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Thrips-infesting soybeans were considered of minor economic importance, but recent evidence of their ability to transmit a newly identified soybean virus, Soybean vein necrosis virus (SVNV), has raised their profile as pests. Season-long surveys were conducted using suction traps to determine the effects of temperature and precipitation on the spatiotemporal patterns of three vector species of SVNV, Neohydatothrips variabilis (Beach) (Thysanoptera: Thripidae) (soybean thrips), Frankliniella tritici (Fitch) (Thysanoptera: Thripidae) (eastern flower thrips), and Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) (tobacco thrips) in soybean fields in Indiana in 2013 and 2014. In addition, soybean fields were surveyed for presence of SVNV in both years. We found that the magnitude and timing of thrips activity varied greatly for the three species. N. variabilis activity peaked in mid-August each year. The peak activity for F. tritici occurred between late-June, and a second peak in activity was observed in early-August, while F. fusca activity remained more or less the same with no peak. There was no gradient in thrips populations from southern to northern locations. This suggests that these insects are not migratory and may overwinter in soil or perennial noncrop host plants and other weed hosts in Indiana. The capture rates of N. variabilis and F. tritici were only related to temperature, and capture rates of F. fusca were not related to either variable. SVNV was first detected in mid-late August, which coincided with the peak of the primary vector, N. variabilis. The virus was not detected earlier in the season despite peaks in F. tritici activity. Our results may be used in weather-based models to predict both thrips dynamics as well as SVNV outbreaks.

A 2-yr study in cotton (Gossypium hirsutum L.) was conducted to determine the abundance and species composition of thrips (Thysanoptera: Thripidae) on different plant parts throughout the season in Alabama, Georgia, North Carolina, South Carolina, and Virginia. Plant parts sampled included seedlings, terminals with two expanded leaves, leaves from the upper, middle, and lower sections of the canopy, white flowers, and medium-sized bolls. Adult thrips were significantly more abundant on seedlings and flowers in 2014, and on flowers followed by seedlings and leaves from the middle canopy in 2015. Immature thrips were significantly more abundant on seedlings, followed by flowers in 2014, and on seedlings followed by leaves from the lower canopy and flowers in 2015. Across locations and plant parts, thrips consisted of Frankliniella tritici (Fitch) (46.8%), Frankliniella fusca Hinds (23.5%), Frankliniella occidentalis (Pergande) (17.1%), Neohydatothrips variabilis (Beach) (7.4%), Thrips tabaci (Lindeman) (1.8%), and other species (3.4%). Frankliniella fusca represented 86.7% of all thrips on seedlings, while F. tritici was more abundant on terminals (51.6%), squares (57.5%), and flowers (75.1%). Across all leaf positions, F. fusca was the most abundant species (28.8%), followed by F. tritici (19.2%), N. variabilis (18.8%), F. occidentalis (12.9%), and T. tabaci (5.2%), as well as other species (15.0%). As neonicotinoid insecticides remain a primary tool to manage seedling infestations of F. fusca, our data indicate that mid- to late-season applications of neonicotinoid insecticides targeting other insect pests will intensify selection pressure for resistance on F. fusca, the primary pest of seedling cotton.

The flower thrips, Frankliniella tritici (Fitch) (Figure 1), is one of the most abundant species of flower thrips (Thysanoptera: Thripidae) in the eastern United States (Reitz 2008). The official common name established by the Entomological Society of America for this species is flower thrips, although the name flower thrips is often applied generically to the numerous species in the genus Frankliniella that inhabit flowers. For this reason, it is frequently referred to as the eastern flower thrips, presumably for its distribution in the eastern United States. Several species in the genus Frankliniella are considered economic pests and cause damage to a wide variety of crops through feeding and oviposition (Childers 1997). Several species are able to vector orthotospoviruses (or tospoviruses), including Tomato spotted wilt virus. However, Frankliniella tritici is not a vector of Tomato spotted wilt virus and is considered a pest of secondary importance (de Assis Filho 2005). Frankliniella tritici may, however, be confused with other similar Frankliniella species in Florida such as Frankliniella bispinosa and Frankliniella occidentalis which are capable vectors of Tomato spotted wilt virus (Riley et al. 2011). This document is also available on the Featured Creatures website at http://entnemdept.ifas.ufl.edu/creatures/. https://edis.ifas.ufl.edu/in1236

