Southwest Michigan field crops update – July 3, 2025

Nicolle Ritchie<ritchi67@msu.edu> and Angie Gradiz<gradizme@msu.edu>, Michigan State University Extension - July 03, 2025

Soybeans are in late vegetative to early reproductive stages. As wheat ripens, consider options for planting a robust cover crop or soybeans after harvest.

Weather

While slightly cooler than our previous week of highs in the 90s, the past week was still quite warm and humid. Precipitation late last week helped relieve crop stress from dry soil, and scattered showers on Monday, June 30, resulted in various amounts of rainfall throughout southwest Michigan. Storms will develop this weekend and will bring some chances for rainfall, but overall the next week is expected to be quite dry and with temperatures similar to those of the past week.

WU forecast as of 7-3.png — Ten-day Weather Underground forecast as of July 3, 2025.

6-10 and 8-14 as of 7-3 (1).png — The 6-10 day (July 8-12, top) and 8-10 day (July 10-16, bottom) outlooks for temperature (left) and precipitation (right).

Crops and pests

Soybeans are in late vegetative stages and early reproductive stages. Cleanup herbicide applications went out this past week, as did some white mold preventative fungicides. Hot temperatures contributed to higher instances of soybean response to post herbicides, but soybeans are very resilient, and in most cases, the damage is only cosmetic and not expected to affect yield. As flowering approaches or has started, glufosinate can be applied until R1, and glyphosate can be applied through R2. Fungicides to prevent white mold should be applied between R1 and R3, with data showing higher efficacy when applied closer to R1.

25 soybean R2 Angie Gradiz.jpeg — Soybeans at R2 (at least one open flower at one of the two top nodes). R3 begins when a pod on one of the upper four nodes is 3/16” long. Photo by Angie Gradiz, MSU Extension.

Corn is on average between V8 and V10. Nitrogen continued to go out, and other field activities included herbicide application and rogueing of earlier planted seed corn. European corn borer (ECB) was found in non-traited corn in St. Joseph County. Scout for it in vulnerable corn varieties by checking for feeding damage, frass and larvae in the whorl. Tar spot was recently confirmed in four more northern Indiana counties, but data shows that the best timing for a single fungicide application is still between VT and R3-4.

25 corn rolled leaves cropped.jpg — Dry conditions during stages of high water use can result in corn rolling its leaves to reduce transpiration losses. With mostly dry weather this past week and another week of mostly dry weather forecast, dryland corn may roll its leaves in response to drought stress. Photo by Nicolle Ritchie, MSU Extension.

Most winter wheat is at Feekes 11.2, where the kernel is at a soft dough stage and can be easily divided with a thumbnail. As wheat ripens, decisions on what to plant afterward must be made. For those thinking of following wheat with soybeans, the article Considering double-crop soybeans after a winter cereal this year? addresses irrigation, planting, profitability and soybean management decisions to consider for double-cropping. For those thinking of following wheat with a cover crop, the Midwest Cover Crops Council has a cover crop recipe for planting after wheat going into corn or soybean, and the fact sheet Cover crop tolerance to winter wheat herbicides has helpful charts for cover crop sensitivity to common wheat herbicides.

25 wheat fingernail indent cropped.jpg — This kernel is still at a soft dough stage, as evidenced by how easily it can be indented and split by a thumbnail. Photo by Nicolle Ritchie, MSU Extension.

Potatoes continue to be at risk of vine rot with the hot weather and lush canopies. Watch out for late blight, colonizing aphids and second-generation Colorado potato beetle this time of year. Forecast late blight risks have been low to medium. The Michigan State University Extension fact sheet “Managing Colonizing Aphids in Ware Potatoes” provides pictures of colonizing aphids that affect potatoes, a list of chemical options for managing aphids and tips for chemical control. One of the most important practices to prevent insecticide resistance is to not apply the same mode of action “more than twice consecutively before switching to a new group.” If a group 4A (neonicotinoid) seed treatment was used, do not use a group 4A foliar application within the same season. Along those same lines, if a neonicotinoid seed treatment was used, avoid foliar application of a group 4C or D without first applying a different mode of action group.

Late blight leaves.jpg — Late blight lesions are dark and generally lack distinct edges. The lesion may have silver fungal spores on the underside of the leaf. Photo by Nicolle Ritchie, MSU Extension.

