Spring Into Action to Protect Early-Planted Soybeans From Pythium

For farmers, “spring fever” tends to manifest as restless energy to get into fields as soon as possible. After all, there’s lots to do, and weather often limits the time to do it.

Research shows planting soybeans early, before corn, has higher potential to increase yield and profit. But that can also increase the risks of planting soybeans into poorer conditions.

Pythium is one of those risks. A water mold, this group of fungal-like organisms live in most soil types or on crop residue as oomycetes that can survive for up to 10 years. When wet soil conditions and the right temperatures trigger the Pythium life cycle, they produce swimming zoospores that infect soybean seeds and roots, as well as some weeds and rotational crops.

University researchers note that Pythium species in the northern U.S. tend to infect plants when temperatures range from 50 to 60°F, while most species found in the South activate under temperatures between 85 and 95°F. In short, various Pythium species are active across a broad temperature range as long as there is moisture in soil pore spaces.

The pathogen causes damping off both before and after emergence. Pre-emergence, Pythium can prevent germination or cause seeds to rot; Post-emergence damping off is caused by Pythium killing young seedlings. Both types can lead to reduced yields associated with reduced plant stands. Under favorable conditions, Pythium can infect soybeans within 90 minutes of planting. It can be activated by stretches of wet weather between soybean planting and emergence.

The resulting poor stand establishment can require replanting, meaning you could miss out on the benefits of planting early in the first place. In 2023, university pathologists estimated that U.S. soybeans lost about 5.9 million bushels of yield to seedling diseases, including Pythium.

Support Soybean Growth to Protect Against Pythium

As soybeans grow, they become less susceptible to Pythium infections, so management practices that promote germination and growth help minimize yield loss.

• Effective drainage prevents saturated soils that allow Pythium organisms to swim to soybean seeds and roots. Tillage or other water management can address problems, especially in low spots where water pools or in areas prone to flooding.
• Planting into warmer soils, especially in northern states, decreases the risk of Pythium
• Setting and monitoring planting depth helps optimize quick germination, emergence and stand establishment.
• Tillage can break up soil compaction and aid with soil drainage in some situations.
• Seed treatments protect soybean seeds and seedlings from Pythium infections during the two to three weeks after planting when they are most vulnerable.

To limit the risk for replants and maximize your seed investment, consider a premium F/I seed treatment like CruiserMaxx^® APX. Powered by novel active ingredient picarbutrazox, along with second mode of action Apron XL, CruiserMaxx APX offers the most powerful Pythium protection available in a seed treatment premix. In addition, CruiserMaxx APX also helps safeguard soybeans against Phytophthora, Rhizoctonia, Fusarium, bean leaf beetles and other early-season pests.

For more information about tackling early-season soybean diseases like Pythium, talk to your local Syngenta representative.