Thrips transmit one of the most devastating plant viruses worldwide-tomato spotted wilt tospovirus (TSWV). Tomato spotted wilt tospovirus is a type species in the genus Orthotospovirus and family Tospoviridae. Although there are more than 7,000 thrips species, only nine thrips species are known to transmit TSWV. In this study, we investigated the molecular factors that could affect thrips ability to transmit TSWV. We assembled transcriptomes of a vector, Frankliniella fusca [Hinds], and a non-vector, Frankliniella tritici [Fitch], and performed qualitative comparisons of contigs associated with virus reception, virus infection, and innate immunity. Annotations of F. fusca and F. tritici contigs revealed slight differences across biological process and molecular functional groups. Comparison of virus cell surface receptors revealed that homologs of integrin were present in both species. However, homologs of another receptor, heperan sulfate, were present in F. fusca alone. Contigs associated with virus replication were identified in both species, but a contig involved in inhibition of virus replication (radical s-adenosylmethionine) was only present in the non-vector, F. tritici. Additionally, some differences in immune signaling pathways were identified between vector and non-vector thrips. Detailed investigations are necessary to functionally characterize these differences between vector and non-vector thrips and assess their relevance in orthotospovirus transmission.

Soybean vein necrosis virus (SVNV), a new virus in the genus Orthotospovirus, has been found in all soybean-growing regions in the United States and Ontario, Canada. Soybean thrips, Neohydatothrips variabilis (Beach) (Thysanoptera: Thripidae), tobacco thrips, Frankliniella fusca (Hinds) (Thysanoptera: Thripidae), and eastern flower thrips, Frankliniella tritici (Fitch) (Thysanoptera: Thripidae) are reported vectors of this virus, but there are no reports on their distribution in Alabama. A monitoring study was conducted in 2015 and 2016 to determine thrips species composition and abundance in Alabama soybean agroecosystems. Thrips were monitored weekly by collecting them on yellow sticky traps and soybean plant parts including foliage and reproductive structures. All three reported vectors of SVNV were identified in Alabama, with N. variabilis and F. tritici as the predominant species, while F. fusca was not consistently collected from soybean plants. Four additional thrips species were collected, of which Echinothrips americanus (Morgan) (Thysanoptera: Thripidae) was commonly found on soybean at all three locations. Results presented in this study provide new information about seasonal thrips species abundance in soybean agroecosystems in Alabama, and is an important first step to understanding thrips vector species of epidemiological importance in the Southern United States.

The potato psyllid, Bactericera cockerelli (Sulc), is the primary insect vector of the bacterium Candidatus Liberibacter solanacearum Leifting et al., the causal agent of zebra chip disease in solanaceous crops. Some phloem-feeding insects harbor bacterial communities determined by the food sources of the insects. Horizontal transmission of bacteria between individuals of the same species and insects of different species, with their host plants as reservoirs occurs in several plant insect systems. Ca. L. solanacearum is symbiotic in potato psyllid and can colonize plants before transmitted to its next insect host. Flower thrips, Frankliniella tritici (Fitch), that co-colonize plants have tested positive for Ca. L. solanacearum, although vector status is unknown. The bacterial community of thrips co-colonizing plants infected with Ca. L. solanacearum was analyzed and compared to that of potato psyllids on the same plants. Bacterial communities of samples were sequenced via the Illumina MiSeq plat...

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

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.

We investigated color preference, seasonal abundance, spatial distribution and species composition of thrips in northern highbush blueberries, Vaccinium corymbosum L, in New jersey (USA). White sticky traps were more attractive to thrips compared with yellow or blue traps. Thrips captures using white sticky traps showed that their flight activity begins 20-30 d after the onset of flowering, with 10, 50 and 90% of trap captures observed at 383, 647 and 1231 degree-day accumulations, respectively (10 degrees C base temperature). Two methods were used to study thrips distribution within a blueberry bush. First, white sticky traps were placed within the bush canopy at three different heights. The highest numbers of thrips were caught on traps in the middle and top one-third of the canopy while the lowest numbers were caught in the bottom one-third. A second method determined the distribution of thrips on the blueberry plant at different heights and phenological stages. The highest numbers of thrips were found on young leaves at lower parts of the canopy, whereas flowers and fruit had fewer thrips and none were found on buds; these thrips were identified as, Scirtothrips ruthveni (88% of adults) and Frankliniella tritici (12%). The distribution of thrips within a blueberry planting was investigated using an evenly-spaced grid of white sticky traps in combination with on bush beating-tray samples. Thrips counts from traps correlated with direct counts on the bush across the entire blueberry field (macro-scale level); however, within the field (micro-scale level), there was no correlation between the number of thrips on traps and on individual bushes near traps. Early in the season, trap counts were higher on bushes closer to the forest, indicative of movement of thrips from wild hosts into blueberry fields. However, this was not the case for direct on bush counts or trap counts for the later part of the season, where there was no clear forest "edge" effect. Percent fruit injury due to thrips feeding was low, and it correlated with thrips counts on bushes but not from counts on traps. Overall, our data show that thrips counts on sticky traps need to be interpreted with care because these numbers weakly correlated with the numbers of thrips on bushes at the micro-scale level and percent fruit injury; however, they can be useful predictors of thrips activity across entire blueberry fields (macro-scale).

