Tomato Spotted Wilt Virus Incidence Research Articles

Registration of ‘Georgia‐23RKN’ peanut

Registration of ‘Georgia‐23RKN’ peanut

Organic Amendments Modulate Soil Microbiota and Reduce Virus Disease Incidence in the TSWV-Tomato Pathosystem.

Application of organic amendments is considered an eco-friendly practice to promote soil fertility and suppressiveness against a wide range of soil-borne pathogens. However, limited information is available about the capabilities of organic amendments to control virus disease. In this study, the suppressiveness of different organic amendments (i.e., compost manure, biochar, alfalfa straw, and glucose) was determined against the Tomato spotted wilt virus (TSWV) on tomato plants in a 1-year-long mesocosm experiment. Organic treatments were compared to the ordinary soil management based on mineral fertilizers and fumigation. Tomato seedlings were inoculated with TSWV and the infection and symptoms were assessed three weeks later. The disease incidence was higher in soil treated with mineral fertilizers and fumigation (>80%) compared to the application of organic amendments, with alfalfa straw and biochar recording the lowest incidence (<40%). Moreover, soil microbiota structure and diversity were assessed by high-throughput sequencing of bacterial and eukaryotic rRNA gene markers. Several members belonging to the bacterial phyla of Acidobacteria, Actinobacteria, Bacteroidetes, and Proteobacteria, as well as members of the fungal genus Acremonium, were positively associated with plant health. This study showed that conventional practices, by shifting microbiome composition, may increase TSWV incidence and severity.

Correction: Interacting Virus Abundance and Transmission Intensity Underlie Tomato Spotted Wilt Virus Incidence: An Example Weather-Based Model for Cultivated Tobacco.

[This corrects the article DOI: 10.1371/journal.pone.0073321.].

Transgressive Segregation and Long-Term Consistency for High TSWV Field Resistance in the ‘Georgia-06G’ Peanut Cultivar

Tomato spotted wilt disease caused by tomato spotted wilt virus (TSWV) is a major peanut (Arachis hypogaea L.) production problem in the United States. TSWV has become endemic since the mid-1980s in the southeastern U.S. peanut production area. ‘Georgia-06G’ is a large-seeded, TSWV-resistant, runner-type peanut cultivar, whereas ‘Georgia Greener’ is a sister line with a smaller seed size than Georgia-06G. Both Georgia-06G and Georgia Greener have greater TSWV general field resistance with higher yields, total sound mature kernels grade, and dollar values than the parents (‘Georgia Green’ and ‘C-99R’), which shows transgressive segregation for these desirable quantitative traits. Therefore, the objective of this 12-year study was to evaluate the higher TSWV host-plant resistance found in the Georgia-06G over time compared with many other runner- and virginia-type peanut cultivars and advanced breeding lines. Despite yearly variability in TSWV and total disease incidence, the data indicate that Georgia-06G exhibited long-term high TSWV and total disease field resistance at midseason and late season, respectively. Georgia-06G was also found to have among the highest pod yield and dollar value every year. The higher general TSWV field resistance of Georgia-06G appears to be consistent across many years and locations, similar to the moderate TSWV resistance in Georgia Green.

Natural incidence of bean viruses in the northwest of Iran

Bean is considered as one of the most important legumes around the world. Viral diseases are a major yield reducing factor in bean production. Bean samples with virus-like symptoms like severe or mild mosaic, vein banding, leaf curling, blistering and necrosis were collected from different bean fields in Urmia (Northwest of Iran) during the growing seasons of 2013 and 2014. Bean common mosaic virus (BCMV), Bean common mosaic necrosis virus (BCMNV), Bean yellow mosaic virus (BYMV), Cucumber mosaic virus (CMV), Tomato spotted wilt virus (TSWV), Tomato mosaic virus (ToMV) and Tomato yellow leaf curl virus (TYLCV) were detected by double antibody sandwich enzyme-linked-immunosorbent assay. Mixed infection of BCMV and BCMNV were found. BCMNV was the most frequent virus in this region whereas BYMV and TYLCV were each detected just in one sample. This is the first report of BCMNV, BCMV, BYMV, TSWV, TMV and TYLCV incidence on bean in Urmia, Iran.

