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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

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...

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).

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.

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

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.

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

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.

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

Seasonal synchrony of phytophagous insects, especially Heterothrips azaleae Hood, and the predaceous mirids Dicyphus rhododendri Dolling and Rhinocapsus vanduzeei Uhler, was determined on five species of native deciduous azaleas ( Rhododendron spp.) during 1990–1993. Florida, Alabama, Piedmont, and Flame azaleas supported populations of H. azaleae ; Plumleaf azalea did not. Peak adult and larval activity of this species of thrips varied with sequence of flowering during April and May. While R. vanduzeei was present on all azalea species, except Plumleaf, D. rhododendri was found to be abundant only on Florida azalea and occurred more rarely on Alabama azalea. Dicyphus rhododendri nymphs emerged in late March or early April, 2–3 wk before R. vanduzeei nymphs emerged from overwintering eggs, which were inserted into the woody plant tissue. Adult D. rhododendri became scarce after mid-May. Rhinocapsus vanduzeei adults were present until the last week of June. Although both species are known to be pollen feeders, scavengers, or both, they were observed to be active effective predators of thrips and other small insects in the field and in laboratory tests. Additional thrips species collected were Terebrantia: Frankliniella tritici (Fitch), Anaphothrips obscurus (Muller), Chaetanaphothrips orchidii (Moulton), Thrips nigropilosus Uzel, and Tubulifera: Leptothrips mali (Fitch). Seasonal occurrence of additional phytophagous Hymenoptera, Lepidoptera, and Homoptera are given.

Flowers of 37 wild plant species located in North Florida were sampled at periodic intervals for selected thrips (Thysanoptera) species. Samples were collected from wooded areas adjacent to two tomato production fields over an 18-mo period beginning March 1989. Of the 2,583 thrips specimens collected, 78% were adults. Adult counts peaked in May at both sites during 1989 and 1990. The genus Frankliniella accounted for 87% of the adult thrips collected. The most common species collected was F. tritici (Fitch) followed by F. bispinosa (Morgan), F. occidentalis (Pergande), and F. fusca (Hinds). Species composition varied by sampled month. Frankliniella tritici was the most abundant species in March, May, and August; F. bispinosa in June and July; and F. occidentalis in February and April. The distribution of thrips that vector tomato spotted wilt virus was similar to that of non vectors in Rowers of wild hosts. Thrips were detected on 31 of the 37 wild plant species surveyed with 61% of all thrips collected inhabiting six plant species. Frankliniella occidentalis and F. tritici used a major proportion of the available wild plant species earlier in the season than F. bispinosa and F. fusca. All Frankliniella species exhibited a wide host range in April and May.

Thrips cause damage to seedling cotton, and they are associated with the spread of Fusarium hardlock, a serious disease affecting cotton bolls that reduces lint yield in the southern United States. The population dynamics and within-plant distribution of Frankliniella spp. thrips in cotton were determined in 2005, 2006, and 2007 in Quincy and in 2006 and 2007 in Marianna, FL. Frankliniella tritici (Fitch) was >98% of the adult thrips collected. The adults of F. bispinosa (Morgan), F. occidentalis (Pergande), and F. fusca (Hinds) also were collected. Populations of F. fusca inhabited the cotton leaves of vegetative-stage cotton. The other species were highly anthophilic, primarily inhabiting cotton during its reproductive growth stages. Densities of these species peaked during mid-season, which also coincided with peak bloom. The adult F. tritici and the thrips larvae were aggregated in the flowers over the other plant parts, with more collected in the upper than the lower canopies. These patterns of aggregation were observed at each location each year, and the numerical differences usually were significant (P < 0.05). Densities of adult F. tritici were low on the leaves, squares, and bolls. The population dynamics and with-plant distribution of individual thrips species has not previously been determined for cotton in the southern United States.

Western flower thrips, Frankliniella occidentalis (Pergande), has become a pest of tomato in the Southeast by causing direct cosmetic damage to fruit and by transmitting tomato spotted wilt virus. Other vectors of tomato spotted wilt virus in the region are tobacco thrips, F. fusca (Hinds); and onion thrips, Thrips tabaci Lindeman. Commercial tomato fields were sampled during the spring cropping seasons of 1987, 1988, and 1989, and during the fall cropping seasons of 1987 and 1988 to determine seasonal abundance of thrips inhabiting tomato flowers. Adult F. occidentalis , F. fusca, and F. tritici (Fitch) accounted for ≈88% of the total thrips collected. All species were common between late April and early June, with greatest densities during May. Densities were very low at other times, especially during each fall cropping season. The effects of sample location within a field, sample location on individual tomato plants, and time of day when sampling on density estimates were investigated. Adult F. occidentalis and F. tritid were more abundant on flowers on the upper half of tomato plants compared with flowers on the lower half of plants. Densities of adult F. occidentalis were greater near field margins. Density estimates were not influenced by time of day when sampling.

