida. Orius are more effective predators of the western flower thrips than the native flower thrips, F. tritici (Fitch) and F. bispinosa (Morgan). The native species are competitors of the western flower thrips. Excessive fertilization and the use of broad-spectrum insecticides in crop fields further enhances populations of the western flower thrips. Interactions with native species clearly limit the abundance of western flower thrips in Florida, but populations are abundant in fertilized crop fields where application of insecticides excludes predators and competitor species.

Spanish moss, Tillandsia usneoides (L.) (Poales: Bromeliaceae), is widely distributed in the southeastern United States. A diversity of arthropod species from numerous taxa are known to inhabit this common epiphytic plant. Thysanoptera species inhabiting Spanish moss were sampled monthly over the course of a year from trees in 4 different genera and included 10 species of thrips from 8 genera and 3 families represented. Breeding populations of predatory Karnyothrips (Phlaeothripidae) were common in Spanish moss during all months of the year. The adults of 2 phytophagous species of Frankliniella (Thripidae) were common in the spring months, but only a few larvae were collected over the course of the year. The adults of other species collected were: Heterothrips quercicola J. C. Crawford (Heterothripidae); Chilothrips pini Hood, Neohydatothrips variabilis (Beach), and Selenothrips rubrocinctus (Giard) (Thripidae); and Hoplandrothrips pergandei Hinds and Liothrips ocellatus Hood (Phlaeothripidae). Although a diverse group of phytophagous thrips species inhabited Spanish moss, there was little evidence that it was a host. It may simply have been a temporary shelter with no other biological significance. The predatory thrips were abundant probably feeding on the diverse group of small arthropods that inhabit Spanish moss.

A push-pull strategy for managing the anthophilous Frankliniella bispinosa (Morgan) in pepper and increasing conservation biological control was evaluated. Push components of ultraviolet (UV)-reflective mulch and foliar applications of kaolin and the pull component of sunflower companion plants were evaluated in replicated field experiments in 2011 and 2012. Adult F. bispinosa rapidly colonized and reproduced in the peppers and sunflowers during early flowering, but populations declined later, as numbers of the predatory Orius insidiosus (Say) and Orius pumilio (Champion) increased in both hosts. Numbers of F. bispinosa were reduced by kaolin during early pepper flowering. Thrips numbers were increased on some of the later sample dates, apparently due to reduced predation that resulted from negative effects of kaolin and UV-reflective mulch on Orius populations. Numbers of thrips increased in peppers with companion plants during the first week of flowering each year, followed by declines in thrips numbers during the next 2 wk in 2011. There was little effect each year of the companion plants on the numbers of Orius in the pepper flowers. There was one date in 2011 and no dates in 2012 in which UV-reflective mulch or kaolin acted in concert with the presence of the companion plants to reduce thrips numbers in the main crop of pepper. Yield effects were not attributed to thrips damage. We conclude that sunflower companion plants did not act additively or synergistically with kaolin or UV-reflective mulch to reduce thrips and increase Orius populations in pepper.

Mango cv. ‘Ataulfo’ is perhaps the most popular mango produced in Mexico. The presence of high densities of thrips in mango blossoms, mainly the species Frankliniella invasor Sakimura, has been linked to yield decline. Growers spray synthetic insecticides on a regular basis against thrips to reduce their numbers, but no studies on the effectiveness of these insecticides have been conducted. The present study was undertaken with the objective of assessing the toxicity of 4 insecticides commonly used by growers. Commercial formulations of spinosad, imidacloprid, malathion, and α-cypermethrin were evaluated on adults of F. invasor under laboratory conditions. Six concentrations of each insecticide were assessed: 0.1, 1, 10, 100, 1000, and 10,000 ppm. Snap bean pods were submerged into the different concentrations of insecticides, dried on paper towels, and placed in a plastic container with the thrips adults. A completely randomized design with 10 replicates per treatment was performed. Probit analyses revealed that spinosad and α-cypermethrin were the most toxic insecticides for F. invasor with estimated LC50 values of 0.413 and 0.636 ppm, respectively. No significant differences in toxicity were found between imidacloprid (LC50 = 23.013 ppm) and malathion (LC50 = 34.422 ppm). Mortality in control treatments (distilled water) was never higher than 14%. Our study suggests the use of spinosad and α-cypermethrin as the best control for F. invasor. However, these results should be complemented with field evaluations before being recommended to mango growers. El Mango cv. ‘Ataulfo’ es probablemente el mango mas popular de Mexico. La presencia de altas densidades de trips durante la floracion, principalmente de la especie Frankliniella invasor Sakimura, ha sido vinculada a la baja productividad. Los productores asperjan insecticidas sinteticos de forma regular contra los trips para reducir sus poblaciones, pero no se han llevado a cabo estudios sobre la efectividad de esos productos. El presente estudio se llevo a cabo con el objetivo de evaluar la toxicidad de cuatro insecticidas comunmente usados por los productores. Las formulaciones comerciales del espinosad, imidacloprid, malation, and α-cipermetrina fueron evaluados sobre adultos de F. invasor bajo condiciones de laboratorio. Fueron evaluadas seis concentraciones de cada insecticida: 0.1, 1, 10, 100, 1000, y 10,000 ppm. Para la evaluacion fueron utilizados ejotes, los cuales fueron sumergidos en diferentes concentraciones de insecticidas, secados en papel toalla, y colocados en contenedores de plastico con los trips adultos. Se utilizo un diseno completamente al azar con 10 replicas por tratamiento. El analisis Probit revelo que el espinosad y la α-cipermetrina fueron los insecticidas mas toxicos a F. invasor, con CL50 estimadas de 0.413 y 0.636 ppm, respectivamente. No se detectaron diferencias significativas entre imidacloprid (CL50 = 23.013 ppm) y malathion (CL50 = 34.422 ppm). La mortalidad en el control (agua destilada) no fue mas del 14% de los individuos. Nuestro estudio sugiere el uso del espinosad y la α-cypermethrin para el control de F. invasor. Sin embargo, estos resultados deberan ser complementados con pruebas de campo antes de ser recomendados a los productores. View this article in BioOne

