A field trial was conducted at the Upper Coastal Plains Research Station in Rocky Mount, NC, to evaluate different fungicide programs for managing target spot in tobacco. The study was set up using a randomized complete block design with four replications to ensure reliable results. Each plot was 14.7 feet wide and 50 feet long, containing four rows of tobacco, with the two center rows used for evaluation. The tobacco variety K326 was transplanted on April 23 using a mechanical tobacco transplanter, following standard non-irrigated tobacco production practices in North Carolina.

The trial compared 5 different fungicide treatments against an untreated control. Each treatment included three applications throughout the season:

• First application: May 22 (4 weeks after transplanting)
• Second application: June 10 (6 weeks after transplanting)
• Third application: June 26 (8 weeks after transplanting)

Fungicides were applied using a CO₂-pressurized backpack sprayer, ensuring proper coverage and accurate application rates.

Target spot severity was monitored by evaluating five plants per plot at different stalk positions:

• Lower stalk (lugs)
• Middle and upper-middle stalk (cutters and leaf)
• Upper stalk (tips)

These assessments were conducted biweekly from May through July to track disease progression. The results were summarized using the Area Under the Disease Progress Curve (AUDPC), a common method for measuring disease severity over time. Harvests took place on July 30, August 13, August 14, and August 22, with leaf samples collected from all stalk positions to test for fungicide residues.

This season presented challenging weather conditions, including an early-season drought followed by hurricanes and heavy rains. Target spot pressure remained low during the first eight weeks after transplanting due to the lack of moisture needed for disease development. While heavy rains at the end of the season did not significantly increase disease pressure, they may have contributed to water stress, potentially reducing plant growth and yield. 

While there were no significant differences between treatments, there were some notable differences. For example, in a rotational program of Quadris Flowable, Manzate Pro-Stick, and Quadris Flowable, there was substantial decrease in disease, as well as a yield increase of 7.5%, resulting in a return on investment (ROI) of approximately $368 (Table 1). Continued research will refine these recommendations, ensuring that growers have data-driven strategies to manage target spot and optimize their production.

 Table 1. Effect of commercially available fungicides on target spot severity and leaf yield, Rocky Mountain, NC, 2024.