Tarnished Plant Bugs
|Immature Tarnished Plant Bug|
In our most mature fields (those in bloom) we need to be sampling for immature plant bugs. This is done by placing a black drop cloth between two rows of cotton and shaking the vigorously the plants on either side of the cloth to dislodge any insects on the plants onto the cloth. Count the number of immature plant bugs on each sample. Threshold is when you find an average of 3 bugs per 5 row feet (one drop cloth sample).
|Adult Tarnished Plant Bug|
Depending on the targeted populations, we have several options for control of plant bugs. When going after adults in pre-bloom cotton, the neonicotinoids provide adequate control of both plant bugs and aphids (e.g. imidacloprid, Centric). When primarily dealing with immature plant bugs in blooming cotton, we tend to shift away from the neonics to other chemistries. The insect growth regulator, Diamond, is a good option that provides 2-3 weeks residual control when used at a rate of 6-9 oz, respectively. Diamond should be combined with a knockdown insecticide such as Transform, acephate, Bidrin or pyrethroids (depending on resistance levels in your area) to provide more immediate control.
|Smaller boll damaged|
by stink bugs
Aphids and Spider Mites
We have received reports of the aphid fungus killing aphids in parts of South Alabama over the past week. Hopefully the fungus will spread statewide quickly and knockout any lingering populations we are dealing with from now on. We have also gotten reports of spider mites in fields in the east central and southeast areas of the state. For now, we are advising folks to watch the populations and wait until the forecast shows a several of hot, dry days in a row before spraying. We want to maximize the effectiveness of the application and reduce the chances of a rain event reducing efficacy.
Take Home Message for the Current Cotton Insect Situation
With the varying stages of cotton (from 1st true leaf to 3rd week of bloom) across the state (and within an individual farm in some cases) we are going to have to do a lot of insect management on a field-to-field basis in 2021. Proper scouting and keying in on the correct pest for the stage of crop and time of year will be critical. We will continue to put out information through twitter, this newsletter and the Alabama Crops Report Newsletter, Podcast and on the Pest Patrol Hotline. As always, if we can ever be of any help please don’t hesitate to let reach out.