Newer, selective insecticides with few negative impacts on natural enemies and competitor species are needed for effective, sustainable management of the western flower thrips, Frankliniella occidentalis (Pergande). The purpose of this study was to evaluate the impacts on natural enemies and competitor thrips species of insecticides used for control of western flower thrips in fruiting vegetables. Trials with tomato (Solanum lycopersicum L.) and with pepper (Capsicum annuum L.) were conducted to evaluate insecticide treatment effects on western flower thrips and natural enemies at the North Florida in 2008, 2009, 2010 and 2011. A number of insecticides from different classes showed moderate to high efficacy against western flower thrips. The broad-spectrum insecticides acetamiprid, methomyl, and tolfenpyrad demonstrated activity against the pest, while also reducing populations of the key predator of thrips in pepper, Orius insidiosus (Say) (Hemiptera: Anthocoridae). Insecticides that showed litt...

Summary Two Asian species of Thripidae are reported breeding in northern Florida on kudzu (Pueraria lobata), Salpingothrips aimotofus Kudo in the shoots, and Megalurothrips distalis Karny in the flowers, the latter being a new record for North America.

The symbiosis of plants with arbuscular mycorrhizal fungi can improve crop growth by enhancing nutrient uptake and by increasing plant tolerance to certain pests. Pest populations also can be affected, but the effects of mycorrhizal colonization of plant hosts on species of thrips are unknown. We inoculated 2-week-old bell pepper seedling roots with a commercial mycorrhizal mixture of Glomus species (Glomales: Zygomycotina) and evaluated the effects 8 wks later on the bell pepper pest, western flower thrips (Frankliniella occidentalis (Pergande)). Females that were 10-days-old after adult emergence significantly preferred plants inoculated with arbuscular mycorrhizae compared with noninoculated plants in a laboratory choice experiment. Their numbers were greater on inoculated plants 48 h after release into cages containing inoculated and noninoculated plants. A no-choice laboratory experiment compared performance of F. occidentalis on noninoculated and inoculated bell pepper plants. Females that ...

Cassava and cacao are 2 of the most important crops grown in Costa Rica, and also are major sources of income for rural farmers. These crops are frequently attacked by Corynothrips stenopterus Williams and redbanded thrips, Selenothrips rubrocinctus Giard (Thysanoptera: Thripidae). Most farmers who grow these crops apply synthetic insecticides on a calendar basis, but there are no well-established studies on the effectiveness or toxicity of different chemical insecticides on these species of thrips. The objective of this study was to determine the toxicity of 8 insecticides with different modes of action that are used in the control of other thrips species. Commercial formulations of chlorfenapyr, imidacloprid, chlorpyrifos, spinosad, malathion, thiamethoxam, spinetoram, and α-cypermethrin were evaluated on adults of both thrips species under laboratory conditions. Probit analyses showed that spinetoram, spinosad, and chlorfenapyr were the most effective against both thrips species, with median lethal dosages of 50% below 1 μg per mL for both species: 0.12, 0.08, and 0.21 μg per mL for C. stenopterus, and 6 × 10-3, 0.06, and 0.53 μg per mL for S. rubrocinctus . For the other 5 insecticides tested, C. stenopterus had a higher susceptibility than S. rubrocinctus . Among all the insecticides tested, malathion was the least efficacious against both thrips species. The mortality rate in the control treatments never exceeded 10%. The results of this study suggest that spinetoram, spinosad, and chlorfenapyr are the most efficacious insecticides for the control of both thrips species. These results should be complemented with field trials for confirmation. Resumen La yuca y el cacao son dos de los cultivos mas importantes que se siembran en Costa Rica y tambien son una importante fuente de ingresos para la mayoria de los agricultores rurales. Estos cultivos son atacados frecuentemente atacados por Corynothrips stenopterus Williams (yuca) y trips de banda roja Selenothrips rubrocinctus Giard (ambos Thysanoptera: Thripidae) (cacao). La mayoria de los agricultores que se dedican a la produccion de estos cultivos aplican insecticidas sinteticos con regularidad contra estos trips, pero no existen estudios bien establecidos sobre la efectividad o toxicidad de los diferentes insecticidas quimicos en estas especies de trips. Por lo tanto, se realizo el presente estudio con el objetivo de determiner la toxicidad de 8 insecticidas con diferentes modos de accion que se utilizan en el control de otras especies de trips. Las formulaciones comerciales de chlorfenapyr, imidacloprid, chlorpyrifos, spinosad, malathion, thiamethoxam, spinetoram y α-cipermetrina se evaluaron en adultos de ambas especies de trips en condiciones de laboratorio. Se usaron las siguientes 6 concentraciones de cada uno de los 8 insecticidas; 0, 1, 1.0, 10, 100, 1,000 y 10,000 ppm. Se utilizo un diseno completamente aleatorizado y cada tratamiento tuvo 5 repeticiones. Los analisis Probit mostraron que spinetoram, spinosad, y chlorfenapyr fueron los mas efectivos contra ambas especies de trips con LD50 por debajo de 1 μg por ml para ambas especies (0.12, 0.08 y 0.21 μg por mL) respectivamente para Corynothrips stenopterus y (6.10-3, 0.06 y 0.53 μg por mL) respectivamente para Selenothrips rubrocinctus . Los otros 5 insecticidas evaluados indicaron que C. stenopterus tenia una susceptibilidad mas alta que S. rubrocinctus . Entre todos los insecticidas probados, malathion fue el menos eficaz contra ambas especies de trips. La tasa de mortalidad en los tratamientos de control (con agua destilada) nunca excedio el 10%. Este estudio sugiere que spinetoram, spinosad, y chlorfenapyr son los mas eficientes para el control de ambas especies de trips. Sin embargo, estos resultados deberian completarse conensayos de campo para su confirmacion. View this article in BioOne

