Update: Whiteflies in Mississippi Cotton – July 31, 2026

This is an update on an original blog post that I posted earlier this week, and that can be found here: https://www.mississippi-crops.com/2026/07/27/whiteflies-in-cotton-july-24th-2026/

Based on my limited knowledge of managing this pest, my original recommendations included focusing on insecticide applications targeting tarnished plant bugs with the hope of managing whiteflies in the process. Since that blog post was written, we have updated 14-day after application efficacy data from a trial we deployed at the Delta Research and Extension Center on Friday, July 17th 2026. These data were collected by pulling newly developed leaves since the 7-day after application sample; in this case, the third node down from the terminal. This ensures that any insects present in counts are of a fresh cohort and not previously sampled. These data can be viewed below:

Figure 1. Insecticide efficacy for the management of adult bandedwing whiteflies in cotton at 7 and 14 days after application.

Neither Centric, acephate, nor imidacloprid provided any benefit for adult whiteflies; in fact, these products actually worsened the situation. Transform, Assail, and Sivanto, however, provided significant reductions in adult whitefly densities.

Figure 2. Insecticide efficacy for the management of immature bandedwing whiteflies in cotton at 7 and 14 days after application.

Data regarding immatures show a similar trend, with Centric, imidacloprid, and acephate exacerbating whitefly issues. Similar to the adult data, Transform, Sivanto, and Assail provided significantly better control of whiteflies 14 days after the application. With what we know, these products should be prioritized if whitefly management is needed. It should be noted that Sivanto provides no tarnished plant bug suppression, and Assail provides very little. A note on pricing to keep in mind: Sivanto is a much pricier option, with Assail being a little more affordable. There are certainly other products out there that could be used that would likely be effective; the products we tested were selected due to limited trial space. 

These plots are under intense whitefly pressure and are beginning to drop lower leaves that are yellowing. I would suspect that this would worsen under drought conditions. As we move to maturity, the most important thing to keep in mind is that the honeydew secreted by this pest can stain lint, and allowing this to occur should be avoided. From talking with colleagues in the Southeast, I am told this can be washed away with a moderate rain; however, relying on a rain is not an optimal decision. This pest is not one that we are going to zero out with an application of any one insecticide. Follow-up applications may be necessary, and even then we may still deal with them to some degree.

Call us with any questions you may have. We can discuss situations and options. My cell phone number is (662) 820-4217.