Late Planting & Evaluating Hail Damage (Collins & Edmisten)
Late-planted or replanted cotton: Now that we have some soil moisture to work with, TAKE ACTION NOW as soon as you can re-enter fields to plant (or replant) those last remaining cotton acres. We are now beyond our crop insurance cutoff dates, therefore the risks associated with planting now are considerably higher, and careful considerations must be taken if cotton is to be planted at this point. To ensure optimal stands for later planted cotton, it might be worthwhile to slightly increase seeding rates to 45-47,000 seed per acre and plant shallow to ensure both adequate stands and to manage for earliness as later planted cotton becomes more sensitive to skippy stands. For various reasons, we have had a noticeable amount of late-planted cotton for the past few years. We will/do not recommend planting beyond the insurance cutoff dates, however, some growers often do plant beyond the recommended cutoff dates with some success at their own risk. With later-planted cotton, we lose the flexibility to account for fruit losses that occur throughout the summer months. Therefore, the success of later-planted cotton is dependent on several things going right throughout the season, such as timely summer rains and a sunny, warm fall without an early frost. Late planted cotton is only successful if growers, with the proper time management and some help with the weather, can retain as much of the earliest-set fruit as possible. With that said, timeliness of management can improve the odds of success with later planted cotton. This applies to PGRs, plant bug management, bollworm management, proper fertility, irrigation, etc. It is absolutely critical to be very timely with any inputs on late planted cotton. Growers can not afford to be late on needed PGR sprays, however, this point is not to be confused with “growers should be aggressive with PGRs”…..timeliness of PGR applications is much more important than using high rates, especially if high rates are not needed. Regardless of when cotton is planted, growers should be timely with sprays for thrips, plant bugs, stink bugs, and bollworms, however, the negative impact of delayed applications can become greater with late planted cotton. The only way to address this is with frequent and thorough scouting (twice per week, at least until applications are first made). Lastly, when possible, timely irrigation can be used to retain as many early set fruit as possible. Naturally, growers should also avoid any practice that may injure or further delay stand establishment or early season growth of late-planted cotton.
Cotton planted recently, or “dusted in” but not yet emerged: In cases where heavy rains occurred on fields that have been planted recently (especially if it was planted deep to chase moisture), or were dusted in and seedlings have not yet emerged, light crust busting or rotary hoeing may be necessary if seedlings are germinating and trying to emerge, particularly on soils that tend to crust. Usually, this practice is done when poor stands are noticed and is usually too late to help seedlings emerge or damages the few seedlings that have emerged. However, in our current situation, growers have a good opportunity to avoid stand problems by rotary hoeing or crust busting as soon as the soil surface begins to dry out and the crust begins to form. Delaying this practice for several days diminishes the likelihood of achieving optimal stands and increases damage to emerged seedlings, therefore quick action could offset many problems. Evaluating planted fields over the next couple of days, and looking for the early signs of potential crusting such as swollen hypocotyls (necks) as the seedling approaches the soil surface, will help growers make the best decisions and take action in a timely manner. Subsequent rains during next week can prevent surface crusts from forming if the surface stays wet, but if rains are not likely in your area, I’d be getting the rotary hoe ready.
Replanting due to poor stands or hail damage: We are already late, so taking action sooner is better than later……DON’T WAIT. Growers should make replanting decisions on a case-by-case basis, and potential benefits must be weighed against additional costs (cost of replanting which can run approximately $35/A, the likelihood of achieving better stands by replanting, time lost, etc). Previous research in the Southeast suggests that replanting may generally be justified if approximately half (or more) of the planted area is occupied by 3-foot skips (2-foot skips in more conservative situations, such as late replanting or poor health/status of remaining seedlings that did emerge the first time). When determining how many 3-foot skips are present, remember to give appropriate credit to large skips (for example, a 12-foot skip should be considered as four 3-foot skips). In cases of poor initial stands, spot replanting in certain parts of a field may suffice. In cases of hail damage, growers should evaluate fields for both stand loss and status of surviving plants. You should be able to tell how many seedlings will survive in a couple of days. As such, consider dead or dying plants as seed that never emerged, and evaluate skips accordingly.
For hail-damaged cotton, remember that seedlings can generally survive if one or both cotyledons and the terminal are still present in whole (preferably) and sometimes in part, although split terminals and delays in maturity are a common result of hail damage. If both cotyledons and the terminal have been destroyed, yield penalties can be expected. Also evaluate the strength of the main stalk in hail damaged situations, as hail can typically damage or bruise the main stem and affect the seedlings’ ability to recover and continue to grow. These observations should be made meticulously in order to make the best decision. Another factor to consider is yield potential of a particular field, based on field history and other factors (soil productivity, irrigated versus dryland, planting/replanting date, etc.) when deciding whether it is worth the extra effort and expense of replanting. Additionally, growers must decide whether or not a better stand can be established by replanting, so act quickly now that we have moisture. Research conducted in Georgia just a few years ago regarding various degrees of simulated hail damage illustrated that significant yield penalties (approximately 35 %) can occur when both cotyledons and the terminal are destroyed, but this assumes that all plants were affected but survived, therefore growers need to take into account stand lossage in addition to damage of surviving plants. Here are the treatment visuals (2 pages) and recovery of the various treatments:
Recent research in NC regarding deer damage illustrated that the terminal lossage (when cotyledons remain intact) can reduce yield approximately 25 to 30 %, with the greater losses occuring on 4-6 leaf cotton compared to 2-3 leaf cotton. Significant delays in maturity due to split terminals can also be expected. Again, this assumes all plants were affected yet survived, so stand loss should also be considered.