BACKGROUND:Thespreadofthewesternflowerthrips,Frankliniellaoccidentalis(Pergande)(Thysanoptera:Thripidae),resulted in the worldwide destabilization of established integrated pest management programs for many crops. Efforts to control the pest and the thrips-vectored tospoviruses with calendar applications of broad-spectrum insecticides have been unsuccessful. The result has been a classic ‘3-R’ situation: resistance to numerous insecticides; resurgence of the western flower thrips populationsasaresultofnaturalpredatorsandnativecompetitorthripsbeingeliminated;replacementbyvariousotherpests. Thispaperreportsonintegratedpestmanagementprogramsforfruitingvegetablesthatareeffective,economical,ecologically sound and sustainable. RESULTS: The components include the following: define pest status (economic thresholds); increase biotic resistance (natural enemiesandcompetition);integratepreventiveandtherapeutictactics(scouting,ultraviolet-reflectivetechnologies,biological control,compatibleinsecticides,companionplantsandfertility);verticallyintegratetheprogramswithotherpests;continually communicate latest science-based management tactics with end-users. CONCLUSION: These programs have been widely implemented in Florida and have significantly improved the management of western flower thrips and thrips-transmitted viruses. c � 2012 Society of Chemical Industry

‘Ataulfo’ mango (Mangifera indica L.) is the most popular cultivar of mango to have originated in Mexico. Because of its relatively recent discovery, few studies have been carried out on the best agricultural practices for production of this cultivar, and there is wide variation in methods among growers. Among other aspects, the insect fauna associated with this cultivar has not been formally studied. However, numerous growers spray synthetic insecticides on a regular basis against thrips to reduce populations. The present study was conducted with the main objective of determining the diversity of thrips in Ataulfo mango flowers in Chiapas, Mexico. Two representative orchards were selected: the orchard “Tres-A” characterized by an intensive use of agrochemicals, especially broad-spectrum synthetic insecticides directed against thrips, and the orchard “Rancho La Escondida” that does not spray insecticides. Inflorescences were sampled every five days, from Nov 2008 to Feb 2009. The results confirm ...

The western flower thrips, Frankliniella occidentalis (Pergande); flower thrips, Frankliniella tritici (Fitch); and tobacco thrips, Frankliniella fusca (Hinds), are abundant, polyphagous species in the southern United States. Paspalum notatum Flugge and Paspalum distichum L. (Poales: Poaceae) are low-maintenance, warm-climate, tolerant grasses that are used for pasture and residential lawns and along roadsides. The potential of P. notatum and P. distichum to serve as sources of the common polyphagous Frankliniella thrips in the southeastern United States was evaluated. The abilities of F. fusca, F. occidentalis, and F. tritici to survive and reproduce on vegetative-stage P. distichum, P. notatum ‘Argentine’, P. notatum ‘Pensacola’, and P. notatum ‘Tifton 9’ were compared in laboratory no-choice tests. Survival of the adults of each thrips species was ≈20% after 12 d on each of the Paspalum treatments. No progeny were produced by F. occidentalis on the U.S. native P. distichum, and the other thrips species produced very few progeny on this host. The number of progeny of each thrips was very low on all P. notatum cultivars. A field survey of the Thysanoptera associated with P. notatum Argentine also was conducted to determine whether the Frankliniella thrips were feeding or reproducing under field conditions. A few male and female adults of F. tritici and F. fusca were noted in the racemes, but larval populations were not observed. Reproducing populations of Caprithrips insularis Beshear and Haplothrips graminis Hood were present in the stems and leaves, and the racemes, respectively. Collectively, the laboratory and field studies revealed that the tested P. notatum cultivars and P. distichum accession are poor hosts for reproduction of the Frankliniella thrips in the southern United States and that the large plantings of these grasses are not serving as sources of pest Frankliniella thrips.

Anthophilous flower thrips in the genus Frankliniella (Thysanoptera: Thripidae) exploit ephemeral plant resources and therefore must be capable of successfully locating appropriate hosts on a repeated basis, yet little is known of interspecific and intraspecific variation in responses to host plant type and nutritional quality. Field trials were conducted over two seasons to determine if the abundance of males and females of three common Frankliniella species, F. occidentalis (Pergande), F. tritici (Fitch) and F. bispinosa (Morgan), their larvae, and a key predator, Orius insidiosus (Say) (Hemiptera: Anthocoridae) were affected by host plant type and plant nutritional quality. Two host plants, pepper, Capsicum annuum L. (Solanales: Solanaceae) and tomato, Solanum lycopersicum L. that vary in suitability for these species were examined, and their nutritional quality was manipulated by applying three levels of nitrogen fertilization (101 kg/ha, 202 kg/ha, 404 kg/ha). F. occidentalis females were more abundant in pepper than in tomato, but males did not show a differential response. Both sexes of F. tritici and F. bispinosa were more abundant in tomato than in pepper. Larval thrips were more abundant in pepper than in tomato. Likewise, O. insidiosus females and nymphs were more abundant in pepper than in tomato. Only F. occidentalis females showed a distinct response to nitrogen fertilization, with abundance increasing with fertilization. These results show that host plant utilization patterns vary among Frankliniella spp. and should not be generalized from results of the intensively studied F. occidentalis. Given the different pest status of these species and their differential abundance in pepper and tomato, it is critical that scouting programs include species identifications for proper management.