Registration of ‘Georgia‐16HO’ Peanut

‘Georgia‐16HO’ (Reg. No. CV‐133, PI 680617) is a new high‐yielding, high‐oleic, Tomato spotted wilt virus (TSWV)‐resistant, large‐seeded, runner‐type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) cultivar released by the Georgia Agricultural Experiment Station in 2016. It was developed at the University of Georgia, Coastal Plain Experiment Station, Tifton, GA. Georgia‐16HO originated from a cross made between ‘Georgia‐07W’ and ‘Florida‐07’. Pedigree selection was practiced within the early segregating generations. Performance testing began in the F4:6 generation with the advanced pure‐line selection, GA 112720, the experimental designation of Georgia‐16HO. During 3 yr (2013–2015) averaged over 23 multiple location tests in Georgia, Georgia‐16HO had significantly less TSWV and total disease incidence and greater pod yield, total sound mature kernel grade, and dollar value return per hectare compared with the high‐oleic, runner‐type cultivars ‘FloRun ‘107”, Florida‐07, and ‘TUFRunner ‘727”. Georgia‐16HO was also found to have a larger percentage of jumbo runner seed size as compared to two of the large‐seeded, high‐oleic, runner‐type check cultivars, Florida‐07 and TUFRunner ‘727’. Georgia‐16HO combines high dollar value and TSWV resistance with the high‐oleic trait for longer shelf life and improved oil quality of peanut and peanut products.

Conservation tillage and thiamethoxam seed treatments as tools to reduce thrips densities and disease in cotton and peanut

Damage to seedling cotton as a result of feeding by adult and immature thrips can result in stunted growth and reduced plant stand. Transmission of Tomato spotted wilt virus by thrips in peanut can result in reduced yield and plant stand. The objectives of this research were to examine the effects of planting cotton and peanut into conventionally (no soil residue) tilled plots or planting into reduced tillage plots including rolled rye and standing rye (cotton only) tillage in conjunction with thiamethoxam seed treatments on seedling thrips counts, thrips associated injury in cotton, Tomato spotted wilt virus incidence in peanut, and yield for both crops. Conservation tillage practices consistently reduced adult and immature thrips populations in cotton. Standing rye residues suppressed thrips similarly to rolled rye, but yielded less lint in one of the two years. Thiamethoxam seed treatment effects were inconsistent, although general numerical trends suggest that this practice can suppress immature thrips for up to three weeks in cotton. Thiamethoxam seed treatment either had no effect or significantly improved cotton lint yield depending on year. Conservation tillage was also effective at reducing immature thrips in peanut. Incidence of Tomato spotted wilt virus in peanut was decreased in conservation tilled plots in 2013, but was slightly greater in 2014. Similarly, effects of tillage on peanut yield were significant but inconsistent between years. Thiamethoxam seed treatments did not consistently reduce thrips in peanut nor did it improve yield in either year. These data demonstrate conservation tillage and thiamethoxam seed treatments are generally effective practices for reducing thrips densities; however, effects on yield and disease transmission were inconsistent.

Registration of ‘Georgia-14N’ Peanut

‘Georgia-14N’ (Reg. No. CV-126, PI 674169) is a new high-yielding, high-oleic, Tomato spotted wilt virus (TSWV)–resistant, root-knot nematode (RKN) [Meloidogyne arenaria (Neal) Chitwood race 1]–resistant, small-seeded, runner-type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) cultivar that was released by the Georgia Agricultural Experiment Station in 2014. It was developed at the University of Georgia, Coastal Plain Experiment Station, Tifton, GA. Georgia-14N originated from a cross made between ‘Georgia-02C’ × F4 (‘Georgia-01R’ × ‘COAN’). Pedigree selection was practiced within the early-segregating generations. Performance testing began in the F4:6 generation with the advanced pure-line selection GA 082522, the experimental designation of Georgia-14N. During 3 yr (2011–2013) averaged over 29 multiple location tests without nematode pressure in Georgia, Georgia-14N had significantly less TSWV and total disease incidence, higher yield, grade, and dollar value return per hectare compared with ‘Tifguard’. Georgia-14N was also found to have a smaller runner seed size compared with the larger runner-type check cultivar Tifguard. Georgia-14N combines high yield, TSWV resistance and RKN resistance with smaller seed size and the high-oleic trait for longer shelf-life and improved oil quality of peanut and peanut products.

