Early season management of cotton for optimum initiation and retention of fruiting forms is critical to the overall success of the eventual crop. Several factors can contribute to poor early season fruit set, resulting in increased vegetative growth and other potential yield limiting scenarios. Insect pressure, specifically from lygus bugs, can cause early season fruit shed. Proper scouting of fields for damaging populations is critical in protecting the crop early. Other factors include moisture and heat stress. Both of these abiotic stressors can result in fruit shed or abnormal fruit development as a result of poor pollination and boll set. Not a lot can be done about heat stress levels, but proper plant water relations are usually within our control. Reduce potential stress from inadequate soil moisture by irrigating in a timely fashion. Research has shown that the first post-plant irrigation usually comes around at 900 heat units accumulated after planting (HUAP), or at about match head square. This will vary, depending on weather and soil water-holding capacity. However, this stage of development can serve as a general indicator for scheduling the first post-plant irrigations. Once this milestone is reached, cotton will need to be irrigated on approximately a 10- to 14-day schedule, again depending on weather and soil water-holding capacity. Consumptive water use estimates can be found at the AZMET website and are sent out weekly in cotton advisories produced by the University of Arizona Cooperative Extension. With the increased level of Pima cotton planted across the state, heat stress becomes more of a significant factor than for Upland variety counterparts. Pima cotton cultivars are more sensitive to heat stress and should be monitored closely for heat-induced fruit abortion. The loss of this carbohydrate “sink” can result in increased vegetative growth, which Pima cotton already has a tendency toward. Be prepared to utilize plant growth regulators aggressively as a means of controlling this vegetative growth, if needed. For more information and specifics regarding these topics, interested persons may go to cals.arizona.edu/crops.
The period from planting to first square is a critical time for the cotton plant. Cool temperatures or competition by pests can delay the onset of squaring. In our April-planted cotton, pinhead square generally occurs 40 to 45 days after planting, as compared to mid-May planted cotton, which generally takes 35 days to square after planting. Keep this in mind when evaluating development. In dry years, consideration to irrigate pre-squaring cotton may arise. We generally do not irrigate cotton during this time frame in the Mid-South. We preach the importance of avoiding stress and irrigation of cotton once it begins squaring. But, how do we evaluate the need for irrigation of pre-squaring cotton? The plant is very predictable in terms of node development from the time it has two leaves until flowering. A healthy plant with good leaves and root system should develop a new node or add a main-stem leaf every 55 to 60 heat units or DD60s. This is usually one node every 2.5 to three days. If the plants are requiring five to six days to add a new node where temperatures indicate only three days are needed, the plant is stressed, and you may need to irrigate. However, be advised that many things can cause this type of stress. Insect pests such as aphids and spider mites will also slow growth. Be sure to know what is causing the stress before spending time and money on a cure for the wrong problem.