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.

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...

Flower thrips are considered key pests in southern highbush (Vaccinium corymbosum L. × V. darrowi Camp) and rabbiteye (Vaccinium ashei Reade) blueberry fields in Florida. During 2005 and 2006, we evaluated the effectiveness of selected natural enemies (preventative and curative releases) for control of flower thrips in blueberries. Experimental designs were randomized complete blocks with 4 treatments and 4 replicates in 2005 and 3 treatments and 4 replicates in 2006. In 2005, treatments were evaluated as a preventative tactic and included the following biological control agents: (1) Thripor-I [Orius insidiosus Say (Hemiptera: Anthocoridae)], (2) Thripex-plus [Amblyseius cucumeris (Oudemans) (Acari: Phytoseiidae)], (3) combination of both O. insidiosus and A. cucumeris in 50% of standard dosages, and (4) untreated control (no natural enemies). Orius. insidiosus (Thripor-I) was released at 0.5 insects per m2 and A. cucumeris (Thripex-Plus) at 0.5 sachets of 1000 mites per m2. For the combination t...

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.

The thrips-borne tomato spotted wilt tospovirus is a serious economic threat to Georgia's flue-cured tobacco crop. Two thrips vectors, Frankliniella fusca (Hinds) and F. occidentalis (Pergande), are commonly encountered on tobacco foliage and blooms, respectively. Yellow sticky traps were monitored after a 48-h field exposure from March through June in 2003–2005 to assess thrips movement and species composition in the tobacco farm scape. During March each year there were similar numbers of F. fusca and the flower thrips complex [F.occidentalis, F. tritici (Fitch) and F. bispinosa (Morgan), combined] captured on sticky cards. During April, May and June, the flower thrips complex steadily became more abundant comprising around 60, 70, and 95% of the trap capture, respectively. Thrips vector species were captured throughout the entire sampling period. In April and May, F. fusca captures on stick traps related to F. fusca population densities on tobacco foliage. Some sampling periods had differences in thrips captures relative to a north, south, east, or west orientation, with each direction having the highest thrips numbers at least once each season. However, the overall seasonal mean capture was higher on the eastward direction all 3 yrs and on the westward direction on 2 of the 3 yrs, compared to the southern and northern directions. In a time-of-day study, very few thrips were captured between 1830 h and 0,700 h the following morning. Thrips movement increased in midmorning and peaked during midafternoon. It appears that sticky cards can be used to monitor early colonization of thrips species in tobacco fields plus monitor thrips movement throughout the day, thus providing information on when potential vectors arrive and move within the field. Sticky trap monitoring provides an alternative to direct plant observation for predicting thrips abundance on tobacco foliage and the need for thrips controls.

Two species of thrips (Frankliniella tritici and Limothrips cerealium) were reported biting people in Georgia during 1986 and 1990. Frankliniella bispinosa was the only thrips species documented biting people in Florida between 1986 and 1997. This species occurs in great abundance throughout Florida and is a recognized plant pest on numerous crops. Because of the tremendous numbers of F. bispinosa that are produced on dozens of different cultivated and weed host plants during the spring months, this species can become a serious nuisance problem. Frankliniella bispinosa will bite people and produce variable reactions from slight irritation to formation of a rash with associated intense itching that can last for several days. The problem usually is seasonal and associated with maximum seasonal increase in F. bispinosa populations and favorable environmental conditions that can occur anytime between February and April in central and south Florida. Colored sticky-trap tests in Florida demonstrated th...

The common species of thrips that are considered pests of cotton, Gossypium hirsutum (L.), include flower thrips, Frankliniella tritici (Fitch); tobacco thrips, Frankliniella fusca (Hinds); western flower thrips, Frankliniella occidentalis (Pergande); onion thrips, Thrips tabaci (Lindeman); and soybean thrips, Neohydatothrips variabilis (Beach). Thrips feeding on cotton seedlings can inhibit plant growth, reduce plant stand, delay crop maturity, and reduce seed-cotton yield. Surveys were conducted in Alabama, Arkansas, Georgia, Louisiana, Mississippi, and Tennessee to determine the thrips species infesting cotton seedlings during 1996 to 1999. Cotton seedlings were sampled weekly between 7 and 48 days after plant emergence at one to four field sites in each state. Over 12,000 thrips adults were collected using plant washing procedures with 9,005 individuals mounted on slides, and identified to species. The tobacco thrips was the most common species collected in all states, except Georgia, and comprised at least 63% of the thrips adults in all instances, except four. The occurrence of flower thrips and soybean thrips was variable; however, neither species accounted for more than 21% of thrips identified in each state. Western flower thrips accounted for less than 15% of adults collected in all instances except two (28% and 30%) in Louisiana. Also, individual specimens of Thrips nigropilosus Uzel and Anophothrips obscurus Müller were collected in Alabama, and several specimens of Microcephalothrips abdominalis (Crawford) were collected in Arkansas and Louisiana.

