Thrips Flight and TSWV Risk Assessment Report – June 2, 2020

— Written By

This is the ninth weekly TSWV and tobacco thrips risk assessment update. Third generation flights have now occurred at all our report locations, and fourth generation flights have occurred 2 of our 8 report locations. Fields planted within a month of the fourth generation flight may warrant additional attention. Interestingly, we also starting seeing some early hornworms of both species in the field this week.

We have produced weekly reports from the TSWV and Tobacco Thrips Risk Forecasting Tool for selected locations in eastern NC where TSWV may be problematic in order to help growers determine management decisions. We will conclude these reports next week, when most of our locations will have completed the fourth generation thrips flight.

The information presented here is intended to supplement, but not replace, farm-specific predictions. In order to generate data for your farm, the following information is required:

1. Field location, selected on 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

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 a typical year. Last year the third generation thrips flight occurred on May 24. This year, the third generation tobacco thrips flight (the generation that typically transmits the most TSWV) began on May 27. Because Kenly is a lower risk location, additional treatments against TSWV were not recommended here. Growers who are interested in making additional treatments against TSWV should consult their local Extension agent for recommendations or contact Hannah.

Keanansville is a higher TSWV risk site in Duplin County. As of today, TSWV infection risk in Keanansville is higher than a typical year. The third generation tobacco thrips flight typically transmits the most TSWV. Last year the third generation thrips flight occurred on May 16. This year, the third generation tobacco thrips flight (the generation that typically transmits the most TSWV) began on May 17. Greenhouse float water treatments of Actigard are effective for up to two weeks post-transplant. Because the flight has already begun, additional field applications of Actigard at this time will be less effective. The fourth-generation thrips flight is predicted for June 5, and late-planted tobacco may also benefit from protection against this generation as well. Growers should consult their local Extension agent for recommendations or contact Hannah for more information.

Kinston is a moderate TSWV risk site in Lenior County and also houses the N.C. Department of Agriculture and Consumer Services (NCDA&CS) Cunningham Research Station where we conduct tobacco research. As of today, TSWV infection risk in Kinston is slightly higher than a typical year. Last year the third generation thrips flight occurred on May 17. This year, the third generation tobacco thrips flight (the generation that typically transmits the most TSWV)  began on May 20. The fourth-generation thrips flight is predicted for June 8, and late-planted tobacco may also benefit from protection against this generation as well. Growers should consult their local Extension agent for recommendations or contact Hannah for more information.

New Bern is a higher TSWV risk site. As of today, TSWV infection risk in New Bern is higher than 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) began on May 9. The fourth-generation thrips flight was predicted for June 2, and late-planted tobacco may also benefit from protection against this generation as well. Because both of these flights have occurred, no additional management action is recommended.

Windsor is a moderate TSWV risk site. As of today, TSWV infection risk in Windsor is slightly higher than in a typical year. 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) began on May 26. Greenhouse float water treatments of Actigard are effective for up to two weeks post-transplant. Because the flight has already begun, additional field applications of Actigard at this time will be less effective. The fourth-generation thrips flight was predicted for June 13, and late-planted tobacco may also benefit from protection against this generation as well. Growers should consult their local Extension agent for additional recommendations or contact Hannah for more information.

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 9. This year, the third generation tobacco thrips flight (the generation that typically transmits the most TSWV) was expected to begin on May 4. The fourth-generation thrips flight was predicted for May 29, and late-planted tobacco may also benefit from protection against this generation as well. Because both of these flights have occurred, no additional management action is recommended.

Clinton is a higher TSWV risk site in Sampson County. As of today, TSWV infection risk in Clinton is slightly higher than in a typical year. Last year the third generation thrips flight occurred on May 14. This year, the third generation tobacco thrips flight (the generation that typically transmits the most TSWV) began on May 16. Greenhouse float water treatments of Actigard are effective for up to two weeks post-transplant and would not be recommended for growers who have not already transplanted. Because the flight has already occurred, additional field applications of Actigard at this time will be less effective. The fourth-generation thrips flight is predicted for June 4, and late-planted tobacco may also benefit from protection against this generation as well. Growers should consult their local Extension agent for recommendations or contact Hannah for more information.