The San Joaquin Valley weather has been a bit of a roller coaster this year, with a warm mid-March that encouraged plantings followed by quite variable April and May weather (still not much rain, but periods of wind and heat interspersed into cooler periods). Even with significantly reduced acreage and fewer total fields in cotton, we have still seen some fairly widespread occurrences of above-average losses in both Pima and Upland fields associated with both disease and pest problems. These problem situations included: (1) difficult-to-control armyworm damage that was severe enough to cause terminal damage in seedlings and stand losses; (2) moderate to even severe thrips pressure that affected Uplands (as usual) and Pima cultivars (usually Pima cultivars show less injury from thrips); and (3) Fusarium race 4 stand losses, in some cases made worse when combined with damage from other seedling diseases. These issues singly or in combination have resulted in some fields that look behind expected development, considering that most fields were planted relatively early this year. While it is not possible to know the range of strategies producers will use for water and crop management in SJV cotton this year, it is easy to assume that many diversified producers will be making hard decisions regarding which crops and fields will be “fully irrigated” and which will be “deficit irrigated.” With limited water supplies and the real need to eliminate or reduce irrigations in a year like this, what do you do? Suggestions include: (1) look ahead and try to decide how you’d like to manage the crop – (i.e. full-season or earlier-maturing based on crop planting date, growth progress and water limits?); (2) consider being more aggressive about limiting early fruit loss, since you may not have enough growing season length to wait for later season bolls; (3) determine if you can limit total water applications by practices such as alternate row irrigation in mid- or late-season; or (4) evaluate the top crop when that time comes and eliminate a final irrigation if top crops don’t warrant the water. In some production areas, delayed progression of early season growth and known limitations to water supplies mean lower yield goals, such that some dollar savings could be achieved from reduced fertilizer applications With limited rain and drought conditions, the good news might be that early lygus sources may be a more limited problem this year. However, the highly diversified agriculture of the SJV means that we have multiple sources of both pests and beneficials, so cotton producers still need to keep watch for developing insect and mite pest problems. In this setting, cotton is still one of the crops best suited to achieve some decent production even when deficit irrigated, water stressed, and even when the plants have to be irrigated with moderately saline irrigation water. I think the key in this type of limited water situation is to build a small- to moderate-sized plant where vegetative development is under control, combined with more aggressive early season pest management and irrigation timing. While mid- and late-season bolls may still come, holding and maturing them out will be more challenging if you are dealing with very limited water supplies.
With most of the cotton planted in May, we start to see a lot of stink bug pressure in June since most of the corn silks and tassels in mid to late May and early June. As the ear matures and shucks get thicker and wheat dries down and is harvested, stink bugs move into crops like cotton to feed on tender squares and bolls. It is very critical that insects are controlled during this period so that cotton sets fruit early. June is also the period when residual herbicides applied at planting run out, allowing weeds to break through, so producers are often managing weeds and applying nitrogen. Therefore, June is one of the most critical times for a cotton crop to be managed properly for high yields. Cotton growth is often rapid during this period, and growth regulators need to be applied. It is important to know how aggressively the varieties grow, and how they respond on different soil types to be properly managed. Even though many decisions have to be made when growing a cotton crop, June is probably the most critical month with the most decisions being made.
Much of the North Carolina cotton crop was planted during the first two weeks of May. Cool, wet weather during the last week of April gave way to very good planting conditions and soil moisture in early May. Tropical storm Ana slowed planting progress slightly during the May 10-12 time period but replenished soil moisture in most areas. All in all, the 2015 season is off to a very good start, as I write this in mid May. June is a time for monitoring the developing crop prior to bloom. Timely post-emergence herbicide sprays targeting small pigweed may be necessary to avoid yield loss and to minimize handweeding later in the year. Mid to late June will bring the early PGR and irrigation decisions. It’s important to remember that even though cotton does not utilize much water during squaring, drought stress during this time could result in significant yield loss. Therefore, it may be necessary in some cases. Lastly, monitoring for plant bugs during squaring and taking quick action if thresholds are reached is important to avoid significant losses resulting from this insect pest. North Carolina cotton producers are encouraged to follow us on the cotton portal: http://cotton.ces.ncsu.edu/, which is one of many platforms that we use to address production issues and provide information throughout the 2015 season and beyond. Producers are also encouraged to follow us on Twitter for updates, using the Twitter list: NCSU Cotton or our individual Twitter handles (@NCcotton, @Cotton_Guy, @DominicDReisig).
As of May 15, cotton planting in the state is now approximately 80 to 90 percent completed with a significant portion of the acres going in the ground during the last week of April and the first week of May. Overall, temperatures have been excellent for cotton emergence. Cotton was emerging in four to six days. During the last 30 days, we have accumulated 14 percent more heat units compared to 2013. Once planting was completed and cotton had emerged, side-dress applications of nitrogen were made. Insect pressure from thrips has been heavy enough to warrant foliar insecticide applications. This year, early season seedling disease pressure was minimal. Once cotton has begun to square, producers and consultants will be concentrating on square retention and managing plant height with mepiquat products to reduce rank and vegetative growth later in the season. The No.1 tool for managing plant height is a good fruit load of about 70 to 80 percent retention of first position squares. When the cotton plant has reached match head square stage, begin to monitor plant growth, environmental conditions and square load. Pre-bloom mepiquat applications are made ahead of the growth curve to help manage vegetative growth more effectively. These applications will not shrink the cotton plants; they only restrict vegetative growth after the application. Primary factors to consider in applying pre-bloom mepiquat applications include knowing the variety and its growth habits. Some grow more aggressively than others. Know and understand the history of the field and the capacity of its soil type to produce excessive or rank growth. Last, but not least, consider the total nitrogen available to the crop and the amount yet to be applied.