Cutting and baling of alfalfa and grass hay continued. Starting about a week after cutting, scout alfalfa regrowth for potato leafhopper. Hopperburn becomes visible after the damage has already been done and cannot be treated, so it’s important to actively scout for the insect itself. The article “Potato leafhopper on alfalfa” from PennState Extension contains in-depth alfalfa scouting information and economic thresholds based on hay value and insecticide costs.

Weekly water use

With recent high temperatures leading to dry soils conditions, irrigation activity has increased. Corn at the V8-V10 growth stages is currently using approximately 0.8 to 1.15 inches of water per week. Water demand will continue to increase as the crop approaches V14, where it typically peaks and remains high through reproductive stages.

25 irrigated corn Angie Gradiz cropped.jpg — Irrigation during vegetative stages involves applying water only when it’s needed, while avoiding over-irrigation. Photo by Angie Gradiz, MSU Extension.

Soybean water use ranges from 0.9 to 1.5 inches per week, depending on the growth stage. As soybeans progress through vegetative and early reproductive stages, adequate soil moisture is necessary to support canopy development.

Wheat, now at the soft dough stage, has decreased its water use. If there is adequate soil moisture to carry the crop to maturity, irrigation can be shut off at this stage to achieve the best results. Additional irrigation beyond the soft dough stage is typically unnecessary and may even increase the risk of lodging. If you plan to plant a second crop after wheat, there are important considerations to keep in mind; most notably, ensuring there is sufficient soil moisture to support quick germination and uniform emergence for successful establishment.

In addition to meeting crop water needs, early summer irrigation can also help incorporate fertilizers or herbicides. However, it’s important to provide just the necessary water, avoiding overwatering. Leaving room in the soil profile for forecasted rainfall helps reduce the risk of excess water, which can lead to deep percolation and leaching, especially in sandy soils.

It’s essential to monitor soil moisture closely and adjust irrigation accordingly. Irrigation Scheduling Tools can help estimate crop water needs and decide timing and application.

Estimated weekly crop water use for field crops in Michigan (in/week) for the week of June 30-July 6

Crop	Growth stage	Constantine	Entrican	Hart
	Reference ET	1.49	1.51	1.52
Corn	V6	0.58	0.59	0.59
	V8	0.83	0.85	0.85
	V10	1.13	1.15	1.16
	V12	1.49	1.51	1.52
Soybeans	V1 1st Node	0.45	0.45	0.46
	V2 2nd Node	0.74	0.76	0.76
	V3 3rd Node	0.89	0.91	0.91
	R1 Beginning Bloom	1.49	1.51	1.52
Wheat	Boot / Heading / Flowering / Grain fill	1.63	1.66	1.67
	Soft Dough	1.49	1.51	1.52
	Ripening	0.74	0.76	0.76

The table above presents estimated crop water use for various field crops across three locations in Michigan. This data helps irrigation management decisions by showcasing potential crop evapotranspiration, calculated based on reference evapotranspiration and crop coefficients for each crop growth stage. It is crucial to note that crop water use values vary across regions due to differences in weather conditions, growth stages, agronomic practices and soil properties.     

When using these values for irrigation scheduling, be mindful that they assume all applied irrigation water will be utilized by the plants without any loss. Additionally, these values do not account for any precipitation that may occur during the week of calculation.     

Reference evapotranspiration data was obtained from Michigan State University Enviroweather, which also offers a model for determining potential crop evapotranspiration. To access this tool, visit Enviroweather, click on "Crops," select your crop and use the potential evapotranspiration tool by choosing your nearest weather station, the latest date of interest and other crop information.  

Field Crops Virtual Breakfast Series

2025 VB graphic (5).jpg

Insects, presented by Chris DiFonzo, was the topic for the MSU Extension Field Crops Virtual Breakfast this week. This presentation covered updates on several invertebrate pest-related topics. Metaldehyde did not get approved for special local need use on slugs in soybeans in Michigan, and soybean defoliation thresholds have been updated.

Recordings of this and all the Virtual Breakfast meetings are closed-captioned and available at the Field Crops Virtual Breakfast webpage and the MSU Extension Field Crops Team social media platforms: Facebook, Spotify, YouTube, Apple Podcasts and Twitter/X.   

This work is supported by the Crop Protection and Pest Management Program [grant no 2024-70006-43569] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.  

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).