Cooler, Wet Spring Raises Concern for Early-Season Pests and Diseases

Less-than-ideal weather conditions across the U.S. this spring raise concerns about the potential for early-season pests and diseases in corn and soybeans, according to agronomy experts at Pioneer Hi-Bred, a DuPont business.

Corn planted early may encounter more problems than corn that's been planted later due to cooler, wetter soils. Fields planted in early April may encounter seed rot or damping off, when the seed emerges, wilts and dies as the plant is working to get established. Damping off occurs when fungal pathogens, such as Fusarium, Pythium and Rhizoctonia, are present in the soil and seedbed conditions are challenging. Pioneer suggests growers scout fields and evaluate stand establishment.

In areas where planting has been delayed, growers may see fewer seed rot issues. Fusarium and Pythium concerns lessen with warmer temperatures and drier soil conditions.

However, growers planting into late May could find their fields are more susceptible to black cutworm. The larvae grow larger with time, increasing the chances of cutting down newly emerged plants. When black cutworms are about 1/2-inch long, they can kill the plant. The pest leaves small shot holes in corn leaves. Stand loss or irregular stands may result. Growers who have planted hybrids with Herculex®I or Herculex®XTRA insect protection can expect protection in their corn against black cutworms and other corn pests.

Three soybean diseases for growers to scout for early this year include Pythium, Phytophthora and Rhizoctonia. Pythium occurs in cold, wet soils. Phytophthora occurs in cool saturated soils, while Rhizoctonia occurs in warmer soils. According to Scott Heuchelin, Pioneer research scientist for field pathology, tracking emergence is key. A number of factors, including crusting, can cause uneven emergence, but if the seedbed is in good condition and emergence is uneven, a pathogen or pest may be affecting the seed. Seed treatments may reduce early season disease and pest pressures for both corn and soybeans.

For more information or to schedule an interview with a Pioneer agronomist in your coverage area, please contact Jerry Harrington at 1 800-247-6803, ext. 56908 or [email protected].

For additional timely insights, visit Pioneer's agronomy resource library at