Mississippi cotton producers were in a holding pattern for much of the spring due to cold, wet environmental conditions. However, planting went into hyperdrive during the first full week in May. Producers made as much progress in the span of seven days as I have ever seen. As of this writing, several areas of the state are awaiting rainfall, which is needed to complete planting and facilitate stand establishment. Progress has been relatively smooth with respect to planting in 2015 and hopefully by the time this issue of Cotton Farming reaches your hands, planting will be completed, and all farmers will have adequate stands. Everyone is aware of the issue that Mid-South producers have had with thrips over the past several growing seasons. It almost goes without saying that thrips have developed another challenge that cotton farmers must face. Everyone is encouraged not to rely solely on seed treatments for thrips control. Be sure your fields are scouted, and thrips are treated when necessary. While thrips infestations do not typically result in yield losses, heavy thrips infestations can cause delayed maturity. We have been fortunate with weather during harvest season for the past several years. However, no one knows what the weather will do this fall. As such, do not let thrips get on your cotton and delay maturity, which may lead to bigger problems at the end of the year.
This has been a very interesting planting season in Missouri. We were delayed in planting due to cold, wet soils. Then, we had a large window for planting, and now we are wet again. According to the Crop Progress and Condition Report of May 11, cotton planting had increased from 15 to 66 percent. For reference, we had 39 percent at this time last year and 35 percent for the five-year average. With fewer acres this season, it shouldn’t take many days to complete planting. Although we are past the optimum planting date, we still have time before the yields drop off. When we had the dry conditions, we had some very windy conditions, and the seedlings were bounced around, resulting in some injury if there was not enough wheat or other windbreak materials. The warm, dry winds also caused some desiccation of weakened seedlings. Due to the wet conditions and inability to burn down, we also had some pigweed that had to be controlled with tillage. We have had enough moisture to activate herbicides. It would have been nice to have already finished planting, but we could be in worse shape. Everything will depend on the weather for the remainder of the season. With El Niño coming back this year, anything could happen.
The recent rainfall has been a real blessing for western Oklahoma. Significant inflows into reservoirs have been noted, with some lakes rising considerably for the first time since at least 2010. All of this has been good news for the region. Along with the rain, cooler temperatures were encountered, which was good news for wheat maturity. However, cotton planting delays are being noted in the area. As of this writing (May 13), we are entering our historical prime cotton planting window, with few acres in the ground. That is probably a good thing as soil temperatures were negatively affected by cool night-time lows and daytime highs on several days. Once we come out of the wet weather, we should be ready to roll the planters, as soil temperatures should be suitable if we encounter our normal late May temperatures. One thing for certain is that fewer acres will be planted, if any, for the next several days. This means that much of our irrigated crop (which is normally the earliest planted) will be somewhat late. Whether this results in maturity challenges for this year’s crop remains to be seen. Dryland fields should have good yield potential based on soil profile moisture. With wet conditions, weed management will be an issue for many producers. Hopefully, the “residual herbicide use” message that was discussed in meetings and the ag media were wisely noted by producers.