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

Seasonal flight activity of thrips was examined in commercial tomato fields, Lycopersicon esculentum L., on Virginia’s (USA) Eastern Shore in 2000 and 2001. In each of three regions along the Shore, populations of adult thrips infesting tomato flowers and dispersing within tomato fields were monitored weekly. Frankliniella fusca (Hinds) was the only thrips species captured that is currently considered as a competent vector of Tomato spotted wilt virus (TSWV) in most of the mid-Atlantic US region. Seasonal patterns of F. fusca capture were dissimilar among tomato fields across all regions; yet, more F. fusca were captured between midMay and mid-June in all regions compared with those captured between transplanting and mid-May each year. Despite the relatively low observed dispersal activity of F. fusca before mid-May, the threat of TSWV transmission warrants protection of the crop from immigrating F. fusca from transplanting until the end of marketable fruit set. Frankliniella tritici (Lindeman) was the most frequently encountered thrips species dispersing in tomato fields and infesting tomato flowers. Seasonal patterns of F. tritici capture were similar among tomato fields in all regions in 2000, but were dissimilar among regions in 2001. Dispersal of F. tritici was most pronounced between mid-May and mid-June across all fields in each year. Because F. tritici was the dominant species recovered from tomato flowers, it is likely responsible for cosmetic injury to tomato fruit and should be managed to reduce fruit injury when infestations are highest, between mid May and mid June. r 2003 Elsevier Science Ltd. All rights reserved.

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.

Field experiments were conducted in 1997–1999 in Washington Co., NC, to examine how cotton, Gossypium hirsutum, is affected by thrips species composition and abundance, environmental factors, and insecticide applications. Populations of adult and juvenile thrips were monitored in seedling cotton treated with insecticide applications of either imidacloprid as a seed treatment, acephate as a foliar spray, or aldicarb applied in-furrow. The number of plants per 3.05 row-m, location of the first fruiting branch, number of open bolls per 1.52 row-m, yields, accumulated degree-d 60′s (DD60′s), and accumulated rainfall were recorded each year the studies were conducted. Aldicarb and acephate provided better thrips control than did imidacloprid in all 3 yrs. Thrips species ratios differed among years. In 1997, the aldicarb treatment resulted in a better “earliness profile” (lower fruit set and more early opening bolls) than either acephate or imidacloprid, while in 1998 and 1999 there were few differences in these plant parameters. In 1997, all insecticide treatments resulted in statistically higher yields compared with the untreated check. Accumulated DD60′s were consistently higher in 1998 and 1999 than in 1997 after the first thrips sampling date. Cumulative rainfall appeared to be inversely associated with juvenile thrips populations.

Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), the western flower thrips, is the primary insect pest of tomatoes and other vegetable crops in northern Florida and the rest of the southeastern USA. However, it is not the only flower thrips present in the region nor is it always the most abundant species. To determine the seasonal and within plant distribution of these various Frankliniella species, experimental tomato plants, grown under different nitrogen fertilization regimes, were sampled during the fall and spring growing seasons. Contrary to expectations, different levels of nitrogen fertilization did not affect the abundance of thrips species. Thrips were much more abundant in the spring than in the fall. In the spring F. occidentalis was the most abundant species, while in the fall F. tritici (Fitch) was the most abundant species. In both the fall and spring, significantly more adults occurred in flowers in the upper part of the plant canopy than in flowers in the lower part of the plant canopy. The sex ratio tended to be female biased, but with a greater percentage of males occurring in the upper canopy flowers. In contrast, significantly more immature thrips occurred in the lower part of the plant canopy than in flowers in the upper part of the plant canopy. Differences in seasonal patterns and within plant distribution should be considered in developing sampling protocols and management plans for thrips.