1. Species invasions are often linked to reductions in biodiversity, and competitive superiority is often cited as the main reason for the success of an invasive species. Although invaded ecosystems are often examined, few have studied areas in which an invasive species has failed to successfully invade. 2. The western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is a damaging pest and tospovirus vector that has invaded most of the world, and competitive superiority is considered one of the main reasons for this species' success. 3. However, a recent study demonstrated that competition between larval F. occidentalis and a native thrips species may be limiting F. occidentalis abundance in much of the eastern United States. Frankliniella occidentalis also has a limited abundance in central and southern Florida, which is dominated by the endemic F. bispinosa (Morgan). The potential for interspecific competition to limit F. occidentalis abundance in Florida was assessed. 4. The effects of competition between F. occidentalis and F. bispinosa on adult reproduction on a common host (Capsicum annuum L.) were quantified, using a response surface experimental design and a combination of linear and non-linear competition models. 5. Evidence of symmetric competition between these thrips species was found, but contrary to expectations, F. occidentalis reproduced more in dense interspecific populations than F. bispinosa. These results suggest that, unlike most of the eastern US, interspecific competition is not important in limiting F. occidentalis abundance in central and southern Florida.

Frankliniellafusca (Hinds) (Thysanoptera: Thripidae) is the predominant thrips species found inhabiting and reproducing in peanut, Arachis hypogaea L. (Fabaceae), and is one of at least seven thrips species reported to transmit Tomato spotted wilt virus (TSWV). The entomogenous nematode Thripinema fuscum Tipping & Nguyen (Tylenchida: Allantonematidae), a natural enemy of F. fusca, parasitizes larval and adult populations under field conditions. All known Thripinema species render the host female thrips sterile and have the potential to suppress pest populations to near extinction. As a result, secondary spread of TSWV in peanut is reduced. Reduction of the virus under field conditions may also be due to lower transmission rates caused by parasite-induced alterations in host feeding behavior. Therefore, the feeding rates of healthy and parasitized F. fusca male and female cohorts on leaf discs were recorded daily for 10 days and digital images were subjected to image analysis and viral transmission rates were compared daily using double antibody sandwich enzyme-linked immunosorbent assay. Thripinema fuscum reduced the feeding of female F. fusca by nearly 65%, and the ability of females to transmit TSWV by 50%. Potential mechanisms underlying the parasite-induced alterations in feeding behavior and transmission are discussed. Parasitism by T. fuscum significantly reduced male longevity, but female longevity was not affected. These results provide further evidence that T. fuscum aids in regulating viruliferous F. fusca pest populations and suggests its potential as a biological control agent for inoculative release in peanut.

Cotton hardlock caused by Fusarium verticillioides (Sacc. Nirenberg) can reduce cotton, Gossypium hirsutum L., yields >70% in the southeastern United States. The spores infect flowers on the day of pollination, resulting in hardlock, which is the failure of the fiber to fluff as the boll opens at maturity. Frankliniella spp. Thrips (Thysanoptera: Thripidae) inhabiting the flowers are hypothesized to increase hardlock by spreading the conidia or by creating entranceways for the germinating Fusarium conidia. Experiments were conducted at Marianna and Quincy in Florida in 2006 and 2007 to determine whether there was a relationship between the number of adult and larval thrips inhabiting the flowers of cotton and the incidence of cotton hardlock. Frankliniella tritici (Fitch) was >98% of the adult thrips in the samples at both locations each year. The adults of Frankliniella bispinosa (Morgan) and Frankliniella occidentalis (Pergande) also were collected. There were no significant regression relationships between weekly mean densities of thrips in the flowers and the incidence of cotton hardlock at harvest in any of the experiments. Additional experiments were conducted at each location in 2006 and 2007 to determine whether weekly applications during flowering of the insecticide lambda-cyhalothrin, the fungicide thiophanate methyl, and the combination of the two reduced the incidence of cotton hardlock at harvest. Applications of the insecticide significantly reduced the numbers of adult F. tritici, the number of thrips larvae, and the incidence of hardlock at harvest. Applications of the insecticide were as affective as applications of the insecticide plus fungicide. In one experiment, applications of the fungicide reduced the incidence of hardlock at harvest. Applications of the insecticide usually significantly increased the number of adult F. occidentalis. None of the pesticide treatments significantly affected the numbers of the key thrips predator Orius insidiosus (Say). We conclude that insecticidal control of the adults and larvae of F. tritici during flowering reduced the incidence of cotton hardlock. However, there were no significant regression relationships between the incidence of cotton hardlock at harvest and the number of thrips in the flowers.

Populations of the invasive Frankliniella occidentalis (Pergande) are serious pests of agricultural crops in the Aconcagua Valley of central Chile. An extensive survey was conducted of 55 plant species in 24 families to identify plant hosts of F. occidentalis and to determine its relative abundance on each host during each season. A more intensive study was conducted on selected plant species serving as reproductive hosts to determine the population dynamics of F. occidentalis and to evaluate the potential importance of Orius species and other natural enemies for controlling F. occidentalis. Adults of F. occidentalis were active during each season of the year inhabiting the flowers of 91% of the sampled plant species in 22 families, and 86% of these plant species in 19 families served as reproductive hosts. The number of host plant species used was greatest in the spring and least in the winter. All of the hosts except Medicago sativa L. were used only when flowering. Populations of F. occidentalis were significantly aggregated in M. sativa in the terminal buds over the leaves when the host was not flowering, and in the flowers, followed by the terminal buds, followed by the leaves when the host was flowering. Larvae were 1.3-2.3 times more abundant on dates when M. sativa was flowering. There were no identifiable patterns in plant hosts based on endemicity or plant family. Most of the plant species used by F. occidentalis were inferior quality hosts where populations either declined or were stable. Populations of F. occidentalis on low-quality hosts generally escaped predation by Orius species and competition by other species of thrips. Only 25% of the food hosts and 28% of the reproductive hosts for F. occidentalis in the extensive survey, respectively, were host plants for Orius. Parasitoids and other predators were not found to be important in suppressing thrips on any of the plant hosts. Populations of F. occidentalis increased on only a few hosts, including M. sativa and Sisymbrium officinale L. Scop. These apparently are major sources of F. occidentalis adults invading crops. We conclude that F. occidentalis is established in central Chile and that it has replaced and possibly displaced the native Frankliniella australis (Morgan) as the most common thrips species.

