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In the next week or so, corn fields across Iowa will start to tassel and the buzz of crop dusters will no doubt join the buzz of insects. Research has consistently shown that the best time to apply a fungicide to manage foliar diseases, like tar spot, southern rust, northern corn leaf blight and gray leaf spot, is at tassel (VT) through milk (R3) stage. But do you really need to spray a fungicide? Fungicides protect yield potential by reducing foliar disease within the canopy.

Regional Update: 

Crop Lookout is a new interactive tool on the Crop Protection Network. This interactive map shows real-time what has been observed in fields this growing season, not only in Iowa but across the U.S. and in Canada. It can help farmers and agronomists see what’s being found in fields to help guide local scouting and management decisions. 

Another week with a similar pattern in rainfall with northwest and west-central Iowa getting lower amounts and heavier amounts in east-central and southeast Iowa. Both of these extremes are having an impact on crops. With corn getting into the mid-vegetative stages now and soybeans starting to reach the reproductive stages, ISU Extension and Outreach field agronomists share what they are hearing and seeing in their respective areas of the state.  

It is June 19, 2026, and another round of storms moved through the state earlier this week, bringing high winds and rain. This is yet another storm that has impacted the state in the past week.

 So far in June, Iowa has experienced

From industrial applications to hobbyist platforms, Unmanned Aerial Vehicles (UAVs), commonly referred to as drones, have rapidly integrated into the agricultural landscape. Equipped with high-resolution sensors, these aerial platforms have fundamentally altered how modern production agriculture monitors crop development.

The storms that rolled across the state last week also brought along with them heavy rain, wind, and even some hail. While most areas did receive some rainfall, parts of northwest Iowa missed out and the drier conditions are starting to show. Weeds continue to be the biggest challenge across the state as many are struggling to get their postemergence herbicide applications made with the wet field conditions. Read on for more specifics on what’s happening around the state.

Photo by: John Sawyer, ISU Extension Retired

It's a question that arrives in our inboxes every spring without fail: "It's been raining — have I lost nitrogen, and do I need to apply more?" This year is no exception. With a highly variable spring precipitation pattern across Iowa (see map below) and corn now approaching or past the critical V6 growth stage, many producers are seeing yellowing in their fields and wondering what to do next.

Reports of tar spot from Madison, Jaspar and Calhoun counties have been received over the weekend and today (June 13-15, 2026). The disease is present at very low incidence (one to a few plants in a field) and low severity (one spot on a leaf).  In addition, the disease is being observed on the lowest leaves of the canopy.

The storm systems that moved across the state this week have brought wind, heavy rainfall, and hail. Below are resources to help assess crop damage following these storms.  

Recent rainfall brought some much-needed moisture to many parts of Iowa, but totals varied widely. Unfortunately, some of the recent rainfall events also resulted in localized flooding and some storm damage. Common challenges or issues reported by ISU Extension and Outreach field agronomists across the state include weed pressure, herbicide injury, black cutworms, white grubs, and thistle caterpillars. Read on for more specific updates on what’s happening in fields across the state.

If you have been out in the field checking stand or doing early-season scouting for weeds, diseases, and insects, you might be noticing that insect activity is picking up across the state. We are approximately 200 growing degree days ahead of schedule this spring, which means insect development is happening quickly for insects that overwintered or arrived here with strong storm systems.

The trapping season for black cutworm has come to an end. We appreciate our cooperators for tirelessly checking traps the last two months and reporting their captures so we can provide the most accurate scouting information for these pests. To recap, we had 15 volunteers participate from 18 counties in Iowa. A total of 22 black cutworm traps were placed and monitored during April and May.

Crops have really started to take off with the warmer temperatures, though growth stages vary depending on planting date. Over the past week, field activity has been strong across the state, including postemergence herbicide applications, sidedressing, planting and/or replanting, and first-cutting hay being put up. For more specific updates on crop conditions and regional activity around the state, Extension field agronomists share insights below

With Spring here and crop stands beginning to grow, it is time to shift focus to the next operation of the 2026 growing season: spraying. These operations are "make or break" for crop health, whether you are applying weed control, warding off insects, or managing bacteria and fungus. While these operations require financial and time investments, performing proper maintenance and calibrations directly impacts success rates and your ultimate return on investment.

This summer, Iowa State University’s Research and Demonstration Farms are once again hosting a series of field days across the state. These events offer a valuable opportunity to learn about the latest crop production research, management practices, and emerging agricultural technologies directly from Iowa State specialists and researchers.

Residual soil nitrogen levels last year were relatively high and extremely variable from field to field. That means the Late Spring Nitrate Test (LSNT) can generate a large return on investment for in-season nitrogen decision-making this year. For those making in-season nitrogen applications, there may be significant opportunity for savings on fertilizer inputs.

With the recent dry conditions and highly variable forecasted chances for rainfall for parts of Iowa just as postemergence herbicide applications begin, questions often come up regarding use of residual herbicides and efficacy of postemergence applications during these conditions.