SUSCEPTIBILITY OF BURLEY AND FLUE-CURED TOBACCO TYPES TO TOMATO SPOTTED WILT VIRUS TRANSMITTED BY THRIPS (ORDER: THYSANOPTERA)

Tomato spotted wilt virus (TSWV) is an economically important plant virus, belonging to the family Bunyaviridae and genus Tospovirus, first identified in the United States in the middle to late 1980s and in North Carolina tobacco in 1988. By 1997 TSWV had been identified in nearly every North Carolina county. TSWV incidence has increased since its introduction. Tobacco plants infected with TSWV display a range of symptoms, including wilting and yellowing of leaves, ring spots, necrotic lesions, discoloration of leaf veins, and stunting. The majority of tobacco plants infected with TSWV will eventually die. TSWV is transmitted mechanically by 7 thrips species worldwide. The tobacco thrips, Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) is the most important vector of TSWV in eastern and central North Carolina, and the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) is a locally important vector in the western piedmont and mountainous region of the state. Previo...

Stem Rot (White Mold) and Tomato Spotted Wilt Resistance among Peanut Genotypes

ABSTRACT Stem rot, also known as white mold (WM), caused by Sclerotium rolfsii Sacc., and tomato spotted wilt, caused by Tomato spotted wilt virus (TSWV), are two major disease problems in Georgia peanut (Arachis hypogaea L.) production. Current fungicides for stem rot control are very effective but expensive, and insecticides usually have little effect on TSWV, which is transmitted by thrips. Consequently, the objective of this study was to evaluate different peanut genotypes for resistance to both of these pathogens. Field test evaluations were conducted for four consecutive years (2010-13) at a site on the agronomy research farm near the Coastal Plain Experiment Station which has a long history of continuous peanut production and a high incidence of stem rot (WM) and TSWV. Results from these field tests showed significant differences among the peanut genotypes evaluated for combined resistance to both diseases. Several genotypes showed low TSWV incidence at mid-season and mid-to-late season. However by late season and after digging, the best combination of stem rot (WM) and TSWV disease resistance and highest consistent yield over years was in the runner-type peanut cultivar ‘Georgia-12Y’, along with ‘York’, ‘Georgia-07W’, and ‘Georgia-10T’.

Interacting virus abundance and transmission intensity underlie tomato spotted wilt virus incidence: an example weather-based model for cultivated tobacco.

Through a modeling approach, we investigated weather factors that affect the summer incidence of Tomato spotted wilt virus (TSWV), a virus vectored exclusively by thrips, in cultivated tobacco. Aspects of thrips and plant biology that affect disease spread were treated as functions of weather, leading to a model of disease incidence informed by thrips and plant biology, and dependent on weather input variables. We found that disease incidence during the summer was influenced by weather affecting thrips activity during the preceding year, especially during a time when thrips transmit TSWV to and from the plant hosts that constitute the virus’ natural reservoir. We identified an interaction between spring precipitation and earlier weather affecting thrips, relating this to virus abundance and transmission intensity as interacting factors affecting disease incidence. Throughout, weather is the basic driver of epidemiology in the system, and our findings allowed us to detect associations between atypically high- or low-incidence years and the local climatic deviations from normal weather patterns, brought about by El Niño Southern Oscillation transitions.

Second Generation Peanut Genotypes Resistant to Thrips-Transmitted Tomato Spotted Wilt Virus Exhibit Tolerance Rather Than True Resistance and Differentially Affect Thrips Fitness