Feeding by the western flower thrips, Frankliniella occidentalis (Pergande), causes damage to the fruits of vegetables, and the species is the key vector of Tomato spotted wilt virus. Frankliniella tritici (Fitch) and Frankliniella bispinosa (Morgan) are not pests of fruiting vegetables. Both species compete with F. occidentalis. Effective management of F. occidentalis in pepper integrates conservation of natural populations of the predator, Orius insidiosus (Say), with the use of reduced-risk insecticides such as spinetoram for the control of western flower thrips and other pests. Naturally occurring O. insidiosus are very effective predators and their effectiveness is predictable based on the number of the predator relative to the number of thrips prey. Populations of F. occidentalis resurge when natural enemies and competing thrips are killed. Some insecticides especially pyrethroids have beneficial effects on the development and reproduction of F. occidentalis. The predator O. insidiosus does...

All parties involved in growing the world's food, including growers, crop consultants, university researchers, extension personnel, national and regional regulatory agencies, and the agrochemical and seed industry, spend significant time, money, and effort to solve the problems associated with growing food. The needs of these parties are varied and sometimes in conflict, which is not always conducive to developing and implementing integrated pest management (IPM) systems that are both sustainable and economical. IPM encompasses simultaneous management of multiple pests, regular monitoring of pests and their natural enemies and antagonists, use of economic or treatment thresholds when applying pesticides, and integrated use of multiple, suppressive tactics. IPM components with the greatest impact on resistance management are rotating classes of chemistry, use of recommended rates, not exceeding label restrictions, and avoiding sequential treatments of products with the same mode of action. The best way to insure that these components are followed is to have pesticide record keeping and reporting. However, pesticide use record keeping and reporting are not currently required in all areas. Other activities that can be integrated include educational workshops on IPM, resistance monitoring of pests to pesticides, proper identification of pests and natural enemies, real time scouting reports on the pests that are being found, maintenance of a data base on the effects of various products on natural enemies, and field validation of IPM use.

Frankliniella spp. (Thysanoptera: Thripidae) thrips damage a variety of crops, feed on a broad range of hosts, and often migrate into cropping systems from adjacent vegetation. To determine potential sources of Frankliniella spp. thrips on crops, annual cycles of abundance of Frankliniella occidentalis (Pergande), Frankliniella fusca (Hinds), Frankliniella bispinosa (Morgan), and Frankliniella tritici (Fitch) were evaluated on seven common, uncultivated reproductive hosts. These hosts included Raphanus raphanistrum L., Rubus trivialis Michx., Rubus cuneifolius Pursh., Vicia sativa L., Trifolium repens L., Solidago canadensis L. and Chenopodium ambrosioides L. Thrips were collected from R. cuneifolius, and T. repens in the spring, R. raphanistrum in the summer, and C. ambrosioides and S. canadensis in the fall. The most common Frankliniella species on every plant species was F. tritici, and a fifth species, Pseudothrips inequalis (Beach), was collected in the fall on C. ambrosioides and S. canadensis. All thrips species were highly aggregated in the flowers or flower racemes, rather than leaves or fruit, and they were generally only collected from flowering plants. R. raphanistrum supported large populations, and they may be an important link for thrips between spring and fall. In addition, it may be an essentially enemy free host, as only one O. insidiosus, an important thrips predator, was collected from this host. S. canadensis also supported large thrips populations in the fall, and it may be a source of thrips migrating into crops the following spring. Controlling thrips on these hosts in their respective seasons may limit the number migrating into cropping systems.

A survey was conducted to identify the thrips species associated with native terrestrial orchids in northern Florida. The above-ground plant structures were sampled when each species was flowering yielding adults of polyphagous species of the common flower thrips Frankliniella tritici (Fitch), Frankliniella fusca (Hinds), and Microcephalothrips abdominalis (Crawford). There is little indication that the orchids were reproductive hosts of these species. Other species of thrips that are more host-specific to orchids were collected and included adults of the orchid-living species Aurantothrips orchidaceus (Bagnall) and Pseudothrips beckhami Beshear and Howell. The presence of larvae of P. beckhami indicated the suitability of at least some orchid species as reproductive hosts. The adults of 2 predatory species in the Family Phlaeothripidae also were collected, Leptothrips mali(Fitch) and Karnyothrips melaleucus (Bagnall).

Crapemyrtle is a common landscape planting that is a resource subsidy for beneficial insects. Field studies were conducted to determine the influence of crapemyrtle flower color on the population abundances and predator-prey dynamics of the herbivorous Frankliniella species and the predator Orius insidiosus. Adults and immatures of predator and prey were highly anthophilous, preferring white 'Acoma' flowers compared with lavender 'Apalachee', red 'Carolina Beauty', and pink 'Choctaw'. The predator was aggregated with its prey in a density-dependent manner: the adults by preferring the crapemyrtle clones also preferred by the thrips and the nymphs by direct tracking or as a function of increased prey and fecundity. Acoma was best for preference and buildup of O. insidiosus populations, and it was the only clone where there was no buildup in thrips populations. Two species of Karnyothrips (Thysanoptera: Phlaoethripidae), predators of small insects, were common in Tillandsia usneoides, an epiphyte on the crapemyrtle. Crapemyrtle is a bridge to enhance populations of O. insidiosus during summer months when there are few other hosts in the southern USA.

