Early spring rains make cotton more susceptible

Despite the economic crunch farmers are currently facing, this may not be the year to save money by eliminating your preplant fungicide application.

Weeks of soil-saturating early spring rains may make much of the Delta's 2002 cotton crop more susceptible than usual to stand-crippling seedling disease, according to Louisiana crop specialists.

Sandy Stewart, Extension cotton specialist with the LSU AgCenter, says growers planting relatively early into moist soils should strongly consider protecting their cottonseed with a fungicide application. “While field history of seedling disease and other factors are important, the likelihood of seedling diseases that reduce stands is high in wetter, early-planted conditions.

“Attempting to save money by cutting back on well-justified expenditures seldom pays at the end of the season and can often result in less profitability,” says Stewart, who is based at the Dean Lee Research Station in Alexandria, La.

Boyd Padgett, Extension plant pathologist at the Macon Ridge branch of the Northeast Research Station in Winnsboro, says cotton producers planting into conditions conducive for seedling disease should first determine their magnitude of risk for seedling disease development.

Those growers planting before May 1 into fields with a history of seedling disease at reduced seeding rates are most likely to benefit from an in-furrow fungicide application. Cotton that is planted using poor quality seed, or at a time when bad weather is imminent, is also at increased risk for developing seedling disease.

Stewart says he has seen a justifiable trend toward lower seeding rates in recent years. However, he says, “If you are planting into wet conditions in April this is not the place to cut back. Avoid low-end seeding rates when planting in less than ideal conditions.”

Padgett adds, “Less seed means fewer plants, so it is especially important to protect those seed. Consider using an in-furrow fungicide when reducing the seeding rate to three seed per foot or less.”

Depending on the fungicide and rate, an in-furrow application will cost anywhere from $6 to $22 per acre, according to Padgett. “Fungicide rates can be reduced depending on the scenario occurring at planting. For example, lower fungicide rates should be considered when planting in late April. Eliminating the need for a product effective against Pythium can also save a producer around $4 per acre.”

Which fungicide product you choose will depend on which diseases are most likely to attack your young cotton plants. Among the seedling diseases most common in the Mid-South are Rhizoctonia solani, Fusarium and Pythium. While Rhizoctonia is the culprit behind the majority of seedling disease in this region, Pythium is most active during cool, wet conditions.

Padgett says that although the protection provided from a liquid or granule formulation of the same product should not differ, he recommends growers use liquid formulations whenever possible.

“Liquids provide better coverage and give producers more tank-mix options. In addition, there are more liquid products, which increases competition and potentially reduces costs,” he says.

“In uncertain times such as these, there is always a tendency to cut production inputs or try some new, unproven practices in hopes of reducing costs even more,” Stewart notes. “While we need to reduce unnecessary inputs as much as possible, there are always basics of a cotton production system that cannot be ignored.”

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