Studies on insect biology often require insects to be confined on a plant surface with cages. E. A. Hartley (1923) discussed the use of glass lantern globes for caging insects on plants shortly after the beginning of the 20th century. He devised improvements in cage production that included such things as use of perforated celluloid that provided better air circulation and use of melted paraffin to reduce insect escape. A substantial improvement in cage production was the development of clip cages that enabled small insects to be caged on a small portion of the plant, i.e., branches and foliage (MacGillivary and Anderson, 1957; Guthrie and Bishop, 1960; and Mowry, 1993). These cages, however, are not without their problems. Although clip cages may work well with aphids and whiteflies, they may be unsuccessful in preventing escape of smaller insects like thrips. Further, standard clip cages are not suitable for confining certain plant structures like flowers. Salguero et al (1991) used perforated plastic bags to cage thrips on tomato blooms. Bags were secured with paraffin strips. Although this method successfully confined thrips to small blooms, the process is time consuming and difficult. Thrips are considered a major insect pest of cowpea, Vigna unguiculata (L.) Walp, worldwide with different species attacking either the blooms or foliage of cowpea (Singh and van Emden, 1 979; Jackai and Daoust, 1986). Chalfant (1976) reported Frankliniella tritici (Fitch) to be the most abundant species on cowpea. F. tritici attack cowpea flowers and can cause damage to reproductive portions of blooms resulting in premature senescence (Jackai and Daoust, 1986). The impact of thrips, especially F. tritici, on cowpea is not well defined. Although several studies have correlated F. tritici management with improved cowpea yield (Chalfant and Johnson, 1972; Sweeden et al, 1994) other studies suggest that yield increase may actually be caused by other factors such as insecticides directly inducing plant responses (Hundley, 2004). In order to define the impact of F. tritici on cowpea, known numbers of thrips will need to be confined on cowpea flowers. The objective of this manuscript is to describe a caging system that successfully confines thrips on cowpea flowers. Thrips cages (Fig. 1) were constructed by taking a square of No-Thrip Insect Screen (Green-Tek, Edgerton, WI) measuring approximately 13 cm X 13 cm and rolling it into a tube 3.5 cm in diameter. Duct tape (Duck® Brand, Henkel Consumer Adhesives, Inc., Avon, OH) strips approximately 2.5 cm wide were used to seal inner and outer seams of the rolled mesh. A 29.5 ml plastic cup (Solo Cup Co., Highland Park, IL) was placed bottom-side inward in one end of the tube. Another 2.5 cm wide strip of duct tape was used to secure the cup to the tube and tape was burnished around the juncture to ensure a seal. The end opposing the cup was also taped shut and burnished. The bottom of the cup was then removed with a carpet knife. A hole was punched in the center of the cup lid approximately 0.5 cm in diameter and a slit was created from the hole to the edge of the lid to allow placement over the peduncle of the cowpea

Daily occurrence and flight activity of Frankliniella spp. (Thysanoptera: Thripidae) in tomato fields was studied on five dates in 1990 and four dates in 1992. Higher number of Frankliniella occidentalis (Pergande) were observed on tomato flowers in the morning than in the afternoon on 3 of 5 and 2 of 4 sample dates in 1990 and 1992, respectively. Numbers of Frankliniella tritici (Fitch), Frankliniella fusca (Hinds) and immature thrips on flowers or foliage did not differ among sample hours. On tomato foliage, F. fusca and immature thrips were dominant, while few F. occidentalis or F. tritici were collected. Temperature was an important factor in the flight activity of F. tritici. Populations of F. tritici peaked earlier in the season and declined sooner than those of F. occidentalis. F. occidentalis and F. tritici both inhabited tomato flowers and subdivided this niche temporally, while F. fusca occupied a different niche, tomato foliage.