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

Spotted Wilt Disease Evaluation Among High-Oleic Peanut Cultivars

The release of high-oleic, United States runner and virginia market type peanut (Arachis hypogaea L.) cultivars has been steadily increasing during the past several years. Two planting dates were utilized for disease evaluation and agronomic performance among these newer high-oleic cultivars. The first planting date test was in mid-April to allow for increased incidence of spotted wilt disease caused by Tomato spotted wilt virus (TSWV). The second planting date test was in mid-May to allow for less TSWV and provide more of an optimum time by comparison. Significant differences (P ≤ 0.05) were found within each of the three (3-year) averages among cultivars for TSWV and total disease (TD) incidence, pod yield, and dollar values. Among the virginia-types, Georgia Hi-O/L, Georgia-05E, and Georgia-08V, and runner-types, Georgia-02C and Georgia-09B, consistently had the lowest TSWV and TD incidence and the highest pod yield and dollar values in both the mid-April and mid-May planting date tests. No significant differences were found between the mid-April and the mid-May planting dates when averaged across this 5-year study for TSWV and TD incidence, pod yield, and dollar values. This suggests that the high-level of TSWV-resistance among these newer high-oleic cultivars should have a greater influence than planting dates on agronomic performance. Accepted for publication 8 June 2013. Published 12 August 2013.

Development of a Tomato spotted wilt virus (TSWV) risk evaluation methodology for a processing tomato region

A risk map for the Tomato spotted wilt virus (TSWV) was elaborated for the main Portuguese processing tomato producing region, the “Ribatejo e Península de Setúbal” region, where periodically this virus causes severe losses. Forty nine tomato fields were monitored. Risk factors for TSWV infection were identified and quantified according to their relative importance in TSWV incidence. The risk factors considered for each field were: (1) presence of TSWV in the crop plants; (2) presence of TSWV in weeds which are hosts of TSWV vectors; (3) presence of TSWV vector thrips; (4) presence of TSWV host crops previously (in the two years before), namely, tomato, potato and sweet pepper; (5) presence of greenhouses, urban areas or TSWV host crops next to the field (up to about 100m from its borders). A risk estimator was calculated for each field. Among the thrips (Thysanoptera) identified, belonging to 11 genera, four vector thrips species were detected: Frankliniella occidentalis (Pergande) and Thrips tabaci Lindman, the two most abundant ones, and F. intonsa (Trybom) and F. schultzei (Trybom). Blue sticky traps placed up to about 75 cm above the crop canopy caught F. occidentalis and T. tabaci more efficiently than the beating technique. The weeds Datura stramonium L., Arctotheca calendula (L.), and Conyza bonariensis (L.) were identified as TSWV winter repositories. This study proposes a methodology to be used by field technicians for the annual evaluation of TSWV risk at a regional level, for an improved planning of processing tomato crop in the following season.

Agronomic Performance and Economic Return among Peanut Genotypes with Maximum and Minimum Production Inputs

Abstract Maximum (Max) and minimum (Min) peanut (Arachis hypogaea L.) input production tests were conducted for three consecutive years (2004–06) to evaluate agronomic performance and economic return among several runner and virginia genotypes. Mid-April planting dates were used each year. The Max tests included recommended production practices of seeding rate, fertilization, irrigation, and pesticides; whereas, the Min tests excluded irrigation, insecticides, and included only three fungicide sprays. Results showed variation among years, locations, and genotypes for TSWV and total disease incidence, pod yield, gross dollar value, and dollar value return above variable cost. The performance results also show the benefit to growers from agronomic and economic improvement with many of the newly released peanut cultivars in Georgia. Significant differences (P ≤ 0.05) among the peanut genotypes for tomato spotted wilt disease [caused by Tomato spotted wilt virus (TSWV)] where noted. The lowest TSWV incidence was noted for the cultivars Georgia-06G, Georgia Greener, Georgia-07W, Georgia-08V, Georgia-05E, Georgia-03L, Georgia-02C, Georgia-01R, and AP-3. Highest pod yields were found among Georgia-06G, Georgia Greener, Georgia-07W, Georgia-08V, Georgia-05E, and Georgia-01R. In general, the highest average dollar value return above variable cost was found in the Max test as compared to the Min test, and the highest average dollar value return above variable cost including seed cost was found with the runner-type cultivars Georgia-06G and Georgia Greener.

Management of the Spread of Tomato spotted wilt virus in Tobacco Crops with Insecticides Based on Estimates of Thrips Infestation and Virus Incidence.

