Alabama Cotton Insect Situation: August 26, 2022

Sunshine. That’s what the Alabama cotton crop across much of central and south Alabama is missing as of today. The 10-day forecast shows 50% or greater chances of rain across much of the state. As a lot of cotton is starting to open, we need to get out of this pattern. We realize that while insects are still in many fields, they do not pose the greatest risk to our crop at this time.  We have started seeing and hearing about some boll rot and hardlock going on in central Alabama and have seen a little bit of germination as well. Hopefully we get some sunshine and hot weather to dry all this cotton out and save as much of the lower bolls as we can.

With that in mind, we still have some fields with a ways to go and that need to be protected from insects. We are getting more calls on plant bugs than we are stink bugs right now, which is pretty unusual. Some things thoughts about insect management we enter the final push of the season.

Last effective bloom date: This is simply the day when you drop below at least a 50% chance for a white bloom to make it to the picker basket. Alabama is far too diverse to give a general LEBD, but most folks know how far out they can push a bloom and reasonably expect it to make it to the basket in their area.

With a given LEBD in mind, here are some key things to remember for insect controls:

Plant bugs can damage bolls until they are about 10-12 days old

Stink bugs can damage bolls until they are about 25 days old

Spider mites can cause reduced yields until harvestable bolls are     finished filling

Knowing we have stink bugs and plant bugs in some of these fields that need to be cleaned up, what are we going to do? Depending on your local weather pattern, I would avoid acephate at this point. While it is a very good bug material, it also has high wash off potential. We need a minimum of 8 hours with no rain, but really would prefer 12 or more. We are still hearing in some places that Bidrin is getting harder to find, hopefully we can still have that option. That leaves pyrethroids, primarily bifenthrin. We have heard reports of the past week about issues controlling plant bugs in south Alabama with pyrethroids. We could chase a lot of the issues back to several weeks prior when generics were used. In general, bifenthrin is the best “bug” pyrethroid we have. While the others are good on some other pests, we really would like bifenthrin better, particularly on plant bugs.

Another thought on late season insect management. Let’s try to get our “clean up” spray on before the cotton starts to fall over and cross rows with each other. While the sprayer tracks wont runover that much cotton, we would rather not runover any at all.

If you would like to provide reports or observations on the insect situation from your region, please let us know. You can reach Scott Graham at 662-809-3368 or scottg@auburn.edu or Ron Smith at 334-332-9501 or smithrh@auburn.edu.

As always, if we can ever be of any help, please let us know.