Two of the most abundant thrips in the south eastern USA are Frankliniella occidentalis (Per gande) and Frankliniella tritici (Fitch) (Thysan optera: Thripidae). Frankliniella occidentalis is a key pest because of damage caused by its feeding and oviposition in many crops and because it is a vector oiTomato spotted wilt virus (Childers 1997; Ullman et al. 1997). Although F. tritici is not a vector oiTomato spotted wilt virus (Assis Filho et al. 2005), its abundance and morphological simi larity to F. occidentalis makes it a management concern for growers and crop consultants (Reitz 2002). Despite superficial similarities in their habits and host plants, the seasonal population dynamics of these species differ dramatically (Eckel et al. 1996; Funderburk et al. 2000; Reitz et al. 2002), yet efforts to better understand their population dynamics are hindered by a lack of comparative biological data and because observ ing individual thrips in the field is almost impos sible. Therefore, laboratory studies can provide critical information to better understand their population dynamics. The objectives of this study were to compare development and reproductive success oiF. occidentalis and F tritici. To determine immature development time, in dividual adult females were allowed to oviposit for 8 h in 2.5-cm sections of green bean pods con tained in 30-ml clear plastic cups. Then females were removed, and the bean sections were held in an environmental chamber (28.0 ? 1.0?C, 65.0 ? 10.0% r.h., 14:10 L: D photoperiod). Bean sections were observed every 12 h under a stereomicro scope to determine when larvae began to emerge. Then a single newly emerged larva from each fe male was transferred to fresh bean pod section. These individuals were checked every 12 h to de termine when molting occurred. There are 2 ac tive larval stages followed by 2 relatively quies cent non-feeding stages, the propupa and pupa (Moritz 1997). Because data were recorded on an interval scale and composed of different events (molts), survival analyses based on the Wei, Lin and Weissfeld model were used to compare devel opment of the life stages (Li & Lagakos 1997; Wei et al. 1989). In this model, molts were stratified according to their order of occurrence with adult eclosi?n as the terminating event. Because of the stratification, separate hazard ratios can be esti mated for each life stage as well as a comparison of the overall development of the species. Subjects that did not complete development were censored. To determine female adult longevity and fecun dity, newly emerged adult females were placed in dividually in small Petri dishes containing a 2.5 cm piece of green bean, with the ends sealed with Parafilm. Beans were replaced every 24 h, and this process continued for each thrips until death. Beans were subsequently examined over 7 d for l rval emergence. The total number of offspring produced per adult female was recorded. Fecundity was analyzed by repeated measures analysis of co variance, with species as a treatment and longev ity as a covariate. This analysis allowed a compar ison of total fecundity and daily fecundity of thrips. Adult longevity was compared based on survival analysis in which mortality was examined by com paring the Cox proportional hazard for each spe cies (Cox 1972) with ties handled by Breslow's method (Breslow 1974). Insects that were acciden tally lost during the experiment were considered censored observations and not included in fecun dity analyses. Experiments were replicated 3 times with colonies that had been established for 4-8 months from specimens collected in Gadsden County, FL. Voucher specimens are deposited in the collections of the author. All statistical analy s s were performed in SAS ver. 9.1 (SAS 2004). Time to egg hatch was approximately 3 d for both F occidentalis (range 2.5-3.5 d) and F. tritici (range 2.5-3 d). Overall immature development from oviposition to adult eclosi?n was signifi cantly faster for F tritici (median = 11.0 d, range = 9.5-14.0 d, n = 26) than for F. occidentalis (me dian = 12.0 d, range = 9.5-14.5 d, n = 20; %2 = 14.10, df=5,P = 0.015). There were no significant differences between the species in development times of the 2 larval stages (median = 2.0 d, range = 1.0-4.0 d, and 3.0 d, 2-4 d, for first and second stadia, respectively), and the propupal stage (me dian = 1.0 d, range = 0.5-3 d; P > 0.25 for each stage comparison). The difference in total devel opment resulted from the shorter pupal stage of F tritici (median = 2.0 d, range = 1-3 d) compared with/*! occidentalis (median = 3.0 d, range = 2-5 d; X2 = 5.14,df=l,P = 0.02). Adult longevity of females differed between the species, with F occidentalis having a signifi cantly greater longevity than F. tritici (log rank test x2 = 8.2, df=l,P = 0.004). The quartile esti mates of times at which 25%, 50%, and 75% of the individuals had died were all significantly greater for F occidentalis (Fig. 1A) indicating that the greater survivorship of F occidentalis was consis tent throughout the adulthood. Initial survivor ship was high for both species, with less than 10% mortality in the first week after eclosi?n. The maximum longevity was similar for both species

The mechanism leading to vector competence of thrips species to transmit tomato spotted wilt virus (TSWV) is not well characterized. We investigated the interaction of TSWV and the non-vector species Frankliniella tritici .A monoclonal antibody to the non-structural protein (NSs) of the TSWV was used to detect TSWV replication within the thrips by immunofluorescence microscopy and enzyme-linked immonosorbent assay (ELISA). TSWV was acquired by F. tritici, replicated and moved within the alimentary canal of F. tritici similar to a known vector of TSWV, Frankliniella occidentalis. However, virus was not found in the salivary glands of F. tritici, which is a prerequisite to virus transmission. Thus, movement to the salivary glands may determine vector incompetence of F. tritici.

