Thrips Flight and TSWV Risk Assessment Report – May 28, 2018

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This is the fifteenth thrips flight and TSWV risk assessment report. Read about why we are posting these reports and more in our first reportRead more about tobacco thrips biology and TSWV transmission.

Third generation thrips flights are now underway at all of our report sites. We’ll continue to post reports through the predicted fourth generation flights, as this may be relevant for some growers who transplanted tobacco later. Once thrips flight have begun, no additional preventative treatments can be made.

TSWV symptoms have begun appearing in fields. Some locations we have visited have about the expected level of incidence, but we have also gotten reports from areas in southeastern NC, where TSWV incidence is typically highest, of high rates of infection. The conditions we experience last growing season had the potential to result in higher carryover this year, but our cold winter and wet spring had the potential to reduce risk. The next several weeks will tell us which had the biggest effect. We’ll be paying close attention to how disease incidence develops throughout the state.

Growers are reminded to use the most recent information available to make management decisionsPredictions are most accurate closer to predicted thrips flight dates. The information presented here is intended to supplement, but not replace, farm-specific predictions.

One of our extension agents pointed out that ZIP codes were not generating reports at some locations. If an address or ZIP code produces an error message at the Tobacco Thrips and TSWV Risk Forecasting Tool, please use the map to select your location instead. Using the map has not produced error messages.

Kenly is a relatively low TSWV risk site, situated within large acreage production areas in Johnston and Wilson Counties. As of today, TSWV infection risk in Kenly is about the same as in a typical year. Last year the third generation thrips flight occurred on May 10. This year, the third generation tobacco thrips flight (the generation that typically transmits the most TSWV) was expected to begin on May 23Because TSWV infection is predicted to be similar to a typical year and Kenly is a lower risk location, additional treatments against TSWV are not recommended for this location.The fourth generation thrips flight, which can also contribute to some TSWV transmission is predicted to occur on June 11. Tobacco plants transplanted more than 5 weeks prior to June 11 are at lower risk of TSWV infection and likely do not require additional treatment. Growers who are interested in making additional treatments against TSWV should consult their local extension agent for recommendations or contact Hannah.

Beulaville is a higher TSWV risk site in Duplin County. As of today, TSWV infection risk in Beulaville is lower than in a typical year. The third generation tobacco thrips flight typically transmits the most TSWV. Last year the third generation thrips flight occurred on May 4. This year, the third generation tobacco thrips flight (the generation that typically transmits the most TSWV) occurred on May 18Treatments effective at reducing TSWV infection in tobacco must be applied before predicted thrips flights, so additional treatments against TSWV are not recommended for this location. The fourth generation thrips flight, which can also contribute to some TSWV transmission is predicted to occur on June 4. Tobacco plants transplanted more than 5 weeks prior to June 4 are at lower risk of TSWV infection and likely do not require additional treatment. Growers who are interested in making additional treatments against TSWV in later transplanted tobacco should consult their local extension agent for recommendations or contact Hannah.

Kinston is a moderate TSWV risk site in Lenior County and also houses the NCDA & CS Cunningham Research Station where we conduct tobacco research. As of today, TSWV infection risk in Kinston is slightly lower than in a typical year. Last year the third generation thrips flight occurred on May 5. This year, the third generation tobacco thrips flight (the generation that typically transmits the most TSWV) began on May 20Treatments effective at reducing TSWV infection in tobacco must be applied before predicted thrips flights, so additional treatments against TSWV are not recommended for this location. The fourth generation thrips flight, which can also contribute to some TSWV transmission is predicted to occur on June 7. Tobacco plants transplanted more than 5 weeks prior to June 7 are at lower risk of TSWV infection and likely do not require additional treatment. Growers who are interested in making additional treatments against TSWV in later transplanted tobacco should consult their local extension agent for recommendations or contact Hannah.

New Bern is a higher TSWV risk site. As of today, TSWV infection risk in New Bern is lower than in a typical year. Last year the third generation thrips flight occurred on May 5. This year, the third generation tobacco thrips flight (the generation that typically transmits the most TSWV) began on May 19Treatments effective at reducing TSWV infection in tobacco must be applied before predicted thrips flights, so additional treatments against TSWV are not recommended for this location at this time. The fourth generation thrips flight, which can also contribute to some TSWV transmission is predicted to occur on June 6. Tobacco plants transplanted more than 5 weeks prior to June 6 are at lower risk of TSWV infection and likely do not require additional treatment. Growers who are interested in making additional treatments against TSWV in later transplanted tobacco should consult their local extension agent for recommendations or contact Hannah.

Windsor is a moderate TSWV risk site. As of today, TSWV infection risk in Windsor is about the same as in a typical year. At this time last year, we were 109% of the way to the third generation thrips flight, and this year, we are 95% of the way to the third generation thrips flight. This means that the population is maturing slower in 2018 than in 2017. Last year the third generation thrips flight occurred on May 19. This year, the third generation tobacco thrips flight (the generation that typically transmits the most TSWV) was expected to begin yesterday, May 27Because treatments effective against TSWV are preventative, no additional treatments are recommended at this point.

Whiteville is a higher TSWV risk site in Columbus County and also houses the NCDA & CS Border Belt Tobacco Research Station where we conduct tobacco research. As of today, TSWV infection risk in Whiteville is about the same as in a typical year. Last year the third generation thrips flight occurred on May 2This year, the third generation tobacco thrips flight (the generation that typically transmits the most TSWV) began May 17. Treatments effective at reducing TSWV infection in tobacco must be applied before predicted thrips flights, so additional treatments against TSWV are not recommended for this location at this time. The fourth generation thrips flight, which can also contribute to some TSWV transmission is predicted to occur on June 3. Tobacco plants transplanted more than 5 weeks prior to June 3 are at lower risk of TSWV infection and likely do not require additional treatment. Growers who are interested in making additional treatments against TSWV in later transplanted tobacco should consult their local extension agent for recommendations or contact Hannah.

Clinton is a higher TSWV risk site in Sampson County. As of today, TSWV infection risk in Clinton is slightly less than in a typical year. Last year the third generation thrips flight occurred on May 3This year, the third generation tobacco thrips flight (the generation that typically transmits the most TSWV) began May 16. Treatments effective at reducing TSWV infection in tobacco must be applied before predicted thrips flights, so additional treatments against TSWV are not recommended for this location at this time. The fourth generation thrips flight, which can also contribute to some TSWV transmission is predicted to occur on June 2. Tobacco plants transplanted more than 5 weeks prior to June 2 are at lower risk of TSWV infection and likely do not require additional treatment. Growers who are interested in making additional treatments against TSWV in later transplanted tobacco should consult their local extension agent for recommendations or contact Hannah.

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. The following information is needed:

1. Field location (address, coordinates, nearest ZIP code, or selected from a map)

2. TSWV infection percentage in a typical year at this location

In addition, you can provide the following optional information which will improve recommendations:

3. Anticipated planting date

4. Greenhouse applications of imidacloprid and/or Actigard

More Information

Tobacco thrips – Tobacco Growers Information

Written By

Photo of Dr. Hannah BurrackDr. Hannah BurrackAssoc. Professor and Extension Specialist (Berry, Tobacco and Specialty Crops) (919) 513-4344 hannah_burrack@ncsu.eduEntomology and Plant Pathology - NC State University
Updated on May 31, 2018
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