Bt By the Numbers

Bt field trials produce interesting results for its use in tank mix or rotation with other chemistries.


The numbers don’t lie, and the results are dramatic.

Marcus Adair is the Senior Field R&D Scientist at Valent BioSciences in Oxford, MS. When he coordinated a series of Bt field trials with cooperators in Florida, California, Texas, and the Carolinas, the objective was to gather hard data on the economic impact of using Bt in tank mix and rotation alongside a variety of other effective chemistries.

The trials revealed what many progressive growers already know: an integrated program incorporating Bts has definitive and measureable economic impact. Economic impact was expressed as marketable yield and/or seasonal cost of applications. Trials integrated Bt with products such as Coragen, SpinTor, Warrior, Proclaim, and others. Complete information on all trials can be found by clicking here.

Side By Side Comparisons

Here’s a snapshot view of the results from each trial. In each example:
UTC = Untreated Control, Product + Product = Tank Mix combination, Product/Product = Rotation

DiPel and SpinTor – Cabbage

Product Foliage Rating
(0 = Poor; 6 = Good)
Seasonal Cost ($)
UTC 3.25  
SpinTor (4) 5.65 260.88
DiPel + SpinTor (4) 6 224.32
DiPel/SpinTor (2/2) 5.8 177.38

Conclusion: Both the Bt rotation and the Bt tank mix programs performed better than SpinTor as a stand alone, and a lower cost.

XenTari and SpinTor – Cabbage

Product Marketable Heads / 10 Plants Seasonal Cost ($)
UTC 6.5  
SpinTor (5) 9.5 326.1
XenTari (5) 9.75 166.76
XenTari + SpinTor (5) 10 329.81
XenTari / SpinTor (3/2) 10 230.49

Conclusion: The Bt tank mix and rotational programs produced higher yields at equal or lower cost than the SpinTor-alone program.

XenTari and Proclaim – Cabbage

Product Damage Rating
1 = No Damage; 6 = Heavy Damage
Seasonal Cost ($)
UTC 5  
XenTari + Proclaim (5) 0.48 396.51
Proclaim (5) 0.58 459.51
XenTari / Proclaim (3/2) 2.75 283.86
XenTari (5) 3.1 166.76

Conclusion: Only Bt + Proclaim and Proclaim alone were commercially acceptable. The Bt + Proclaim treatments performed slightly better at a lower cost than Proclaim alone.

XenTari and Coragen – Fresh Market Tomato

Product Undamaged Fruit/10 Plants Seasonal Cost ($)
UTC 160  
Coragen (2x) 185 62
XenTari (2x) Coragen (1x) 188 54

Conclusion: Bt in rotation with Coragen works as well as Coragen alone, and at lower cost.

XenTari and Warrior – Cabbage

Product Larvae/5 Plants Seasonal Cost ($)
UTC 290  
Warrior 267.5 99.31
Warrior/XenTari 201 149.71
XenTari/Warrior 98.5 149.71
XenTari 58 200.11
XenTari + Warrior 32.5 299.42

Conclusion: Programs that incorporated Bt performed better than the pyrethroid-alone program.