Thrips were surveyed in tomato spotted wilt-susceptible crops in five areas across North Carolina. Tomato, pepper, and tobacco plants in commercial fields were sampled and 30 species of thrips were collected over a 3-year period. The most common species overall was Frankliniella tritici (Fitch). The most common thrips species that are known to vector Tomato Spotted Wilt Virus (TSWV) were F. fusca (Hinds), and F. occidentalis (Pergande). Relatively low numbers of Thrips tabaci Lindeman, another reported vector, were collected. The spatial and temporal occurrence of vectors varied with sampling method, crop species, region of North Carolina, and localized areas within each region. In a laboratory experiment, no difference was detected between the ability of F. fusca and F. occidentalis to acquire and transmit a local isolate of TSWV. Based on vector efficiency and occurrence, F. fusca is considered the most important vector of TSWV in tobacco, whereas both F. fusca and F. occidentalis are important vectors of TSWV in tomato and pepper.

Thrips are presumed to be the major cause of bronzed strawberry (Fragaria ×ananassa Duchesne) fruit in the Midwestern United States. The objectives of this study were to 1) identify thrips species present in Iowa strawberry fields and 2) determine the relationship between the numbers of thrips collected from flowers and fruit and the percentage of mature fruit exhibiting bronzing damage. Thrips were collected from flowers and fruit for three growing seasons at three sites in central Iowa. Approximately 82% of these thrips were eastern flower thrips, Frankliniella tritici (Fitch) (Thysanoptera: Thripidae); the remaining 18% were primarily Frankliniella fusca (Hinds) (Thysanoptera: Thripidae). Mean number of adult and immature thrips per flower or fruit ranged from 0 to 7 in 2000, from 0 to 22 in 2001, and 0 to 16 in 2002. In 2001 and 2002, the incidence of thrips on both flowers and fruit was common; the mean number of thrips on flowers was 2 to 16 times greater than on fruit. However, in both years

Phytophagous thrips were sampled in commercial tomato, Lycopersicum esculentum L., fields in western North Carolina during a 3-yr period from 1990 to 1992. Tomato flowers were collected to sample thrips and evaluate 3 different sampling units (2, 5, and 10 flowers) for their relative net precision. Flower thrips, Frankliniella tritici (Fitch), and western flower thrips, frankliniella occidentalis (Pergande), were the dominant species collected, accounting for 96% of all specimens. Relative net precision values indicated that a 10-flower unit was more precise and cost-efficient than either the 2- or 5-flower unit. Frequency data collected from the 10-flower unit were described by the negative binomial distribution. Both F. occidentalis and F. tritici exhibited an aggregated distribution in tomato fields. Taylor power law provided a better fit to the data than Iwao patchiness regression. Slopes and intercepts of Taylor power law did not differ among thrips species or total thrips. A fixed-precision-level sequential sampling plan was developed using the parameters of Taylor power law generated from total number of thrips in a 10-flower sampling unit. The resulting sampling plan was tested with sequential sampling bootstrap simulations ( n = 500) using 11 independent data sets for the validation. Bootstrap simulation over a range of densities demonstrated that actual Do values at Do = 0.30 averaged

Thrips species composition and seasonal abundance were studied in winter wheat, Triticum aestivum L., and winter rye, Secale cereale L., during 3 seasons in the coastal plain region of Georgia. Thrips abundance also was examined in wild radish, Raphanus raphanistrum L., a common annual winter weed in small-grain fields. Limothrips cerealium (Haliday) and Frankliniella fusca (Hinds) were the 2 dominant species comprising >89% of the adult thrips collected in both crops. Frankliniella tritici (Fitch), F. bispinosa (Morgan), F. occidentalis (Pergande), F. williamsi Hood, Haplothrips graminis Hood and Plesiothrips perplexus (Beach) also were collected in low numbers in most years. Winter rye supported breeding populations of F. fusca during the autumn, winter, and early spring. Few thrips of any species were collected in winter wheat before spike emergence in March. However, large numbers of F. fusca and L. cerealium developed in wheat during the spring. Winter rye also served as a spring host for these thrips, but population increases were limited by grazing and early crop destruction. Differences in F. fusca phenology between wheat and rye probably are related to crop planting time in that rye for grazing is planted ≈6 wk earlier than wheat for grain production. Small grains grown for grain production presumably are planted too late for colonization by F. fusca in autumn. Although F. tritici , F. bispinosa , and F. occidentalis adults were present in the spring, these thrips probably did not breed extensively in wheat or rye. However, flowering wild radish in wheat fields supported large populations of F. tritici and F. occidentalis in late winter and spring. Therefore, winter small grains, particularly wheat, are important sources of F. fusca and L. cerealium that attack summer hosts. Small grains are not a major source of other Frankliniella spp., except possibly F. williamsi , but wild radish within winter small grains probably is an important spring source of F. tritici and F. occidentalis .