Cosmetic fruit damage on tomato recently has resulted in downgrading and cullout of freshmarket fruit in the southeastern U.S. The damage consists of small indentations that are sometimes surrounded by a light-colored halo; it began at the same time that western flower thrips, Frankliniella occidentalis (Pergande), populations moved into the geographical area. In addition to F. occidentalis, populations of other Frankliniella spp. commonly inhabit tomato flowers in the region. An understanding of the cause of the damage and its association with Frankliniella spp. is necessary to implement management programs. The objectives were to determine if thrips species inhabiting tomato flowers cause the newly observed cosmetic damage, and to determine the relationship between number of scars per fruit and thrips densities on tomato flowers and small fruit. Results showed that damage was caused by oviposition of female F. occidentalis inhabiting either flowers or small fruit. Other Frankliniella species were not found to cause cosmetic fruit damage. The relationship between the number of scars per tomato fruit and density per flower of F. occidentalis was evaluated by using regression. The relationship was quadratic, although the amount of variation explained by the model was very low (r2 = 0.07). Our research revealed that management efforts should focus on reducing populations of female F. occidentalis to nondamaging levels.

The response of sunflower ( Helianthus annuus L.) to feeding damage by insects and to mechanical damage was studied in the leaves of the plant. One class of chemicals found to accumulate after stress, the coumarins, was quantified by analysis with HPLC. Sunflowers were damaged by sunflower beetle, Zygogramma exclamationis (F.), flower thrips, Frankliniella tritici (Fitch), or by mechanical puncture. Scopoletin concentrations were 252 μ g/g fresh weight at 22 d and ayapin concentrations were 165 μ g/g at 25 d, in beetle-damaged sunflowers. The scopoletin concentration was three times higher and the ayapin concentration five times higher than that in control sunflowers ( P < 0.05). Thrips induced significantly higher scopoletin concentrations at 11 d and higher ayapin concentrations at 16 d after feeding began ( P < 0.05). Mechanical damage induced significantly higher scopoletin concentrations 11 d after the damage was inflicted. The initial type of induced response in sunflower was of the “halo type”; that is, highest in successive concentric circles approaching the wound site. A 3-mm puncture induced coumarins within a diameter of at least 1 cm at 1 wk. A systemic response may have begun after the first week. To study the effects of coumarin on host acceptability to the sunflower beetle, coumarins were applied to unstimulated sunflower leaf disks. Beetles chose between treated or control disks in a closed arena. The control disks were preferred over treated disks when 20 μ g/ml of scopoletin or coumarin and 100 μ g/ml of ayapin or scopoletin were sprayed onto leaves. The coumarins are apparently induced by insect feeding and slowly increase in sunflower tissue. Induced coumarins may subsequently deter additional feeding of sunflower beetles.

In a study of thrips populations in central Georgia peach orchards in 1983 and 1984 (Crawford, Houston, and Peach Counties), 31 species of thrips were identified. Frankliniella tritici (Fitch), the flower thrips; Neohydatothrips (Sericothrips) variabilis (Beach), the soybean thrips; and Leptothrips mali (Fitch), a predaceous thrips were the most abundant species recovered. Sprayed orchards were monitored in 1984 and 1986. F. tritici and N. Variabilis were again the predominant phytophagous thrips species. Comparison with numbers found in unsprayed orchards suggested that use of pesticides did not reduce their abundance. Thrips injury to peaches in sample orchards was minimal. In 1988, Frankliniella occidentalis (Pergande), the western flower thrips, was four times more abundant in sprayed orchards than F. tritici . Thrips injury also was more prevalent in 1988. Light to moderate silvering (a benign surface blemish) was found on >90% of fruit of early maturing cultivars in grower orchards. Russeting, a more serious tan-colored blemish that can be severe enough to cause fruit to be culled, was found on 10-20% of fruit in commercial orchards.

