Southwest Michigan field crops update – June 4, 2026

Nicolle Ritchie<ritchi67@msu.edu> and Angie Gradiz<gradizme@msu.edu>, Michigan State University Extension - June 04, 2026

Sporadic potato flowering began. Great progress was made on planting and field work.

Closeup of a white flower growing on top of a potato. — Photo by Nicolle Ritchie, MSU Extension.

Weather

No precipitation fell over the past week, and temperatures were warm but not too hot. Overall, it was a good week for field work, although some emerged crops are showing symptoms of drought stress. Rain is expected over the next 24 to 48 hours and again early next week. As the wind shifts, pests from farther south that travel on air currents (such as leafhoppers and aphids) may make their way up to Michigan.

The 6-10 day (Jun 9-13, top) and 8-14 day (Jun 11-17, bottom) outlooks for temperature (left) and precipitation (right).

Crops and pests

Corn and soybean planting is wrapping up. At this point, most fields have at least emerged. Flaming of male rows in seed corn occurred over the past week. For tips and tricks on distinguishing seed corn from commercial corn, check out the article “Drive-by crop identification in southwest Michigan.”

A soybean plant at V1, which is one unfurled trifoliate leaf. — This soybean is at V1, which is one unfurled trifoliate leaf. Photo by Nicolle Ritchie, MSU Extension.

This year, adult moth counts peaked early in St. Joseph County and then remained for several weeks. Moth counts were collected from bucket traps in Berrien (near Berrien Springs), St. Joseph (Centreville) and Van Buren (Lawrence) counties have caught the following:

A graph showing True armyworm moth captures this spring in three southwestern Michigan counties. The graph shows peak captures in St. Joseph County on April 13 with 105 moths and for all counties on April 27 with 53 moths in St. Joseph County and 35 in both Berrien and Van Buren Counties. — True armyworm moth captures this spring in three southwestern Michigan counties. The graph shows peak captures in St. Joseph County on April 13 with 105 moths and for all counties on April 27 with 53 moths in St. Joseph County and 35 in both Berrien and Van Buren Counties.

A graph of Black cutworm moth captures this spring in three southwestern Michigan counties. The graph shows peak captures at differing times for each county, but all counts remained at 15 moths or fewer throughout the spring. — Black cutworm moth captures this spring in three southwestern Michigan counties. The graph shows peak captures at differing times for each county, but all counts remained at 15 moths or fewer throughout the spring.

Winter wheat is mainly at Feekes 10.5.4 (kernel watery ripe) and moving into Feekes 11.1 (kernel milky ripe). Some true armyworm (TAW) larvae are in wheat fields. The threshold for TAW after heading is 2 or more larvae per square foot. If heads are being clipped, action is recommended. In most cases, TAW populations are below threshold. Stripe rust was confirmed in the Thumb over the past week.

Wheat kernels in a hand. — Kernels at Feekes 10.5.4 (kernel watery ripe). Clear fluid comes out of the kernel when squeezed. Photo by Nicolle Ritchie, MSU Extension.

Flowers are beginning to open on early-planted potatoes. Most potatoes are still at tuber initiation, while a few fields emerged only recently. Potato leafhopper (PLH) is a concern in both potatoes and alfalfa this time of year. PLH is an especially difficult pest because visible symptoms (referred to as hopperburn) don’t appear until after it is too late to correct them.

26 Potato start bloom_nicolle ritchie.jpeg — Flowers are just starting to open on early-planted fields. Full bloom is soon to follow. Photo by Nicolle Ritchie, MSU Extension.

Potato leafhoppers with a circle around them on a sweep net. — Potato leafhoppers (PLH, circled here) are a pest in both potatoes and alfalfa. They are small, bright green and somewhat triangularly shaped. Photo by Nicolle Ritchie, MSU Extension.

Alfalfa and forage cutting and baling continued, with great progress made during the dry week we had. As fields start to regrow, keep an eye out for PLH and a reoccurrence of earlier pests from this season, such as alfalfa weevil. Some growers have reported TAW in alfalfa.

Irrigation and water use

Early corn and soybean crops are currently using approximately 0.14 to 0.50 inches of water per week, depending on crop growth stage, weather conditions, and location. Potato water demand remains substantially higher, with early vegetative potatoes using approximately 0.7 inches of water per week and potatoes in the tuberization stage requiring up to 1.4 inches per week.

Rainfall is forecast across much of the region this week; however, amounts are expected to vary, and some locations may not receive enough precipitation to fully meet crop water needs. Producers are encouraged to monitor rainfall in their fields using rain gauges and to regularly assess soil moisture within the crop root zone. Irrigation decisions should be based on both recent rainfall and available soil moisture to ensure adequate water is available for crop growth while avoiding unnecessary irrigation applications.

This year, weekly crop water use updates will continue to be shared through the Southwest Michigan Crop Updates, and for added convenience, updates will also be sent through direct email and text messages. Sign up here. If you would like to see an additional location included in the report, please contact Angie Gradiz at gradizme@msu.edu or 531-249-4956.

Estimated weekly crop water use for field crops in Michigan (inches/week) for the week of June 1-7, 2026:

Crop	Growth stage	Constantine	Berrien Springs	Entrican	Hart
Crop	Reference ET	1.36	1.41	1.36	1.38
Corn	V2	0.14	0.14	0.14	0.14
Corn	V4	0.24	0.25	0.24	0.25
Soybeans	VC	0.14	0.14	0.14	0.14
	V1	0.27	0.28	0.27	0.28
	V2	0.54	0.56	0.54	0.55
Potato	Early vegetation	0.68	0.71	0.68	0.69
Potato	Tuberization	1.36	1.41	1.36	1.38

Field Crops Virtual Breakfast Series

Virtual Breakfast promotional image

IPM in Sugar Beets, presented by Jaime Willbur, was the topic for the MSU Extension Field Crops Virtual Breakfast this week. Sugarbeet varieties with genetic resistance to cercospora have different lesions than typical cercospora lesions. Most notably, lesions are larger and less well-defined, making it more difficult to distinguish cercospora from other foliar diseases.

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, Mediaspace, 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).

MSU Extension Field Crops