The response of flower thrips, Frankliniella spp., to various colors and sticky trap designs was evaluated in staked tomato fields in western North Carolina. Yellow sticky traps caught significantly more thrips compared with blue or white traps. There were no differences in the relative proportion of thrips species caught on different colored traps. The size of the flower sampling unit (i.e., 10-flowers versus all flowers per plant) did not influence the correlation between sticky trap catches and thrips abundance in flowers. Only F. occidentalis (Pergande) exhibited a significant correlation between percent abundance on all colors of sticky traps and percent abundance in flowers. Colored sticky traps caught high numbers of F. tritici (Fitch), despite the fact that few F. tritici were collected from flowers. In tests to evaluate different trap designs, cylindrical and cup traps caught more F. tritici than glass slide traps. Cylindrical sticky traps were more economical and enabled easier identification of thrips than glass slide or cup traps.

tritici (Fitch, 1855) (Fig. 154) Described in the genus Thrips, this is a common insect in northern temperate areas, recorded in Canada, USA and Mexico. It was reported in 1930 from Argentina by Blanchard (according to De Santis et al. 1980), but this record needs confirmation. In Brazil tritici was recorded on wheat in Rio Grande do Sul (Biezanko et al. 1949) but this is possibly a misidentification of some other Frankliniella species. However, Lima (2011) recorded several yellow adults of this thrips on many unrelated plants in northeastern Brazil. This species is readily identified by the swollen pedicel of antennal segment III, and the sparse posteromarginal comb on abdominal tergite VIII, which is absent medially with only a few slender teeth laterally., Published as part of Cavalleri, Adriano & Mound, Laurence A., 2012, Toward the identification of Frankliniella species in Brazil (Thysanoptera, Thripidae), pp. 1-30 in Zootaxa 3270 on page 14, DOI: 10.5281/zenodo.246160, {"references":["De Santis L., De Sureda, A. E. G. & Merlo, E. Z. (1980) Estudio sinoptico de los Tisanopteros Argentinos (Insecta). Obra del centenario de Museo de La Plata, 6, 91 - 166.","Biezanko, C. M. de, Bertholdi, R. E & Baucke, O. (1949) Relacao dos principais insetos prejudiciais observados nos arredores de Pelotas nas plantas cultivadas e selvagens. Agros, Pelotas, 2, 156 - 213.","Lima, E. F. B. (2011) Tripes (Thysanoptera) associados a especies de Fabaceae no Meio-Norte do Brasil. MSc. Thesis, ESALQ, Piracicaba, 120 pp."]}

Flower thrips (FT): Frankliniella tritici (Fitch) Western flower thrips: Frankliniella occidentalis (Pergande) Tobacco thrips (TT): Frankliniella fusca (Hinds) Flea beetle (FB): Epitrix spp. Potato aphid (PA): Macrosiphum euphorbiae (Thomas) Twospotted spider mite (TSSM): Tetranychus urticae Koch Tomato fruitworm (TFW): Helicoverpa zea (Boddie) Armyworms (AW): Spodoptera spp. Brown stink bug: Euschistus servus (Say) Green stink bug: Acrosternum hilare (Say)

Cowpeas grown under dry conditions had significantly higher yield increases following acephate insecticide application at or just before first bloom compared with those receiving other treatments. Yield responses to acephate were lower in fields with abundant moisture or irrigation than in dry fields. Acephate applications for thrips, Frankliniella fusca (Hinds), F. tritici (Fitch), and Neohydatothrips variabilis (Beach) (= Sericothrips variabilis [Beach]), control during early seedling stages resulted in less foliage insect damage. However, acephate applications to seedling stages did not result in yield increases. Corn earworm, Helicoverpa zea (Boddie), had little impact on yield in fields where earworms were monitored.

Western flower thrips, Frankliniella occidentalis (Pergande), females inhabit tomato flowers and insert eggs into developing fruit, causing cosmetic damage. The species is a vector for tomato spotted wilt virus. Only larval thrips acquire the disease, and larvae developing to adult on infected plants can disperse and infect additional plants in a field. Tobacco thrips, F. fusca (Hinds), another vector species, and flower thrips, F. tritici (Fitch), a nonvector species, also inhabit tomato flowers but apparently do not reproduce in the flowers. Our objectives were to determine dispersion characteristics of these thrips in tomato flowers and to determine relationships between density and incidence for developing a presence/absence sampling program. Taylor’s power law indices indicated that populations of F. occidentalis and F. tritici were aggregated. Larvae of F. occidentalis were more aggregated than adults. Populations of F. fusca were aggregated in 1988, but randomly dispersed in 1989. Aggregation indices were used to determine relationships between incidence and density and to develop sample size curves for use in a binomial sampling program. Adults of F. occidentalis and F. tritici were estimated using presence/absence sampling at densities