We investigated interactions between the generalist predator Orius insidiosus (Say) (Heteroptera: Anthocoridae) and two species of thrips prey, Frankliniella bispinosa (Morgan) and Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), and interspecific differences in morphology and behavior between these prey species that could contribute to differences in predation by O. insidiosus . Frankliniella occidentalis is significantly larger than F. bispinosa . Frankliniella bispinosa has greater mobility compared with F. occidentalis . When O. insidiosus was offered either F. bispinosa or F. occidentalis as prey in single species trials, there were no significant differences in the number of prey captured. However, O. insidiosus had significantly more encounters with F. bispinosa than with F. occidentalis . In arenas with equal numbers of both species, O. insidiosus encountered and captured F. occidentalis more than F. bispinosa . In large arenas with two pepper plants ( Capsicum annuum L.), O. insidiosus preyed on more F. occidentalis than on F. bispinosa . These results indicate that O. insidiosus can prey on both thrips species, but that it preferentially captures F. occidentalis . The greater locomotion and movement of F. bispinosa , perhaps combined with its smaller size, allow it to evade predation by O. insidiosus better than F. occidentalis . Consequently, the observed preference of O. insidiosus for F. occidentalis is not exclusively a function of active selection by the predator but also could arise from inherent differences among prey. We propose this differential predation as a mechanism contributing to observed differences in the temporal dynamics of these species in pepper fields.

Frankliniella occidentalis is the key vector responsible for the emergence of Tomato spotted wilt virus as a global threat to agriculture. Frankliniella bispinosa is a common thrips in Florida, the Bahamas, and Bermuda, but the role of F. bispinosa in the epidemiology of the virus is not known. The purpose of this study was to determine the ability of F. bispinosa to acquire and transmit Tomato spotted wilt virus in pepper. In laboratory experiments, the number of larvae produced per F. bispinosa female was less than the number of larvae produced per F. occidentalis female. The larvae of F. bispinosa successfully acquired Tomato spotted wilt virus, although at a lower percentage than F. occidentalis. Viruliferous adults of both species transmitted the virus to pepper. Our results confirm the competence of F. bispinosa as a vector of Tomato spotted wilt virus.

A biologically based integrated pest managefor pepper by Funderburk et al. (2000) and Reitz et ment program is fundamental in preventing al. (2003). Experimental design was a randomized the development of insecticide resistance, recomplete block, with 4 replications. Plot size was 1 surgence of populations of western flower thrips, raised, plastic mulched bed 9 m long on which there Frankliniella occidentalis (Pergande) (Thysanopwere 2 linear rows of pepper with a 13.8-cm plant tera: Thripidae), and replacement with nontarget spacing between and within rows for a total of 48 pest damage (Demirozer et al. 2012). The conservaplants per plot. Beds were irrigated with a single tion biological control component of the integrated trickle tube with emitters spaced every 30 cm at a pest management program is the most effective rate of 20,000 Ivha/day. Dates and rates of insecti way to manage thrips in pepper (Capsicum spp.; cide applications and of insect sampling are includ Solanales: Solanaceae) (Reitz et al. 2003). Species ed in Table 1. Foliar insecticides were applied with a of Anthocoridae are the most important worldwide C02-powered backpack sprayer equipped with 4 D7 predators of thrips. Within this family are minute nozzles with the amount of spray 430 L/ha. Drench pirate bugs with 2 species in Florida, Orius insidiotreatments were applied in a water solution of 200 sus (Say) and O. pumilio (Champion) (Hemiptera: mL/plant. Trickle tube treatments were applied in Anthocoridae). The minute pirate bugs are a valua water solution of 5.7 L/plot with a C02-powered able tool for controlling thrips as they prey preferinjector pressurized to 103 kPa, followed by 8 L of entially on the adults of the western flower thrips clean water rinse. Inline connectors with shut-off over the adults of the non-damaging native thrips valves were used to isolate the plots. Ten flowers species, F. tritici (Fitch) and F. bispinosa (Morgan) per plot (whenever possible) were collected on each (Baez et al. 2004). The damaging thrips larvae also of 6 sample dates and preserved in 70% alcohol with are preferred prey (Baez et al. 2004). About 1 minthe number of thrips and O. insidiosus determined ute pirate bug for every 180 thrips is sufficient for using 7 to 100 X magnification. The data for each suppression of the populations of thrips, and at a sample was converted to number per flower, pooled ratio of about 1 predator to 40 thrips, thrips populaover date, and transformed to log (x + 0.5) for anal tions are controlled (Funderburk et al. 2000). Natuysis of variance. When the overall treatment effect ral populations of minute pirate bug adults rapidly was significant at the P = 0.05 level, orthogonal invade pepper fields in sufficient numbers to control comparisons were used to separate treatment dif western flower thrips adults and larvae, but they ferences. Untransformed means per 10 flowers are must be conserved with judicious insecticide use reported in Table 1. (Funderburk et al. 2000, Demirozer et al. 2012). The adults of F. occidentalis and F. tritici ac An integrated pest management program for counted for 6 and 19% of the total thrips in the rm peppers that encompasses the simultaneous mantreated controls and there were no significant treat agement of multiple pests is being developed and ment differences (data not shown). The numbers of implemented (Demirozer et al. 2012). Ta further thrips were well below the economic thresholds es enhance the effectiveness of the conservation biotablished by Demirozer et al. (2012), with the ratio logical control component of this program, updated of predators in relation to prey sufficient in the cm information on insecticides labeled for fruiting vegtreated plots to result in thrips suppression. There etables against thrips or other pests that have little were treatment differences in the number of F. impact on populations of minute pirate bugs was bispinosa females, thrips larvae, and O. insidiosus reported (Funderburk et al. 2011). In the present nymphs (Table 1). When compared to the untreat report, imidacloprid 4.6SC (Bayer Crop Protection, ed control, 2 applications of cyantraniliprole 20SC Research Triangle Park, North Carolina) and cyanin the trickle tube did not reduce the numbers of traniliprole 10SE and 20SC (DuPont Crop Protecthrips or O. insidiosus in the flowers. However, the tion, Newark, Delaware) were evaluated against 2 applications of cyantraniliprole 20SC combined populations of thrips and minute pirate bugs, with a transplant treatment of imidacloprid 4.6SC Spinetoram SC (Dow AgroSciences, Indianapolis, resulted in 94, 82, and 88% reductions in numbers Indiana) was included as a standard foliar treatof F. bispinosa adults, thrips larvae, and O. insid ment. iosus nymphs, respectively. Unless there are unex Experimental procedures to evaluate the treatpected synergistic effects, this result showed that ment effects on adult and immature O. insidiosus the residual effect of a transplant application of and flower thrips were similar to those established imidacloprid lasted through pepper flowering and

