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Regional Crop Update: June 30 - July 8, 2025

Tassels started showing in cornfields across the state, while soybean fields are flowering and some are starting to set pods. ISU Extension field agronomists reported a range of concerns and observations over the past week, including potential herbicide failures, low levels of foliar diseases such as gray leaf spot, tar spot, and northern corn leaf blight, rootworm injury, and soybean gall midge being found in two new counties. Below, field agronomists share more details about what they’re seeing in their respective regions.

July soybean insects update

Regional Crop Update: June 23 - June 30, 2025

While some areas across the state were grateful for recent rainfall, others received excessive amounts, resulting in standing water in fields and raising concerns about nitrogen needs for corn. Along with the wetter conditions, ISU Extension field agronomists reported observations and inquiries about wind and hail damage from localized storms, the presence of Japanese beetles, corn rootworm injury, herbicide drift issues, weeds surviving herbicide applications, and what’s being seen for disease pressure so far. Read on for more insights into what’s being seen in fields across the state.

Before You Pull the Trigger: 2025 Fungicide Smarts for Corn

With reports of tar spot already showing up in some corn fields this growing season—combined with the wetter conditions over the past couple of weeks—a common question is: when is the right time to pull the trigger on spraying a foliar fungicide?

Corn insect update: usual suspects and one surprise

Regional Crop Update: June 16 - 23, 2025

Heavy rainfall in areas, isolated hail, herbicide injury, weeds surviving post herbicide applications, and nutrient deficiencies were some of the common issues seen by ISU Extension field agronomists this last week. Read on for more specifics about what is happening across the state from your local ISU Extension and Outreach field agronomists. 

Japanese Beetles Active Around Iowa

Attend the 2025 Weed Science Field Day!

Regional Crop Update: June 9 - June 16, 2025

Hail damage in parts of northern Iowa, herbicide injury, weeds not dying, true armyworms, and nutrient deficiencies were some of the more common issues seen by ISU Extension field agronomists this last week. Read on for more specifics about what is happening across the state from your local ISU Extension and Outreach field agronomists. 

Tar spot in central Iowa should not be a surprise.

Hail Damage in NW and NC Iowa

On June 11 parts of Palo Alto, Kossuth, and Hancock counties experienced hail damage. 

June 12, 2025 Climate Outlook

Why Are My Soybeans Growing So Slowly?

While it is true that soybean can germinate with cool soil temperatures (36F to 39F) at planting, the optimum temperature is 65F. Soybean need three things for growth, those are moisture, heat, and sucrose. 

Regional Crop Update: June 2 - 9, 2025

Start checking soybean roots for SCN females now

The soybean cyst nematode (SCN) is Iowa’s most damaging soybean pathogen. It is widespread in the state, but many infested fields go unnoticed because of subtle or lacking above-ground symptoms. A quick and easy way to check for SCN in fields is to dig roots and look for small, white SCN females. Now’s the time to do that! This blog post tells how and what to look for.

Regional Crop Update: May 19 - June 2, 2025

In the last two weeks, field activities across the state have included planting wrapping up, replanting soybeans in fields with thinner stands, side-dressing nitrogen in corn, applying post-emergence herbicides, and putting up the first cutting of hay. Common issues and concerns reported by ISU Extension field agronomists during this period included weed pressure in fields, herbicide damage, anhydrous ammonia injury in corn, and sulfur deficiency symptoms in corn. Read on for more specifics about what is happening across the state from your ISU Extension and Outreach field agronomists. 

Moth Trapping Network 2025 Final Update

The moth trapping season for black cutworm (BCW) and true armyworm (TAW) has wrapped-up. As a recap in 2025, we had 18 black cutworm sites in 14 counties and 16 true armyworm sites in 13 counties across the state that were monitored from early to mid April through the end of May. During the final week (May 25 – May 31, 2025) of the moth trapping network, a total of 7 black cutworm (BCW) moths were reported, with no significant flights. Additionally a total of 23 TAW moths were reported last week. For the 2025 trapping season, 334 total BCW moths and 238 TAW moths were caught across the state. 

New Crop Disease Risk Tool To Assist Disease Management Decisions

Scout field edges for stalk borer