With each passing year, crop seasons appear to get shorter and shorter. Oh, to be young again when time seemed to crawl. As we approach mid-September, every region has reached their last bloom date except for maybe the extreme coastal sections. Thus, what we have is what we got, given we can gather it.
Except in a few late-planted fields where stinkbug controls may still be needed, insect controls can be abandoned. Our attention now shifts to preparing this crop for harvest. Successful defoliation is necessary to preserve fiber quality and maximize yields. This month’s edition of the Turn Row will focus on ways to best do this.
Southeast Crop Conditions
As it’s been all year, the 2021 crop continues to be a mixed bag. Looking across the Southeast, one can find some outstanding cotton and some around average while excessive rainfall has severely weakened a portion.
Of course, cotton is now entering what I call it’s “ugly stage” where mature leaves are shedding, bolls only partially open, and plants seem to be shrinking. This can often skew one’s view of yield potential, so I’m hoping some of this average crop surprises us once defoliated and fully open.
With insect pressure being relatively light this year, one of our biggest in-season expenses has been growth regulators. It’s not uncommon for some fields to have received up to 80 ounces of mepiquat chloride (Pix) to keep plant growth manageable amid season-long rains. Herein lies our biggest threat.
It’s critical these wet weather patterns be replaced by several weeks of sunshine. Otherwise, boll rot is going to rob us of our money bolls and natural plant shed will reduce the top crop. It’s really a blessing in disguise the overall crop is late as a high incidence of boll rot is being detected in our earlier planted cotton.
AgFax Weed Solutions
With each rain event up to now we’ve rationalized it was helping fill out top bolls thus more beneficial than damaging. However, from this point forward, similar weather will do serious harm to yield and fiber quality.
Unfortunately, while writing this, Tropical Storm Nicholas is making its way around the Gulf Coast and expected to drop copious amounts of rain in Southeast Texas, Louisiana, Mississippi, and possibly into Alabama and Georgia. If that’s not enough, a tropical wave has just moved off the African Coast and is given an 80 percent chance of development within the next five days.
It’s too early to tell the exact path it will take, but for now is heading west towards us. Though only mid-September, this is eerily starting to resemble 2018 all over again.
Southwest Crop Conditions
After 27 days in a row of above normal temperatures, the crop in the southwest has made a lot of progress. Hot and dry conditions have made it evident that it’s not the widespread bumper crop we were once so hopeful for; however, for many, it is better than they’ve seen in several years.
Cotton is over 50 percent open in parts of the panhandle and it’s likely we’ll see some producers starting to defoliate next week. Even though the first bale of cotton has been ginned in West Texas, the majority of this crop will need more time to finish.
Yields have been especially difficult to estimate this year. From the highway, most of the dryland crop looks very promising, and a lot of it is. However, once out in it, you start to notice a lot of the bolls are small and the bottom crop is either thin or just not there at all. Time will tell what kind of impact this has on yields.
Irrigated cotton across the southwest looks really good. There are very few areas where producers aren’t pleased with their irrigated crop. The rain we had early on got us off to a great start. For the most part, we’ve been able to stay on top of the watering, unlike most years where we’re usually having to water hard just to keep it going. Again, most all of the irrigated cotton will need more time to finish strong, but, as of today, looks very promising.
Timing of Harvest Aids
This season, with such a wide range in cotton maturity, the timing of defoliation applications must be made on a field-by-field basis. Keep in mind, defoliating too early can reduce yields and lower micronaire, while defoliating too late can increase boll rot and fiber damage due to weathering. There are three tried and true methods to determine when a defoliant can be safely applied.
- Open Boll Method – When looking across a field and you observe 60 to 70 percent of the bolls are open, defoliant materials can be used. If there are inconsistencies in the field, err to the high side.
- Nodes Above Cracked Boll (NACB) – When the node count above the upper most cracked boll is four or less, it’s safe to make applications.
- Knife Test – This is probably the most accurate test. Cut into bolls with a knife and, if mature, the fiber will string out and the seed coat will be a tan/brown color. The youngest bolls you hope to harvest should pass this test.
Recommended Defoliant Products
Once you’ve determined a field is ready to treat, you have a host of excellent products from which to choose, each with their own advantages and disadvantages so read the labels carefully. Some simply provide leaf drop while others exhibit boll opening properties and prevent regrowth. Crop conditions within the field and expected weather following applications should influence your choice of products.
Research has shown using a combination of materials provides the best results. Be sure the tank mix includes a phosphate material such as Folex for leaf drop, Prep (ethephon) for boll opening, and Dropp (thidiazuron) to prevent regrowth. Use a minimum of 20 gallons of water when applying by ground to get the best coverage.
A late crop will certainly need a product containing ethephon to enhance boll opening. Even though soils have been depleted of nitrogen, I would still use a product containing thidiazuron for regrowth control to safeguard against a wet fall and delays in harvest. Under current temperatures, expect excellent defoliation within 10 to 14 days. The same materials will take longer to work as cooler temperatures prevail.
Looking Behind and Ahead
Harvest is a good time to assess weak spots in a field and determine their cause so corrective actions might be taken next year. This could entail making a mental weed map to determine if adjustments need to be made to your current herbicide program. It could be noting low areas within a field which need some land preparation to improve soil drainage.
Lastly, some weak places in the field may be a sign of nematode infestations. Fall and early winter, when nematode populations are at their highest, is the optimum time to sample for them. Collect soil from the root zone, put it in a plastic bag to retain moisture, and send to a soil lab for testing.
More on Cotton
Harvest is also a good time to evaluate production practices and variety performance from the previous season. Extreme field conditions this year makes this a challenge, and we will know much more after harvest is complete. Nevertheless, a few items have come to light we would like to note.
DP1646, a widely used variety, once again seems to be performing well yield wise. However, we are seeing a lot of it laid over on the ground as its weak stalk strength succumbed to wind, rain, and a heavy boll load creating the potential for greater boll rot. The new reniform nematode resistant varieties appear to be performing very admirably this year, especially in fields with moderate to high populations of nematodes.
In side-by-side field trials, they all visually seem to be outperforming non-resistant varieties. These resistant varieties include PHY 443, PHY 332, DPL 2141, and DP 2143. We will know more after yield data is collected, but they look to be a viable option where nematodes are present.