Tomato spotted wilt virus (TSWV) causes serious losses in the tobacco-producing areas of northern Greece. Following a destructive epidemic of TSWV in the prefecture of Kilkis in 2003, a coordinated disease management scheme was developed in collaboration with the local tobacco farmers' associations on 1,000 ha in 2004 and 500 ha in 2005 of tobacco crops of the cv. Virginia. Insecticides first were evaluated for efficiency to control Thrips tabaci, the only TSWV vector present in tobacco crops in Greece. Field data on T. tabaci infestation, population fluctuation, and TSWV incidence were used to coordinate insecticide applications. T. tabaci overwinters in the soil covered by wild flora close to infested fields. The first adults of each season were recorded on blue sticky traps in week 13 and viruliferous individuals were found on weeds close to the tobacco fields in week 16 of both years. Tobacco seedlings were protected against thrips by a preventive drench application of carbofuran to soil in seedling beds, followed by two methomyl and one malathion foliage applications. To achieve an effective decrease of primary inoculum in the fields, malathion was applied to weeds on the field borders before transplanting the tobacco seedlings. In the tobacco crops, carbofuran was applied directly after transplanting. Early transplanted (week 19 to 20) seedlings were sprayed with methomyl. Subsequently, two rounds of foliar applications were started in week 23, consisting of cypermethrin, followed by malathion and methomyl, followed by one or two malathion sprays. At transplanting (week 19 to 23 or 22 in 2004 or 2005, respectively), 340 ± 160 (mean + standard deviation, n = 4 weeks) and 230 ± 130 (n = 3) T. tabaci individuals per trap were recorded in 2004 and 2005, respectively, and 52% of the thrips trapped in the neighboring flora in 2004 were TSWV infected. Afterwards, T. tabaci populations did not increase significantly until harvest (up to 350 individuals were counted per trap). In a control field of an oriental tobacco cultivar in which no insecticides were applied, up to 5,000 and 3,300 thrips were found per trap in 2004 and 2005, respectively. The final incidence of tobacco plants with TSWV infection fluctuated from 10 to 20% in the Virginia tobacco crops whereas, in the control crop, it was 60 and 85% in 2004 and 2005, respectively. This study showed that a well-coordinated collective plan based on data on infection pressure by TSWV and the vector population fluctuation during the growing season can represent an effective way of combating epidemics in tobacco.

Verbena as a trap crop to suppress thrips-transmitted Tomato spotted wilt virus in chrysanthemums

The effect of verbena as a trap crop on the occurrence of western flower thrips, Frankliniella occidentalis, and the incidence of Tomato spotted wilt virus (TSWV) in chrysanthemums were investigated. Verbena cvs. Pink Parfait and/or Fancy Parfait were cultivated alongside chrysanthemum cv. Jimba in a greenhouse in the proportion of 17%–25% of the chrysanthemum plants. Verbena plants attracted vector thrips, reducing western flower thrips colonization of chrysanthemum until flower bud initiation, and markedly suppressing TSWV incidence on chrysanthemums until flowering. Significant quantities of linalool oxide pyran were produced by the flower of cv. Fancy Parfait; and the ratio of cis-linalool oxide pyran, an attractant for vector thrips, to the trans-type was approximately 1 : 5. Our results suggest that cultivation of verbena as a trap crop may be useful in integrated pest management programs as a control for thrips-transmitted TSWV in chrysanthemums.

TOMATO YIELD AND SPOTTED WILT VIRUS INCIDENCE AMONG CULTIVARS IN A MISSISSIPPI TRIAL

Mississippi's two largest tomato-growing areas are in Smith and George Counties. The Truck Crops Branch Experiment Station in Crystal Springs is the closest vegetable research site to Smith County but does not share the same soil type. Tomato spotted wilt virus (TSWV) reduces fruit yield and marketability, and its incidence appears to be increasing in the state. The objectives of this trial were 1) to determine fruit yield and TSWV incidence in tomatoes (Lycopersicon esculentum) grown in central Mississippi, and 2) compare yield and relative yield among cultivars and between locations. Tomato seedlings were transplanted to the field in April 2004 in Smith and Copiah County plots. Production practices included raised beds, black plastic mulch, drip irrigation, and fertilizer applied pre-plant and as side-dressings based on soil test and regionally recommended practices. TSWV incidence was recorded in each plot in Smith Co. in June 2004. In both locations, `Amelia' and `Mountain Spring' were among the top yielding entries. In Smith, the top entries also included `BHN 543' and two commercial experimental entries. In Copiah, `Florida 47 R', `Biltmore', `Mountain Fresh', and `BHN 543' also produced high marketable yields. `Florida 47R', `Bush Celebrity', and `Mountain Fresh' were among the poorest yielding varieties in Smith County. Incidence of TSWV was not formally rated in Copiah. In Smith, percent symptomatic plants per plot were negatively correlated with yield. Symptoms were found on entries reportedly resistant or tolerant to TSWV.

