Alabama Thrips Risk: April 18, 2024

The Thrips Infestation Predictor Model for Cotton (link) is a useful tool to use to help understand which planting dates or planting windows are at the highest risk of thrips injury. This model predicts how thrips movement and cotton growth will line up based on recent and predicted weather patterns. The model also provides some context with the last 5 years for thrips pressure at your given planting date. We started running the model to get an idea of what thrips pressure is predicted as we move into the early planting window.

South Alabama

We ran the model in Henry and Escambia counties and cotton planted until about the first week of May is at the highest risk of thrips injury.

Central Alabama

The model showed in Autauga, Lee, Talladega and Fayette counties that cotton planted after about May 10^th is at the highest risk of thrips injury.

North Alabama

North Alabama (Cherokee and Limestone counties) were similar to central Alabama with cotton planted after about May 10^th being at the highest risk of thrips injury.

To look at the models we ran, you can click here.

Keep in mind that the model is fluid and things can change based on an unexpected rain event (or a missed expected rain). You should update the model every couple days before and after planting to make sure you are seeing the most accurate version. Remember that the model is used to understand risk of thrips injury and which fields may need a supplemental foliar application.

If we can be of any help, please don’t hesitate to reach out and let us know (Scott Graham: 662-809-3368; Ron Smith: 334-332-9501). To stay up-to-date on the Alabama insect situation, subscribe to the Alabama Cotton Shorts Newsletter, Alabama Crops Report Newsletter, and the Syngenta Pest Patrol Hotline.

Preparing for the 2024 Cotton Season

The latest USDA estimate has cotton up significantly (430,000 acres) compared to last year. Hopefully, this means we will be able to spread insect pressure across more acres and dilute some of the populations. We cannot rely on this, however, and farmers should be prepared (budgeted) to make multiple applications for insects in 2024.

Some thoughts and considerations for this season in Alabama.

1.    Scouting and Monitoring. To most economically manage insects, fields should be scouted weekly to know what insects are in the field, and at what levels they are present. The situation changes week to week and timely applications can only be made if damaging levels are found in time to react.

2.   Spread the Risk. Consider planting the crop across a range of planting dates if possible. This can protect some of the crop from being vulnerable to variable weather patterns during the season. The current predicted weather for this season looks favorable for an early crop, so don’t be scared to jump out and get started as soil temperatures allow in the coming weeks.

3.   Pre-Plant Insects. To best reduce risk to “stand robbers” like cutworms, slugs and other pests, good winter cover burndown is essential. Ideally, covers would be terminated (dead) at least 3 weeks before planting. To quote my advisor at UT, Dr. Scott Stewart, “If it ain’t brown, don’t put seed in the ground.” If termination is closer to planting, consider adding a pyrethroid ±7 days of planting to reduce risk.

4.   Thrips. Use the Thrips Infestation Model (link) to prepare which fields may need a supplemental foliar application. Planting dates with a dark red or number close to “1” will likely benefit from an application, particularly if just a standard seed treatment is used. Note: ThryvOn cotton will likely NOT benefit from a foliar spray, regardless of planting date.

5.   Plant Bugs. Adult plant bugs will likely infest our earliest planted cotton first. These fields have the most food sources available when daisy fleabane begins to dry down. Our goal with adult plant bug management is to maintain at least 80% square retention and to reduce egg lay. Apply imidacloprid or Centric early season to accomplish this goal. As the crop begins to bloom, our attention turns to immature plant bugs that hatch out from the above-mentioned eggs. 

     Sometime around 1^st bloom, or 10-14 days after a June adult plant bug spray, is a good time for a tank-mixture of a knockdown insecticide and the insect growth regulator, Diamond. This material provides 2 to 3 weeks (6 -9oz rate) of residual “suppression” of nymphs and may be enough to get us to the stink bug window (around the 3^rd week of bloom). Using a black drop cloth in a couple areas of the field is the best way to scout for immature plant bugs and threshold is 3 nymphs per drop (=5 row feet).Note: ThryvOn cotton will likely NOT benefit from an application of Diamond.

6.   Stink Bugs. Beginning around the 3^rd week of bloom, every insecticide application should include a material that controls stink bugs (pyrethroid or organophosphate). Peak bloom (weeks 3-6) is the most important time to manage stink bugs. Instead of looking for stink bugs with a sweep-net or drop cloth, sample 10–12-day old bolls (≈1 in diameter) for internal signs of injury. Threshold is 10% damage during peak bloom. We should mention that this 10% does not represent every boll in the field, but 10% of the 10-12-day old bolls during that week of sampling.

     This year is the 100^th year of Extension Cotton Entomology at Auburn University and Alabama Extension. Our goal is the same today as it was in 1924: to help Alabama cotton farmers make the best insect management decisions possible. You can read a nice write up of the history of Extension Cotton Entomology in Alabama in Cotton Farming Magazine. 

      If we can be of any help, please don’t hesitate to reach out and let us know (Scott Graham: 662-809-3368; Ron Smith: 334-332-9501). To stay up-to-date on the Alabama insect situation, subscribe to the Alabama Cotton Shorts Newsletter, Alabama Crops Report Newsletter, and the Syngenta Pest Patrol Hotline.