Thrips Flight and TSWV Risk Assessment Report – 10 April 2018

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TSWV virus incidence was higher in 2017 than in previous years due, in part, to warm winter temperatures and spring conditions that maintained winter weed hosts of thrips for a longer time than typical. Read more about tobacco thrips biology and TSWV transmission here.

Because of increased damage due to TSWV infection last year, growers are cautious as we move toward transplant. We have developed a decision aid to provide growers with a sense of potential TSWV risk. The TSWV and Tobacco Thrips Risk Forecasting Tool provides growers with both current year (April through May) and historic TSWV infection and tobacco thrips flight predictions. These predictions are based on over 30 site years of thrips trapping and weather data.

In order to give growers a sense of TSWV risk moving into 2018 transplant, we will be producing twice weekly reports from the TSWV and Tobacco Thrips Risk Forecasting Tool for selected locations around eastern NC where TSWV may be problematic. In these posts, we’ll provide a summary of model outputs to date for each location and suggestions as to how growers might use this information to make management decisions. These predictions will improve as we get closer to transplant dates, and growers should use the most recent information to make management decisions!

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 slightly lower than in a typical year. The third generation tobacco thrips flight (the generation that typically transmits the most TSWV) is not expected to occur during the next 14 days. At this time last year, we were 62% of the way to the third generation thrips flight, and this year, we are 47% 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 10Growers near Kenly planning to transplant within the next 14 days likely do not need to take additional management precautions for TSWV at this time.

Beulaville is a higher TSWV risk site in Duplin County. As of today, TSWV infection risk in Beulaville is slightly lower than in a typical year. The third generation tobacco thrips flight (the generation that typically transmits the most TSWV) is not expected to occur during the next 14 days. At this time last year, we were 64% of the way to the third generation thrips flight, and this year, we are 53% 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 4Growers near Beulaville planning to transplant within the next 14 days likely do not need to take additional management precautions for TSWV at this time.

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. The third generation tobacco thrips flight (the generation that typically transmits the most TSWV) is not expected to occur during the next 14 days. At this time last year, we were 63% of the way to the third generation thrips flight, and this year, we are 51% 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 5Growers near Kinston planning to transplant within the next 14 days likely do not need to take additional management precautions for TSWV at this time.

New Bern is a higher TSWV risk site. As of today, TSWV infection risk in New Bern is slightly lower than in a typical year. The third generation tobacco thrips flight (the generation that typically transmits the most TSWV) is not expected to occur during the next 14 days. At this time last year, we were 73% of the way to the third generation thrips flight, and this year, we are 48% 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 April 29Growers near New Bern planning to transplant within the next 14 days likely do not need to take additional management precautions for TSWV at this time.

Windsor is a higher TSWV risk site. As of today, TSWV infection risk in Windsor is slightly lower than in a typical year. The third generation tobacco thrips flight (the generation that typically transmits the most TSWV) is not expected to occur during the next 14 days. At this time last year, we were 49% of the way to the third generation thrips flight, and this year, we are 39% 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 19Growers near Windsor planning to transplant within the next 14 days likely do not need to take additional management precautions for TSWV at this time.

Whiteville is a moderate 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 slightly lower than in a typical year. The third generation tobacco thrips flight (the generation that typically transmits the most TSWV) is not expected to occur during the next 14 days. At this time last year, we were 75% of the way to the third generation thrips flight, and this year, we are 61% 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 April 28Growers near Whiteville planning to transplant within the next 14 days likely do not need to take additional management precautions for TSWV at this time, but they should check back before transplant!

Carthage is a relatively low TSWV risk site in Moore County. As of today, TSWV infection risk in Carthage is slightly lower than in a typical year. The third generation tobacco thrips flight (the generation that typically transmits the most TSWV) is not expected to occur during the next 14 days. At this time last year, we were 62% of the way to the third generation thrips flight, and this year, we are 41% 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 11Growers near Carthage planning to transplant within the next 14 days likely do not need to take additional management precautions for TSWV at this time.

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 thripsTobacco 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
Posted on Apr 10, 2018
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