Tobacco, Thrips, and Tomato Spotted Wilt
Despite uncertainty, adverse weather during the past few growing seasons, and lower market value, flue-cured tobacco continues to be a staple in the diverse agriculture economy here in Sampson County for good reason. Our climate and soil characteristics in a large portion of Sampson and other surrounding counties allow tobacco growers here to produce some of the highest quality tobacco in the entire world. Tobacco has been grown on this land for centuries and the production tradition has been passed down through generations. While they have had to diversify their farms over the years, growers take pride in the art of producing this unique crop from a tiny seedling all the way to a perfectly cured leaf.
Tobacco growers in Sampson County are now in full swing transplanting the tobacco seedlings they have been producing in greenhouses since February. Once the transplants are in the field, they will spend the remainder of the growing season there until harvest. Growers have a relatively small window of time for transplanting into the field depending on the weather conditions. This window can be even smaller depending on the flight of the tobacco thrip insect.
Tobacco thrips are foliar feeding insects that chew on the leaves of tobacco plants. Although they are named after the crop, this subspecies of thrips do not necessarily prefer tobacco when feeding. These insects overwinter on weeds and brush around fields. The time that these winter weeds begin to die out just happens to coincide with the timeframe tobacco growers need to transplant their crop into the fields. When the thrips winter host begin their dieback, they scramble to find a new plant to feed on, and often tobacco is the closest plant. The tobacco thrips do not cause direct physical damage to the plants when feeding, however they can transmit a disease called Tomato Spotted Wilt Virus (TSWV) that can be detrimental to young tobacco plants. TSWV can affect the marketable quality of the tobacco leaves, and in severe cases cause complete death of the tobacco plant, thus leading to yield loss. While there are many growers who seldom have an issue with TSWV, there are pockets of Sampson County that seem to be hotspots for the plant disease. These growers take extra caution during transplanting time, using preventatives in the greenhouse and transplant water that help defend the plants against the feeding of tobacco thrips. Growers also have an online forecasting tool that allows them to better predict when thrips will be more likely to feed on their tobacco plants.
The TSWV and Thrips Exposure Tool for Tobacco uses temperature and rainfall data in an effort to predict the seasonal thrips flights. The ultimate goal is to minimize the thrips exposure to tobacco plants. The purpose of this tool is to help guide growers in decision making regarding the best optimum time to make management decisions for thrips. All growers can use this tool by simply entering a field location, the type of tobacco grown, the anticipated transplant date, and any protective greenhouse treatments they plan to make. The tool will use the information to help predict if that particular field will experience a thrips flight within two weeks and will also provide the grower with some potential management options. This tool relies especially on weather forecast data availability, therefore it will only provide a prediction two weeks out from the date the grower uses the tool. TSWV has also been reported in other counties as well, with varying severity depending on weather conditions.