August 20th is generally considered the last date that we can with 100% accuracy assume that a cotton bloom will successfully make a harvestable boll. This is an outstanding target date to manage our cotton to reach absolute cut-out of 3.5 NAWF (nodes above white flower) and finish out for the year with all dollars spent on making those quality bolls.
Many of us in Hale & Swisher actually try to manage cotton for an August 24th absolute cut-out date when we can assume a 90-95% chance of a bloom making a harvestable, high quality boll. In most seasons that certainly seems like a reasonably good bet but with a high enough load we usually hit the August 20th anyway. With this season’s rough start and general ‘lateness’ of the crop many of us were managing, crunching, and hoping for an August 27th date when there is roughly a 70% chance of a bloom successfully making a harvestable boll.
One of my biggest fears for the cotton season earlier in the year was that the surviving irrigated cotton would only start ‘looking’ good by August 15th and producers would not start pushing it until then, counting on a September 7th date when there is only a 15% chance or so of making a harvestable boll. For all but a handful of fields, that seems like a moot point now.
Our program cotton this week ranged from 5.6 NAWF through to absolute cut-out. All but a few fields were below 4.6 NAWF and more than half were at or past absolute cut-out. We have not found any open bolls to date. Boll set remains high for the most part unless water availability became an issue recently and even those fields seemed to retain more bolls than a cotton field usually does when stress, peak bloom, and cut-out all occur at once.
As I write this on August 22nd most of our program fields should be setting some of their very last ‘plant holdable’ bolls just a few days behind a target August 20th date and right on time for the 24th target date. Those later fields that are still running 4.5 NAWF or higher this week look to be following the lead of the earlier maturing fields. Boll load, plenty of heat units, and timely irrigations combined with light pest pressure should set a high percentage of squares to bolls that will draw those fields down toward cut-out very soon, which will be just a touch late but near our once hoped upon target of August 27th.
I do urge producers not to push fields too hard well into September. Once fields reach absolute cut-out and set their last harvestable boll, water needs drop to only boll fill levels. Any additional water above that point sets the plant to regrowth which only makes the plant hard to kill for harvest aids, hard to strip, and trashy at the gin.
Likewise, if there are late fields out there that fly past our last emergency target cut-out date of August 27th, they would need to be reined in pretty hard to avoid too much of the same problems.
It has been a quiet week for pests in our program cotton. We still have a few Lygus turning up, the highest was from the Edmonson area just this morning where our scouts found 1 Lygus per 3 row feet. This nears our economic threshold (ET) but was not on it yet and there was not enough Lygus induced fruit damage and loss in the field to justify the expense of treatment. We will continue to monitor that situation closely.
In the same area this morning we found a few fields with bollworm eggs, the highest being 22,000 eggs per acre. Earlier in the week we discovered a small but building cotton aphid population near Hale Center.
These two factors are certainly worth keeping an eye on and could easily develop into a problem, especially if the two pests develop to economic levels in the same non Bt cotton field. Our predator counts remain high this week and I am optimistic that these hot spot bollworm and aphid fields will not reach ET.
We will need to continue scouting to make certain.