ThryvOn Cotton in the Florida Panhandle – Summary of Trial Data at UF/IFAS NFREC Quincy

At the start of the 2024 season, we talked about early-season thrips management in cotton and peanut. I mentioned the potential for ThryvOn cotton and its efficacy on thrips as a potential new tool to combat early-season thrips and plant bug pressure. For the past two years, our team has compared ThryvOn and non-ThryvOn cotton to see what it means for us in the Panhandle. In short, ThyvOn works extremely well in keeping early season thrips pressure at low populations and will be important for the cotton growing region, not only in the Florida Panhandle, but across the US cotton belt. We will get into the details below, but first, here is a quick reminder of what exactly ThryvOn is.

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What is ThryvOn Cotton?

ThryvOn^® is a new cotton variety expressing the Bacillus thuringiensis (Bt) toxin Cry51Aa2, commercially trademarked as ThryvOn and developed by Bayer Crop Science. It was brought on the market in 2023. ThryvOn is different from other current Bt toxins that target caterpillar pests in cotton, corn, and soybean. This new toxin has activity against several key insect pest species of cotton in the Southeast, the most important being tobacco thrips, western flower thrips, and tarnished plant bugs. ThryvOn reduces target pest populations by reducing feeding and egg-laying activities of these pests during critical periods of the season that cause economic losses. ThryvOn cotton is unique from other types of Bt cotton because it does not result in high levels of pest mortality. The driving factor for the protection of seedling cotton is that adult thrips avoid feeding on and laying eggs in ThryvOn cotton, resulting in fewer immature thrips and less injury. The same effect is also seen for the tarnished plant bug.

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Two years at NFREC-Quincy

In 2023, we evaluated the efficacy of at-plant insecticides in ThryvOn (DP 2131 BG3TXF) and non-ThryvOn (DP1646 BG2XF) cotton. The insecticides used were Gaucho as an insecticide seed treatment, in-furrow applications of Admire Pro (9.2oz/a) and AgLogic (5 lb./a), and a foliar application of Acephate (3 lb./A) at the 1st true leaf. In 2023, the number of total thrips on average was significantly less in ThryvOn cotton than in non-ThryvOn cotton. Further, all 4 insecticide treatments were similar. Since there did not appear to be a benefit of plant insecticides in ThryvOn cotton, we decided to test insecticide vs. fungicide-only seed treatments in ThryvOn (DP 2211 BG3TXF) and non-ThryvOn cotton (DP 2127 BG3XF). Similar to 2023, ThryvOn had significantly fewer thrips than non-ThryvOn cotton in both fungicide-only and insecticide-seed-treated plots in our 2024 trial.

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Summary

In collaboration with specialists in the Southeastern Row Crop Working Group, these trials were replicated in 8 locations. Combined data shows similar results across the region. ThryvOn cotton consistently provides excellent protection against thrips across a range of planting dates, geographies and thrips pressure. Up to a 61% reduction in thrips populations and a 44% reduction in thrips injury across locations. No obvious benefits were observed in adding an insecticide to ThryvOn for thrips management across the locations. While we did not get enough plant bug pressure in Quincy, but data from across the region shows that ThryvOn cotton consistently suppresses plant bug populations.  Even so, you will still need some insecticide applications. However, fewer applications and lower rates may be needed compared to non-ThryvOn Cotton. If you have any questions about ThryvOn cotton, thrips, and plant bug management, contact me or your county extension agent.