Tennessee was blessed with a warm, relatively dry planting window, beginning on May 1. A system moved through parts of the state on May 11 and temporarily delayed planting for a few farmers, but most planters were running again prior to the latest round of rain, which is still working through the area today (5/18). Given that close to three quarters of our cotton acreage has already been planted, it looks like the 2015 crop has the potential to be quite timely. Still, managing for earliness extends far beyond planting, and several stresses must be prevented or addressed in order to capitalize on our timely planting. Studies have indicated positive impacts from foliar applications of insecticides, targeting thrips at the one- to twoleaf stage. Preventing thrips from damaging the young seedling will allow it to quickly progress out of the susceptible growth stages. This is particularly important for seedlings struggling through injury from a pre-emergence herbicide, as the two stresses commonly interact to delay maturity. For additional information, on these and other management activities which emphasize earliness, visit our website at UTcrops.com or blog at news.utcrops.com.
As of mid-May, we remain extremely wet in South and East Texas, which has caused a significant decrease in planted acres. The latest reports from the Texas Boll Weevil Eradication Foundation (TBWEF) indicate about half of the expected cotton acres were planted in the Rio Grande Valley, and the crop is easily four weeks behind normal in development. In the Coastal Bend, about a third of the expected cotton acres were planted, down to 123,000 acres from 449,000 acres in 2014, and the crop is three to four weeks behind normal. The Upper Gulf Coast and Blacklands received most of the cotton planted in bits and spurts, but saturated soils and cloudy weather have the seedling cotton plants off to a very slow start. The wet weather conditions across South and East Texas are increasing the pest pressure, including thrips and weeds, and getting into the fields to manage these pests was a major hurdle. The entire Rolling Plains has received some substantial rainfall this winter, and spring and lake levels have risen substantially. Generally speaking, the soil profile is full of moisture, and sufficient planting moisture is present to establish a good stand. Despite the good soil moisture conditions, I continue to hear from many producers who are considering conventional cotton varieties, as one method to cut input costs. As mentioned previously, the one place not to cut costs is on weed management, especially if glyphosate-resistant pigweeds are on or near your farms. Crediting soil residual nitrogen and/or nitrates in irrigation water is one of the simplest and least risky ways to cut input costs for this season. Additional crop information can found at cotton.tamu.edu.
Although I have yet to hear any significant complaints about the rainfall amounts, there are some quiet rumblings about the timing. Some locations in the region have received upwards of 12 inches since the beginning of April with up to three inches forecast for the next few days (May 18-22). Some fields have been planted in areas where lower rainfall amounts were observed or where soil type has allowed. In addition to the rainfall, some cooler than normal temperatures were observed as well. Most are optimistic that following this next round of showers, planting will resume, and temperatures will rebound, making conditions optimal for good stand establishment. Regardless of the timing of planting, producers should still be diligent in terms of keeping fields as free of weeds as possible (preferably zero tolerance on the glyphosate-resistant Palmer amaranth). Watch for early season thrips infestations and apply fertilizers as needed in order to take advantage of the moisture and minimize the effects of the later planting dates. If the early season fruit set is protected, there is still the opportunity to manage for earliness and have high yields of good quality cotton harvested from the region.
More than 80 percent of the cotton planted in Virginia occurred in a 14-day span during the first full two weeks of May. This planting window had good soil moisture coupled with favorable temperatures for germination. As we move into June, producers will be faced with plant growth regulator and nitrogen management decisions. Harvesting winter wheat and side-dress nitrogen timing in cotton tends to overlap in Virginia. Some producers will apply side-dress nitrogen early (one to two weeks prior to squaring) to minimize the time conflict. If this describes your system, timely plant growth regulator applications are needed to minimize excess vegetative growth. Virginia recommendations are for producers to apply side-dress nitrogen at first square. The quantity of nitrogen applied may depend on soil type, soil moisture status and variety to avoid excess vegetative growth. Nitrogen rate trials in Virginia indicate that total nitrogen rates of 100 to 120 pounds of N per acre have maximized lint yields when rainfall was not limiting. Splitting side-dress nitrogen applications may be needed on coarser sandy soils to limit leaching losses. Producers need to also recognize the need for sulfur application on low organic matter and sandy soils in the coastal plain regions. Virginia recommendations are to apply 20 pounds of total sulfur per acre and 10 pounds of total sulfur per acre following peanuts.View More in our Archives