Impact of Early-Season Thrips Management on Reducing the Risks of Spotted Wilt Virus and Suppressing Aphid Populations in Flue-Cured Tobacco

The influence of tray drench (TD) treatments, with and without foliar applications of the plant activator acibenzolar-S-methyl (Actigard), was examined in replicated field plots in 2000–2002. TD treatments of Actigard, imidacloprid (Admire), and these two products combined had little effect on seasonal mean thrips populations; however, thrips densities were lower in the Admire-treated plots at 4 and 5 wk after transplanting. Actigard and Admire TD treatments significantly reduced the seasonal incidence of tomato spotted wilt virus (TSWV) symptomatic plants in 2 yr in the study. The combination of both products was better in reducing TSWV than Actigard alone. Three early-season foliar sprays of Actigard had no effect on thrips population densities, but they did reduce TSWV incidence. The tobacco thrips, Frankliniella fusca (Hinds), comprised 92–95% of the thrips complex each year. Other thrips collected on tobacco foliage at very low densities included Haplothrips spp., Chirothrips spp., Limothrips cerealium (Haliday), other Frankliniella spp. and other unidentified species. Using nonstructural TSWV protein enzyme-linked immunosorbent assay, 1.5–2.3% of the F. fusca tested positive for nonstructural TSWV protein. Cured yields were higher in the TD treatments and the Actigard foliar treatments in the years with high TSWV in the untreated plots. The TD treatments and foliar Actigard had little impact on plant height or grade index; however, TD treatments with Admire had low tobacco aphid, Myzus nicotianae Blackman, populations through 10 wk after transplanting. The early-season Actigard and Admire treatment options are management decisions that can effectively reduce the risks of TSWV incidence in flue-cured tobacco.

Impact of Early-Season Thrips Management on Reducing the Risks of Spotted Wilt Virus and Suppressing Aphid Populations in Flue-Cured Tobacco

The influence of tray drench (TD) treatments, with and without foliar applications of the plant activator acibenzolar-S-methyl (Actigard), was examined in replicated field plots in 2000--2002. TD treatments of Actigard, imidacloprid (Admire), and these two products combined had little effect on seasonal mean thrips populations; however, thrips densities were lower in the Admire-treated plots at 4 and 5 wk after transplanting. Actigard and Admire TD treatments significantly reduced the seasonal incidence of tomato spotted wilt virus (TSWV) symptomatic plants in 2 yr in the study. The combination of both products was better in reducing TSWV than Actigard alone. Three early-season foliar sprays of Actigard had no effect on thrips population densities, but they did reduce TSWV incidence. The tobacco thrips, Frankliniella fusca (Hinds), comprised 92-95% of the thrips complex each year. Other thrips collected on tobacco foliage at very low densities included Haplothrips spp., Chirothrips spp., Limothrips cerealium (Haliday), other Frankliniella spp. and other unidentified species. Using nonstructural TSWV protein enzyme-linked immunosorbent assay, 1.5-2.3% of the F. fusca tested positive for nonstructural TSWV protein. Cured yields were higher in the TD treatments and the Actigard foliar treatments in the years with high TSWV in the untreated plots. The TD treatments and foliar Actigard had little impact on plant height or grade index; however, TD treatments with Admire had low tobacco aphid, Myzus nicotianae Blackman, populations through 10 wk after transplanting. The early-season Actigard and Admire treatment options are management decisions that can effectively reduce the risks of TSWV incidence in flue-cured tobacco.