Tales of Cotton Insects: Tuesday, July 1, 2025

Early candle stage square with signs of plant bug feeding. 

Over the past week, we have received reports of plant bugs in older cotton fields across the whole state of Alabama. The traditional movement of insects seems to be off this year. Wet, relatively cool and cloudy conditions for a lot of June have caused to not grow off as quick as usual and has seemed to keep insects in weedy hosts for the most part. Plant bugs have been trickling into fields and have or are now requiring action. Our plan of attack hasn’t changed since our last blog of adult plant bugs (link). However, we are approaching the time that immatures will begin showing up.

As we get to bloom and target immatures, we must change the plan. Transform (1.75 oz) is an excellent material for control of nymphs. Additionally, acephate (0.75 lb) provides consistent control. Bidrin (6 oz) comes back into play when cotton reaches the first week of bloom. Pyrethroids provide adequate control on some areas but we are increasingly seeing slippage of control and outright failures in some areas. Regardless of the knockdown insecticide used, Diamond (6-9 oz) plays an important role in control. We generally expect 2-3 weeks of residual suppression from Diamond at the 6-9 oz rate, respectively. Note that this is suppression and not knockdown. Diamond is best utilized when applied at the first appearance of nymphs (which will likely happen some where between 10-14 days after an adult application was made). Diamond is an important piece of the plant but management puzzle, particularly with all the rain and pop up showers we have experienced recently.

We also have some fields at peak bloom that are highly susceptible to stink bugs. Populations seemed light in corn this year but that does not mean we can forget about them. As cotton reaches the 3rd-6th weeks or bloom, threshold is just 10% internal boll injury on quarter-sized (~1 in diameter bolls). Pyrethroids and organophosphates provide good control.

Finally in cotton, we have seen some heavy infestations of aphids in many fields. The fungus may be starting to build so applications solely for aphids may not be warranted. However, most plant bug materials provide good control of aphids. 

Soybean update. We have received reports and observed fields with redbanded stink bugs in central Alabama. Adults can be killed with high labeled rates of pyrethroids but immatures are a different story. In order to get adequate control, 2 way tank-mixtures of pyrethroids (highest rate), acephate (0.5 lbs) or imidacloprid (highest rate) are needed. Threshold for RBSB is 4 per 25 sweeps (lower than the traditional stink bug threshold =6 per 25 sweeps). If a complex is found, RBSB should be counted as 1.5 of other sink bug species.

As always, if we can ever be of any help, or if you would like to provide input on the situation in your area, please don’t hesitate to reach out to your local Extension Agent or myself (Scott Graham: 662-809-3368) and Ron Smith (334-332-9501). For more information on thresholds and insecticide recommendations, visit the Alabama Cotton IPM Guide (IPM-0415). To stay up-to-date on the Alabama cotton insect situation, subscribe to the Alabama Cotton Shorts Newsletter, Alabama Crops Report Newsletter and Podcast, and the Syngenta Pest Patrol Hotline.