We compared predation of Orius insidiosus (Say) on adult and second instars of Frankliniella occidentalis (Pergande) and on adults of F. occidentalis and F. tritici (Fitch) in arenas with pepper flowers. Also, we compared the dispersal of these thrips in the presence and absence of the predator. For each experiment, two densities of thrips (10 and 20 total thrips) and two time exposures (10 and 34 h) were tested. Second instars were more likely to move from the flower where they were released than were F. occidentalis adults. F. tritici dispersed more than F. occidentalis. The presence of the predator enhanced movement by thrips from flowers in which they were released. Despite differences in prey movement, O. insidiosus successfully preyed on all types of prey that were offered. However, O. insidiosus appeared to deal differently with each type of prey. Predation of both larvae and adults was most likely to occur inside flowers. In trials with adults and second instars of F. occidentalis, larvae...

Summary Bittersweet nightshade, Solanum dulcamara L. (Solanales: Solanaceae), was sampled at numerous locations in Washington and Idaho. Adults of 8 species of thrips (Thysanoptera) from 3 families were collected, including the worldwide plant pests Frankliniella occidentalis (Pergande) and Thrips tabaci Lindeman (Thripidae), which are vectors of the serious plant viruses in the genus Tospovirus. Aeolothrips fasciatus Hinds (Aeolothripidae), a predator of small insects, also was collected.

We evaluated the within-plant distribution of Frankliniella spp. and the predator Orius insidiosus (Say) in pepper (Capsicum anuum L.), over a range of field conditions, and we conducted behavioral experiments to examine the time budgets of F. occidentalis (Pergande) and F. tritici (Fitch) females on pepper plant parts. In the field experiments Frankliniella species composition varied by season and location. Still, all populations of thrips and O. insidiosus in untreated and insecticide-treated pepper were highly concentrated in the flowers, with 82–99% of individuals of each taxa found in flowers. This preference for flowers was corroborated by laboratory-choice experiments. Adult females of F. occidentalis and F. tritici showed a strong preference for pepper flowers over leaves and buds. In laboratory observations, females of F. occidentalis spent 3.6× as much time on flowers as on all other plant parts, and females of F. tritici spent over 6.3× as much time on flowers as on all other plant par...

In a 2-yr study, the impacts of different plastic soil mulches, insecticides, and predator releases on Frankliniella thrips and their natural enemies were investigated in field-grown peppers. Ultraviolet light (UV)-reflective mulch significantly reduced early season abundance of adult thrips compared with standard black plastic mulch. This difference diminished as the growing seasons progressed. Late season abundance of thrips larvae was higher in UV reflective mulch compared with black mulch plots. The abundance of the predator Orius insidiosus (Say) was significantly lower in UV-reflective mulch compared with black mulch treatments. Infection of plants with tomato spotted wilt virus, a pathogen vectored by Frankliniella occidentalis (Pergande), was

Thripinema khrustalevi (Chizov et al.) isolate Chile, a parasite of Frankliniella australis (Morgan), was collected from Cestrum parqui (L’Herit.) in the Aconcogua Valley of central Chile. Percent infection of males and females of F. australis by T. khrustalevi in the flowers of C. parqui was estimated biweekly for two years at three locations, including the La Campana National Park. Males were less infected than females. Numbers of F. australis adults and larvae in the flowers of C. parqui were greatest in the winter and early spring when parasitism of the adult females was low. Populations declined in late spring when parasitism was high. Parasitism remained high through the summer and fall, and populations of thrips remained very low. Highest parasitism of the females and males of F. australis was 84 and 60%, respectively.

We investigated the effects of ultraviolet (UV)-reflective mulch and two rates of nitrogen fertilization on populations of Frankliniella spp. thrips and on the incidence of tomato spotted wilt in field-grown tomato in northern Florida. The higher of the two soil nitrogen fertilizer treatments significantly increased populations of Frankliniella occidentalis (Pergande), whereas mulch reflectance significantly decreased populations of F. occidentalis. Populations of Frankliniella tritici (Fitch) were decreased only by UV-reflective mulch. Decreased thrips populations in UV-reflective mulch plots were probably due to disruptions in host-finding behavior. Increased thrips populations in tomatoes treated with the higher nitrogen fertilization rate were probably due in part to increased nutrients available in flowers. Incidence of tomato spotted wilt was significantly decreased in tomatoes grown on UV-reflective mulch, whereas disease incidence was significantly greater in increased nitrogen-fertilized plots. This research reveals that cultural practices resulted in up to 45% reduction in the numbers of vector and nonvector species of flower thrips and up to 50% reduction in tomato spotted wilt.

Frankliniella fusca (Hinds) is a species of thrips that is a pest of peanuts and an important vector of tomato spotted wilt virus. In previous research, populations of thrips declined in peanut during midseason for unexplained reasons. Nematodes in the genus Thripinema are parasites of thrips that render infected females sterile. A new species, T. fuscum Tipping & Nguyen, was recently described as a parasite of F. fusca in peanut. In 1997 and 1998, the temporal changes in percent parasitism of F. fusca in plots of peanuts were determined. Parasitism of adult female thrips increased from an estimated 1% on seedling peanut each year to a maximum of 68% later in the 1997 growing season and 38% in the 1998 growing season. Treatments of several insecticides for control of thrips reduced percent parasitism of the females on most sample dates in 1997, but parasitism was not significantly affected in 1998. Estimates of the numbers of F. fusca in the flowers and terminal buds of peanuts declined each year as parasitism increased. The very high levels of parasitism in 1997 were associated with near extinction of larval populations of thrips during midseason. As a result, the spread of tomato spotted wilt virus by this vector species was reduced. Thus, T. fuscum may be an important natural enemy of F. fusca responsible for suppression of populations of thrips in peanut.

