Thrips Flight and TSWV Risk Assessment Report – June 4, 2025
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Collapse ▲To help growers determine the potential of management practices for TSWV, we have created step-by-step guides on how to use the Tobacco Thrips Flight and TSWV Intensity Predictor to create Current Year TSWV Risk Assessments and Historical TSWV Predictions. Growers are strongly encouraged to create their own models using the information from their fields and season dates to plan for Tomato Spotted Wilt Virus (TSWV) management.
UPDATE: Predictive models for the locations below indicate a higher estimated TSWV Risk than expected, especially for the Whiteville area (14.6%), followed by the New Bern and Kinston areas (8.4% risk). The 4th generation of tobacco thrips has dispersed in these areas for the last 1-2 weeks. This is one of the generations that can cause the most TSWV infection, particularly in fields planted late in April or after. In the Kenly area, this generation is expected to disperse by the end of this week (6/8/2025).
The Small Fruit and Tobacco IPM Lab monitors TSWV incidence weekly in tobacco fields in Wilson, Kenly, and New Bern. Monitoring efforts showed a steady increase in TSWV incidence over time; however, none of our fields have shown incidence above the NC action threshold of 10% (Table 1). Treatment in addition to standard insecticides is probably not required for areas with a history of <10% TSWV incidence.
TSWV incidence is affected by temperature, rainfall, age of the plants, among other factors, such as disruption of neighboring small-grain fields or weed patches. Avoid applying herbicides on these fields between April and June when 3rd and 4th generations of tobacco thrips began to disperse. Disturbance of this fields may exacerbate thrips movement to tobacco fields and contribute to TSWV infections. Spikes in TSWV in localized areas (20+% TSWV incidence) are often related to this types of disturbances.
At this point of the season, insecticides sprays solely focused on thrips management are probably not required as most thrips generations have already dispersed and plant growth has advance in most areas. Additionally, since most growers have already applied imidacloprid at planting or greenhouse stage, using it again at this point is not reccomended.
For growers with TSWV outbreaks around or above 20% that are concerned with TSWV increasing incidence, and the start of budworm infestations, spinosad (Blackhawk®) and Besiege® an insecticide application can be helpful can be helpful. These NON-neonicotinoid insecticides are effective against budworms and can suppress tobacco thrips.
Table 1. TSWV incidence in three commercial tobacco fields monitored weekly in NC.
| Date | Location | # plants/acre with TSWV symptoms | # of plants sampled | Percentage of sampled plants with TSWV |
| 5/16/2025 | Wilson | 3 | 200 | 1.5% |
| 5/16/2025 | Kenly | 1 | 200 | 0.5% |
| 5/16/2025 | New Bern | 8 | 200 | 4.0% |
| 5/23/2025 | Wilson | 9 | 200 | 4.5% |
| 5/23/2025 | Kenly | 9 | 200 | 4.5% |
| 5/23/2025 | New Bern | 13 | 200 | 6.5% |
| 5/30/2025 | Wilson | 12 | 200 | 6.0% |
| 5/30/2025 | Kenly | 11 | 200 | 5.5% |
| 5/30/2025 | New Bern | 16 | 200 | 8.0% |
This update was compiled based on Thrips Flight and TSWV Risk Assessments conducted for the four key tobacco-growing locations in NC included below. These models were created assuming no insecticide treatment and including the average historical TSWV incidence for each location as listed below (Fig. 8.1 modified from Mina, 2011).
- Kenly is a relatively low TSWV risk site (typically less than 8%), situated within large acreage production areas in Johnston and Wilson Counties.
- Kinston is a moderate TSWV risk site (typically less than 10%) in Lenoir County and also houses the NCDA & CS Cunningham Research Station, where extensive tobacco research is conducted.
- New Bern is a higher TSWV risk site (typically above 10%) in Craven County.
- Whiteville is a moderate to high TSWV risk site (around 8% or above 10%) in Columbus County and also houses the NCDA & CS Border Belt Tobacco Research Station, where tobacco research is conducted.
The models used for this summary are attached below for your reference. In order to get the most accurate risk assessment, we recommend you enter your own farm data into the TSWV and Tobacco Thrips Risk Forecasting Tool and check for any updates frequently. See the NC Agricultural Chemicals Manual and the NC Flue Cured and Burley Tobacco Guide for details on TSWV management practices.
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