Most all cotton-producing regions of the Mid-South and Southeast have some acres infested with Roundup-resistant Palmer pigweed. To manage this beast, producers need to have good, overlapping residual herbicide applications on their cotton acres. Roundup is useless to control resistant Palmer pigweed.
The best approach is to plant a cotton variety that is Liberty Link or tolerant to Ignite herbicide to provide an opportunity for postemergence applications to control Palmer pigweed. Liberty Link varieties have excellent tolerance to Ignite herbicide. The analogy can be made that Liberty Link cotton can tolerate Ignite like Roundup Ready Flex cotton can tolerate Roundup. Cotton varieties that contain the WideStrike trait from PhytoGen can “tolerate” applications of Ignite, but are nowhere near as forgiving as true Liberty Link varieties.
Producers applying Ignite to WideStrike cotton varieties should be prepared to accept significant foliar burn and yellowing of cotton after application, which will dissipate as new leaves emerge. While we have not seen yield decreases from applying Ignite two times (29 ounces for each application) to WideStrike cotton, we have seen complete crop loss from not using Ignite to control glyphosate-resistant weeds.
We have been very fortunate in Missouri in that our cotton-planting season was far better than last year. According to the Missouri Crop Progress and Condition Report for the week ending May 30, planting was complete, and we had two percent of the cotton with squares. This is about 20 days ahead of last year and five days ahead of the five-year average.
Looking at the DD-60 data, we had 225 DD-60s from May 1 through May 26. This compares with 186 during the same time frame last year. However, last year we had a lot less of our cotton planted by May 1, and we had more planted much earlier this year. We were fortunate that we didn’t have as much replanting this year. Our crop condition is rated 73 percent good or excellent. On June 18 last year, we had only 45 percent rated that good.
We have had plenty of rainfall but have been dry in some areas. A few center pivots have been running since we have shallow roots, and plants are vulnerable to the higher temperatures this year. Our University of Missouri Insect Trapping Report has shown that cotton bollworms were high in Stoddard, Scott and Pemiscot Counties.
As of the June 13 NASS crop progress report, the Texas cotton crop is considered 57 percent good to excellent, 39 percent fair and four percent poor. Overall, the cotton crop in the Rio Grande Valley (RGV), Gulf Coast, Blacklands, Central and Rolling Plains looks really good with timely rains and hot weather.
The early planted cotton in the RGV and Gulf Coast regions will be at or near cutout by the third and fourth week in June, respectively. The cotton in the Blacklands ranges from early squaring to early bloom, while the Rolling Plains regions are from 80 percent planted to approaching the early squaring stage.
The Northern Rolling Plains received some precipitation the second week of June, while the Southern Rolling Plains began irrigating some cotton. The major yield-limiting factor this season in the RGV, Gulf Coast and Blacklands has been extremely high levels of cotton fleahoppers. Many producers are making four to six insecticide applications to suppress the fleahopper levels, and square set is running below normal.
Management of cotton in July and August is critical since this is the main bloom and boll set period. Most of the decisions (herbicides, fertility, row spacing plant population, etc.) for cotton were made prior to planting with much of the work done during planting and the first four to six weeks of the growing season.
However, as soon as summer rains start, weed management decisions have to be made along with insect and disease control that occur late in the season. Weeds and insects are treated as they occur, while disease problems are anticipated, and treatments are made in advance since they are often difficult to control once they reach a certain level.
July and August are often peak periods for pest development, so scouting is very critical to cotton and treating timely and appropriately is critical. Since seed costs have gotten higher with cotton due to genetic technology (often $40 to $55/acre), and the insect or herbicide resistance is bought in the seed, it is critical to protect the investment through good scouting and treating.
The cotton crop in Georgia appears to be progressing well in most places throughout the state. As I write this on June 10, we are currently plant-ing the last 10 percent of our cotton acreage, which is right on schedule. Timely rainfall across the state during the first week of June has helped the crop stay on schedule, and most of the early planted cotton has now reached eight to 10 leaves and is squaring.
There have been a few issues with herbicide injury that could delay maturity in some fields. There have also been issues with plant bugs in the last couple of days, resulting in some significant damage in places. July is a critical month for cotton producers in Georgia. The early planted cotton is scheduled to begin blooming around July 1, marking the point of increasing water demands by the crop.
The weather pattern seemed to change in the past few weeks, with occasional thunderstorms puncturing the broad blanket of dry weather. Not every producer has received the rain he needs, but enough rain has fallen that the overall cotton crop is in much better shape. The rains brought fresh weed flushes, and producers are returning to the fields with necessary herbicide applications.