Continuous generations of Frankliniella occidentalis (Pergande) and F. fusca (Hinds) develop through the winter and spring in northern Florida on plant hosts such as hairy vetch, Vicia villosa Roth. Previously reported research compared development under field conditions of these thrips to predictions of temperature-dependent developmental models obtained in laboratory experiments and concluded that accumulated degree-days of ambient temperatures recorded at a nearby national weather station underestimated development of populations developing under field conditions. Thus, the objective of this study was to compare ambient temperatures to microclimate temperatures in V. villosa plots and its effect on thrips development. An electronic data logger was used in this experiment to continuously record over 63 d ambient, upper plant canopy, middle plant height, lower plant height, and soil temperatures in plots of V. villosa. The microclimatic temperatures and their degree-day accumulations, based on daily maximum and minimum records, were significantly greater (P= 0.05) than the ambient temperature and degree-day accumulations obtained from a nearby National Oceanic and Atmospheric Administration (NOAA) weather station. There were no significant differences in mean temperature and degree-day accumulations within the upper, middle and lower portions of V. villosa plants. Based on degree-day accumulations in the upper plant canopy, 3.1 generations were predicted for F. occidentalis and 2.4 generations for F. fusca during the study. However, using the NOAA degree-day accumulations, only 2.5 and 1.9 generations were predicted, respectively. During this study, an accumulated discrepancy of 3/4 of a generation was calculated for F. occidentalis and more than half of a generation for F. fusca between the NOAA weather data and the microclimate data. Thus, ambient temperatures obtained from the NOAA weather station would underestimate development, as was observed and reported previously. The results demonstrated the importance of using microclimatic measurements, rather than ambient records, for best estimating developmental potential of thrips.

In a 2-year study, we manipulated flower chemistry of field grown Lycopersicon esculentum in North Florida and examined subsequent effects on populations of Frankliniella occidentalis. We examined variation in amino-acid profiles and total nitrogen concentrations of flowers, flower number and plant size seasonally and in response to variable rates of nitrogen fertilization (202 kg ha -1 and 309 kg ha -1 ). Populations of F. occidentalis sampled every 6 to 10 days were then related to seasonal and treatment effects on plant variables. For both years, F. occidentalis was abundant on L. esculentum tomatoes for only short intervals (2-3 weeks), and populations were significantly higher on hosts receiving higher rates of nitrogen fertilization. Seasonal trends in F. occidentalis on L. esculentum were correlated to number of flowers per host plant, as well as concentrations of total nitrogen in flowers. Moreover, treatment (fertilization) effects were consistent with changes in the nitrogen status of flowers. Plants subjected to higher fertilization rates produced flowers that had higher nitrogen content as well as variations in amino-acid profiles during the period of peak thrips populations. Abundance of F. occidentalis (particularly adult females) were most highly correlated to flower concentrations of phenylalanine during population peaks. Our results are consistent with beneficial effects of high dietary nitrogen to thrips populations, and also support the hypothesis that aromatic amino acids (e.g., phenylalanine) play a central role in the nutritional ecology of F. occidentalis.

The detection of species and strains of baculoviruses in natural field insect populations facilitates ecological studies, risk assessment evaluation and quality control programs where wild type and/or recombinant baculoviruses are used. The polymerase chain reaction (PCR) was evaluated as a detection tool for determining viral persistence and spread in Anticarsia gemmatalis Hubner and predatory hemipteran populations in fields of soybean, Glycine max (L.) Merril. Two isolates of the A. gemmatalis nucleopolyhedrovirus (AgMNPV-2D and AgMNPV-D7) were applied individually and mixed in replicated field plots. The insect populations were sampled 1, 10, 15, 30, and 45 d after viral application and taken to the laboratory for PCR analysis. PCR analysis targeted the coding region of the viral polyhedrin gene and the highly variable homologous region 4 (hr4 region). The size of the expected products was 575 base pairs (bp) for the polyhedrin-PCR, and 1,726 bp (AgMNPV-2D) and 1,345 bp (AgMNPV-D7) for the hr4 region. The virus was detected in A. gemmatalis larvae and predators collected on all sample dates by PCR amplification of the polyhedrin region. AgMNPV was detected in the host and predator populations 1–45 d after application in the field. Virus movement into the control plots indicated that AgMNPV dispersed at a rate of 2–3 m per day. PCR amplification of the hr4 region was effective in distinguishing between AgMNPV-2D and AgMNPV-D7 isolates. The polymerase chain reaction proved to be a useful tool in ecological studies of this baculovirus.

Flower thrips, Frankliniella spp., are important pests of tomatoes, Lycopersicon esculentum Mill., throughout the mid-Atlantic region. Several species cause direct damage to the leaves and fruits, and species such as the western flower thrips (WFT), F occidentalis (Pergande), and the tobacco thrips, E fusca Hinds, also vector tomato spotted wilt virus (Zitter et al. 1989). Damage caused by F occidentalis to tomato can appear in several forms. In greenhouses, E occidentalis will feed on the leaves of young transplants, causing a spotting and desiccation of the leaves. Sclar (2000) states that E occidentalis are attracted to pollen sources, and will feed extensively on flower tissues and degrade flower quality. This results in reduced length of bloom and flower tissue damage. Salguero Navas et al. (1991) report that small indentations appear in tomato fruit from female oviposition, and these indentations are sometimes surrounded by a light-colored halo. This damage can result in rejection of fruit and lowering of grade. Although originally reported in the southwestern portion of the United States, WFT was first reported along the east coast in Georgia in 1981 (Beshear 1983). It is now present throughout the east coast, including New Jersey. Cosmetic damage to tomatoes, appearing as 'goldflecking' and or goldfleck rings on red tomatoes, began to occur simul