Rain in the forecast is a welcome change from the lingering dry conditions Alabama producers have battled this spring. Producers generally plant cotton between April 20 and the first week of June. Although early spring weather was conducive for planting, the end of May was hot and dry, creating significant challenges for stand establishment.
Alabama Extension cotton specialist Dr. Steve Brown says cotton established by mid-May or earlier should fare well for a while yet.
“Cotton is very heat tolerant and early season water requirements are minimal,” Brown says. “However, the need for soil moisture increases considerably as the crop progresses toward flowering. Those with irrigation may consider watering pre-bloom cotton that shows wilt before noon.”
“Dusting In” Alabama Cotton
Brown said producers have considered “dusting in” cotton in the absence of adequate moisture. Dusting in—planting in dry soil with hopes of later rain—is a risky practice, but seasonal planting demands and crop insurance deadlines often require planting by a certain calendar date.
“Dusting in is always risky, but given the predictions of one to three inches throughout the rest of the week, producers should proceed with planting plans,” Brown says. “As long as the rains do not come too quickly, the ground should absorb moisture.”
Too much rain could lead to washing, where water could carry seeds away.
The effects of high soil temperatures on seed in the ground—as well as in the bag—have also been concerns for producers.
“Heat killing the seed is unlikely,” he says. “Cotton seed in the soil (and in the bag) is much more heat tolerant than soybeans and peanuts. Historically, we’ve observed cotton seeded in dry conditions emerge weeks after planting concurrent with adequate soil moisture.”
Brown says the challenge with dusting is that a light shower may germinate the seed, but not sustain the plant to emergence.
“Sufficient water for both germination and seedling establishment is critical to planting under high temperature, drought conditions,” he says.
Warm, dry winters increase the risk for overwintering grasshoppers, leading to higher numbers of these insects in the spring. In recent years, this has become a special challenge in reduced tillage systems.
Likewise, warmer and drier winters promote the overwintering of bollworm and tobacco budworm pupae.Warm, dry spring conditions likely will result in earlier movement of thrips from host plants onto early planted cotton. Nuisance pests, such as false chinch bugs and white munching burrowing bugs, will likely be common in these weather conditions.
Warmer and drier spring conditions also affect plant bug movement from wild plants onto cotton. They will move quickly onto cotton during the early fruiting season as wild host plants dry down.
The increased incidence of miscellaneous pests, such as chinch bugs, is also likely with drier and warmer weather.
Insect Management Strategies
Movement of plant bugs from wild plant hosts to cotton typically occurs under warmer and drier spring conditions, so growers should anticipate more insecticide applications to control this pest.
To manage thrips, growers typically use a seed treatment or in-furrow application of a systemic insecticide. Dry soil can also limit insecticide uptake by seedlings, thereby increasing the risk of significant thrips damage to the cotyledons and first true leaves.
Supplemental foliar insecticide applications may be necessary if environmental conditions are not conducive to uptake of at-planting systemic insecticides or if heavy thrips infestations occur.
Following integrated pest management strategies, growers should scout for other insect species and react accordingly throughout the crop season.
Weed Risks and Management Strategies
Pre-emergence herbicides are applied to the soil before weed emergence. Warm conditions can affect the herbicide’s half-life and shorten the weed control period.
“Dry conditions, apart from irrigation, prevent activation of residual herbicides; that is, movement of the product into the zone of weed germination,” Brown says. “This typically leads to weed escapes and heavy early-season weed pressure.”
To prevent losses from weed pressure and avoid herbicide-resistance development, weed management strategies should include residual and post-emergence options before planting, in early season, and during the lay-by period.
Brown says in recent years, foliar diseases such as target spot and areolate mildew have flourished during mid- to late-season, especially during wet periods.
“Current conditions certainly do not favor these foliar pathogens,” he says “However, hot, dry weather may reduce potassium uptake and result in leaf decline and infection from secondary pathogens such as Stemphylium, Alternaria and Cercospera. Under such conditions, potassium needs may be partially addressed with foliar fertilizer applications.
Alabama Cooperative Extension contributed this article.