Adults of nine species of thrips were collected from canola fields:Aeolothrips fasciatus(L.),Anaphothrips obscurus(Müller),Frankliniella occidentalis(Perg.),Frankliniella tritici(Fitch),Limothrips denticornisHaliday,Odontothrips loti(Haliday),Thripsnr.fuscipennisHaliday,Thrips tabaciLindeman, andThrips vulgatissimusHaliday. Of these,F.triticiwas the most abundant in the collections and appears to have the greatest potential to be a significant canola pest, followed byT.tabaciandT.vulgatissimus.

Four series of experiments to control the two-spotted spider unite, Tetranychus telarius (L.), with systemic insecticides applied only on the soil show significant results. Test plants were potted chrysanthemums grown in a greenhouse under usual commercial conditions. Demeton at the rate of 32 milliliters of the commercial preparation in 32 gallons of water per 100 square feet of soil surface protected the plants from mites for approximately 5 weeks. Ten per cent phorate granules at the rate of 2.50 grams per 100 square feet required 1 week to become effective, but usually protected the plants from mites until blooms appeared. It was the most effective chemical tested in control of flower thrips, Frankliniella tritici (Fitch). Phosphamidon and Zectran® (4-dimethylarnino-3. 5-xylyl methylcarbamate) remained effective in control of mites for a shorter period of time than phorate, and a stronger dosage of granules of Di-Syston® ( O,O -diethyl S -[2-(ethy]thio)ethyl] phosphorodithioate) was required to control mites adequately. Dimethoate burned the plants severely at all concentrations used.

Laboratory and field studies were conducted to investigate the relationship between Orius tristicolor (White) and the green peach aphid, Myzus persicae (Sulzer), in potato fields. O. tristicolor provided with 1,5, and 10 aphids per day killed 11.4 ± 1.2, 37.2 ± 1.1, and 53.7 ± 1.2 aphids, respectively, during development. Adults killed an average of 0.9 ± 0.6, 1.9 ± 0.5, and 2.7 ± 0.6 aphids per day when supplied with 1,5, and 10 aphids per day, respectively. Development time was not affected by prey density; the mean time required for development (at 24.4°C)was 14.6 days. At low aphid densities, predation rates among nymphal instars were not significantly different. When O. tristicolor were supplied with 10 aphids per day, 3rd instars killed more aphids than either the 5th instars or adults. O. tristicolor populations did not appear to be a significant cause of decline of green peach aphid populations in potatoes. Where the thrips, Frankliniella tritici . occurred, its occurrence was strongly correlated with O. tristicolor .

Safflower, Carthamus tinctorius L., is an important drought-tolerant oilseed crop, used for the production of vegetable oil and protein meal. It is one of the few broadleaf crops that can be used for crop rotation in the small grains agroecosystem of the Northern Great Plains. Safflower is currently produced on about 60 000 ha in eastern Montana and northwestern North Dakota and about 10 000 ha in Alberta and Saskatchewan. There is little information available on the pest insect species on safflower in the Northern Great Plains; however, four pest species have been reported from California, including the westem flower thrips (Frankliniella occidentalis (Pergande)), lygus bug (Lygus hesperus Knight), green peach aphid (Myzus persicae (Sulzer)), and the bean aphid (Aphis fabae Scopoli) (Carlson 1966, 1972).

Kring (1964) and Smith et at (1964) demonstrated that aphids are repelled by reflective aluminum surfaces, and this repellency was shown to be useful in reducing the incidence of aphid-borne virus diseases in squash (Moore et at 1964) and gladiolus (Johnson et al. 1967, Smith and Webb 1968). In addition, the aluminum repelled flower thrips, Frankliniella tritici (Fitch) (Ota and Smith 1965) and gladiolus thrips, Taeniothrips simplex (Morison) (Smith et al. 1972). Wolfenbarger and Moore (1968) reported that aluminum foil repelled green peach aphids, Myzus persicae (Sulzer), and leafminers, Liriomyza sp., in squash and tomato plots, but that honey bees, Apis mellifera L., and pickleworms, Diaphania nitidalis (Stoll), were attracted to the aluminum-mulched squash plots. Also, we (Smith and Webb 1969) found that melon aphids, Aphis gossypii Glover, were attracted to aluminum-mulched cucumber and muskmelon. Thus, though some insects are repelled by aluminum-mulched plots, other insect species may be attracted.