Early spider mite reports gave way to talk about differences in thrips damage among the various seed treatments, and now plant bugs are starting to become more of a concern.
Many producers are commenting that this season’s cotton crop is more spread out than they can recall in quite a while, with some cotton planted in early April already receiving growth regulator applications and other cotton not much past the seedling stage. Although planting-timing studies suggest lower yields are more likely with very late-planted cotton, the big confounding variable is what the weather will be like the rest of the growing season.
If we have not learned so already, a normal growing season may actually be a contradiction in terms more so than something that actually occurs. Weather conditions in the Mid-South have varied widely depending on your location, and, in many instances, have varied widely between locations close in proximity.
While our neighbors to the north have had high levels of rainfall and flooding problems early on, our neighbors to the southwest endured a long stretch with little to no rainfall. While some acres in Mississippi were planted later than “optimum,” many were planted in a timely manner and are off to a good start.
As we move into July, two issues that will be on the minds of many include tarnished plant bugs and glyphosate-resistant Palmer amaranth. Tarnished plant bugs have become our primary insect pest over the past few years and have proven to be difficult and costly to control in many areas. Although always a lingering pest, a combination of factors has led to these insects moving to the head of the class in regard to insect pests.
Acres infested with glyphosate-resistant Palmer amaranth continue to grow and are forcing many producers to alter their weed management programs.
The Arkansas cotton crop is off to a great start; fields in Southeast Arkansas were blooming around June 12 this year, which is as early as many can remember. July is always a critical month for decision making in the cotton production business. July weather and key management decisions will determine the bulk of the crop in regard to fruit retention and boll distribution.
Hopefully, fruit retention has been a priority thus far and at least 80 percent of the fruit has been retained by bloom. Practicing strong IPM programs is crucial to protect the fruit or young squares and bolls that will eventually determine yield. Up through the middle of June, insect pressure in Arkansas has been scattered. However, July is always a busy month as it pertains to plant bug and worm infestations, and once the corn silks begin to turn, populations of plant bugs will most likely build in many cotton fields as they have in years past.
Decisions regarding irrigation timing and frequency will also be important. If July turns out to be average, Arkansas producers could see two back-to-back months with temperatures well into the upper 90-degree range. Under these long periods of elevated temperatures, especially high nighttime temperatures, cotton will stress and fruit will shed.
The cool spring that was experienced by a majority of the crop during the first few months of the 2010 season is finally behind us. Temperatures have risen, and the crop is finally starting to grow. Developmentally, the crop is beginning to enter early to mid-bloom. Nitrogen fertilizer applications should be nearing completion. Nitrogen applications have proven to be the most effective and efficient when applied between the phenological growth stages of first square to
Applications made after peak bloom have a tendency to delay maturity and result in a crop that is difficult to terminate and defoliate. This is also the time to be monitoring crop vigor and fruit load for the potential need of plant growth regulator applications. If a scenario of either low fruit retention or high vigor exists in your crop, an application of a mepiquat chloride-based plant growth regulator will assist in bringing the crop under control in terms of vegetative growth.
Plant growth regulator applications made under conditions of high vigor and/or low fruit load can also result in improved earliness and a crop that is more manageable in terms of defoliation. For more information on these crop management topics or other cotton related topics, go to cals.arizona.edu/crops.
In our observations, a relatively small percentage of SJV cotton fields in mid-June were perhaps seven to 10 days behind what we think is a more normal rate of development and progression toward first bloom, while most of the rest seem closer to two-plus weeks behind typical development this time of year.
It has been a rough couple of months of irregular weather and irregular growth in many fields, but most are coming out of it and moving forward now. Things change with warmer weather, and when plants outgrow early season pests such as thrips, some good growth and at least moderate yields should still be possible. First irrigations were delayed (a good idea, in general) in most fields, and the late start will have most of us assuming that we need: (a) good, tight management of water, nitrogen and insect pests to try to retain early season and mid-season fruit; and (b) some cooperation from September/October weather to allow the fruit to mature out in this later-than-normal year.
Holding early and mid-canopy fruit will be the key in fields reaching potential for good yields in a year like this one. An extended, warm fall alone won’t make up for early losses. While we don’t have extravagant water supplies, some limits in available irrigation water have loosened, which will help out if you need to apply the last irrigation of the season a little later to help with later-maturing fruit.
One of the other things that can happen with delayed plant development is that the period of rapid vegetative development (putting on a lot of leaves) and flowering/fruit development get shifted even more into what is typically our warmest time of the year. If we get into periods with very hot weather and hot nights, this can negatively impact fruit retention and give even more tendency for strong vegetative growth. Too much water stress can increase square and early fruit loss.