Alabama Crops Report
September 28, 2021
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Cotton Report
Dr. Tyson Raper of the University of Tennessee recently published a blog about cotton boll opening and crop maturity. It is a great, thought-provoking piece that compels careful consideration of the timing of harvest aid applications in cotton.(Image above courtesy of Dr. Tyson Raper, University of Tennessee)
Answering the specific question Dr. Raper surveyed, “What is the lowest number boll you believe you can open with ethephon?”, I believe ethephon at upper-end rates can force open EVERY one of these bolls, even the least mature (boll 1). Even so, the younger, smaller bolls – even if forced opened with ethephon -- will contribute very little to overall yield and may not fluff out sufficiently for spindle harvest.
In the field, waiting on the last bolls in the terminal is often a mistake. It puts at risk the remainder of the crop, and the potential weight of these bolls is often inconsequential. In some situations, these top bolls may also be riddled with stink bug damage.
In the Lower Southeast, it is more common to be LATE rather than too early in applying harvest aids. It is not unusual to see crop termination at 90 percent open. In terms of crop maturity, we can and SHOULD (in most cases) defoliate earlier than that.
A critical question from Dr. Raper’s exercise is: Which bolls are ready for harvest aid application; in other words, which bolls can be terminated without loss of yield (fiber weight) and quality?
In the progression of bolls in the UT picture above, I think boll 8 and certainly boll 9 are sufficiently developed to proceed with defoliation without penalty to yield or quality.
The image below depicts two bolls on a fruiting branch. For fruiting structures on the same fruiting branch, the accepted age difference for bolls at positions 1 and 2 is 4.5 to 6 days. The image has an open boll at position 1 and the 2nd position boll, which is no more than 6 days behind, doesn’t have real dark seed coats but should be ready for termination. Think about where this 2nd position boll fits in Tyson’s progression … maybe boll 8?
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Other cotton harvest aid decision tools are referenced in the September 17 Alabama Cotton Shorts newsletter (here). An additional source of related information can be found on the Cotton Specialists Corner Podcast, which captures thoughts from Extension Specialists from across the U.S. The latest edition from this national site, Episode 10 and 11 (coming soon), provide further discussions on harvest aid timing and products, including comments from Steve Brown and Tyler Sandlin.
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Regional Roundup with the REA's
Here at the Alabama Crops Report, we know how growing conditions and pest populations can vary across our diverse state. Therefore, our Regional Extension Agents (REA’s) will be providing updates during the growing season so we can stay informed no matter what county we’re in.
Southwest Alabama
The temperature dropped since September 22 as low as 57 ⁰F and we have had good sunny days in the past few days. The month of September had a big rain on September 15 (around 3 inches in South Baldwin) and scattered showers after that (See graph above). The corn harvest is almost done in the region. Few farmers have couple more acres to finish in the next week.
Peanut farmers in Escambia and Monroe started to dig peanuts. Farmers in the Baldwin County received a little bit more rain last week and they are still wet for digging. However, the digging of early plantings might start in couple days when the fields are dry enough for the machines to get in the field.
Last week on September 16, we had a meeting to discuss cotton management strategies and variety selection for nematode control (see picture below). We had a good attendance and great exchange of information related to nematode control. In case you missed the meeting and would like to receive a copy of the presentation, please send me an email and I will share it with you.
Contact Guilherme Morata for more information.
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West Central Alabama
In many areas in west central Alabama field conditions dried out enough late last week or over the weekend to get combines back in the field and continue with harvest. Harvest has been delayed due to the weather, but corn harvest is done or winding down for many growers. Full season soybean harvest is ramping up. From what I have heard and seen both corn and soybean yields are looking good around the region.
I did find a few stink bugs in some double crop soybeans but nothing at threshold. As harvest continues this will be something growers and scouts are keeping an eye on. The later planted soybeans will become especially attractive for stink bugs looking for anything to feed on. More information on soybean insect thresholds can be found in the Soybean IPM Guide.
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We had a pod blast and overall peanuts are looking good in the region. Some growers have started digging already and would have started sooner if field conditions would have allowed. More producers plan to start within a week to 10 days if conditions are right.
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After several days of cloudy and wet conditions I saw and heard of several producers that had sprouts and hard lock issues in some of their cotton. The sunshine and breezy conditions will hopefully help the cotton crop out as we move closer to defoliation.
The short-range weather is looking favorable for harvest to continue.
Contact John Vanderford for more information.
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Weed Management Following Crop Harvest
Now that our statewide corn harvest is more than halfway complete, this is a reminder to remain diligent in weed management as we move into fall. As crops are removed and daylength shortens, surviving weeds will try their best to produce mature seed prior to colder weather. Palmer amaranth, morningglory, prickly sida or teaweed, and hophornbeam copperleaf are just a few of the most troublesome species that are also prolific seed producers. Mowing, disking, and herbicide application can be effective methods to minimize this weed pressure ahead of next year’s crop.
In areas where mowing or tillage may not be an option or where cover crops will soon be planted, Roundup or Gramoxone has provided the quickest and most effective control of prickly sida, crabgrass, and copperleaf when applied prior to seed maturity. If copperleaf and/or pigweeds are the biggest problem, Gramoxone may provide a more effective kill. The addition of FirstShot has also performed better than Sharpen on henbit populations when applied in a fall burndown. Remember that adequate regrowth is necessary for any postemergence herbicides to work effectively on weed species. Read and follow labels for plant-back restrictions, especially if using Group 14 herbicides with soil residual.
Our Weed Science team is currently collecting weed seed from mature pigweeds, sicklepod, and other weeds that may have recovered from in-season herbicide applications. If you are aware of any such populations from around the state, please notify David Russell or Steve Li.
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Soybean Rust in 2021
Soybean rust (SBR) has been found in 21 counties in Alabama this year. Most of the sightings have been on kudzu and at very low disease levels. In the past few weeks, we have been detecting the disease in research plots in central and south Alabama, but at this point it does not appear the disease will cause significant yield losses in soybean fields that were not sprayed with a fungicide as opposed to what we experienced in 2020. I believe the low impact of the disease in 2021 could be traced back to a few cold periods along the Florida panhandle back in the winter which likely killed-back much of the kudzu that the pathogen needs to overwinter on successfully for it to be a problem in Alabama during the growing season.
I suspect we will find SBR in North Alabama this week because cooler temperatures favor disease development. However, because the soybean crop is maturing rapidly it is very unlikely the disease was detrimental to crop production. Other foliar diseases such as frogeye leaf spot and web blight have been reported this year, but growers applying a single fungicide in a timely manner would have been able to keep these diseases in check.
Contact Ed Sikora for more information.
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