Thursday, December 8, 2022

Effective, Three-Gene Bt Varieties Shine


Scott Asher, Ph.D.
Regional Agronomy Manager, BASF
Spring Hope, North Carolina

Over the past couple of growing seasons, there have been some hot spots of increased damage from cotton bollworm in two-gene Bt cotton in certain areas of the eastern Cotton Belt. We at BASF, in cooperation with university cotton entomology experts, conduct sentinel plots across the Cotton Belt evaluating efficacy of our Bt trait packages against cotton bollworm.

Cotton Bollworm Thresholds Adjusted
In these trials, data is collected to quantify damage caused by the cotton bollworm on non-Bt, two-gene Bt and three-gene Bt cotton varieties over a five- to seven-week period once flowering has occurred. In most of these trials, damage levels have remained below threshold, even on two-gene Bt cotton, but there have been some hot spots in the Delta and North Carolina where damage has been elevated.

Thresholds for cotton bollworm management in two-gene Bt cotton have moved from damage thresholds to egg-lay thresholds once bloom has occurred in parts of the eastern Cotton Belt. Due to this development, many growers and consultants want to move to three-gene Bt cotton varieties.

Excellent Results In The Eastern Cotton Belt
In 2020, Stoneville® cotton seed will offer multiple three-gene Bt varieties broadly adapted for the eastern Cotton Belt, all of which have shown outstanding performance.

In 2018 university Official Variety Trials across this region, ST 4550GLTP and ST 5471GLTP were among the best performing three-gene Bt cotton varieties. The 2019 results are showing the same level of consistent performance with ST 4550GLTP and ST 5471GLTP. Both varieties were among the best performing varieties in the North Carolina on-farm testing program and were the top-performing three-gene Bt cotton varieties.

ST 4990B3XF is a new variety we broadly showcased in our Agronomic Performance Trials in 2019. Its performance across the eastern Cotton Belt has been great, especially on high-performing ground. ST 4990B3XF is a variety that is easy to manage, which is very beneficial on the top-producing ground where some varieties are difficult to manage.
So, if you are looking to incorporate some three-gene Bt cotton varieties into your farm plan in 2020, consider the top-performing three-gene Bt varieties from Stoneville.

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