By Scout Nelson
Recent rainfall has improved crop conditions across many parts of Minnesota, helping corn and soybeans continue healthy growth. During the June 24 Strategic Farming: Field Notes webinar, Matt Pfarr, Extension Educator – Crops, and Dr. Bob Koch, Extension Soybean Entomologist, shared important updates for growers. The webinar was moderated by Dave Nicolai, Extension Educator – Crops.
Corn is progressing well, with many fields reaching the V8 growth stage. Matt Pfarr advised farmers to carefully follow herbicide labels, especially as corn grows taller. Many herbicides require special application methods once plants exceed V8 or reach about 30 inches in height. He also noted that corn is entering a period of rapid nutrient demand, particularly for nitrogen.
Disease monitoring remains important this season. Tar spot has been reported in neighboring states and continues to be a concern. Pfarr described tar spot as a “Goldilocks disease,” requiring environmental conditions that are neither too dry nor too wet, and neither too cold nor too warm. Farmers are encouraged to scout fields regularly and make fungicide decisions based on disease presence and economic return.
Recent storms have caused hail damage in some areas. Pfarr recommended waiting one to two weeks before making management decisions. Both corn and soybeans can often recover well if key growing points remain undamaged.
In soybean fields, second-pass herbicide applications are ongoing. Pfarr stressed the importance of controlling small weeds, especially waterhemp, before they became difficult to manage. He also discussed iron deficiency chlorosis (IDC), which causes yellowing of soybean leaves in high-calcareous soils. Selecting tolerant soybean varieties remains the best management strategy.
Dr. Bob Koch reported that soybean aphids are present in many Minnesota fields, although populations remain below treatment thresholds. Farmers should begin regular scouting and continue through the R5 growth stage. Beneficial insects often help reduce aphid numbers naturally.
Koch also warned about widespread pyrethroid-resistant aphid populations. He explained that some newer insecticide products are providing better control while protecting beneficial insects. In addition, soybean gall midge continues to expand across southern Minnesota, making field-edge scouting increasingly important.
The Strategic Farming: Field Notes webinar series continues every Wednesday morning, providing timely research-based information to help farmers manage crops throughout the growing season.
Photo Credit: gettyimages-livingimages
Categories: Minnesota, Crops, Corn, Soybeans, Weather